<PAGE>   1
================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                        ------------------------------

                                    FORM 10-K

          (Mark One)

            [X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                        OF THE SECURITIES EXCHANGE ACT OF 1934

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 1997

                                       OR

            [ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                   For the transition period from _____to_____

                         Commission file number: 0-7062

                             NOBLE AFFILIATES, INC.
             (Exact name of registrant as specified in its charter)


<TABLE>
           <S>                                                         <C>
                           Delaware                                                  73-0785597
                   (State of incorporation)                            (I.R.S. employer identification number)

                       110 West Broadway
                       Ardmore, Oklahoma                                                73401
           (Address of principal executive offices)                                  (Zip Code)
</TABLE>


              (Registrant's telephone number, including area code)
                                 (580) 223-4110

           SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:


<TABLE>
<CAPTION>
                                                                              Name of Each Exchange on
                      Title of Each Class                                         Which Registered
                      -------------------                                         ----------------
               <S>                                                          <C>
               Common Stock, $3.33-1/3 par value                            New York Stock Exchange, Inc.
                Preferred Stock Purchase Rights                             New York Stock Exchange, Inc.
</TABLE>


        SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: None

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes X  No
                                             ---   ---

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K.
                            ---

     Aggregate market value of Common Stock held by nonaffiliates as of 
February 17, 1998: $1,918,000,000.

     Number of shares of Common Stock outstanding as of February 17, 1998:
56,958,238.

                       DOCUMENT INCORPORATED BY REFERENCE

         Portions of the Registrant's definitive proxy statement for the 1998
Annual Meeting of Stockholders to be held on April 28, 1998, which will be filed
with the Securities and Exchange Commission within 120 days after December 31,
1997, are incorporated by reference into Part III.

================================================================================





<PAGE>   2

                                TABLE OF CONTENTS


<TABLE>
<S>           <C>                                                                                            <C>

                                                      PART I.


Item 1.       Business....................................................................................    1

              General.....................................................................................    1

              Oil and Gas.................................................................................    1

                  Exploration Activities..................................................................    2

                  Production Activities ..................................................................    4

                  Acquisitions of Unproved Properties.....................................................    5

                  Marketing...............................................................................    5

                  Regulations and Risks...................................................................    6

                  Competition.............................................................................    7

              Employees...................................................................................    7


Item 2.       Properties..................................................................................    8

              Offices.....................................................................................    8

              Oil and Gas.................................................................................    8


Item 3.       Legal Proceedings...........................................................................   15


Item 4.       Submission of Matters to a Vote of Security Holders.........................................   16

              Executive Officers of the Registrant........................................................   16


                                                     PART II.


Item 5.       Market for Registrant's Common Equity and Related Stockholder Matters.......................   18


Item 6.       Selected Financial Data.....................................................................   19


Item 7.       Management's Discussion and Analysis of Financial Condition and Results of Operations.......   20


Item 7A.      Quantitative and Qualitative Disclosures About Market Risk..................................   27


Item 8.       Financial Statements and Supplementary Data.................................................   28


Item 9.       Changes in and Disagreements with Accountants on Accounting and Financial Disclosure........   51


                                                     PART III.


Item 10.      Directors and Executive Officers of the Registrant..........................................   52


Item 11.      Executive Compensation......................................................................   52


Item 12.      Security Ownership of Certain Beneficial Owners and Management..............................   52


Item 13.      Certain Relationships and Related Transactions..............................................   52


                                                     PART IV.


Item 14.      Financial Statement Schedules, Exhibits and Reports on Form 8-K.............................   53
</TABLE>




                                       ii

<PAGE>   3





                                     PART I



ITEM 1.       BUSINESS.


         Part I and Part II of this Annual Report on Form 10-K include
"forward-looking statements" within the meaning of Section 27A of the Securities
Act of 1933, as amended (the "Securities Act"), and Section 21E of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"). All statements
other than statements of historical facts included in this Annual Report on Form
10-K and the documents incorporated herein by reference regarding the Company's
estimates of oil and gas reserves and the future net cash flows attributable
thereto, anticipated capital expenditures, business strategy, plans and
objectives of management of the Company for future operations and industry
conditions, are forward-looking statements. Although the Company believes that
the expectations reflected in such forward-looking statements are reasonable, it
can give no assurance that such expectations will prove to have been correct.
Important factors that could cause actual results to differ materially from the
Company's expectations ("Cautionary Statements") include without limitation
future production levels, future prices and demand for oil and gas, results of
future exploration and development activities, future operating and development
costs, the effect of existing and future laws and governmental regulations
(including those pertaining to the environment) and the political and economic
climate of the United States and the foreign countries in which the Company
operates from time to time, as discussed in this Annual Report on Form 10-K and
the other documents of the Company filed with the Securities and Exchange
Commission. All subsequent written and oral forward-looking statements
attributable to the Company or persons acting on its behalf are expressly
qualified in their entirety by the Cautionary Statements.

GENERAL

         Noble Affiliates, Inc. is a Delaware corporation organized in 1969. The
Registrant is principally engaged, through its subsidiaries, in the exploration,
production and marketing of oil and gas.

         In this report, unless otherwise indicated or the context otherwise
requires, the "Company" or the "Registrant" refers to Noble Affiliates, Inc. and
its subsidiaries, "Samedan" refers to Samedan Oil Corporation and its
subsidiaries, "EDC" refers to Energy Development Corporation and its
subsidiaries, "NGM" refers to Noble Gas Marketing, Inc. and its subsidiary, and
"NTI" refers to Noble Trading, Inc. Samedan's subsidiaries include EDC. In this
report, quantities of oil are expressed in barrels ("BBLS"); and quantities of
natural gas are expressed in thousands of cubic feet ("MCF"), millions of cubic
feet ("MMCF"), billions of cubic feet ("BCF"), trillions of cubic feet ("TCF"),
million British Thermal Units ("MMBTU"); or barrel of oil equivalent ("BOE")
converting gas to oil at six thousand cubic feet of gas to one barrel of oil.

OIL AND GAS

         The Company's wholly owned subsidiary, Samedan, has been engaged in the
exploration, production and marketing of oil and gas since 1932. Samedan has
exploration, exploitation and production operations in nine prominent areas:
four domestic areas and five international areas. The domestic areas consist of:
offshore in the Gulf of Mexico, the Gulf Coast (Texas and Louisiana), the Mid
Continent (Oklahoma and Southern Kansas), and the Rocky Mountain division
(Colorado, Montana, North Dakota, Wyoming and California). The international
areas of operations include Argentina, China, Ecuador, Equatorial Guinea and the
U.K. Sector of the North Sea. For more information regarding Samedan's oil and
gas properties, see "Item 2. Properties--Oil and Gas" of this Form 10-K.

         The Company's wholly owned, indirect subsidiary, EDC, was acquired on
July 31, 1996, when Samedan purchased all of the outstanding common stock of
EDC, previously a wholly owned, indirect subsidiary of Public Services
Enterprise Group Incorporated. The consolidated financial statements of the
Registrant (Item 8. of this Form 10-K) include EDC from and after July 31, 1996,
unless otherwise indicated.


                                       1

<PAGE>   4



         During 1997, the Registrant sold its Canadian operations. The
consolidated financial statements of the Registrant (Item 8. of this Form 10-K)
include the Canadian operations throughout the year. There will be no Canadian
operations in 1998.

         The Company's wholly owned subsidiary, NGM, markets the Company's
natural gas as well as third-party gas. For more information regarding NGM's
operations, see "Item 1. Business--Oil and Gas--Marketing" of this Form 10-K.
The Company's wholly owned subsidiary, NTI, markets a portion of the Company's
oil as well as third-party oil. For more information regarding NTI's operations,
see "Item 1. Business--Oil and Gas--Marketing" of this Form 10-K.

         Exploration Activities

         Samedan, by itself or through various arrangements with others,
investigates potential oil and gas properties, seeks to acquire exploration
rights in areas of interest and conducts exploratory activities, including
geophysical and geological evaluation and exploratory drilling on properties for
which it acquired such exploration rights.

         Gulf of Mexico. Samedan has been actively engaged in exploration,
exploitation and development of oil and gas properties in the Gulf of Mexico
(offshore Texas and Louisiana) since 1968. Generally, properties in the Gulf of
Mexico are characterized by prolific reservoirs with high production rates,
which therefore tend to deplete more rapidly than the Company's onshore
properties. The Company's current production in the Gulf of Mexico is derived
from 282 wells operated by Samedan and 525 wells operated by others. During the
past 29 years, Samedan has drilled or participated in the drilling of 833 gross
wells in the Gulf of Mexico. At December 31, 1997, the Company held offshore
federal leases covering 908,261 gross undeveloped acres in the Gulf of Mexico,
with expiration dates ranging from 1998 to 2007, on which the Company currently
intends to conduct future exploration activities.

         Gulf Coast. Samedan has been actively engaged in exploration,
exploitation and development of oil and gas properties on the Gulf Coast
(onshore Louisiana and Texas) since the 1930's. The Company's current production
in the Gulf Coast areas is derived from 428 wells operated by Samedan and 2,391
wells operated by others. Properties in the Gulf Coast area are characterized by
gas reservoirs with strong production rates and oil fields with primary and
secondary recovery operations which tend to deplete more gradually than the
Company's offshore properties. At December 31, 1997, the Company held 245,260
gross undeveloped acres in the Gulf Coast area on which the Company currently
intends to conduct future exploration activities.

         Mid Continent. Samedan has been actively engaged in exploration,
exploitation and development of oil and gas properties in the Mid Continent
region (Oklahoma and Southern Kansas) since 1932. The Company's current oil and
gas production in the Mid Continent is derived from 435 wells operated by
Samedan and 1,198 wells operated by others. Reservoirs in the Mid Continent
region tend to be characterized by stable oil and gas production from primary
and secondary recovery operations. These reservoirs tend to produce for longer
periods compared to the Company's offshore properties. At December 31, 1997, the
Company held 76,443 gross undeveloped acres in the Mid Continent area on which
the Company currently intends to conduct future exploration activities.

         Rocky Mountain. Samedan has been actively engaged in exploration,
exploitation and development of oil and gas properties in the Rocky Mountain
division (Colorado, Montana, North Dakota, Wyoming and California) since 1960.
The Company's current production in the Rocky Mountain division is derived from
945 wells operated by Samedan and 786 wells operated by others. Reservoirs in
the Rocky Mountain division are primarily characterized by oil and gas
production from primary recovery, secondary recovery and horizontally drilled
wells. The Rocky Mountain division has two unitized gas fields with an estimated
reserve life of 50 years. At December 31, 1997, the Company held 252,857 gross
undeveloped acres in the Rocky Mountain division on which it currently intends
to conduct future exploration activities.



                                       2

<PAGE>   5



         Argentina. Samedan, through its subsidiary EDC, has been actively
engaged in exploration, exploitation and development of oil and gas properties
in Argentina since acquiring EDC in 1996. The Company's properties are located
in southern Argentina in the El Tordillo Field, which is characterized by
secondary recovery oil production from a 10,000 acre reservoir. There appear to
be other exploitation opportunities within the field which the Company intends
to pursue in future programs. At December 31, 1997, the Company held 28,988
gross developed acres and 85,760 gross undeveloped acres in Argentina, with an
expiration date of 2016, on which the Company currently intends to conduct
future exploration activities.

         China. Samedan, through its subsidiary EDC, has been actively engaged
in exploration and development of oil and gas properties in China since
acquiring EDC in 1996. The Company has four concessions in Bo Hai Bay, offshore
China. The Company was approved to operate two of the concessions by the Chinese
government in 1997. These concessions, Cheng Dao Xi and Cheng Zi Kou, are
contiguous and adjoin non-owned production in the southern portion of Bo Hai
Bay. The other two concessions, Laopu and Getuo, are located in the northern
portion of Bo Hai Bay. At December 31, 1997, the Company held 316,676 gross
undeveloped acres in China, on which the Company currently intends to conduct
future exploration activities.

         Ecuador. Samedan, through its subsidiary EDC, has been actively engaged
in exploration and development of oil and gas properties in Ecuador since
acquiring EDC in 1996. The Company's presence in Ecuador is primarily in the
Amistad gas field (Offshore Ecuador) which was discovered in 1970. The
concession, which covers 864,126 gross acres and encompasses the Amistad field,
was awarded to EDC in 1996 by the Ecuadorian government.

         Equatorial Guinea. Samedan has been actively engaged in exploration,
exploitation and development of oil and gas properties Offshore Equatorial
Guinea (West Africa) since 1990. The primary Offshore Equatorial Guinea
production is from the Alba field. The field produces approximately 2,300 net
BBLS per day of condensate. The field also has a sizable gas reserve which will
be utilized as feedstock by the Company's methanol plant (see Item 2. of this
Form 10-K) that is currently in the preliminary stages of development. The plant
will be capable of producing 2,500 metric tons of methanol per day which is
equivalent to approximately 20,000 BBLS per day. Based on reserve estimates, the
Alba field can deliver gas sufficient for the plant to operate for 30 years. At
December 31, 1997, the Company held 26,651 gross developed acres and 284,000
gross undeveloped acres Offshore Equatorial Guinea, on which the Company
currently intends to conduct future exploration activities.

         U.K. Sector of the North Sea. Samedan, through its subsidiary Brabant
Petroleum Limited ("Brabant"), has been actively engaged in exploration,
development and production of oil and gas properties in the U.K. Sector of the
North Sea since acquiring EDC in 1996. The Company's current production in the
U.K. Sector of the North Sea is derived from seven non-operated fields, of which
three are oil fields in the northern portion of the North Sea and four are gas
fields in the southern gas basin. The seven fields comprise a total of 116
producing wells. The Company's total average daily production from these
interests for 1997 was 2,400 BBLS of oil per day and 14,000 MCF of gas per day.

         When acquired in July 1996, the Brabant interests were producing 8.7
MMCF of gas per day. At year end 1997, production had increased by 200 percent
to 26.1 MMCF per day and proven gas reserves had increased 6.6 percent to 47.3
BCF. Oil reserves at the end of 1997 were seven million BBLS. Key oil fields are
Buchan, Claymore and Forties. Key gas fields are Guinevere, Lancelot, Pickerill
and Windermere.

         At December 31, 1997, the Company held 125,107 gross developed acres
and 533,816 gross undeveloped acres, with expiration dates ranging from 1999 to
2020, on which the Company intends to conduct future exploration activities.


                                       3

<PAGE>   6



         Production Activities

         Operated Property Statistics. The percentage of oil and gas wells
operated and the percentage of sales volume from operated properties are shown
in the following table as of December 31:


<TABLE>
<CAPTION>
                                          1997                       1996                      1995
                                 -------------------------------------------------------------------------
(In percentages)                     Oil          Gas          Oil           Gas          Oil          Gas
- ----------------------------------------------------------------------------------------------------------
<S>                                 <C>          <C>          <C>           <C>          <C>          <C> 
Operated well count basis           15.1         60.8         22.4          57.4         19.1         56.8
Operated sales volume basis         48.8         63.5         56.6          68.3         54.5         64.6
</TABLE>


         Net Production. The following table sets forth Samedan's net production
including royalty and working interest of oil and natural gas, for the three
years ended December 31:


<TABLE>
<CAPTION>
                                             1997                       1996                     1995
- -----------------------------------------------------------------------------------------------------
<S>                                         <C>                        <C>                       <C> 
Oil Production
   (million BBLS)                            14.0                       12.6                      9.3
Gas Production
   (BCF)                                    206.4                      171.8                     99.4
</TABLE>


         Oil and Gas Equivalents. The following table sets forth Samedan's net
production stated in oil and gas equivalents, for the three years ended December
31:


<TABLE>
<CAPTION>
                                             1997                       1996                     1995
- -----------------------------------------------------------------------------------------------------
<S>                                         <C>                        <C>                      <C>  
Total Oil Equivalents
   (million BBLS)                            48.4                       41.3                     25.9
Total Gas Equivalents
   (BCF)                                    290.4                      247.6                    155.5
</TABLE>


         Oil and Gas Wells. The number of productive oil and gas wells in which
Samedan held an interest as of December 31, 1997, 1996 and 1995 were as follows:


<TABLE>
<CAPTION>
                                      1997(1)(2)(3)               1996(1)(3)                1995(1)(3)
                               ---------------------------------------------------------------------------
<S>                              <C>          <C>          <C>           <C>          <C>            <C>  
                                   Gross          Net        Gross           Net        Gross          Net
OIL WELLS
   United States - Onshore       4,614.5        881.4      4,607.0         860.8      3,554.5        796.0
   United States - Offshore        327.0        140.3        343.0         151.1        256.5        110.9
   International                   549.0         58.5        629.0          91.8        126.0         41.9
                               ---------------------------------------------------------------------------
Total                            5,490.5      1,080.2      5,579.0       1,103.7      3,937.0        948.8
                               ---------------------------------------------------------------------------

GAS WELLS
   United States - Onshore       1,568.5        920.9      1,476.0         847.2      1,346.5        765.6
   United States - Offshore        480.0        176.6        530.0         186.9        432.5        166.0
   International                    25.0          1.9         89.0          32.6         74.0         18.9
                               ---------------------------------------------------------------------------
Total                            2,073.5      1,099.4      2,095.0       1,066.7      1,853.0        950.5
                               ---------------------------------------------------------------------------
</TABLE>



    (1) Productive wells are producing wells and wells capable of production. A
        gross well is a well in which a working interest is owned. The number of
        gross wells is the total number of wells in which a working interest is
        owned. A net well is deemed to exist when the sum of fractional
        ownership working interests in gross wells equals one. The number of net
        wells is the sum of the fractional working interests owned in gross
        wells expressed as whole numbers and fractions thereof.

    (2) The reduction in gross international wells from December 31, 1996 to
        December 31, 1997 was a result of the sale of the Company's Canadian oil
        and gas operations during 1997.


                                       4

<PAGE>   7

    (3) One or more completions in the same bore hole is counted as one well in
        the table above. The following table summarizes multiple completions and
        non-producing wells as of December 31 for the years shown. Included in
        wells not producing are wells awaiting additional action, pipeline
        connections or shut-in for various reasons.


<TABLE>
<CAPTION>
                                 1997                       1996                      1995
                       --------------------------------------------------------------------------
                          Gross          Net        Gross           Net        Gross          Net
- -------------------------------------------------------------------------------------------------
<S>                     <C>            <C>        <C>             <C>          <C>          <C>  
MULTIPLE COMPLETIONS
      Oil                  24.5         18.1         21.0          14.4         28.0         18.2
      Gas                  48.5         21.6         47.0          23.6         46.0         19.4

NOT PRODUCING (SHUT-IN)
      Oil               1,017.0        127.3      1,086.0         136.7        824.0        131.8
      Gas                  79.5         50.1         63.5          32.0         81.0         42.7
</TABLE>


         Samedan spent approximately $3.9 million in 1997 on the purchase of
producing oil and gas properties. Approximately $687 million of the EDC purchase
price was allocated to producing properties in 1996, and $43.7 million was spent
to purchase producing properties in 1995.

         Acquisitions of Unproved Properties

         During 1997, Samedan spent approximately $19.8 million on acquisitions
of unproved properties. These properties were acquired primarily through
domestic onshore lease acquisitions, various offshore lease sales and
international concession negotiations.

         Marketing

         NGM seeks opportunities to enhance the value of the Company's gas by
marketing directly to end users and accumulating gas to be sold to gas marketers
and pipelines. During 1997, approximately 47 percent of NGM's total sales were
to end users. NGM is also actively involved in the purchase and sale of gas from
other producers. Such third-party gas may be purchased from non-operators who
own working interests in the Company's wells or from other producers' properties
in which the Company may not own an interest. NGM, through its wholly owned
subsidiary, Noble Gas Pipeline, Inc., engages in the installation, purchase and
operation of gas gathering systems.

         Samedan and EDC have gas sales contracts with NGM, whereby Samedan and
EDC are paid an index price for all gas sold to NGM. Sales, including hedging
transactions, are recorded as gathering, marketing and processing revenues. NGM
records as cost of sales in gathering, marketing and processing costs, the
amount paid to Samedan, EDC and third parties. All intercompany sales and
expenses are eliminated in the Company's consolidated financial statements.

         Oil produced by the Company is sold to purchasers in the United States
and foreign locations at various prices depending on the location and quality of
the oil. The Company has no long-term contracts with purchasers of its oil
production. Crude oil and condensate are distributed through pipelines and
trucks to gatherers, transportation companies and end users. NTI markets a
portion of the Company's oil as well as certain third-party oil. The Company
records all of NTI's sales as gathering, marketing and processing revenues and
records cost of sales in gathering, marketing and processing costs. All
intercompany sales and expenses are eliminated in the Company's consolidated
financial statements.

         Oil prices are affected by a variety of factors that are beyond the
control of the Company. The principal factors influencing the prices received by
producers of domestic crude oil continue to be the pricing and production of the
members of the Organization of Petroleum Exporting Countries. The Company's
average oil price decreased from $18.28 per BBL in 1996 to $17.86 per BBL in
1997. Due to the volatility of oil and gas prices, the Company, from time to
time, has used hedging and may do so in the future as a means of controlling its
exposure to price 



                                       5

<PAGE>   8

changes. The Company's average oil price reflected a reduction of $.19 per BBL
in 1997 and $2.35 per BBL in 1996, from hedging oil production.

         Substantial competition in the natural gas marketplace continued in
1997. Gas prices, which were once determined largely by governmental
regulations, are now being influenced to a greater extent by the marketplace.
The Company's average gas price increased from $2.17 per MCF in 1996 to $2.48
per MCF in 1997. Due to the volatility of oil and gas prices, the Company, from
time to time, has used hedging and may do so in the future as a means of
controlling its exposure to price changes. The Company's average gas price for
1997 and 1996 reflected a reduction of $.12 and $.33 per MCF, respectively, from
hedging gas production.

         The largest single non-affiliated purchaser of the Company's oil in
1997 accounted for approximately 25 percent of its oil sales, and the five
largest purchasers accounted for approximately 63 percent of total oil sales.
The largest single non-affiliated purchaser of the Company's gas in 1997
accounted for approximately two percent of its gas sales, and the five largest
purchasers accounted for approximately six percent of total gas sales. The
Company does not believe that its loss of a major oil or gas purchaser would
have a material effect on the Company.

         Regulations and Risks

         General. Exploration for and production and sale of oil and gas are
extensively regulated at the national, state and local levels. Oil and gas
development and production activities are subject to various state laws and
regulations (and orders of regulatory bodies pursuant thereto) governing a wide
variety of matters, including allowable rates of production, marketing, pricing,
prevention of waste and pollution, and protection of the environment. Laws
affecting the oil and gas industry are under constant review for amendment or
expansion and frequently increase the regulatory burden on companies. Numerous
governmental departments and agencies are authorized by statute to issue rules
and regulations binding on the oil and gas industry. Many of these governmental
bodies have issued rules and regulations that are often difficult and costly to
comply with, and that carry substantial penalties for failure to comply. These
laws, regulations and orders may restrict the rate of oil and gas production
below the rate that would otherwise exist in the absence of such laws,
regulations and orders. The regulatory burden on the oil and gas industry
increases its costs of doing business and consequently affects the Company's
profitability.

         Natural Gas. The natural gas industry has been regulated under the
Natural Gas Act and the Natural Gas Policy Act of 1978 (the "NGPA"). Under the
Natural Gas Wellhead Decontrol Act of 1989, price ceilings were eliminated over
a transition period which ended on January 1, 1993.

         Certain Risks. In Samedan's exploration operations, losses may occur
before any accumulation of oil or gas is found. If oil or gas is discovered, no
assurance can be given that sufficient reserves will be developed to enable
Samedan to recover the costs incurred in obtaining the reserves or that reserves
will be developed at a rate sufficient to replace reserves currently being
produced and sold. Samedan's international operations are also subject to
certain political, economic and other uncertainties including, among others,
risk of war, expropriation, renegotiation or modification of existing contracts,
taxation policies, foreign exchange restrictions, international monetary
fluctuations and other hazards arising out of foreign governmental sovereignty
over areas in which Samedan conducts operations.

         Environmental Matters. As a developer, owner and operator of oil and
gas properties, Samedan is subject to various federal, state, local and foreign
country laws and regulations relating to the discharge of materials into, and
the protection of, the environment. The release or discharge of oil from
Samedan's domestic onshore or offshore facilities could subject Samedan to
liability under federal laws and regulations, including the Oil Pollution Act of
1990, the Outer Continental Shelf Lands Act and the Clean Water Act, for
pollution cleanup costs, damage to the environment, civil or criminal penalties,
and orders or injunctions requiring the suspension or cessation of operations in
affected areas. The liability under these laws for a substantial release or
discharge of oil, subject to certain specified limitations on liability, may be
extraordinarily large. If any oil pollution was caused by willful 



                                       6

<PAGE>   9

misconduct, willful negligence or gross negligence, or was caused primarily by a
violation of federal regulations, such limitations on liability may not apply.
Certain of Samedan's facilities are subject to regulations of the United States
Environmental Protection Agency, including regulations that require the
preparation and implementation of spill prevention control and countermeasure
plans relating to the possible discharge of oil into navigable water.

         The Comprehensive Environmental Response, Compensation and Liability
Act ("CERCLA"), also known as "Superfund", imposes liability on certain classes
of persons that contributed to the release or threatened release of a hazardous
substance into the environment or that own or operate facilities or vessels onto
or into which hazardous substances are disposed. The Resource Conservation and
Recovery Act ("RCRA") and regulations promulgated thereunder regulate hazardous
waste, including its treatment, storage and disposal. CERCLA currently exempts
crude oil, and RCRA currently exempts certain oil and gas exploration and
production drilling materials, such as drilling fluids and produced waters, from
the definitions of hazardous substances and hazardous wastes. Samedan's
operations, however, may involve the use or handling of other materials that may
be classified as hazardous substances and hazardous wastes, and therefore, these
statutes and regulations promulgated under them would apply to Samedan's
generation, handling and disposal of these materials. In addition, there can be
no assurance that such exemptions will be preserved in future amendments of such
acts, if any, or that more stringent laws and regulations protecting the
environment will not be adopted.

         Certain of Samedan's facilities may also be subject to other federal
environmental laws and regulations, including the Clean Air Act with respect to
emissions of air pollutants. Certain state or local laws or regulations may
impose liabilities in addition to or restrictions more stringent than those
described herein. The environmental laws, rules and regulations of foreign
countries are generally less stringent than those of the United States, and
therefore, the requirements of such jurisdictions do not generally impose an
additional compliance burden on Samedan.

         Samedan has made and will continue to make expenditures in its efforts
to comply with environmental requirements. The Company does not believe that it
has to date expended material amounts in connection with such activities or that
compliance with such requirements will have a material adverse effect upon the
capital expenditures, earnings or competitive position of the Company. Although
such requirements do have a substantial impact upon the energy industry,
generally they do not appear to affect the Company any differently or to any
greater or lesser extent than other companies in the industry.

         Insurance. Samedan believes that it has such insurance coverages as are
customary in the industry and that it is adequately protected by public
liability and physical damage insurance.

         Competition

         The oil and gas industry is highly competitive. Since many companies
and individuals are engaged in exploring for oil and gas and acquiring oil and
gas properties, a high degree of competition for desirable exploratory and
producing properties exists. A number of the companies with which Samedan
competes are larger and have greater financial resources than Samedan.

         The availability of a ready market for Samedan's oil and gas production
depends on numerous factors beyond its control, including the level of consumer
demand, the extent of worldwide oil and gas production, the costs and
availability of alternative fuels, the costs and proximity of pipelines and
other transportation facilities, regulation by state and federal authorities and
the costs of complying with applicable environmental regulations.

EMPLOYEES

         During the year, the total number of employees of the Company increased
nine percent from 563 at December 31, 1996, to 614 at December 31, 1997.



                                       7

<PAGE>   10




ITEM 2.       PROPERTIES.

OFFICES

         The principal executive office of the Company is located at 110 West
Broadway, Ardmore, Oklahoma 73401. The principal office of Samedan is in
Ardmore, Oklahoma. Samedan also maintains offices in Oklahoma City, Houston,
Denver, United Kingdom, China and Ecuador. Samedan maintains three separate
offices in Houston for its international, offshore and onshore oil and gas
operations. NGM's office is located in Houston, Texas and NTI's office is
located in Ardmore, Oklahoma.

OIL AND GAS

         Samedan, by itself or through various arrangements with others,
investigates potential oil and gas properties, seeks to acquire exploration
rights in areas of interest and conducts exploratory activities, including
geophysical and geological evaluation and exploratory drilling, where
appropriate, on properties for which it acquired such exploration rights. During
1997, Samedan drilled or participated in the drilling of 384 gross (210.6 net)
wells, comprised of 38 gross (7.7 net) international wells and 346 gross (202.9
net) domestic wells. Additionally, Samedan completed 87 square miles of 3-D and
145 miles of 2-D seismic programs in the Amistad field, Ecuador and two 3-D
seismic programs covering 140 blocks in the Gulf of Mexico. For more information
regarding Samedan's oil and gas properties, see "Item 1. Business -- Oil and
Gas" of this Form 10-K.

         Gulf of Mexico. In the Gulf of Mexico during 1997, Samedan drilled or
participated in the drilling of 72 gross wells, 24 exploratory wells (10.99 net)
and 48 development wells (22.28 net) in federal and state waters offshore Texas
and Louisiana. Of the 72 gross wells, 60 wells (27.50 net) were completed as
productive and 12 wells (5.76 net) were abandoned as dry holes. Samedan acquired
24 federal and seven state leases, in the offshore Gulf of Mexico sales during
1997. The Company intends to remain active in these areas of the Gulf of Mexico.

         During 1997, a platform drilling rig was utilized on Samedan's 100
percent owned Main Pass 306 E platform, drilling five wells which were being
completed at year end. The wells are expected to deliver approximately 1,000
BBLS of oil per day when fully operational.

         Six wells were drilled in Samedan's 50 percent owned Vermilion 279
field during 1997. The wells logged oil and gas pay ranging from 61 to 230 feet
in multiple zones. The field was producing approximately 3,500 BBLS of oil and
50 MMCF of gas per day from eight wells at year end 1997. Two additional wells
remain to be completed, and a third well was being drilled at year end 1997.
During 1998, Samedan expects to drill three additional wells in the field.

         Samedan drilled three wells in its East Cameron 331/332 field in which
it owns a 70.4 percent interest. At year end 1997, the A-16 well reached its
target depth encountering approximately 87 feet of oil and gas pay in five
zones. The well is expected to be completed in 1998. During 1998, Samedan
expects to drill one additional well in the field.

         At the South Timbalier 195 field, owned 100 percent, Samedan drilled
three wells. One well had been completed at year end 1997, and the remaining two
wells are scheduled to be completed in early 1998. The wells are expected to
deliver approximately 45 MMCF of gas per day when fully operational. At year end
1997, Samedan was preparing to drill one additional well, the A-7.

         Samedan installed a 3.5 mile pipeline in the South Timbalier production
area in December 1997. The pipeline will allow for the flow of more gas from the
production area by reducing the pipeline pressure and increasing pipeline
capacity.



                                       8

<PAGE>   11

         Drilling and completion operations were underway at year end on
Samedan's 50 percent owned Main Pass 261 lease. The field contains three wells;
two of which are completed and awaiting production facilities. The third well
was drilling at year end 1997. Two additional wells are projected to be drilled
in 1998. Production facilities are expected to be operational in the second
quarter of 1998. When fully operational, the field is projected to produce
approximately 40 MMCF of gas and 1,000 BBLS of oil per day, net to Samedan's
interest.

         Samedan drilled a successful infill well in its Ship Shoal 315 field.
The 100 percent owned A-1 Sidetrack well encountered approximately 62 feet of
pay in two zones. At year end 1997, the well was producing approximately 1,100
BBLS of oil and 12 MMCF of gas per day.

         Samedan made a gas discovery on its 67 percent owned South Timbalier
220 lease during 1997. The discovery well encountered approximately 229 feet of
pay as determined by electric logs. Development plans include drilling an
additional well and installing production facilities. Initial production of
approximately 15 MMCF of gas and 150 BBLS of oil per day, net to Samedan's
interest, is projected to begin in the third quarter of 1998.

         Development is underway on Samedan's 25 percent owned East Cameron
371/381 field which was a gas discovery in 400 feet of water. Completion
operations on the two wells drilled and production facilities are scheduled to
be finished in the second quarter of 1998. Two additional wells are scheduled to
be drilled in 1998. Production from the field is expected to be approximately 22
MMCF of gas and 200 BBLS of oil per day, net to Samedan's interest.

         An oil discovery was made on Vermilion 379 which is 25 percent owned by
Samedan and located in 325 feet of water. The discovery well was drilled to a
measured depth of 6,253 feet and logged 60 feet of apparent pay in one zone.
Development plans include drilling five additional wells and installing
production facilities. Initial production is expected to commence in the second
quarter of 1999.

         At Viosca Knoll 864, Samedan participated with a 35 percent working
interest in a discovery well which logged approximately 200 feet of oil pay in
five zones. The well is located in approximately 1,460 feet of water and tested
oil rates as high as 4,350 BBLS of oil per day. Evaluation of the estimated
development costs and potential reservoir size were underway at year end 1997.

         Gulf Coast. During 1997, a productive well was drilled in Samedan's
23.2 percent owned Kaplan field, Vermilion Parish, Louisiana. The well was
completed in the Camerina sand at approximately 16,810 feet. At year end 1997,
the well was producing approximately 20 MMCF of gas and 800 BBLS of condensate
per day. During 1998, Samedan anticipates participating in the drilling of three
additional wells in the field.

         Samedan successfully recompleted the Glenn #3 well in the South Lake
Arthur gas field, Vermilion Parish, Louisiana. The well was plugged back to the
Miogyp sand at 16,735 feet and was flowing 13.7 MMCF of gas per day at year end
1997.

         Samedan also has a deep gas prospect lying beneath the South Lake
Arthur field which encompasses approximately 5,000 acres. In order to test the
deep prospective zone Samedan expects to drill a 20,000 foot test well in 1998.

         In South Texas, seven wells were drilled in Samedan's 100 percent owned
Rincon field, located in Starr County. The wells were completed in the Rincon or
Vicksburg sands. During 1998, five wells are expected to be drilled.

         Mid Continent. Samedan is actively drilling wells in its multiple
objective Washita Mountain Front play in Beckham County, Oklahoma. Samedan
participated in drilling eight wells during the year and each encountered 30 to
250 feet of oil and gas pay in multiple zones, as determined from electric logs.
Samedan owns approximately 40



                                       9

<PAGE>   12



percent in 26,000 gross acres in the prospect. During 1998, Samedan expects to
participate in drilling 15 wells. Additionally, Samedan has a 45 percent
participation interest in a 3-D seismic program covering 227 square miles within
this area.

         Rocky Mountain. Samedan drilled 100 wells in its Bowdoin gas field
located in Phillips and Valley counties, Montana. The wells were completed in
the field pay, but also encountered a new shallow pay zone in the Niobrara
formation. Gas from the field is sold under a long-term contract in which the
price escalates monthly through May 2007. At year end 1997, the price was $4.31
per MMBTU.

         In Dawson County, Montana, Samedan kept a drilling rig engaged
throughout 1997, drilling horizontal oil wells in its Deer Creek prospect. Seven
wells were drilled in the field during 1997, including five wells that had
multiple lateral well bores. The typical well in the field stabilizes production
at approximately 100 BBLS of oil per day. Samedan owns a 75 percent working
interest in the prospect and anticipates keeping a rig active throughout 1998.

         Argentina. Throughout 1997, two drilling rigs were utilized for
expanding infill drilling in the El Tordillo oil field. At year end 1997, a
third rig was placed in service to accelerate the drilling program. Twenty-six
wells were completed in the main field during the year and drilling to a
prospective deeper horizon was in process at year end. Samedan owns 13.7 percent
interest in the El Tordillo field which in 1997 produced an average of 2,800
BBLS of oil per day, net to Samedan's interest.

         China. Samedan opened its Beijing, China office during 1997 to operate
its existing exploration activities and seek additional opportunities. Samedan
currently owns and operates the Cheng Dao Xi and Cheng Zi Kou concessions in the
southern portion of Bo Hai Bay, China. Samedan also owns a one-third interest in
the Laopu and Getuo concessions located in the northern portion of Bo Hai Bay.
During 1997, Samedan drilled a dry hole on the Laopu concession.

         Drilling plans for 1998 include three wells on the Cheng Dao Xi
concession and one well on the Getuo concession. It is anticipated that a
drilling rig will be available during the second quarter of 1998 and two of the
Cheng Dao Xi wells will be drilled consecutively. If successful, Samedan intends
to present a development plan to the Chinese government for the Cheng Dao Xi
field during 1998.

         Ecuador. In 1997, Samedan opened an office in Guayaquil, Ecuador to
manage the activities of its 864,126 acre offshore concession. The concession
includes the Amistad gas field which was discovered in 1970, but was never
developed. Additionally, during the year Samedan completed an 87 square mile 3-D
seismic program on the Amistad gas field and a 145 mile 2-D seismic program
within the concession. Samedan's Ecuador staff is focused on developing a gas
market for the Amistad field. The best prospect appears to be supplying fuel to
electric power plants. Ecuador's existing plants currently burn imported diesel
or bunker fuel. Samedan is negotiating with the government and power producers
to determine a mutually beneficial price and deliverability arrangement.

         Equatorial Guinea. Samedan will be participating, with a 35 percent
expense interest, in a joint venture to construct a methanol plant in Equatorial
Guinea. The plant is estimated to cost $317 million and is being designed to
produce 2,500 metric tons of methanol per day, which equates to approximately
20,000 BBLS per day. The plant will use the gas from Samedan's 35 percent owned
Alba field as feedstock. The plant is being designed to utilize approximately
115 MMCF of gas per day. The gas will be priced at $.25 per MMBTU. The
construction contract stipulates that first commercial production of methanol
should be achieved by January 2001. Current marketing plans are to enter into
long-term contracts with methanol users in the United States and Europe.

         As a result of developing an economic market for the Alba gas through
the methanol plant, Samedan added 322.2 BCF of gas to its proved reserves in
1997. Based upon its cash flow projections from methanol sales with the $.25 per
MMBTU wellhead price, Samedan expects to realize a blended value of
approximately $3.83 per MCF for its gas production from the Alba field. Based
upon reserve estimates, the Alba field can deliver sufficient gas for the 




                                       10

<PAGE>   13

plant to operate for 30 years. In conjunction with the plant investment, the
Alba field owners are evaluating a plan to drill additional wells, install a
platform and construct a pipeline system. The plan includes evaluating gas
reinjection which would accelerate condensate production. During 1997, the Alba
field produced approximately 2,300 BBLS of condensate per day, net to Samedan's
interest.

         U.K. Sector of the North Sea. Production commenced from Samedan's 20
percent owned Windermere property in mid 1997. The field, located in the
southern gas basin of the North Sea, was producing 13.1 MMCF of gas per day at
year end, net to Samedan's interest.

         Development operations are underway for Samedan's 25 percent owned
Malory field which is also located in the southern gas basin of the North Sea.
Samedan estimates the production will commence in the fourth quarter of 1998.
Samedan's projected share of production will be approximately 7.5 MMCF per day.
At year end 1997, Samedan was drilling an exploratory well on the Goldeneye
prospect in the North Sea.

         Oil and Gas Reserves and Standardized Measure. The following table
summarizes the estimated proved oil and gas reserves of Samedan and the
standardized measure of discounted future net cash flows attributed thereto, as
of December 31, 1997, 1996 and 1995. Additional information is contained in
"Item 8. Financial Statements and Supplementary Data--Supplemental Oil and Gas
Information (Unaudited)" of this Form 10-K, and incorporated herein by
reference.


<TABLE>
<CAPTION>
                                        1997                             1996                        1995
                        --------------------------------  -----------------------------  ---------------------------
(dollars in millions)         U.S.     Int'l       TOTAL       U.S.    Int'l      TOTAL      U.S.    Int'l     TOTAL
- --------------------------------------------------------------------------------------------------------------------
<S>                      <C>         <C>       <C>        <C>         <C>     <C>         <C>       <C>      <C>    
PROVED RESERVES:
  Natural gas and
  casinghead
  gas (MMCF)             1,107,158   375,057   1,482,215  1,079,607   76,643  1,156,250   818,301   32,038   850,339

  Crude oil and
  condensate (BBLS
  in thousands)             89,065    41,798     130,863     82,317   33,430    115,747    70,907   13,101    84,008

STANDARDIZED MEASURE
  OF DISCOUNTED FUTURE
  NET CASH FLOWS            $1,063      $289      $1,352     $1,967     $255     $2,222    $1,173     $101    $1,274
</TABLE>


         Samedan has less than five percent of its oil and gas sales volumes
committed to long-term supply contracts and has no similar agreements with
foreign governments or authorities in which Samedan acts as producer as of year
end 1997.

         Since January 1, 1997, no oil or gas reserve information has been filed
with, or included in any report to, any federal authority or agency other than
the Securities and Exchange Commission and the Energy Information Administration
(the "EIA"). Samedan files Form 23, including reserve and other information,
with the EIA.

         At January 30, 1998, Samedan was drilling 32 gross (15.9 net)
exploratory wells, and 15 gross (6.6 net) development wells. These wells are
located onshore in the United States in California, Colorado, Louisiana, North
Dakota, Oklahoma, Texas, Wyoming, Offshore Gulf of Mexico and internationally in
Argentina and the U.K. Sector of the North Sea. These wells have objectives
ranging from approximately 3,700 to 18,000 feet. The estimated drilling cost to
Samedan of these wells is approximately $42.7 million if all are dry and
approximately $61 million if all are completed as producing wells.



                                       11

<PAGE>   14



         Net Exploratory and Developmental Wells. The following table sets forth
for each of the last three years the number of net exploratory and development
wells drilled by or on behalf of Samedan. An exploratory well is a well drilled
to find and produce oil or gas in an unproved area, to find a new reservoir in a
field previously found to be productive of oil or gas in another reservoir, or
to extend a known reservoir. A development well, for purposes of the following
table and as defined in the rules and regulations of the Securities and Exchange
Commission, is a well drilled within the proved area of an oil or gas reservoir
to the depth of a stratigraphic horizon known to be productive. The number of
wells drilled refers to the number of wells completed at any time during the
respective year, regardless of when drilling was initiated. Completion refers to
the installation of permanent equipment for the production of oil or gas, or in
the case of a dry hole, to the reporting of abandonment to the appropriate
agency.


<TABLE>
<CAPTION>
                                Net Exploratory Wells                               Net Development Wells
                       Productive(1)                Dry(2)                Productive(1)                  Dry(2)
                 ------------------------------------------------    -------------------------------------------------
Year Ended
December 31,      U.S.    International      U.S.   International      U.S.    International     U.S.    International
- ----------------------------------------------------------------------------------------------------------------------
<S>              <C>             <C>        <C>           <C>        <C>            <C>         <C>             <C>
1995             12.44           .80        14.42         4.72       107.09         5.50        20.49           .14
1996             15.37           .69        22.16         1.04        74.97         1.17        19.91
1997             13.98           .76        25.08         3.79       155.93         3.13         7.89
</TABLE>


    (1) A productive well is an exploratory or a development well that is not a
        dry hole.

    (2) A dry hole is an exploratory or development well found to be incapable
        of producing either oil or gas in sufficient quantities to justify
        completion as an oil or gas well.

         Average Sales Price. The following table sets forth for each of the
last three years the average sales price per unit of oil produced and per unit
of natural gas produced, and the average production cost per unit.


<TABLE>
<CAPTION>
                                                                           Year Ended December 31,
                                                                ------------------------------------------
                                                                   1997             1996              1995
- ----------------------------------------------------------------------------------------------------------
<S>                                                             <C>               <C>              <C>    
Average sales price per BBL of oil (1):

         United States                                          $ 18.49           $17.83           $ 16.80
         International                                          $ 15.55           $20.32           $ 15.57

              Combined  (2)                                     $ 17.86           $18.28           $ 16.78

Average sales price per MCF of natural gas (1):

         United States                                          $  2.48           $ 2.18           $  1.75
         International                                          $  2.29           $ 1.90           $  1.02

              Combined (3)                                      $  2.48           $ 2.17           $  1.72

Average production (lifting) cost per unit of oil and 
         natural gas production, excluding depreciation 
         (per equivalent BBL)(4):

         United States                                          $  3.85           $ 3.45           $  4.17
         International                                          $  4.60           $ 6.47           $  4.70

              Combined                                          $  3.93           $ 3.70           $  4.21
</TABLE>



    (1) Net production amounts used in this calculation include royalties.



                                       12

<PAGE>   15

    (2) Reflects a reduction of $.19 per BBL in 1997 and $2.35 per BBL in 1996
        and includes an increase of $.16 per BBL in 1995 from hedging.

    (3) Reflects a reduction per MCF of $.12 in 1997, $.33 in 1996 and $.004 in
        1995 from hedging.

    (4) Gas production is converted to oil BBL equivalents based on the average
        sales prices per BBL of oil and per MCF of gas. Net production amounts
        used in the calculation of average sales prices for purposes of
        computing the conversion ratio exclude royalties. Conversion ratios for
        1997, 1996 and 1995 are set forth below:


<TABLE>
<CAPTION>
                            United States    International
                            -------------    -------------
                <S>           <C>              <C>
                1997          7.44 to 1         6.71 to 1
                1996          8.12 to 1        10.66 to 1
                1995          9.61 to 1        16.43 to 1
</TABLE>




                                       13

<PAGE>   16




                       OFFSHORE GULF OF MEXICO OPERATIONS
                             as of December 31, 1997

                                      [MAP]




SIGNIFICANT OFFSHORE UNDEVELOPED LEASE HOLDINGS (interests rounded to nearest 
whole percent)


<TABLE>
<CAPTION>
              Net Working                   Net Working                      Net Working                      Net Working 
Block         Interest(%)     Block         Interest(%)        Block         Interest(%)        Block         Interest(%) 
- -------------------------------------------------------------------------------------------------------------------------
<S>              <C>          <C>               <C>            <C>              <C>             <C>             <C>
Matagorda Island (Brazos)     East Cameron                     Vermilion                        Viosca Knoll              
- -------------------------     ------------                     ---------                        ------------              
    441-L          100             16             95                64            100               251             40    
    450-L          100             71             73               103            100               864*            35    
    439-L          100            142             40               111             95           Garden Banks              
East Breaks                       154             38               163             50           ------------              
- -----------                       161             50               194             25                35            100    
    208*            40            178             32               263            100                62             25    
    475*           100        West Cameron                         278             50                63             25    
    519*           100        ------------                         283             50                64             25    
    563*           100            499             75               286            100                78            100    
Ship Shoal                        518             75               293             50               107             25    
- ----------                        583            100               310             50               115            100    
    313             40            602            100               312            100               116            100    
West Delta                        604             50               337             98               122            100    
- ----------                        619             33               342             38               163            100    
     59             25            644             25               343             73               326*           100    
Green Canyon                  Breton Sound                         345             75               534*            35    
- ------------                  ------------                         347             71               536*            35    
     23*            50             41             95               349             75               537*            35    
Eugene Island                      42             95               350             75               538*            35    
- -------------                      49             95               352             74               578*            35    
     84             95             50             95               358             55               580*            35    
    300             67        South Pass                           360             67               581*            35    
South Marsh Island            ----------                           361             67               582*            35    
- ------------------                 41             50               365             50               625*            35    
     62             67             43             50               366             75               751*           100    
     63             67             58             48               372             74               795*           100    
     65             67        South Timbalier                      374             55           Galveston                 
    104            100        ---------------                      392             38           ---------                 
    179             35             98             50               394             75               249-L           50    
    180             35            156             67               402             30               250-L           50    
    185             35            174            100               407             38               277-L           50    
    186             35            201            100               408             38               338-S           50    
    191             50            207            100                                                349-S           50    
Mississippi Canyon            Ewing Bank               
- ------------------            ----------               
    573            100            993             50   
    705             25
    583*            50     
    618*            50
</TABLE>


*Located in water deeper than 1,000 feet.



                                       14

<PAGE>   17



         The developed and undeveloped acreage (including both leases and
concessions) that Samedan held as of December 31, 1997, is as follows:


<TABLE>
<CAPTION>
                                                      Developed Acreage (1)(2)         Undeveloped Acreage (2)(3)
                                                   -----------------------------      -----------------------------
Location                                           Gross Acres        Net Acres       Gross Acres         Net Acres
- -------------------------------------------------------------------------------------------------------------------
<S>                                                  <C>                 <C>            <C>               <C>      
United States Onshore
    Alabama                                              2,610             1,264            3,391             1,368
    California                                          21,475            10,684           15,896             9,473
    Colorado                                            67,665            63,364           44,330            35,773
    Kansas                                              96,608            58,076           19,715            12,097
    Louisiana                                           43,171            23,868            7,570             4,031
    Michigan                                               637               151            2,423               557
    Mississippi                                         13,077             7,827            4,339             2,073
    Montana                                            176,123           120,714          100,906            53,307
    New Mexico                                           5,875             3,107           80,858            51,574
    North Dakota                                        24,290            11,416           42,052            25,269
    Oklahoma                                           166,114            66,320           56,728            23,427
    Texas                                              137,616            58,828          149,102            47,472
    Wyoming                                             34,276            13,874           43,310            15,252
    Other                                                5,760             2,893            3,940             2,058
- -------------------------------------------------------------------------------------------------------------------
     Total United States Onshore                       795,297           442,386          574,560           283,731
- -------------------------------------------------------------------------------------------------------------------
United States Offshore (Federal Waters)
    Alabama                                             11,520             5,822          149,760            65,108
    California                                          17,280             2,938           79,678             8,625
    Louisiana                                          723,217           301,391          445,609           232,910
    Mississippi                                         10,891             7,260           50,815            36,895
    Texas                                              319,169            91,491          182,399           120,347
- -------------------------------------------------------------------------------------------------------------------
     Total United States Offshore (Federal Waters)   1,082,077           408,902          908,261           463,885
- -------------------------------------------------------------------------------------------------------------------
International
    Argentina                                           28,988             3,778           85,760            11,177
    Australia                                                                             938,980           373,244
    China                                                                                 316,676           161,558
    Ecuador                                                                               864,126           864,126
    Equatorial Guinea                                   26,651             9,272          284,000            98,806
    Ireland                                                                               296,797           169,174
    Portugal                                                                              343,455           154,554
    United Kingdom                                     125,107            12,423          533,816           165,387
    Other                                                                                 777,277            32,063
- -------------------------------------------------------------------------------------------------------------------
       Total International                             180,746            25,473        4,440,887         2,030,089
- -------------------------------------------------------------------------------------------------------------------

    Total                                            2,058,120           876,761        5,923,708         2,777,705
- -------------------------------------------------------------------------------------------------------------------
</TABLE>


    (1) Developed acreage is acreage spaced or assignable to productive wells.

    (2) A gross acre is an acre in which a working interest is owned. A net acre
        is deemed to exist when the sum of fractional ownership working
        interests in gross acres equals one. The number of net acres is the sum
        of the fractional working interests owned in gross acres expressed as
        whole numbers and fractions thereof.

    (3) Undeveloped acreage is considered to be those lease acres on which wells
        have not been drilled or completed to a point that would permit the
        production of commercial quantities of oil and gas regardless of whether
        or not such acreage contains proved reserves. Included within
        undeveloped acreage are those lease acres (held by production under the
        terms of a lease) that are not within the spacing unit containing, or
        acreage assigned to, the productive well so holding such lease.


ITEM 3.       LEGAL PROCEEDINGS.

         There are no material pending legal proceedings, other than ordinary
routine litigation incidental to the business of the Registrant and its
subsidiaries, to which the Registrant or any of its subsidiaries is a party or
of which any of their property is the subject.



                                       15

<PAGE>   18




ITEM 4.       SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

         There were no matters submitted to a vote of security holders during
the fourth quarter of 1997.

EXECUTIVE OFFICERS OF THE REGISTRANT

         The following table sets forth certain information, as of March 16,
1998, with respect to the executive officers of the Registrant.


<TABLE>
<CAPTION>
Name                         Age                                        Position
- -------------------------------------------------------------------------------------------------------------
<S>                           <C>         <C>                                                                
Robert Kelley (1)             52          Chairman of the Board, President, Chief Executive Officer, Director

George L. DeMare Jr. (2)      52          Senior Vice President and Operating Committee Member of Samedan

William D. Dickson (3)        49          Senior Vice President-Finance and Treasurer of the Registrant and
                                          Operating Committee Member of Samedan

Dan O. Dinges (4)             44          Senior Vice President and Operating Committee Member of Samedan

W. A. Poillion (5)            48          Senior Vice President and Operating Committee Member of Samedan

Orville Walraven (6)          53          Corporate Secretary of the Registrant and Senior Vice President and
                                          Operating Committee Member of Samedan

James C. Woodson (7)          55          Senior Vice President and Operating Committee Member of Samedan
</TABLE>


    (1) Robert Kelley has served as President and Chief Executive Officer of the
        Registrant since August 1, 1986, and as Chairman of the Board since
        October 27, 1992. Prior to August 1986, he had served as Executive Vice
        President of the Registrant from January 1986. Mr. Kelley also serves as
        President and Chief Executive Officer of Samedan, positions he has held
        since 1984. For more than five years prior thereto, Mr. Kelley served as
        an officer of Samedan. He has served as a director of the Company since
        1986.

    (2) George L. DeMare, Jr. was promoted to Senior Vice President and Onshore
        Division Manager of Samedan on January 1, 1998. Prior thereto, he had
        served as Vice President and Onshore Division Manager of Samedan since
        1989. Mr. DeMare has been a member of the Operating Committee of Samedan
        since January 31, 1995.

    (3) William D. Dickson was promoted to Senior Vice President-Finance and
        Treasurer on January 1, 1998. Prior thereto, he served as Vice
        President-Finance and Treasurer of the Company since October 1985. He
        has served as Vice President-Finance, Treasurer and Assistant Secretary
        of Samedan since 1984 and as a member of the Operating Committee of
        Samedan since February 9, 1994.

    (4) Dan O. Dinges was promoted to Senior Vice President and Division General
        Manager, Offshore Division of Samedan on January 1, 1998. Prior thereto,
        he served as Vice President and General Manager Offshore Division of
        Samedan since January 1989. Mr. Dinges has been a member of the
        Operating Committee of Samedan since January 31, 1995.

    (5) W. A. Poillion was promoted to Senior Vice President-Production and
        Drilling of Samedan on January 1, 1998. Prior thereto, he served as Vice
        President-Production and Drilling and a member of the operating
        committee of Samedan since November 1, 1990. From March 1, 1985 to
        October 31, 1990, he served as Manager of Offshore Production and
        Drilling for Samedan.


                                       16

<PAGE>   19

    (6) Orville Walraven has served as Corporate Secretary of the Registrant
        since January 1, 1989. He was promoted to Senior Vice President-Land of
        Samedan on January 1, 1998. Prior thereto, he served as Vice
        President-Land of Samedan and as a member of the Operating Committee of
        Samedan since January 1, 1989.

    (7) James C. Woodson was promoted to Senior Vice President-Exploration of
        Samedan on January 1, 1998. Prior thereto, he served as Vice
        President-Exploration since September 1, 1983. Mr. Woodson has been a
        member of the Operating Committee of Samedan since August 1, 1986.

       The terms of office for the officers of the Registrant continue until
their successors are chosen and qualified. No officer or executive officer of
the Registrant has an employment agreement with the Registrant or any of its
subsidiaries. There are no family relationships between any of the Registrant's
officers.



                                       17

<PAGE>   20




                                     PART II


ITEM 5.       MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER 
              MATTERS.

         Common Stock. The Registrant's Common Stock, $3.33 1/3 par value
("Common Stock"), is listed and traded on the New York Stock Exchange under the
symbol "NBL." The declaration and payment of dividends are at the discretion of
the Board of Directors of the Registrant and the amount thereof will depend on
the Registrant's results of operations, financial condition, contractual
restrictions, cash requirements, future prospects and other factors deemed
relevant by the Board of Directors.

         Stock Prices and Dividends by Quarters. The following table sets forth,
for the periods indicated, the high and low sales price per share of Common
Stock on the New York Stock Exchange and quarterly dividends paid per share.


<TABLE>
<CAPTION>
                                                                   Dividends
                                        High           Low         Per Share
- ----------------------------------------------------------------------------
<S>                                    <C>         <C>                <C> 
1997 
- ---- 
First quarter                          $ 50        $ 37 1/2           $.04
Second quarter                         $ 43 3/4    $ 32 1/4           $.04
Third quarter                          $ 47 9/16   $ 38 1/8           $.04
Fourth quarter                         $ 46        $ 32 3/16          $.04 

1996
- ----
First quarter                          $ 33 3/8    $ 26 7/8           $.04
Second quarter                         $ 38 3/8    $ 32 1/8           $.04
Third quarter                          $ 42 1/2    $ 37 3/8           $.04
Fourth quarter                         $ 49        $ 41 5/8           $.04
</TABLE>


         Transfer Agent and Registrar. The transfer agent and registrar for the
Common Stock is Bank One N.A., Post Office Box 26848, Oklahoma City, Oklahoma
73125.

         Stockholders' Profile. As of December 31, 1997, the number of holders
of record of Common Stock was 1,512. The following chart indicates the common
stockholders by category.


<TABLE>
<CAPTION>
                                                                                                        Shares
December 31, 1997                                                                                  Outstanding
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                                 <C>       
Individuals                                                                                            514,165
Joint accounts                                                                                          79,116
Fiduciaries                                                                                            185,050
Institutions                                                                                         2,559,070
Nominees                                                                                            53,560,652
Foreign                                                                                                    485
- --------------------------------------------------------------------------------------------------------------
   Total                                                                                            56,898,538
- --------------------------------------------------------------------------------------------------------------
</TABLE>




                                       18

<PAGE>   21




ITEM 6.       SELECTED FINANCIAL DATA.


<TABLE>
<CAPTION>
                                                                             Year Ended December 31,
- -----------------------------------------------------------------------------------------------------------------------
(In thousands, except per share amounts and ratios)    1997           1996           1995           1994           1993
- -----------------------------------------------------------------------------------------------------------------------
<S>                                              <C>            <C>            <C>            <C>            <C>       
REVENUES AND INCOME
   Revenues                                      $1,116,623     $  887,203     $  487,018     $  358,389     $  286,583
   Net cash provided by operating activities        445,571        380,945        238,920        188,621        139,381
   Net income                                        99,278         83,880          4,086          3,166         12,625
PER SHARE DATA
   Basic earnings per share                      $     1.75     $     1.63     $      .08     $      .06     $      .26
   Cash dividends                                $      .16     $      .16     $      .16     $      .16     $      .16
   Year end stock price                          $    35.25     $    47.88     $    29.88     $    24.75     $    26.50
   Basic weighted average shares outstanding         56,872         51,414         50,046         49,970         48,098
FINANCIAL POSITION (at year end)
   Property, plant and equipment, net:
     Oil and gas mineral interests,
     equipment and facilities                    $1,546,426     $1,559,691     $  831,827     $  804,009     $  784,235
   Total assets                                   1,875,484      1,956,938        989,176        933,516      1,067,996
   Long-term obligations:
     Long-term debt, net of current portion         644,967        798,028        376,992        376,956        453,760
     Deferred income taxes                          144,083        108,434         69,445         61,802         45,108
     Other                                           56,425         50,603         33,650         19,455          7,158
   Shareholders' equity                             812,989        720,067        411,911        412,066        415,432
   Ratio of debt to book capital                        .44            .54            .48            .48            .52
CAPITAL EXPENDITURES
   Oil and gas mineral interests,
     equipment and facilities                    $  320,561     $  982,499     $  252,977     $  158,973     $  508,506
   Other                                              8,499          3,485          6,265          2,371          1,607
- -----------------------------------------------------------------------------------------------------------------------
   Total capital expenditures                    $  329,060     $  985,984     $  259,242     $  161,344     $  510,113
- -----------------------------------------------------------------------------------------------------------------------
</TABLE>


For additional information, see "Item 8. Financial Statements and Supplementary
Data" of this Form 10-K.

OPERATING STATISTICS


<TABLE>
<CAPTION>
                                                           Year ended December 31,
- ------------------------------------------------------------------------------------------------------
                                      1997           1996           1995           1994           1993
- ------------------------------------------------------------------------------------------------------
<S>                             <C>            <C>            <C>            <C>            <C>       
GAS
Sales (in millions)             $    499.4     $    365.4     $    167.4     $    174.5     $    159.2
Production (MMCF per day)            565.4          469.4          272.2          247.6          211.1
Average price (per MCF)         $     2.48     $     2.17     $     1.72     $     1.97     $     2.10

OIL
Sales (in millions)             $    243.6     $    225.2     $    153.5     $    122.9     $    111.3
Production (BBLS per day)           38,345         34,520         25,617         22,751         19,496
Average price (per BBL)         $    17.86     $    18.28     $    16.78     $    14.90     $    15.91

Royalty sales (in millions)     $     18.1     $     13.9     $      7.2     $      8.8     $      7.5
</TABLE>



                                       19

<PAGE>   22




ITEM 7.       MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
              RESULTS OF OPERATIONS.

SIGNIFICANT EVENTS IN 1997

o For eight straight years the Company recorded record levels of gas production.
o For nine straight years the Company recorded record levels of oil production.
o The Company expended $356.9 million on acquisition, exploration and
  development costs during 1997.
o The Company added 34.6 million BBLS of oil and 557.4 BCF of gas to its reserve
  base in 1997 primarily through drilling.
o During 1997, the Company sold non-strategic Canadian properties for $43.1
  million.

LIQUIDITY AND CAPITAL RESOURCES

CASH FLOW FROM OPERATIONS

         Net cash provided by operating activities was $445.6 million for 1997,
a 17 percent and 86.5 percent increase from the $380.9 million and $238.9
million in 1996 and 1995, respectively. Cash and short-term cash investments
decreased to $55.1 million at December 31, 1997, from $94.8 million at year-end
1996.

         During 1997, the Company utilized its beginning cash balance and cash
flow from operations to fund its exploration and development expenditures, as
well as to repay $203 million in long-term debt.

         The Company's current ratio (current assets divided by current
liabilities) was 1.19:1 at December 31, 1997, compared with 1.13:1 at December
31, 1996.

RESERVES ADDED AND COST OF FINDING

         During 1997, the Company spent $356.9 million on acquisitions,
exploration and development of oil and gas properties. Total proved gas reserves
increased from 1.16 TCF at year-end 1996 to 1.48 TCF at year-end 1997, and total
proved oil reserves increased from 115.7 million BBLS at year-end 1996 to 130.9
million BBLS at year-end 1997.

         An accepted method of calculating cost of finding is to divide the
Company's expenditures for oil and gas acquisition, exploration and development
by the net BOE's added during the year. Using this method, the Company's cost of
finding for 1997 was $2.80 per BOE.

          A three year summary of cost of finding follows:


<TABLE>
<CAPTION>
                                                                                                         Three
       (BOE's and Dollars stated in millions,                                                             Year
       except finding cost)                           1997             1996              1995            Total
       -------------------------------------------------------------------------------------------------------
       <S>                                          <C>              <C>               <C>            <C>     
       Oil reserves added                             34.6             46.3              18.2             99.1
       Gas reserves added BOE (6:1)                   92.9             88.0              29.0            209.9
       -------------------------------------------------------------------------------------------------------
       Total reserves added BOE                      127.5            134.3              47.2            309.0
       -------------------------------------------------------------------------------------------------------
       Costs incurred in oil and gas
         acquisition, exploration
         and development activities                 $356.9           $1,009            $  266         $1,631.9
       Average finding cost per BOE                 $ 2.80           $ 7.51            $ 5.64         $   5.28*
</TABLE>


- ----------------------------
         *Three year weighted average


                                       20

<PAGE>   23



FINANCING

         Total long-term debt at December 31, 1997 was $645 million compared to
$848 million (including current portion) at December 31, 1996, a decrease of 24
percent. The ratio of debt to book capital (defined as the Company's debt plus
its equity) was 44 percent at December 31, 1997, compared with 54 percent at
December 31, 1996.

         The $300 million credit agreement is a revolving credit facility with a
group of banks with a final maturity of December 24, 2002. The interest rate
charged, which is based upon a Eurodollar rate plus 22.5 basis points, was 5.9
percent at December 31, 1997. Financial covenants include maintenance of a cash
flow multiple of at least four times interest cost and maintenance of a debt
level which does not exceed 60 percent of the Company's shareholders' equity
plus its debt.

         The $800 million credit agreement was terminated on December 24, 1997,
and the outstanding balance of $200 million was refinanced in the $300 million
credit agreement. The weighted average interest rate on the borrowings during
1997 was 6.9 percent.

         Total long-term debt outstanding at December 31, 1997, included $100
million of 7 1/4% Notes Due 2023, $250 million of 8% Senior Notes Due 2027, and
$100 million of 7 1/4 % Senior Debentures Due 2097.

         The only principal payment on long-term debt due during the next five
years is the outstanding balance of the $300 million credit agreement on
December 24, 2002.

         On November 1, 1996, all of the Company's $230 million 4 1/4%
Convertible Subordinated Notes Due 2003 were converted into 6,275,510 shares of
common stock.

OTHER

         The Company follows an entitlements method of accounting for its gas
imbalances. The Company's estimated gas imbalance receivables were $18.5 million
and $19.3 million at December 31, 1997 and 1996, respectively, and estimated gas
imbalance liabilities were $21.6 million and $21.7 million at December 31, 1997
and 1996, respectively. These imbalances are valued at the amount that is
expected to be received or paid to settle the imbalances. The settlement of the
imbalances can occur either during, or at the end of, the life of a well on a
volume basis or by cash settlement. The Company does not expect that a
significant portion of the settlements will occur in any one year. Thus, the
Company believes the periodic settlement of gas imbalances will have little
impact on its liquidity.

         The Company has sold a number of non-strategic oil and gas properties
over the past three years, recognizing pretax gains of approximately $15.9
million, $1.9 million and $3.6 million for 1997, 1996 and 1995, respectively.
Total amounts of oil and gas reserves associated with these dispositions during
the last three years were 6.6 million BBLS of oil and 89.3 BCF of gas. In 1997,
the Company sold its Canadian operations for $43.1 million, with estimated
reserves sold of 2.6 million BBLS of oil and 23.1 BCF of gas. The Company
believes the disposition of non-strategic properties furthers the goal of
concentrating its efforts on its strategic properties.

         The Company has paid quarterly cash dividends of $.04 per share since
1989, and currently anticipates it will continue to pay quarterly dividends of
$.04 per share.

         In October 1995, the Financial Accounting Standards Board issued
Statement of Financial Accounting Standards (SFAS) No. 123, "Accounting for
Stock-Based Compensation." The Company adopted the disclosure requirements of
SFAS No. 123 during 1996 and has presented in the footnotes to its financial
statements pro forma disclosure as if the provisions of SFAS No. 123 had been
adopted for all years reported within the Company's financial statements.



                                       21

<PAGE>   24

         The Financial Accounting Standards Board issued SFAS No. 128 "Earnings
per Share," SFAS No. 129 "Disclosure of Information about Capital Structure,"
SFAS No. 130 "Reporting Comprehensive Income" and SFAS No. 131 "Disclosure about
Segments of an Enterprise and Related Information," in the first half of 1997.
SFAS No. 128 and No. 129 are effective for the Company's financial statements in
both interim and annual periods ending after December 15, 1997. SFAS No. 130 and
No. 131 are effective for 1998. The Company adopted disclosure requirements of
SFAS No. 128 and No. 129 in 1997 and has presented disclosure as if the
provisions of SFAS No. 128 and No. 129 had been adopted for all years reported
within the Company's financial statements.

RESULTS OF OPERATIONS

         The Company's consolidated financial statements for the year ended
 December 31, 1997, include a full year of EDC operations as a wholly owned
 subsidiary of Samedan. The consolidated financial statements for the year ended
 December 31, 1996, include five months of consolidated operations. EDC was
 acquired by the Company on July 31, 1996.

NET INCOME AND REVENUES

         1997 VERSUS 1996. Net income for 1997 was $99.3 million, or $1.75 per
share, compared with $83.9 million, or $1.63 per share in 1996. The increase in
net income was achieved through record gas production, substantially higher gas
prices and the sale of non-strategic properties. Total revenues were $1,116.6
million in 1997 and $887.2 million in 1996.

         Oil and gas revenues were $761.1 million in 1997, an increase of $156.5
million, or 26 percent, over 1996. The Company received an average oil price for
1997 of $17.86 per BBL, a two percent decrease from the average 1996 price of
$18.28 per BBL. The average gas price increased 14 percent in 1997 to $2.48 per
MCF from the 1996 average of $2.17 per MCF.

         Gathering, marketing and processing revenues were $329.9 million, an
increase of 21 percent from the $273.7 million in 1996. The increase reflects an
increase in marketed volumes for each of NTI and NGM, both wholly owned
subsidiaries of the Company.

         Other income in 1997 was $25.6 million, compared with $8.9 million in
1996. Other income in 1997 included non-recurring income of $14.1 million
resulting from the Company's sale of its Canadian operations, with estimated
reserves sold of 2.6 million BBLS of oil and 23.1 BCF of gas. The proceeds of
$43.1 million received from the sale of the Canadian properties were used to
reduce the Company's debt existing under its credit agreement.

         1996 VERSUS 1995. Net income for 1996 was $83.9 million, or $1.63 per
share, compared with $4.1 million, or $.08 per share in 1995. The increase in
net income was achieved through increased oil and gas production and
substantially higher oil and gas prices. Total revenues were $887.2 million in
1996 and $487.0 million in 1995.

         Oil and gas revenues were $604.6 million in 1996, an increase of $276.5
million, or 84 percent, over 1995. The Company received an average oil price for
1996 of $18.28 per BBL, a nine percent increase from the average 1995 price of
$16.78 per BBL. The average gas price increased 26 percent in 1996 to $2.17 per
MCF from the 1995 average of $1.72 per MCF. The increase in gas price was due
primarily to higher demand and lower levels of gas storage than in the previous
year.

         Gathering, marketing and processing revenues were $273.7 million, an
increase of 143 percent from the $112.7 million in 1995. The increase reflects a
full year of operations for NTI and NGM.

         Other income in 1996 was $8.9 million, compared with $46.2 million in
1995. Other income in 1995 included non-recurring income of $39.0 million
resulting from the settlement of a Columbia Gas Transmission Corporation
bankruptcy claim with Samedan.



                                       22

<PAGE>   25



NATURAL GAS INFORMATION

         A three-year summary of gas-related information follows:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
       -------------------------------------------------------------------------------------------------------
       <S>                                                       <C>               <C>                <C>    
       Proved reserves at year end (MMCF)                         1,482,215         1,156,250          850,339
       Gas revenues (millions)                                   $    499.4        $    365.4         $  167.4
       Average price per MCF*                                    $     2.48        $     2.17         $   1.72
       Average daily production (MMCF)                                565.4             469.4            272.2
       Gas sales as a percent of oil and gas sales                       67%               62%              52%
</TABLE>


- --------------------
        *The average price reflects a reduction per MCF of $.12 in 1997, $.33 in
         1996 and $.004  in 1995 from hedging.

         1997 VERSUS 1996. Gas sales for 1997 increased 37 percent to $499.4
million from $365.4 million in 1996. Average daily production in 1997 increased
20 percent to 565.4 MMCF from 469.4 MMCF in 1996.

         The average gas price in 1997 increased 14 percent to $2.48 per MCF
from $2.17 per MCF in 1996. During 1997, the Company's average gas prices ranged
from a low of $1.80 in April to a high of $3.35 in January.

         International sales accounted for three percent of 1997 gas sales
compared with two percent in 1996. Average daily gas production outside of the
United States was 20,873 MCF in 1997 and 5,757 MCF in 1996.

         1996 VERSUS 1995. Gas sales for 1996 increased 118 percent to $365.4
million from $167.4 million in 1995. Average daily production in 1996 increased
72 percent to 469.4 MMCF from 272.2 MMCF in 1995.

         The average gas price in 1996 increased 26 percent to $2.17 per MCF
from $1.72 per MCF in 1995. During 1996, the Company's average gas prices ranged
from a low of $1.82 in April and October to a high of $3.15 in December.

CRUDE OIL INFORMATION

         A three-year summary of oil-related information follows:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
       -------------------------------------------------------------------------------------------------------
       <S>                                                         <C>               <C>               <C>   
       Proved reserves at year end
         (thousands of BBLS)                                        130,863           115,747           84,008
       Oil revenues (millions)                                     $  243.6          $  225.2          $ 153.5
       Average price per BBL*                                      $  17.86          $  18.28          $ 16.78
       Average daily production (BBLS)                               38,345            34,520           25,617
       Oil sales as a percent of
         oil and gas sales                                               33%               38%              48%
</TABLE>


- --------------------
       *The average price reflects a reduction of $.19 per BBL in 1997 and $2.35
       per BBL in 1996 and includes an increase of $.16 per BBL in 1995 from
       hedging.

         1997 VERSUS 1996. Oil sales for 1997 increased eight percent to $243.6
million from $225.2 million in 1996. Average daily production in 1997 increased
11 percent to 38,345 BBLS from 34,520 BBLS in 1996.

         The average oil price for 1997 was $17.86 per BBL, a two percent
decrease from the 1996 average of $18.28 per BBL. The Company's 1997 average oil
prices ranged from a low of $15.74 per BBL in December to a high of $21.92 per
BBL in January.



                                       23

<PAGE>   26

         International sales accounted for 19 percent of 1997 oil sales compared
with 20 percent in 1996. Average daily oil production outside the United States
was 8,250 BBLS in 1997 and 6,230 BBLS in 1996.

         1996 VERSUS 1995. Oil sales for 1996 increased 47 percent to $225.2
million from $153.5 million in 1995. Average daily production in 1996 increased
35 percent to 34,520 BBLS from 25,617 BBLS in 1995.

         The average oil price for 1996 was $18.28 per BBL, a nine percent
increase from the 1995 average of $16.78 per BBL. The Company's 1996 average oil
prices ranged from a low of $17.11 per BBL in January to a high of $19.74 per
BBL in September.

         International sales accounted for 20 percent of 1996 oil sales compared
with 15 percent in 1995. Average daily oil production outside the United States
was 6,230 BBLS in 1996 and 3,777 BBLS in 1995.

HEDGING ACTIVITY

         The Company, through its subsidiaries, from time to time, uses various
hedging arrangements in connection with anticipated crude oil and natural gas
sales of its production to minimize the impact of product price fluctuations.
Such arrangements include fixed price hedges, costless collars and other
contractual arrangements. Although these hedging arrangements expose the Company
to credit risk, the Company monitors the creditworthiness of its counterparties,
which generally are major institutions, and believes that losses from
nonperformance are unlikely to occur. Hedging gains and losses related to the
Company's oil and gas production are recorded in oil and gas sales and
royalties.

         During 1997, the Company had natural gas hedging contracts that ranged
from 20 percent to 32 percent of its average daily natural gas production.
Natural gas hedges were in the price range of $1.88 to $3.30 per MMBTU. The net
effect of these 1997 hedges was a $.12 per MCF reduction in the average natural
gas price realized by the Company. At December 31, 1997, the Company had no
natural gas hedging contracts.

         During 1997, the Company had crude oil hedging contracts that ranged
from 19 percent to 50 percent of its average daily oil production. Crude oil
hedges were in the price range of $16.81 to $24.35 per BBL. The net effect of
these 1997 hedges was a $.19 per BBL reduction in the average crude oil price
realized by the Company. At December 31, 1997, the Company had no crude oil
hedging contracts.

         During 1996, the Company had natural gas hedging contracts that ranged
from 39 percent to 86 percent of its average daily natural gas production.
Natural gas hedges were in the price range of $1.60 to $3.59 per MMBTU. The net
effect of these 1996 hedges was a $.33 per MCF reduction in the average natural
gas price. At December 31, 1996, the Company was a party to natural gas hedging
contracts to hedge approximately 21 percent of its estimated 1997 average daily
natural gas production at an average price per MMBTU of $2.20.

         During 1996, the Company had crude oil hedging contracts that ranged
from 48 percent to 55 percent of its average daily oil production for January
through July and 62 percent to 100 percent of its average daily oil production
for August through December. Crude oil hedges were in the price range of $16.50
to $24.27 per BBL. The net effect of these 1996 hedges was a $2.35 per BBL
reduction in the average crude oil price. At December 31, 1996, the Company was
a party to crude oil hedging contracts to hedge approximately 26 percent of its
estimated 1997 annual crude oil production at an average price per BBL of
$20.48.

         During 1995, Samedan had natural gas hedging contracts for November and
December to hedge from 20 percent to 46 percent of its average daily natural gas
production. For May to December 1995, Samedan had hedged approximately 20
percent of its daily crude oil production. Natural gas hedges were in the range
of $1.60 to $1.96 per MMBTU and crude oil hedges were in the range of $18.56 to
$20.27 per BBL. The net effect of these 1995 hedges was a $.004 per MCF
reduction in the average natural gas price and a $.16 per BBL increase in the
average crude oil price realized by the Company.


                                       24

<PAGE>   27

         In addition to the hedging arrangements pertaining to the Company's
production as described above, NGM employs various hedging arrangements in
connection with its purchases and sales of third party production to lock in
profits or limit exposure to gas price risk. Most of the purchases made by NGM
are on an index basis; however, purchasers in the markets in which NGM sells
often require fixed or NYMEX related pricing. NGM may use a hedge to convert the
fixed or NYMEX sale to an index basis thereby determining the margin and
minimizing the risk of price volatility. During 1997, NGM had hedging
transactions with broker-dealers that ranged from 317,693 MMBTU's to 768,599
MMBTU's of gas per day.

         At December 31, 1997, NGM had in place hedges ranging from
approximately 645 MMBTU's to 29,279 MMBTU's of gas per day for January 1998 to
March 1999 for future physical transactions. At December 31, 1996, NGM had in
place hedges ranging from approximately 7,475 MMBTU's to 551,126 MMBTU's of gas
per day for January 1997 to March 1998 for future physical transactions. During
1995, NGM had hedging transactions with large financial institutions that
averaged approximately 126,000 MMBTU's of gas per day at prices linked to
certain indices. NGM records hedging gains or losses relating to fixed term
sales as gathering, marketing and processing revenues in the periods in which
the related contract is completed.

COSTS AND EXPENSES

         1997 VERSUS 1996. Oil and gas exploration expense increased in 1997 by
$36.8 million from 1996 to $86.7 million. The increase resulted primarily from a
$14.1 million increase in dry hole expense and a full year of EDC foreign
exploration costs for 1997.

         Oil and gas operations expense in 1997 increased $34.7 million from
1996 to $160.8 million. Lease operating expense increased $35 million in 1997
due to higher oil and gas production and a full year's ownership of EDC
properties. Production taxes increased $1.8 million in 1997 due to higher
production levels and gas prices.

         In 1997, depreciation, depletion and amortization ("DD&A") expense
increased $67 million over 1996 due to the higher production levels and a full
year of production from the EDC properties. The unit rate of DD&A expense per
BOE, converting gas to oil on a 6:1 basis, was $6.33 for 1997, compared with
$5.66 for 1996.

         The Company provides for the cost of future liabilities related to
restoration and dismantlement costs for offshore facilities. This provision is
based on the Company's best estimate of such costs to be incurred in future
years based on information from the Company's engineers. These estimated costs
are provided through charging DD&A expense using a ratio of production divided
by reserves multiplied by the estimated costs to dismantle and restore. The
Company has provided $59.5 million for such future restoration and dismantlement
costs which are classified in accumulated DD&A on the balance sheet at December
31, 1997. Total estimated future dismantlement and restoration costs of $143.9
million are included in future production and development costs for purposes of
estimating the future net revenues relating to the Company's proved reserves.

         1996 VERSUS 1995. Oil and gas exploration expense increased in 1996 by
$16.6 million from 1995 to $49.9 million. The increase resulted primarily from a
$15.2 million increase in dry hole expense for 1996.

         Oil and gas operations expense in 1996 increased $44.3 million from
1995 to $126 million. Lease operating expense increased $37.7 million in 1996
due to higher oil and gas production from a greater number of properties and the
acquisition of EDC. Production taxes increased $6.7 million in 1996 due to
higher production levels and oil and gas prices.

         In 1996, DD&A expense increased $32.7 million over 1995 due to the
record production levels and the EDC acquisition. The unit rate of DD&A expense
per BOE, converting gas to oil on a 6:1 basis, was $5.66 for 1996, compared with
$7.75 for 1995. The 1995 rate included $59.5 million of additional impairment
for the writedown of certain long-lived assets in accordance with provisions of
SFAS No. 121.


                                       25

<PAGE>   28

         The Company has provided $51.6 million for future liabilities related
to dismantlement and restoration costs which are classified in accumulated DD&A
on the balance sheet at December 31, 1996. Total estimated future dismantlement
and restoration costs of $130.2 million are included in future production and
development costs for purposes of estimating the future net revenues relating to
the Company's proved reserves.

         In 1996, Selling, General and Administrative ("SG&A") expense increased
$15.1 million over 1995 to $51.6 million. Administrative costs increased $11.1
million in 1996 due to the acquisition of EDC and the hiring of additional
personnel to oversee increased operations. The Company estimates that
approximately 32 percent of the EDC increase is due to non-recurring costs.

INTEREST EXPENSE

         1997 VERSUS 1996. During 1997, interest expense increased $14.5 million
from 1996 to $53 million. This increase was due primarily to the indebtedness of
the Company incurred in the financing of the acquisition of EDC. During 1996,
the interest on the EDC acquisition reflects five months costs compared to
twelve months of interest during 1997.

         1996 VERSUS 1995. In 1996, interest expense increased $16.6 million
from 1995 to $38.5 million. This increase was due primarily to the financing of
the EDC acquisition offset in part by the conversion into common stock on
November 1, 1996, of the $230,000,000 4 1/4% Convertible Subordinated Notes Due
2003.

MARKETING SUBSIDIARIES

         NGM markets the Company's natural gas, as well as certain third-party
 gas. NGM sells gas directly to end-users, gas marketers, industrial users,
 interstate and intrastate pipelines, and local distribution companies. The
 Company records all of NGM's non-affiliated sales as gathering, marketing and
 processing revenues. All intercompany sales and expenses have been eliminated.

         NTI markets a portion of the Company's oil, as well as certain
 third-party oil. The Company records all of NTI's non-affiliated sales as
 gathering, marketing and processing revenues. All intercompany sales and
 expenses have been eliminated.

         During 1997, NGM recorded $228.4 million in gathering, marketing and
processing revenues and $218.8 million in gathering, marketing and processing
expenses, generating a gross margin of $9.6 million for the year. In 1996, NGM
recorded $197.4 million in gathering, marketing and processing revenues and
$184.6 million in gathering, marketing and processing expenses, generating a
gross margin of $12.8 million for the year. In 1995, NGM recorded $104.6 million
in gathering, marketing and processing revenues and $100.6 million in gathering,
marketing and processing expenses, generating a gross margin of $4.0 million for
the year.

         During 1997, NTI recorded $101.5 million in gathering, marketing and
processing revenues and $95.0 million in gathering, marketing and processing
expenses, generating a gross margin of $6.5 million for the year. In 1996, NTI
recorded $76.3 million in gathering, marketing and processing revenues and $68.9
million in gathering, marketing and processing expenses, generating a gross
margin of $7.4 million for the year. In 1995, NTI began marketing a portion of
the Company's oil as well as certain third-party oil and recorded $8.1 million
in gathering, marketing and processing revenues and $7.3 million in gathering,
marketing and processing expenses, generating a gross margin of $791,000 for the
year.

FUTURE TRENDS

         The Company expects higher production volumes in 1998 compared to 1997.
The increase in volume is expected primarily due to the production associated
with oil and gas properties acquired from New England Energy Incorporated,
effective January 1, 1998, as well as certain new oil and gas properties
expected to commence 



                                       26

<PAGE>   29

production during the year. Revenue, however, may also be impacted by commodity
prices which are expected to remain volatile during 1998.

         The Company has set its 1998 capital budget at approximately $400
million, exclusive of producing property acquisitions. The capital budget
includes the expected 1998 expenditures for the first phase of construction for
the Equatorial Guinea methanol plant and exploration, exploitation and
development expenditures. The Company expects to fund the 1998 capital budget
through its cash flow from operations. The Company will fund the New England
Energy Incorporated property acquisition through short-term borrowings under its
current $300 million credit agreement.

         Samedan has from time to time settled various claims against parties
which failed to fulfill their contractual obligation to Samedan to purchase gas
at fixed prices greater than market or pursuant to take-or-pay provisions. The
Company's policy, which is consistent with general industry practice, is that
amounts received in such settlements ("settlement payments") do not represent
payment for gas produced and, therefore, are not subject to royalty payments.
Property owners, including governmental authorities and private parties, have in
recent years asserted claims against Samedan and other oil and gas companies for
royalties on settlement payments.

         Samedan participated, in a joint effort with other energy companies and
the Independent Petroleum Association of America ("IPAA"), in a test case which
challenged the determination by the U.S. Minerals Management Service ("MMS")
that royalties were payable to the government on certain settlement payments
received by Samedan (and the other plaintiffs). The District Court for the
District of Columbia (the "D.C. District Court") entered a judgment against
Samedan in the amount of $20,000. In August 1996, the Court of Appeals for the
District of Columbia Circuit reversed the judgment against Samedan. In
subsequent proceedings in the D.C. District Court consistent with the appellate
court decision, on July 25, 1997, the court enjoined the MMS from taking action
to collect from Samedan royalties on non-recoupable settlement payments (the
"MMS Injunction"). The MMS has until April 14, 1998 to appeal the MMS
Injunction.

         Notwithstanding the ultimate outcome with respect to the MMS
Injunction, Samedan may be the subject of future legal actions by property
owners claiming royalties on other settlement payments received by Samedan.
There can be no assurance that Samedan will prevail in any such action. The
Company is unable to estimate the possible amount of loss, if any, associated
with this contingency.

         Management believes that the Company is well positioned with its
balanced reserves of oil and gas to take advantage of future price increases
that may occur. However, the uncertainty of oil and gas prices continues to
impact the domestic oil and gas industry. Due to the volatility of oil and gas
prices, the Company, from time to time, has used hedging and may do so in the
future as a means of controlling its exposure to price changes. The Company
cannot predict the extent to which its operations will be impacted by inflation,
government regulation or changing prices. Market risk is a new disclosure that
the Company is required to report through quantitative and qualitative
disclosures. The required disclosures are presented in the financial statements
and footnotes. For more information concerning market risk, see "Item 8.
Financial Statements and Supplementary Data--Supplemental Oil and Gas
Information (Unaudited)" in this Form 10-K.

         The Company is currently in the process of updating its computer
software programs and operating systems so that these systems will properly
utilize dates beyond December 31, 1999. The Company does not expect the cost to
modify its information systems to be material to its financial condition or
results of operations. The Company does not anticipate any material disruptions
in its operations as a result of its year 2000 compliance plan.


I
TEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

         Under the general instructions, the Registrant's disclosures about
market risk pursuant to this item should be made in the Registrant's Form 10-K
for the year ending December 31, 1998.


                                       27

<PAGE>   30





ITEM  8.      FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.



                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS



<TABLE>
   <S>                                                                                                        <C>
   Report of Independent Public Accountants................................................................   29

   Consolidated Balance Sheet as of December 31, 1997 and 1996.............................................   30

   Consolidated Statement of Operations for each of the three years in the period ended
     December 31, 1997.....................................................................................   31

   Consolidated Statement of Cash Flows for each of the three years in the period ended
     December 31, 1997.....................................................................................   32

   Consolidated Statement of Shareholders' Equity for each of the three years in the period ended
     December 31, 1997.....................................................................................   33

   Notes to Consolidated Financial Statements..............................................................   34

   Supplemental Oil and Gas Information (Unaudited)........................................................   47
</TABLE>



                                       28

<PAGE>   31





REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS

To the Shareholders and Board of Directors of Noble Affiliates, Inc.:

         We have audited the accompanying consolidated balance sheet of Noble
Affiliates, Inc. (a Delaware corporation) and subsidiaries as of December 31,
1997 and 1996, and the related consolidated statements of operations,
shareholders' equity and cash flows for each of the three years in the period
ended December 31, 1997. These financial statements are the responsibility of
the Company's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

         We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

         In our opinion, the financial statements referred to above present
fairly, in all material respects, the financial position of Noble Affiliates,
Inc. and subsidiaries as of December 31, 1997 and 1996, and the results of their
operations and their cash flows for each of the three years in the period ended
December 31, 1997, in conformity with generally accepted accounting principles.


                                                 ARTHUR ANDERSEN LLP


Oklahoma City, Oklahoma
January 30, 1998



                                       29

<PAGE>   32
CONSOLIDATED BALANCE SHEET               NOBLE AFFILIATES, INC. AND SUBSIDIARIES


<TABLE>
<CAPTION>
                                                                                             December 31,
- ---------------------------------------------------------------------------------------------------------------
(In thousands, except share amounts)                                                      1997             1996
- ---------------------------------------------------------------------------------------------------------------
<S>                                                                                <C>              <C>        
ASSETS
CURRENT ASSETS:
   Cash and short-term cash investments                                            $    55,075      $    94,768
   Accounts receivable - trade                                                         162,667          206,151
   Materials and supplies inventories                                                    2,805            4,489
   Other current assets                                                                 38,087           11,395
- ---------------------------------------------------------------------------------------------------------------
       Total current assets                                                            258,634          316,803
- ---------------------------------------------------------------------------------------------------------------
PROPERTY, PLANT AND EQUIPMENT, AT COST:
   Oil and gas mineral interests, equipment and facilities
     (successful efforts method of accounting)                                       2,766,741        2,536,524
   Other                                                                                40,286           35,440
- ---------------------------------------------------------------------------------------------------------------
                                                                                     2,807,027        2,571,964
   Accumulated depreciation, depletion and amortization                             (1,260,601)      (1,000,200)
- ---------------------------------------------------------------------------------------------------------------
       Total property, plant and equipment, net                                      1,546,426        1,571,764
- ---------------------------------------------------------------------------------------------------------------
OTHER ASSETS                                                                            70,424           68,371
- ---------------------------------------------------------------------------------------------------------------
           TOTAL ASSETS                                                            $ 1,875,484      $ 1,956,938
- ---------------------------------------------------------------------------------------------------------------

LIABILITIES AND SHAREHOLDERS' EQUITY
CURRENT LIABILITIES:
   Accounts payable - trade                                                        $   163,563      $   143,408
   Other current liabilities                                                            28,456           75,736
   Current installments of long-term debt                                                                50,000
   Income taxes - current                                                               25,001           10,662
- ---------------------------------------------------------------------------------------------------------------
       Total current liabilities                                                       217,020          279,806
- ---------------------------------------------------------------------------------------------------------------
DEFERRED INCOME TAXES                                                                  144,083          108,434
- ---------------------------------------------------------------------------------------------------------------
OTHER DEFERRED CREDITS AND NONCURRENT LIABILITIES                                       56,425           50,603
- ---------------------------------------------------------------------------------------------------------------
LONG-TERM DEBT                                                                         644,967          798,028
- ---------------------------------------------------------------------------------------------------------------
SHAREHOLDERS' EQUITY:
   Preferred stock - par value $1.00; 4,000,000 shares authorized, none issued
   Common stock - par value $3.33 1/3; 100,000,000 shares authorized;
     58,423,438 and 58,321,297 shares issued in 1997 and 1996, respectively            194,743          194,402
   Capital in excess of par value                                                      358,054          355,651
   Retained earnings                                                                   275,610          185,432
- ---------------------------------------------------------------------------------------------------------------
                                                                                       828,407          735,485
   Less common stock in treasury, at cost (1997 and 1996, 1,524,900 shares)            (15,418)         (15,418)
- ---------------------------------------------------------------------------------------------------------------
       Total shareholders' equity                                                      812,989          720,067
- ---------------------------------------------------------------------------------------------------------------
           TOTAL LIABILITIES AND EQUITY                                            $ 1,875,484      $ 1,956,938
- ---------------------------------------------------------------------------------------------------------------
</TABLE>


See accompanying Notes to Consolidated Financial Statements.


                                       30

<PAGE>   33
CONSOLIDATED STATEMENT OF OPERATIONS    NOBLE AFFILIATES, INC. AND SUBSIDIARIES


<TABLE>
<CAPTION>
                                                              Year ended December 31,
- ---------------------------------------------------------------------------------------------
(In thousands, except per share amounts)               1997             1996             1995
- ---------------------------------------------------------------------------------------------
<S>                                             <C>              <C>              <C>        
REVENUES:
   Oil and gas sales and royalties              $   761,145      $   604,588      $   328,134
   Gathering, marketing and processing              329,868          273,690          112,702
   Other income                                      25,610            8,925           46,182
- ---------------------------------------------------------------------------------------------
       Total Revenue                              1,116,623          887,203          487,018
- ---------------------------------------------------------------------------------------------
COSTS AND EXPENSES:
   Oil and gas exploration                           86,698           49,861           33,246
   Oil and gas operations                           160,765          126,044           81,735
   Gathering, marketing and processing              313,807          253,529          107,867
   Depreciation, depletion and amortization         300,354          233,604          200,914
   Selling, general and administrative               50,545           51,567           36,514
   Interest                                          53,008           38,474           21,871
   Interest capitalized                              (6,239)          (2,165)          (3,127)
- ---------------------------------------------------------------------------------------------
       Total Expenses                               958,938          750,914          479,020
- ---------------------------------------------------------------------------------------------
INCOME BEFORE TAXES                                 157,685          136,289            7,998

INCOME TAX PROVISIONS:
   Current                                           25,569           31,376           (9,123)
   Deferred                                          32,838           21,033           13,035
- ---------------------------------------------------------------------------------------------
       Total Tax Provision                           58,407           52,409            3,912
- ---------------------------------------------------------------------------------------------
NET INCOME                                      $    99,278      $    83,880      $     4,086
- ---------------------------------------------------------------------------------------------
BASIC EARNINGS PER SHARE                        $      1.75      $      1.63      $       .08
- ---------------------------------------------------------------------------------------------
DILUTED EARNINGS PER SHARE                      $      1.73      $      1.55      $       .08
- ---------------------------------------------------------------------------------------------
WEIGHTED AVERAGE SHARES OUTSTANDING:
   Basic                                             56,872           51,414           50,046
   Diluted                                           57,421           57,223           50,466
- ---------------------------------------------------------------------------------------------
</TABLE>


See accompanying Notes to Consolidated Financial Statements.



                                       31

<PAGE>   34
CONSOLIDATED STATEMENT OF CASH FLOWS     NOBLE AFFILIATES, INC. AND SUBSIDIARIES



<TABLE>
<CAPTION>
                                                                          Year ended December 31,
- -------------------------------------------------------------------------------------------------------
(In thousands)                                                       1997           1996           1995
- -------------------------------------------------------------------------------------------------------
<S>                                                             <C>            <C>            <C>      
CASH FLOWS FROM OPERATING ACTIVITIES:
   Net income                                                   $  99,278      $  83,880      $   4,086
   Adjustments to reconcile net income to net cash
       provided by operating activities:
     Depreciation, depletion and amortization                     300,354        233,604        200,914
     Amortization of undeveloped leasehold costs, net               8,146          5,827          6,465
     (Gain) loss on disposal of assets                            (11,007)        (3,335)        (3,289)
     Noncurrent deferred income taxes                              35,650         38,989          7,642
     Increase in other deferred credits                             5,822         14,409         14,194
     (Increase) decrease in other                                   1,684        (16,296)          (399)
   Changes in working capital, not including cash:
     (Increase) decrease in accounts receivable                    43,484        (89,141)       (29,786)
     (Increase) decrease in other current assets                  (25,053)        10,608          5,151
     Increase (decrease) in accounts payable                      (29,845)        37,536         27,063
     Increase (decrease) in other current liabilities              17,058         64,864          6,879
- -------------------------------------------------------------------------------------------------------
NET CASH PROVIDED BY OPERATING ACTIVITIES                         445,571        380,945        238,920
- -------------------------------------------------------------------------------------------------------
CASH FLOWS FROM INVESTING ACTIVITIES:
   Capital expenditures                                          (326,958)      (257,719)      (255,188)
   Acquisition of Energy Development Corporation                                (768,185)
   Proceeds from sale of property, plant and equipment             54,543         26,758         10,745
- -------------------------------------------------------------------------------------------------------
NET CASH USED IN INVESTING ACTIVITIES                            (272,415)      (999,146)      (244,443)
- -------------------------------------------------------------------------------------------------------
CASH FLOWS FROM FINANCING ACTIVITIES:
   Exercise of stock options                                        2,744          7,851          3,766
   Cash dividends paid                                             (9,100)        (8,311)        (8,006)
   Proceeds from bank borrowings                                                 800,000         30,000
   Repayment of bank debt                                        (549,000)       (99,000)       (30,000)
   Proceeds from issuance of long-term debt                       342,507
- -------------------------------------------------------------------------------------------------------
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES              (212,849)       700,540         (4,240)
- -------------------------------------------------------------------------------------------------------
INCREASE (DECREASE) IN CASH AND SHORT-TERM CASH INVESTMENTS       (39,693)        82,339         (9,763)
CASH AND SHORT-TERM CASH INVESTMENTS AT BEGINNING OF YEAR          94,768         12,429         22,192
- -------------------------------------------------------------------------------------------------------
CASH AND SHORT-TERM CASH INVESTMENTS AT END OF YEAR             $  55,075      $  94,768      $  12,429
- -------------------------------------------------------------------------------------------------------

SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
   Cash paid during the year for:
   Interest (net of amount capitalized)                         $  46,140      $  28,652      $  17,659
   Income taxes                                                 $  32,415      $  11,500      $
</TABLE>


See accompanying Notes to Consolidated Financial Statements.



                                       32

<PAGE>   35
CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY  
                                         NOBLE AFFILIATES, INC. AND SUBSIDIARIES


<TABLE>
<CAPTION>
                                                                            Capital in     Treasury
                                               Common Stock                  Excess of     Stock at       Retained
(In thousands, except shares issued)          Shares Issued       Amount     Par Value        Cost        Earnings
- ------------------------------------------------------------------------------------------------------------------
<S>                                              <C>            <C>           <C>           <C>           <C>     
JANUARY 1, 1995                                  51,537,455     $171,790      $141,911      $(15,418)     $113,783
- ------------------------------------------------------------------------------------------------------------------
Net Income                                                                                                   4,086
Exercise of stock options                           185,192          617         3,148
Cash dividends ($ .16 per share)                                                                            (8,006)
- ------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1995                                51,722,647     $172,407      $145,059      $(15,418)     $109,863
- ------------------------------------------------------------------------------------------------------------------
Net Income                                                                                                  83,880
Exercise of stock options                           323,140        1,077         6,774
Redemption of convertible notes                   6,275,510       20,918       203,818
Cash dividends ($ .16 per share)                                                                            (8,311)
- ------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1996                                58,321,297     $194,402      $355,651      $(15,418)     $185,432
- ------------------------------------------------------------------------------------------------------------------
Net Income                                                                                                  99,278
Exercise of stock options                           102,141          341         2,403
Cash dividends ($.16 per share)                                                                             (9,100)
- ------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1997                                58,423,438     $194,743      $358,054      $(15,418)     $275,610
- ------------------------------------------------------------------------------------------------------------------
</TABLE>


See accompanying Notes to Consolidated Financial Statements.



                                       33

<PAGE>   36





                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
             (Dollar amounts in tables, unless otherwise indicated,
                  are in thousands, except per share amounts)

NOTE 1 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

CONSOLIDATION

         The consolidated accounts include Noble Affiliates, Inc. (the
"Company") and the consolidated accounts of its wholly owned subsidiaries: Noble
Gas Marketing, Inc. ("NGM"); Noble Trading, Inc. ("NTI"); NPM, Inc.; and Samedan
Oil Corporation ("Samedan"). Listed below are consolidated entities at December
31, 1997.

     NOBLE AFFILIATES, INC.
         Noble Gas Marketing, Inc.
              Noble Gas Pipeline, Inc.
         Noble Trading, Inc.
         NPM, Inc.
         Samedan Oil Corporation
              Samedan Oil of Canada, Inc.
              Samedan of North Africa, Inc.
                  Samedan LPG
                      Samedan Methanol
              Samedan Pipe Line Corporation
              Samedan Royalty Corporation
              Samedan of Tunisia, Inc.
              Energy Development Corporation ("EDC")
                  Brabant Petroleum Limited
                  EDC Argentina, Inc.
                  EDC Australia, Ltd.
                  EDC China, Inc.
                  EDC Ecuador Ltd.
                  EDC HIPS, Inc.
                  EDC Portugal Ltd.
                  EDC Senegal Ltd.
                  Gasdel Pipeline System Incorporated
                  HGC, Inc.
                  Producers Service, Inc.

NATURE OF OPERATIONS

         The Company is principally engaged, through its subsidiaries, in the
exploration, development, production and marketing of oil and gas. Samedan
operates throughout the major basins in the United States, including the Gulf of
Mexico, as well as international operations with production in Argentina,
Equatorial Guinea and the U.K. Sector of the North Sea. The Company markets its
oil and gas production through NGM, NTI and Samedan.

USE OF ESTIMATES

         The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities. Such
estimates and assumptions also affect the disclosure of contingent assets and
liabilities at the date of the financial statements as well as amounts of
revenues and expenses recognized during the reporting period. Of the estimates
and assumptions that affect reported results, the estimate of the Company's oil
and gas reserves is the most significant.



                                       34

<PAGE>   37



FOREIGN CURRENCY TRANSLATION

The U.S. dollar is considered the functional currency for each of the Company's
international operations with the exception of Canada. The functional currency
for Canada is the Canadian dollar which has been translated into U.S. dollars
for the financial statements. Translation gains or losses were not material in
any of the periods presented.

INVENTORIES

          Materials and supplies inventories, consisting principally of tubular
goods and production equipment, are stated at the lower of cost or market, with
cost being determined by the first-in, first-out method.

PROPERTY, PLANT AND EQUIPMENT

         The Company accounts for its oil and gas properties under the
successful efforts method of accounting. Under this method, costs to acquire
mineral interests in oil and gas properties, to drill and equip exploratory
wells that find proved reserves and to drill and equip development wells are
capitalized. Capitalized costs of producing oil and gas properties are amortized
to operations by the unit-of-production method based on proved developed oil and
gas reserves on a property by property basis as estimated by Company engineers.
Estimated future restoration and abandonment costs are recorded by charges to
depreciation, depletion and amortization ("DD&A") expense over the productive
lives of the related properties. The Company has provided $59.5 million for such
future costs classified with accumulated DD&A in the balance sheet. The total
estimated future dismantlement and restoration costs of $143.9 million are
included in future production and development costs for purposes of estimating
the future net revenues relating to the Company's proved reserves. Upon sale or
retirement of depreciable or depletable property, the cost and related
accumulated DD&A are eliminated from the accounts and the resulting gain or loss
is recognized.

         Undeveloped oil and gas properties, which are individually significant,
are periodically assessed for impairment of value and a loss is recognized at
the time of impairment by providing an impairment allowance. Other undeveloped
properties are amortized on a composite method based on the Company's experience
of successful drilling and average holding period. Geological and geophysical
costs, delay rentals and costs to drill exploratory wells which do not find
proved reserves are expensed. Repairs and maintenance are charged to expense as
incurred.

         Developed oil and gas properties and other long-lived assets are
periodically assessed to determine if circumstances indicate that the carrying
amount of an asset may not be recoverable. The Company performs this review of
recoverability by estimating future cash flows. If the sum of the expected
future cash flows is less than the carrying amount of the asset, an impairment
is recognized based on the discounted amount of such cash flows.

INCOME TAXES

         The Company files a consolidated federal income tax return. Deferred
income taxes are provided for temporary differences between the financial
reporting and tax bases of the Company's assets and liabilities.

BASIC EARNINGS PER SHARE AND DILUTED EARNINGS PER SHARE

         The Financial Accounting Standards Board issued Statement of Financial
Accounting Standards ("SFAS") No. 128 "Earnings per Share" in February 1997. The
Company adopted disclosure requirements of SFAS No. 128 during 1997 and restated
all previously presented financial statements in conformity with SFAS No. 128.
Basic income per share of common stock has been computed on the basis of the
weighted average number of shares outstanding during each period. The diluted
net income per share of common stock includes the effect of outstanding stock
options and the dilutive effect of the convertible subordinated notes, which
were converted on November 1, 1996.



                                       35

<PAGE>   38



         The following table summarizes the calculation of basic earnings per
share ("EPS") and diluted EPS as of December 31:



<TABLE>
<CAPTION>
                                           1997                          1996                          1995
                            ------------------------------   --------------------------   ---------------------------
                                    Income          Shares        Income         Shares        Income          Shares
(shares in thousands)          (Numerator)   (Denominator)   (Numerator)  (Denominator)   (Numerator)   (Denominator)
- ---------------------------------------------------------------------------------------------------------------------
<S>                                <C>       <C>    <C>          <C>      <C>    <C>           <C>      <C>    <C>
Net income/shares                  $99,278          56,872       $83,880         51,414        $4,086          50,046
- ---------------------------------------------------------------------------------------------------------------------
BASIC EPS                                    $1.75                        $1.63                         $.08
- ---------------------------------------------------------------------------------------------------------------------

Net income/shares                  $99,278          56,872       $83,880         51,414        $4,086          50,046
Effect of Diluted Securities
   Stock options                                       549                          556                           420
   4 1/4% Convertible
   Subordinated Notes (1)                                          4,692          5,253
                            -----------------------------------------------------------------------------------------
Adjusted net income
   and shares                      $99,278          57,421       $88,572         57,223        $4,086          50,466
- ---------------------------------------------------------------------------------------------------------------------
DILUTED EPS                                  $1.73                        $1.55                         $.08
- ---------------------------------------------------------------------------------------------------------------------
</TABLE>


         (1)  In 1995, the 4 1/4% Convertible Subordinated Notes were
              anti-dilutive and were converted on November 1, 1996.

CAPITALIZATION OF INTEREST

         The Company capitalizes interest costs associated with the acquisition
or construction of significant oil and gas properties.

STATEMENT OF CASH FLOWS

         For purposes of reporting cash flows, cash and short-term cash
investments include cash on hand and investments purchased with original
maturities of three months or less.

REVENUE RECOGNITION AND GAS IMBALANCES

         Samedan and EDC have a gas sales contract with NGM, whereby Samedan and
EDC are paid an index price for all gas sold to NGM.

         NGM records sales, including hedging transactions, as gathering,
marketing and processing revenues. NGM records as cost of sales in gathering,
marketing and processing costs, the amount paid to Samedan, EDC and third
parties. All intercompany sales and costs have been eliminated.

         The Company follows an entitlements method of accounting for its gas
imbalances. Gas imbalances occur when the Company sells more or less gas than
its entitled ownership percentage of total gas production. Any excess amount
received above the Company's share is treated as a liability. If less than the
Company's entitlement is received, the underproduction is recorded as a
receivable. The Company records the noncurrent liability in Other Deferred
Credits and Noncurrent Liabilities, and the current liability in Other Current
Liabilities. The Company's gas imbalance liabilities were $21.6 million and
$21.7 million for 1997 and 1996, respectively. The Company records the
noncurrent receivable in Other Assets, and the current receivable in Other
Current Assets. The Company's gas imbalance receivables were $18.5 million and
$19.3 million for 1997 and 1996, respectively, and are valued at the amount
which is expected to be received.



                                       36

<PAGE>   39



TAKE-OR-PAY SETTLEMENTS

         The Company records gas contract settlements which are not subject to
recoupment in Other Income when the settlement is received.

TRADING AND HEDGING ACTIVITIES

         The Company, through its subsidiaries, from time to time, uses various
hedging arrangements in connection with anticipated crude oil and natural gas
sales of its production to minimize the impact of product price fluctuations.
Such arrangements include fixed price hedges, costless collars and other
contractual arrangements. Although these hedging arrangements expose the Company
to credit risk, the Company monitors the creditworthiness of its counterparties,
which generally are major institutions, and believes that losses from
nonperformance are unlikely to occur. Hedging gains and losses related to the
Company's oil and gas production are recorded in oil and gas sales and
royalties.

         During 1997, the Company had natural gas hedging contracts that ranged
from 20 percent to 32 percent of its average daily natural gas production.
Natural gas hedges were in the price range of $1.88 to $3.30 per million British
Thermal Units ("MMBTU"). The net effect of these 1997 hedges was a $.12 per
thousand cubic feet ("MCF") reduction in the average natural gas price realized
by the Company. At December 31, 1997, the Company had no natural gas hedging
contracts.

         During 1997, the Company had crude oil hedging contracts that ranged
from 19 percent to 50 percent of its average daily oil production. Crude oil
hedges were in the price range of $16.81 to $24.35 per barrel ("BBL"). The net
effect of these 1997 hedges was a $.19 per BBL reduction in the average crude
oil price realized by the Company. At December 31, 1997, the Company had no
crude oil hedging contracts.

         During 1996, the Company had natural gas hedging contracts that ranged
from 39 percent to 86 percent of its average daily natural gas production.
Natural gas hedges were in the price range of $1.60 to $3.59 per MMBTU. The net
effect of these 1996 hedges was a $.33 per MCF reduction in the average natural
gas price. At December 31, 1996, the Company was a party to natural gas hedging
contracts to hedge approximately 21 percent of its estimated 1997 average daily
natural gas production at an average price per MMBTU of $2.20.

         During 1996, the Company had crude oil hedging contracts that ranged
from 48 percent to 55 percent of its average daily oil production for January
through July and 62 percent to 100 percent of its average daily oil production
for August through December. Crude oil hedges were in the price range of $16.50
to $24.27 per BBL. The net effect of these 1996 hedges was a $2.35 per BBL
reduction in the average crude oil price. At December 31, 1996, the Company was
a party to crude oil hedging contracts to hedge approximately 26 percent of its
estimated 1997 annual crude oil production at an average price per BBL of
$20.48.

         During 1995, Samedan had natural gas hedging contracts for November and
December to hedge from 20 percent to 46 percent of its average daily natural gas
production. For May to December 1995, Samedan had hedged approximately 20
percent of its daily crude oil production. Natural gas hedges were in the range
of $1.60 to $1.96 per MMBTU and crude oil hedges were in the range of $18.56 to
$20.27 per BBL. The net effect of these 1995 hedges was a $.004 per MCF
reduction in the average natural gas price and a $.16 per BBL increase in the
average crude oil price realized by the Company.

         In addition to the hedging arrangements pertaining to the Company's
production as described above, NGM employs various hedging arrangements in
connection with its purchases and sales of third party production to lock in
profits or limit exposure to gas price risk. Most of the purchases made by NGM
are on an index basis; however, purchasers in the markets in which NGM sells
often require fixed or New York Mercantile Exchange ("NYMEX") related pricing.
NGM may use a hedge to convert the fixed or NYMEX sale to an index basis thereby
determining the 


                                       37

<PAGE>   40

margin and minimizing the risk of price volatility. During 1997, NGM had hedging
transactions with broker-dealers that ranged from 317,693 MMBTU's to 768,599
MMBTU's of gas per day.

         At December 31, 1997, NGM had in place hedges ranging from
approximately 645 MMBTU's to 29,279 MMBTU's of gas per day for January 1998 to
March 1999 for future physical transactions. At December 31, 1996, NGM had in
place hedges ranging from approximately 7,475 MMBTU's to 551,126 MMBTU's of gas
per day for January 1997 to March 1998 for future physical transactions. During
1995, NGM had hedging transactions with large financial institutions that
averaged approximately 126,000 MMBTU's of gas per day at prices linked to
certain indices. NGM records hedging gains or losses relating to fixed term
sales as gathering, marketing and processing revenues in the periods in which
the related contract is completed.

SELF-INSURANCE

The Company self-insures the medical and dental coverage provided to certain of
its employees, certain workers' compensation and the first $200,000 of its
general liability coverage.

         A provision for self-insured claims is recorded when sufficient
information is available to reasonably estimate the amount of the loss.

RECLASSIFICATION

         Certain reclassifications have been made to the 1996 and 1995
consolidated financial statements to conform to the 1997 presentation.

RECENTLY ISSUED PRONOUNCEMENTS

         In December 1997, the Financial Accounting Standards Board issued SFAS
No. 130 "Reporting Comprehensive Income" and SFAS No. 131 "Disclosures About
Segments of an Enterprise and Related Information." The Company plans on
adopting both SFAS No. 130 and No. 131 in 1998. The Company anticipates there
will be no material impact associated with the adoption of these standards.

NOTE 2 - DISCLOSURES ABOUT FAIR VALUE OF FINANCIAL INSTRUMENTS

         The following methods and assumptions were used to estimate the fair
value of each class of financial instruments pursuant to the requirements of
SFAS No. 107, "Disclosures about Fair Value of Financial Instruments."

CASH AND SHORT-TERM CASH INVESTMENTS

         The carrying amount approximates fair value due to the short maturity
of the instruments.

OIL AND GAS PRICE HEDGE AGREEMENTS

         The fair value of oil and gas price hedges is the estimated amount the
Company would receive or pay to terminate the hedge agreements at the reporting
date taking into account the creditworthiness of the hedging parties.

LONG-TERM DEBT

         The fair value of the Company's long-term debt is estimated based on
the quoted market prices for the same or similar issues or on the current rates
offered to the Company for debt of the same remaining maturities.



                                       38

<PAGE>   41



         The carrying amounts and estimated fair values of the Company's
financial instruments as of December 31, for each of the years are as follows:


<TABLE>
<CAPTION>
                                                             1997                               1996
                                                ---------------------------        ---------------------------
                                                  Carrying             Fair          Carrying             Fair
                                                    Amount            Value            Amount            Value
- --------------------------------------------------------------------------------------------------------------
<S>                                             <C>              <C>               <C>              <C>       
Cash and short-term cash investments            $   55,075       $   55,075        $   94,768       $   94,768
Oil and gas hedge agreements                                                       $    5,180       $  (26,869)
Long-term debt (including current portion)      $  644,967       $  740,000        $  848,028       $  854,000
</TABLE>


NOTE 3 - DEBT

         A summary of debt at December 31 follows:


<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                <C>                <C>     
$800 million Credit Agreement                                                      $                  $749,000
$300 million Credit Agreement                                                         200,000
7 1/4% Notes Due 2023                                                                 100,000          100,000
8% Senior Notes Due 2027                                                              250,000
7 1/4% Senior Debentures Due 2097                                                     100,000
- --------------------------------------------------------------------------------------------------------------
Outstanding debt                                                                      650,000          849,000
- --------------------------------------------------------------------------------------------------------------
Less: current portion                                                                                   50,000
Less: unamortized discount                                                              5,033              972
- --------------------------------------------------------------------------------------------------------------
Long-term debt                                                                     $  644,967         $798,028
- --------------------------------------------------------------------------------------------------------------
</TABLE>


         Total long-term debt at December 31, 1997, was $645 million compared to
$848 million (including current portion) at December 31, 1996, a decrease of 24
percent. The ratio of debt to book capital (defined as the Company's debt plus
its equity) was 44 percent at December 31, 1997, compared with 54 percent at
December 31, 1996.

         The $300 million credit agreement is a revolving credit facility with a
group of banks with a final maturity of December 24, 2002. The interest rate
charged, which is based upon a Eurodollar rate plus 22.5 basis points, was 5.9
percent at December 31, 1997. Financial covenants include maintenance of a cash
flow multiple of at least four times interest cost and maintenance of a debt
level which does not exceed 60 percent of the Company's shareholders' equity
plus its debt.

         The $800 million credit agreement was terminated on December 24, 1997,
and the outstanding balance of $200 million was refinanced in the $300 million
credit agreement. The weighted average interest rate on the borrowings during
1997 was 6.9 percent.

         Total long-term debt outstanding at December 31, 1997, included $100
million of 7 1/4% Notes Due 2023, $250 million of 8% Senior Notes Due 2027, and
$100 million of 7 1/4 % Senior Debentures Due 2097.

         The only principal payment on long-term debt due during the next five
years is the outstanding balance of the $300 million credit agreement on
December 24, 2002.

         On November 1, 1996, all of the Company's $230 million 4 1/4%
Convertible Subordinated Notes Due 2003 were converted into 6,275,510 shares of
common stock.



                                       39

<PAGE>   42



NOTE 4 - INCOME TAXES

         The components of income from operations before income taxes for each
year are as follows:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                <C>               <C>             <C>      
Domestic                                                           $159,535          $137,462        $  18,368
Foreign                                                              (1,850)           (1,173)         (10,370)
- --------------------------------------------------------------------------------------------------------------
                                                                   $157,685          $136,289        $   7,998
- --------------------------------------------------------------------------------------------------------------
</TABLE>


The income tax provisions relating to operations for each year consist of the
following:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                 <C>              <C>               <C>     
U.S. current                                                        $22,146          $ 26,425          $(9,309)
U.S. deferred                                                        34,344            17,918           11,327
State current                                                           587               844               65
State deferred                                                         (622)              644              258
Foreign current                                                       2,836             4,107              121
Foreign deferred                                                       (884)            2,471            1,450
- --------------------------------------------------------------------------------------------------------------
                                                                    $58,407          $ 52,409          $ 3,912
- --------------------------------------------------------------------------------------------------------------
</TABLE>




         The following table details the difference between the federal
statutory tax rate and the effective tax rate for the years ended December 31:


<TABLE>
<CAPTION>
(Amounts expressed in percentages)                                     1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                    <C>               <C>              <C> 
Statutory rate                                                         35.0              35.0             35.0
Effect of:
   Percentage depletion                                                 (.1)              (.1)            (1.4)
   State taxes                                                                             .7              2.6
   Foreign taxes                                                         .8               3.1             12.8
   Losses from international operations                                 1.4                .1
   Other, net                                                           (.1)              (.3)             (.1)
- --------------------------------------------------------------------------------------------------------------
Effective rate                                                         37.0              38.5             48.9
- --------------------------------------------------------------------------------------------------------------
</TABLE>




                                       40

<PAGE>   43



         The net current deferred tax asset (liability) in the following table
is classified as Other Current Assets in the Consolidated Balance Sheet at
December 31, 1997 and 1996. The tax effects of temporary differences which gave
rise to deferred tax assets and liabilities as of December 31 were:


<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                               <C>               <C>        
U.S. and State Current Deferred Tax Assets:
   Accrued expenses                                                               $    (2,269)      $     (197)
   Deferred income                                                                      3,127              255
   Deferred hedge                                                                                         (219)
   Minimum tax                                                                                             286
   Allowance for doubtful accounts                                                        496            1,186
   Other                                                                                  903             (111)
- --------------------------------------------------------------------------------------------------------------
   Net current deferred tax asset                                                       2,257            1,200
- --------------------------------------------------------------------------------------------------------------
U.S. and State Non-current Deferred Tax Liabilities:
   Property, plant and equipment, principally due to
    differences in depreciation, amortization, lease
    impairment and abandonments                                                      (138,771)        (100,983)
   Accrued expenses                                                                     4,390            3,454
   Deferred income                                                                      6,351            6,629
   Income tax accruals                                                                 10,688           11,215
   Other                                                                                1,548              423
- --------------------------------------------------------------------------------------------------------------
   Net non-current deferred liability                                                (115,794)         (79,262)
- --------------------------------------------------------------------------------------------------------------
   U.S. and state net deferred tax liability                                         (113,537)         (78,062)
- --------------------------------------------------------------------------------------------------------------
Foreign Deferred Tax Liabilities:
   Property, plant and equipment of
    foreign operations                                                                (28,289)         (25,226)
   Valuation allowance                                                                                  (3,946)
- --------------------------------------------------------------------------------------------------------------
   Deferred tax liability                                                             (28,289)         (29,172)
- --------------------------------------------------------------------------------------------------------------
Total deferred taxes                                                              $  (141,826)      $ (107,234)
- --------------------------------------------------------------------------------------------------------------
</TABLE>


         A valuation allowance of $3.9 million for 1996 related to the Company's
foreign operations was established for the portion of the deferred tax assets
which management believed unlikely to have a tax benefit realized. The valuation
allowance for 1996 was related to Canada and was written off in 1997 due to the
sale of the Company's Canadian assets.

NOTE 5 - COMMON STOCK, STOCK OPTIONS AND STOCKHOLDER RIGHTS

         The Company has two stock option plans, the 1992 Stock Option and
Restricted Stock Plan ("1992 Plan") and the 1988 Non-Employee Director Stock
Option Plan ("1988 Plan"). The Company accounts for these plans under APB
Opinion 25, under which no compensation cost has been recognized in the
accompanying financial statements.

         Under the Company's 1992 Plan, the Board of Directors may grant stock
options and award restricted stock. No restricted stock has been issued under
the 1992 Plan. Since the 1992 Plan's adoption, stock options have been issued at
the market price on the date of grant. The earliest the granted options may be
exercised is over a three year period at the rate of 33 1/3% each year
commencing on the first anniversary of the grant date. The options expire ten
years from the grant date. The 1992 Plan was amended in 1997, with a vote of the
shareholders, to increase the maximum number of shares of common stock that may
be issued under the 1992 Plan to 4,000,000 shares. At December 31, 1997, the
Company had reserved 3,735,166 shares of common stock for issuance, including
1,850,282 shares available for grant under its 1992 Plan.

         The Company's 1988 Plan allows stock options to be issued to certain
non-employee directors at the market price on the date of grant. The options may
be exercised one year after issue and expire ten years from the grant date. The
1988 Plan provides for the grant of options to purchase a maximum of 550,000
shares of the Company's authorized but unissued common stock. At December 31,
1997, the Company had reserved 433,000 shares of common stock for issuance,
including 274,000 shares available for grant under its 1988 Plan.



                                       41

<PAGE>   44



         Stock options outstanding under the plans mentioned above and two
previously terminated plans are presented for the periods indicated.


<TABLE>
<CAPTION>
                                                                                      Number          Option
                                                                                    of Shares       Price Range
- ---------------------------------------------------------------------------------------------------------------
OUTSTANDING DECEMBER 31, 1994                                                       1,429,382     $10.63-$30.00
- ---------------------------------------------------------------------------------------------------------------
<S>                                                                                 <C>           <C>          
  Granted                                                                             357,663     $24.25-$25.50
  Exercised                                                                          (185,192)    $10.63-$27.25
  Canceled                                                                            (18,144)    $16.88-$27.25
- ---------------------------------------------------------------------------------------------------------------
OUTSTANDING DECEMBER 31, 1995                                                       1,583,709     $10.63-$30.00
- ---------------------------------------------------------------------------------------------------------------
  Granted                                                                             376,368     $37.63-$40.38
  Exercised                                                                          (323,140)    $10.63-$27.25
  Canceled                                                                            (34,839)    $16.88-$27.25
- ---------------------------------------------------------------------------------------------------------------
OUTSTANDING DECEMBER 31, 1996                                                       1,602,098     $10.63-$40.38
- ---------------------------------------------------------------------------------------------------------------
  Granted                                                                             707,307     $39.63-$39.88
  Exercised                                                                          (102,141)    $10.63-$40.38
  Canceled                                                                             (1,929)    $24.25-$27.25
- ---------------------------------------------------------------------------------------------------------------
OUTSTANDING DECEMBER 31, 1997                                                       2,205,335     $11.63-$40.38
- ---------------------------------------------------------------------------------------------------------------

EXERCISABLE AT DECEMBER 31, 1997                                                    1,158,175     $11.63-$40.38
- ---------------------------------------------------------------------------------------------------------------
</TABLE>


         The following schedule shows the Company's net income and net income
per share for each of the years ended December 31, had compensation costs been
determined consistent with SFAS No. 123 "Accounting for Stock-Based
Compensation."


<TABLE>
<CAPTION>
                                                                        1997              1996            1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                  <C>               <C>              <C>   
Net Income:
   As Reported                                                       $99,278           $83,880          $4,086
   Pro Forma                                                         $90,874           $82,447          $3,651
Basic Earnings Per Share:
   As Reported                                                       $  1.75          $   1.63          $  .08
   Pro Forma                                                         $  1.60          $   1.60          $  .07
Diluted Earnings Per Share:
   As Reported                                                       $  1.73          $   1.55          $  .08
   Pro Forma                                                         $  1.58          $   1.44          $  .07
</TABLE>


         The SFAS No. 123 method of accounting is not required to be applied to
options granted prior to 1995. The pro forma information presented above is
based on several assumptions and should not be viewed as indicative of the
operations of the Company in future periods.

         The fair value of each option grant is estimated on the date of grant
using the Black-Scholes option pricing model with the following weighted-average
assumptions used for grants in 1997, 1996 and 1995, respectively:


<TABLE>
<CAPTION>
(Amounts expressed in percentages)                                     1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                   <C>               <C>              <C>  
Interest rate                                                          6.03              6.62             6.33
Dividend yield                                                          .40               .40              .66
Expected volatility                                                   32.97             32.89            33.33
</TABLE>


         The weighted average fair value of options granted using the
Black-Scholes option model for 1997, 1996 and 1995, respectively:


<TABLE>
<CAPTION>
(Amounts expressed in dollars)                                         1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                  <C>               <C>              <C>   
Black-Scholes model weighted average fair value
   option price                                                      $18.28            $18.95           $11.05
</TABLE>




                                       42

<PAGE>   45

         The Company adopted a stockholder rights plan on August 27, 1997,
designed to assure that the Company's stockholders receive fair and equal
treatment in the event of any proposed takeover of the Company and to guard
against partial tender offers and other abusive takeover tactics to gain control
of the Company without paying all stockholders a fair price. The rights plan was
not adopted in response to any specific takeover proposal. Under the rights
plan, the Company declared a dividend of one right ("Right") on each share of
Noble Affiliates, Inc. Common Stock. Each Right will entitle the holder to
purchase one one-hundredth of a share of a new Series A Junior Participating
Preferred Stock, par value $1.00 per share, at an exercise price of $150.00. The
Rights are not currently exercisable and will become exercisable only in the
event a person or group acquires beneficial ownership of 15 percent or more of
Noble Affiliates, Inc. Common Stock. The dividend distribution was made on
September 8, 1997, to stockholders of record at the close of business on that
date. The Rights will expire on September 8, 2007.

NOTE 6 - EMPLOYEE BENEFIT PLANS

PENSION PLAN

         The Company has a non-contributory defined benefit pension plan
covering substantially all of its domestic employees. The benefits are based on
an employee's years of service and average earnings for the 60 consecutive
calendar months of highest compensation. The Company also has an unfunded
restoration plan to ensure payments of amounts for which employees are entitled
under the provisions of the pension plan, but which are subject to limitations
imposed by federal tax laws. The Company's funding policy has been to make
annual contributions equal to the actuarially computed liability to the extent
such amounts are deductible for income tax purposes. Plan assets consist
principally of equity securities and fixed income investments.

         The periodic pension expense included the following components for the
years ended December 31:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                               <C>                <C>               <C>    
Service cost-benefits earned in the period                        $   3,003          $  2,212          $ 1,781
Interest cost on projected benefit obligation                         4,078             3,382            3,298
Actual return on plan assets                                        (10,060)           (6,734)          (8,611)
Net amortization and deferral                                         6,917             3,621            5,461
- --------------------------------------------------------------------------------------------------------------
Net pension expense                                               $   3,938          $  2,481          $ 1,929
- --------------------------------------------------------------------------------------------------------------
</TABLE>





                                       43

<PAGE>   46



         The funded status of the Company's pension plans at December 31 was as
follows:


<TABLE>
<CAPTION>
                                                                     1997                         1996
                                                            ----------------------      ----------------------
                                                               Funded     Unfunded         Funded     Unfunded
- --------------------------------------------------------------------------------------------------------------
<S>                                                         <C>          <C>            <C>            <C>    
Actuarial present value of:
    Vested benefit obligation                               $  31,350    $   4,202      $  27,694      $ 3,473
    Accumulated benefit
      obligation                                               35,939        4,586         31,476        3,623
- --------------------------------------------------------------------------------------------------------------
Projected benefit obligation                                   52,134       10,353         42,506        5,074
Plan assets at fair value                                      55,611                      47,921
- --------------------------------------------------------------------------------------------------------------
Plan assets in excess of
    (less than) projected
    benefit obligation                                          3,477      (10,353)         5,415       (5,074)
Unrecognized net (gain) loss                                  (12,486)       4,287        (11,775)          32
Unrecognized net (asset)
    liability at transition                                    (1,721)       3,009         (1,936)       3,248
Unrecognized prior
    service cost                                                2,608          521          2,579          451
- --------------------------------------------------------------------------------------------------------------
Accrued pension cost                                        $  (8,122)   $  (2,536)     $  (5,717)     $(1,343)
- --------------------------------------------------------------------------------------------------------------
</TABLE>


The Company's assumptions as of December 31 in determining the pension cost and
liability for the three years were as follows:



<TABLE>
<CAPTION>
(Amounts expressed in percentages)                                     1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                    <C>               <C>              <C> 
Discount rate                                                          7.25              7.75             7.25
Rates of increase in compensation                                      5.50              5.50             5.50
Long-term rate of return on plan assets                                8.50              8.50             8.50
</TABLE>


EMPLOYEE SAVINGS PLAN

         The Company has an employee savings plan ("ESP") which is a defined
contribution plan. Participation in the ESP is voluntary and all regular
employees of the Company are eligible to participate. The Company may match up
to 100 percent of the participant's contribution not to exceed six percent of
the employee's base compensation. Plan contributions of $1,369,000, $1,053,000
and $895,000 for 1997, 1996 and 1995, respectively, were charged to expense.

OTHER EMPLOYEE PLANS

         The Company sponsors other plans for the benefit of its employees and
retirees. These plans include health care and life insurance benefits. The
accumulated postretirement benefit obligation of these plans was computed using
an assumed discount rate of 7.25, 7.75 and 7.25 percent in 1997, 1996 and 1995,
respectively. The health care cost trend rate was assumed to be nine percent for
1997, declining by one percent for three successive years to six percent in 2000
and 2001, decreasing to five percent for 2002 and remaining at that rate
thereafter.

         If the health care cost trend rate was increased one percent for all
future years, the accumulated postretirement benefit obligation as of December
31, 1997, would have increased approximately $352,000. The effect of this change
on the aggregate of service and interest cost for 1997 would have been an
increase of approximately $55,000.



                                       44

<PAGE>   47



         Net postretirement benefit cost included the following components for
the years ended December 31:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                    <C>               <C>              <C> 
Service cost-benefits earned in the period                             $210              $180             $140
Interest cost-accumulated benefit obligation                            154               143              123
Net loss amortization                                                    14                27               12
- --------------------------------------------------------------------------------------------------------------
Net postretirement benefit cost                                        $378              $350             $275
- --------------------------------------------------------------------------------------------------------------
</TABLE>


         The plan's postretirement benefit obligation at December 31 was as
follows:


<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                  <C>               <C>     
Accumulated postretirement benefit obligation:
  Retirees                                                                           $   (143)         $  (357)
  Fully eligible active employees                                                        (272)            (377)
  Active employees, not fully eligible                                                 (1,969)          (1,418)
- --------------------------------------------------------------------------------------------------------------
Total participants                                                                     (2,384)          (2,152)
Plan assets
- --------------------------------------------------------------------------------------------------------------
Funded status                                                                          (2,384)          (2,152)
Unrecognized net loss                                                                     455              554
- --------------------------------------------------------------------------------------------------------------
Accrued postretirement benefit obligation                                            $ (1,929)         $(1,598)
- --------------------------------------------------------------------------------------------------------------
</TABLE>



NOTE 7 - EDC ACQUISITION

         On July 31, 1996, Samedan acquired all the outstanding shares of common
stock of EDC for $768 million. The acquisition has been accounted for using the
purchase method of accounting. Accordingly, the purchase price has been
allocated to EDC's assets and liabilities based on fair values at the date of
the acquisition.

         The operating results of EDC have been included in the Consolidated
Statement of Operations from the date of the acquisition. The pro forma
information includes adjustments for interest expense that would have been
incurred to finance the acquisition, additional depreciation, depletion and
amortization based on the fair value of EDC's property, plant and equipment and
expected savings from the termination of certain EDC employees and facilities
consolidation.

         The following information has been prepared assuming the acquisition
had taken place at the beginning of 1996 and 1995:


<TABLE>
<CAPTION>
                                                                                           Pro Forma
                                                                             -----------------------------------
(unaudited)                                                                         1996                    1995
- ----------------------------------------------------------------------------------------------------------------
<S>                                                                          <C>                        <C>
Revenues                                                                     $ 1,103,334                $842,757
Net income                                                                   $    74,082                $     73
Basic earnings per share                                                     $      1.44                $   0.00
Diluted earnings per share                                                   $      1.29                $   0.00
</TABLE>


         The pro forma information presented above is based on several
assumptions and should not be viewed as indicative of the operations of the
Company in future periods.



                                       45

<PAGE>   48



NOTE 8 - ADDITIONAL BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION

         Included in accounts receivable-trade is an allowance for doubtful
accounts at December 31 of the following:


<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                   <C>               <C>   
Allowance for doubtful accounts                                                       $ 1,401           $3,083
</TABLE>


         Other current assets at December 31 include the following:


<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                   <C>               <C>
Deferred hedges                                                                       $                 $1,684
Deferred tax asset                                                                    $ 2,257           $1,200
</TABLE>


         Other current liabilities at December 31 include the following:



<TABLE>
<CAPTION>
                                                                                         1997             1996
- --------------------------------------------------------------------------------------------------------------
<S>                                                                                    <C>              <C>   
Gas imbalance liabilities                                                              $4,153           $3,583
</TABLE>


         Oil and gas operations expense included the following for the years
ended December 31:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                               <C>               <C>                <C>    
Lease operating expense                                           $ 151,712         $ 116,692          $78,959
Production taxes                                                  $  11,947         $  10,108          $ 3,426
</TABLE>


         Oil and gas exploration expense included the following for the years
ended December 31:


<TABLE>
<CAPTION>
                                                                       1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                 <C>              <C>               <C>    
Dry hole expense                                                    $46,902          $ 32,762          $17,608
Undeveloped lease amortization                                      $ 8,146          $  5,827          $ 6,465
Abandoned assets                                                    $ 4,923          $    545          $   483
Seismic                                                             $19,095          $ 11,885          $ 8,358
</TABLE>


         During the past three years, there was no purchaser that accounted for
more than ten percent of total oil and gas sales and royalties.

NOTE 9 - IMPAIRMENT OF LONG-LIVED ASSETS

         In March 1995, the Financial Accounting Standards Board issued SFAS No.
121, "Accounting for the Impairment of Long-Lived Assets and for Long-Lived
Assets to Be Disposed Of." The Company adopted SFAS No. 121 during the fourth
quarter of 1995.

         The assets impaired under SFAS No. 121 are oil and gas properties
maintained under the successful efforts method of accounting. The excess of the
net book value over the projected discounted future net revenue of the impaired
properties was charged to DD&A expense. The Company recognized a $59.5 million
SFAS No. 121 impairment for 1995. This impairment included $3.2 million in
Tunisia, $4.1 million in Canada, $18.4 million onshore U.S., and $33.8 million
offshore Gulf of Mexico properties.

         The Company recorded no asset impairment under SFAS No. 121 for its
properties during 1997 and 1996.



                                       46

<PAGE>   49



                      SUPPLEMENTAL OIL AND GAS INFORMATION
                                   (Unaudited)

PROVED OIL AND GAS RESERVES (Unaudited)

         The following reserve schedule was developed by the Company's reserve
engineers and set forth the changes in estimated quantities of proved oil and
gas reserves of the Company during each of the three years presented.



<TABLE>
<CAPTION>
                                                Natural Gas and                           Crude Oil & Condensate
                                              Casinghead Gas (MMCF)                         (BBLS in thousands)
                                     ---------------------------------------     --------------------------------------
PROVED RESERVES AS OF:               United States International(1)    TOTAL     United States  International(1)  TOTAL
- -----------------------------------------------------------------------------------------------------------------------
<S>                                    <C>            <C>          <C>              <C>           <C>           <C>    
DECEMBER 31, 1994                        744,245       34,705        778,950        65,536         9,991         75,527
- -----------------------------------------------------------------------------------------------------------------------
Revisions of previous estimates          (35,728)      (4,776)       (40,504)          247          (517)          (270)
Extensions, discoveries and
   other additions                       143,589        6,558        150,147        12,270         3,658         15,928
Production                               (94,038)      (2,946)       (96,984)       (8,175)       (1,405)        (9,580)
Sale of minerals in place                 (2,424)      (3,489)        (5,913)         (115)           (6)          (121)
Purchase of minerals in place             62,657        1,986         64,643         1,144         1,380          2,524
- -----------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1995                        818,301       32,038        850,339        70,907        13,101         84,008
- -----------------------------------------------------------------------------------------------------------------------
Revisions of previous estimates          (30,618)      (2,792)       (33,410)         (187)          731            544
Extensions, discoveries and
   other additions                       127,399        9,825        137,224         7,701         2,507         10,208
Production                              (162,996)      (5,104)      (168,100)      (10,785)       (2,287)       (13,072)
Sale of minerals in place                (49,851)      (4,286)       (54,137)       (1,239)         (216)        (1,455)
Purchase of minerals in place            377,372       46,962        424,334        15,920        19,594         35,514
- -----------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1996                      1,079,607       76,643      1,156,250        82,317        33,430        115,747
- -----------------------------------------------------------------------------------------------------------------------
Revisions of previous estimates           (1,228)      (1,110)        (2,338)        1,516           865          2,381
Extensions discoveries and
   other additions                       226,546      329,230        555,776        16,501        15,211         31,712
Production                              (195,085)      (7,551)      (202,636)      (11,450)       (3,024)       (14,474)
Sale of minerals in place                 (6,934)     (22,299)       (29,233)         (184)       (4,797)        (4,981)
Purchase of minerals in place              4,252          144          4,396           365           113            478
- -----------------------------------------------------------------------------------------------------------------------
DECEMBER 31, 1997                      1,107,158      375,057      1,482,215        89,065        41,798        130,863
- -----------------------------------------------------------------------------------------------------------------------
</TABLE>


         (1) The December 31, 1997, proved reserves for the Company's
international operations are detailed as follows:


<TABLE>
<CAPTION>
              Proved Reserves              Equatorial Guinea       Argentina          United Kingdom          Total
              -----------------------------------------------------------------------------------------------------
              <S>                              <C>                    <C>                  <C>              <C>    
              Oil (thousand BBLS)               22,767               11,997                 7,034            41,798
              Gas (MMCF)                       322,204                5,565                47,288           375,057
</TABLE>


         Proved Reserves. Proved reserves are estimated quantities of crude oil,
natural gas and natural gas liquids which geological and engineering data
demonstrate with reasonable certainty to be recoverable in future years from
known reservoirs under existing economic and operating conditions.

         There are numerous uncertainties inherent in estimating quantities of
proved oil and gas reserves. Oil and gas reserve engineering is a subjective
process of estimating underground accumulations of oil and gas that cannot be
precisely measured, and estimates of engineers other than Samedan's might differ
materially from the estimates set forth herein. The accuracy of any reserve
estimate is a function of the quality of available data and of engineering and
geological interpretation and judgment. Results of drilling, testing and
production subsequent to the date of the estimate may justify revision of such
estimate. Accordingly, reserve estimates are often different from the quantities
of oil and gas that are ultimately recovered.



                                       47

<PAGE>   50



PROVED DEVELOPED OIL AND GAS RESERVES (Unaudited)

         The following reserve schedule was developed by the Company's reserve
engineers and set forth the changes in estimated quantities of proved developed
oil and gas reserves of the Company presented as of the beginning of each year.


<TABLE>
<CAPTION>
                                                Natural Gas and                           Crude Oil & Condensate
                                              Casinghead Gas (MMCF)                         (BBLS in thousands)
                                     ---------------------------------------     --------------------------------------
PROVED DEVELOPED RESERVES:           United States International(1)    TOTAL     United States  International(1)  TOTAL
- -----------------------------------------------------------------------------------------------------------------------
<S>                                    <C>             <C>         <C>              <C>           <C>           <C>    
   January 1, 1995                       658,228       34,705        692,933        63,013         8,305         71,318
   January 1, 1996                       750,753       32,036        782,789        67,368        11,667         79,035
   January 1, 1997                     1,010,837       50,258      1,061,095        78,564        29,334        107,898
   January 1, 1998                     1,022,192       66,279      1,088,471        82,713        29,422        112,135
</TABLE>


         Proved Developed Reserves. Proved developed reserves are proved
reserves which are expected to be recovered through existing wells with existing
equipment and operating methods.


COSTS INCURRED IN OIL AND GAS ACTIVITIES (Unaudited)

         Costs incurred in connection with the Company's oil and gas
acquisition, exploration and development activities during the year are shown
below. Amounts are presented in accordance with SFAS No. 19, and may not agree
with amounts determined using traditional industry definitions.


<TABLE>
<CAPTION>
                                   1997                               1996                            1995
                    -------------------------------  --------------------------------  ------------------------------
                         U.S.     Int'l      TOTAL        U.S.       Int'l      TOTAL       U.S.     Int'l      TOTAL
- ---------------------------------------------------------------------------------------------------------------------
<S>                 <C>        <C>       <C>         <C>         <C>        <C>        <C>        <C>       <C>      
Property acquisition
    costs:
  Proved            $   3,884  $     28  $   3,912   $ 541,363   $ 146,052  $ 687,415  $  36,728  $  6,932  $  43,660
  Unproved             16,668     3,178     19,846      24,672      21,737     46,409      8,209     1,096      9,305
- ---------------------------------------------------------------------------------------------------------------------
Total               $  20,552  $  3,206  $  23,758   $ 566,035   $ 167,789  $ 733,824  $  44,937  $  8,028  $  52,965
- ---------------------------------------------------------------------------------------------------------------------
Exploration
    costs           $  81,141  $ 36,023  $ 117,164   $  81,018   $   9,981  $  90,999  $  39,008  $ 11,586  $  50,594
- ---------------------------------------------------------------------------------------------------------------------
Development
    costs           $ 201,788  $ 14,180  $ 215,968   $ 176,419   $   7,886  $ 184,305  $ 159,405  $  2,981  $ 162,386
- ---------------------------------------------------------------------------------------------------------------------
</TABLE>


AGGREGATE CAPITALIZED COSTS (Unaudited)

         Aggregate capitalized costs relating to the Company's oil and gas
producing activities, and related accumulated DD&A, as of December 31:


<TABLE>
<CAPTION>
                                                          1997                                  1996
                                      -------------------------------------  --------------------------------------
                                             U. S.       Int'l        TOTAL        U. S.        Int'l         TOTAL
- -------------------------------------------------------------------------------------------------------------------
<S>                                   <C>            <C>        <C>          <C>             <C>        <C>        
Unproved oil and gas properties       $     57,666   $   7,190  $    64,856  $    49,380     $ 26,591   $    75,971
Proved oil and gas properties            2,473,989     227,896    2,701,885    2,242,325      218,228     2,460,553
- -------------------------------------------------------------------------------------------------------------------
                                         2,531,655     235,086    2,766,741    2,291,705      244,819     2,536,524
Accumulated DD&A                        (1,201,446)    (36,338)  (1,237,784)    (943,055)     (33,778)     (976,833)
- ------------------------------------------------------------------------------------------------------ ------------ 
Net capitalized costs                 $  1,330,209   $ 198,748   $1,528,957   $1,348,650     $211,041    $1,559,691
- -------------------------------------------------------------------------------------------------------------------
</TABLE>




                                       48

<PAGE>   51



OIL AND GAS OPERATIONS (Unaudited)

         Aggregate results of operations for each period ended December 31, in
connection with the Company's oil and gas producing activities are shown below.


<TABLE>
<CAPTION>
                                      1997                            1996                            1995
                         -----------------------------  ------------------------------  ------------------------------
                             U.S.     Int'l      TOTAL       U.S.     Int'l      TOTAL       U.S.     Int'l      TOTAL
- ----------------------------------------------------------------------------------------------------------------------
<S>                      <C>        <C>       <C>        <C>        <C>       <C>        <C>        <C>       <C>     
Revenues                 $696,882   $64,263   $761,145   $548,488   $56,100   $604,588   $301,710   $26,424   $328,134
Production costs          164,441    22,153    186,594    118,387    20,737    139,124     74,911     7,473     82,384
Exploration
   expenses                56,177    24,555     80,732     43,844    15,473     59,317     40,971    12,262     53,233
DD&A and valuation
   provision              280,862    21,967    302,829    222,426    13,767    236,193    191,227    13,115    204,342*
- ----------------------------------------------------------------------------------------------------------------------
Income (loss)             195,402    (4,412)   190,990    163,831     6,123    169,954     (5,399)   (6,426)   (11,825)
Income tax
   expense (benefit)       67,934      (183)    67,751     57,873     4,850     62,723     (2,046)   (2,296)    (4,342)
- ---------------------------------------------------------------------------------------------------------------------- 
Results of operations
   from producing
   activities (excluding
   corporate overhead
   and interest costs)   $127,468   $(4,229)  $123,239   $105,958   $ 1,273   $107,231  $  (3,353) $ (4,130)  $(7,483)
- ------------------------------------------------------------------------------------------------------------- -------- 
</TABLE>


    *Includes $59.5 million of additional DD&A as a result of adoption of SFAS 
     No. 121.


STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS RELATING TO PROVED OIL
AND GAS RESERVES (Unaudited)

         The following information is based on the Company's best estimate of
the required data for the Standardized Measure of Discounted Future Net Cash
Flows as of December 31, 1997, 1996 and 1995 as required by Financial Accounting
Standards Board's Statement of Financial Accounting Standards No. 69. The
Standard requires the use of a 10 percent discount rate. This information is not
the fair market value nor does it represent the expected present value of future
cash flows of the Company's proved oil and gas reserves.


<TABLE>
<CAPTION>
                                      1997                           1996                          1995
                        ----------------------------   --------------------------------   ---------------------------
(in millions of dollars)   U.S.       Int'l    TOTAL      U.S.         Int'l     TOTAL       U.S.      Int'l    TOTAL
- ---------------------------------------------------------------------------------------------------------------------
<S>                      <C>         <C>      <C>      <C>            <C>       <C>        <C>        <C>     <C>    
Future cash inflows      $4,330      $ 953    $5,283   $ 6,013        $878      $6,891     $3,610     $ 277   $ 3,887
Future production and
  development costs       2,040        330     2,370     2,078         361       2,439      1,055        58     1,113
Future income tax
  expenses                  612        166       778     1,078         147       1,225        709        61       770
- ---------------------------------------------------------------------------------------------------------------------
Future net cash flows     1,678        457     2,135     2,857         370       3,227      1,846       158     2,004
10% annual discount for
  estimated timing of
  cash flows                615        168       783       890         115       1,005        673        57       730
- ---------------------------------------------------------------------------------------------------------------------
Standardized measure of
  discounted future net
  cash flows             $1,063      $ 289    $1,352   $ 1,967        $255      $2,222     $1,173     $ 101   $ 1,274
- ---------------------------------------------------------------------------------------------------------------------
</TABLE>


         The future net cash inflows for 1997 do not include cash flows relating
to the Company's anticipated future methanol sales. For more information
regarding Samedan's methanol plant, see Item 1. and Item 2. "Business--Oil and
Gas" of this Form 10-K.

         Future cash inflows are computed by applying year-end prices of oil and
gas relating to the Company's proved reserves to the year-end quantities of
those reserves, with consideration given to the effect of existing trading and
hedging contracts if any. The year-end weighted average oil price utilized in
the computation of future cash inflows was approximately $16.22 per BBL.


                                       49

<PAGE>   52

         West Texas intermediate crude oil price in mid February 1998 was
approximately $2.72 per BBL lower than year-end 1997. The Company estimates that
a $1.00 per BBL change in the average oil price from the year-end price would
change discounted future net cash flows before income taxes by approximately $74
million.

         The year-end weighted average gas price utilized in the computation of
future cash inflows was approximately $2.55 per MCF. Natural gas index prices at
Henry Hub have decreased approximately $.33 per MCF in mid February 1998
compared with the year-end index. The Company estimates that a $.10 per MCF
change in the average gas price from the year-end price would change discounted
future net cash flows before income taxes by approximately $83 million.

         Future production and development costs, which include dismantlement
and restoration expense, are computed by estimating the expenditures to be
incurred in developing and producing the Company's proved oil and gas reserves
at the end of the year, based on year-end costs, and assuming continuation of
existing economic conditions.

         Future income tax expenses are computed by applying the appropriate
year-end statutory tax rates to the future pretax net cash flows relating to the
Company's proved oil and gas reserves, less the tax bases of the properties
involved. The future income tax expenses give effect to tax credits and
allowances, but do not reflect the impact of general and administrative costs
and exploration expenses of ongoing operations relating to the Company's proved
oil and gas reserves.

         At December 31, 1997, the Company had estimated gas imbalance
receivables of $18.5 million and estimated liabilities of $21.6 million; at
year-end 1996, $19.3 million in receivables and $21.7 million in liabilities;
and at year-end 1995, $12.3 million in receivables and $11.4 million in
liabilities. Neither the gas imbalance receivables nor liabilities have been
included in the standardized measure of discounted future net cash flows as of
each of the three years ended December 31, 1997, 1996 and 1995.

         Principal changes in the aggregate standardized measure of discounted
future net cash flows attributable to the Company's proved oil and gas reserves
at year end are shown below.


<TABLE>
<CAPTION>
(In millions of dollars)                                               1997              1996             1995
- --------------------------------------------------------------------------------------------------------------
<S>                                                                 <C>               <C>               <C>   
Standardized measure of discounted
  future net cash flows at the beginning
  of the year                                                       $ 2,222           $ 1,274           $  736
Extensions, discoveries and improved
  recovery, less related costs                                          501               256              378
Revisions of previous quantity estimates                                 13               (76)             (53)
Changes in estimated future
  development costs                                                     (15)              (21)             (29)
Purchases/sales of minerals in place                                    (45)            1,043              116
Net changes in prices and production costs                           (1,259)              212              378
Accretion of discount                                                   310               178              103
Sales of oil and gas produced, net of
  production costs                                                     (594)             (475)            (241)
Development costs incurred during
  the period                                                             38                74               67
Net change in income taxes                                              332              (368)            (216)
Change in timing of estimated future
  production, and other                                                (151)              125               35
- --------------------------------------------------------------------------------------------------------------
Standardized measure of discounted
  future net cash flows at the end
  of the year                                                       $ 1,352           $ 2,222           $1,274
- --------------------------------------------------------------------------------------------------------------
</TABLE>




                                       50

<PAGE>   53



INTERIM FINANCIAL INFORMATION (Unaudited)

         Interim financial information for the years ended December 31, 1997 and
1996 are as follows:


<TABLE>
<CAPTION>
                                                                        Quarter Ended
                                                --------------------------------------------------------------
                                                  Mar. 31,         June 30,         Sept. 30,       Dec. 31,(1)
- --------------------------------------------------------------------------------------------------------------
<S>                                             <C>              <C>               <C>              <C>       
1997
Revenues                                        $  322,455       $  236,667        $  234,349       $  323,153
Gross profit
   from operations                              $   74,625       $   32,596        $   34,694       $   62,539
Net income                                      $   38,363       $   13,152        $   15,177       $   32,586
Basic earnings per share                        $      .67       $      .23        $      .27       $      .57
Diluted earnings per share                      $      .67       $      .23        $      .26       $      .57
1996
Revenues                                        $  170,423       $  183,572        $  235,933       $  297,275
Gross profit
   from operations                              $   40,410       $   31,066        $   37,333       $   63,789
Net income                                      $   22,679       $   16,859        $   15,306       $   29,036
Basic earnings per share                        $      .45       $      .33        $      .31       $      .53
Diluted earnings per share                      $      .43       $      .32        $      .29       $      .51
</TABLE>


(1)  During the fourth quarter of 1997 and 1996, DD&A expense increased $5.5
     million and $.8 million, respectively, relating to the cumulative effect of
     oil and gas reserve revisions on the DD&A provision for the preceding three
     quarters.


I
TEM 9.       CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
              FINANCIAL DISCLOSURE.

         Not applicable.



                                       51

<PAGE>   54




                                    PART III


ITEM 10.      DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT.

         The section entitled "Election of Directors" in the Registrant's proxy
statement for the 1998 annual meeting of stockholders sets forth certain
information with respect to the directors of the Registrant and is incorporated
herein by reference. Certain information with respect to the executive officers
of the Registrant is set forth under the caption "Executive Officers of the
Registrant" in Part I of this report.

         The section entitled "Section 16(a) Beneficial Ownership Reporting
Compliance" in the Registrant's proxy statement for the 1998 annual meeting of
stockholders sets forth certain information with respect to compliance with
Section 16(a) of the Securities Exchange Act of 1934, as amended, and is
incorporated herein by reference.


ITEM 11.      EXECUTIVE COMPENSATION.

         The section entitled "Executive Compensation" in the Registrant's proxy
statement for the 1998 annual meeting of stockholders sets forth certain
information with respect to the compensation of management of the Registrant,
and except for the report of the Compensation and Benefits Committee and Stock
Option Committee of the Board of Directors and the information therein under
"Executive Compensation--Performance Graph" is incorporated herein by reference.


ITEM 12.      SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT.

         The sections entitled "Security Ownership of Certain Beneficial Owners"
and "Security Ownership of Directors and Executive Officers" in the Registrant's
proxy statement for the 1998 annual meeting of stockholders set forth certain
information with respect to the ownership of the Registrant's common stock and
are incorporated herein by reference.


ITEM 13.      CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS.

         The section entitled "Certain Transactions" in the Registrant's proxy
statement for the 1998 annual meeting of stockholders sets forth certain
information with respect to certain relationships and related transactions, and
is incorporated herein by reference.



                                       52

<PAGE>   55




                                     PART IV


ITEM 14.    FINANCIAL STATEMENT SCHEDULES, EXHIBITS AND REPORTS ON FORM 8-K.

       (a)  The following documents are filed as a part of this report:

            (1) Financial Statements and Financial Statement Schedules: These
            documents are listed in the Index to Consolidated Financial
            Statements in Item 8 hereof.

            (2) Exhibits: The exhibits required to be filed by this Item 14
            are set forth in the Index to Exhibits accompanying this report.

       (b)  No report on Form 8-K was filed by the Registrant during the quarter
ended December 31, 1997.



                                       53

<PAGE>   56




                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

                                                 NOBLE AFFILIATES, INC..

Date:  March 16, 1998                            By: /s/ William D. Dickson
                                                    ----------------------------
                                                 William D. Dickson,
                                                 Senior Vice President-Finance
                                                 and Treasurer

         Pursuant to the requirements of the Securities Exchange Act of 1934,
this report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the dates indicated.


<TABLE>
<CAPTION>
Signature                                          Capacity in which signed                       Date
- ---------                                          ------------------------                       ----
<S>                                                <C>                                       <C>
/s/ Robert Kelley                                  Chairman of the Board, President,         March 16, 1998
- ------------------------------------               Chief Executive Officer and  
Robert Kelley                                      Director (Principal Executive
                                                   Officer)                     


/s/ William D. Dickson                             Senior Vice President-Finance and         March 16, 1998
- ------------------------------------               Treasurer (Principal Financial Officer)
William D. Dickson                                                                        


/s/ James L. McElvany                              Vice President and Controller             March 16, 1998
- ------------------------------------               (Principal Accounting Officer)
James L. McElvany                                                                


/s/ Alan A. Baker                                  Director                                  March 16, 1998
- ------------------------------------
Alan A. Baker


/s/ Michael A. Cawley                              Director                                  March 16, 1998
- ------------------------------------
Michael A. Cawley


/s/ Edward F. Cox                                  Director                                  March 16, 1998
- ------------------------------------
Edward F. Cox


/s/ James C. Day                                   Director                                  March 16, 1998
- ------------------------------------
James C. Day


/s/ Harold F. Kleinman                             Director                                  March 16, 1998
- ------------------------------------
Harold F. Kleinman


/s/ George J. McLeod                               Director                                  March 16, 1998
- ------------------------------------
George J. McLeod
</TABLE>




                                       54

<PAGE>   57






                                INDEX TO EXHIBITS


<TABLE>
<CAPTION>
Exhibit
Number                                               Exhibit **
- -------                                              -------
<S>      <C>    <C>
3.1      --     Certificate of Incorporation, as amended, of the Registrant as currently in effect (filed as Exhibit 3.2
                to the Registrant's Annual Report on Form 10-K for the year ended December 31, 1987 and incorporated
                herein by reference).

3.2      --     Certificate of Designations of Series A Junior Participating Preferred Stock of the Registrant dated
                August 27, 1997 (filed Exhibit A of Exhibit 4.1 to the Registrant's Registration Statement on Form 8-A
                filed on August 28, 1997 and incorporated herein by reference).

3.3      --     Amendments of Articles III and VI of the Bylaws of the Registrant adopted February 3, 1998.

3.4      --     Composite copy of Bylaws of the Registrant as currently in effect.

4.1      --     Indenture dated as of October 14, 1993 between the Registrant and U.S. Trust Company of Texas,  N.A., as
                Trustee, relating to the Registrant's 7 1/4% Notes Due 2023, including form of the Registrant's 7 1/4%
                Notes Due 2023 (filed as Exhibit 4.1 to the Registrant's Quarterly Report on Form 10-Q for the quarter
                ended September 30, 1993 and incorporated herein by reference).

4.2      --     Indenture relating to Senior Debt Securities dated as of April 1, 1997 between the Registrant and U.S.
                Trust Company of Texas, N.A., as Trustee (filed as Exhibit 4.1 to the  Registrant's Quarterly Report on
                Form 10-Q for the quarter ended March 31, 1997 and incorporated herein by reference).

4.3      --     First Indenture Supplement relating to $250 million of the Registrant's 8% Senior Notes Due 2027 dated
                as of April 1, 1997 between the Registrant and U.S. Trust Company of Texas,  N.A., as Trustee (filed as
                Exhibit 4.2 to the Registrant's Quarterly Report on Form 10-Q for the quarter ended March 31, 1997 and
                incorporated herein by reference).

4.4      --     Second Indenture Supplement, between the Company and U.S. Trust Company of Texas, N.A. as trustee,
                relating to $100 million of the Registrant's 7 1/4% Senior Debentures Due 2097 dated as of August 1,
                1997 (filed as Exhibit 4.1 to the Registrant's Quarterly Report on Form 10-Q for the quarter ended June
                30, 1994 and incorporated herein by reference).

10.1*    --     Samedan Oil Corporation Bonus Plan, as amended and restated on September 24, 1996 (filed as Exhibit 10.1
                to the Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 1996 and
                incorporated herein by reference).

10.2*    --     Restoration of Retirement Income Plan for certain participants in the Noble Affiliates Retirement Plan
                dated September 21, 1994, effective as of May 19, 1994 (filed as Exhibit 10.5 to the Registrant's Annual
                Report on Form 10-K for the year ended December 31, 1994 and incorporated herein by reference).

10.3*    --     Noble Affiliates Thrift Restoration Plan dated May 9, 1994 (filed as Exhibit 10.6 to the Registrant's
                Annual Report on Form 10-K for the fiscal year ended December 31, 1994 and incorporated herein by
                reference).

10.4*    --     Noble Affiliates Restoration Trust dated September 21, 1994,  effective as of October 1, 1994 (filed as
                Exhibit 10.7 to the Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 1994
                and incorporated herein by reference).

10.5*    --     Noble Affiliates, Inc. 1992 Stock Option and Restricted Stock Plan, as amended and restated, dated
                November 2, 1992 (filed as Exhibit 4.1 to the Registrant's Registration Statement on Form S-8
                (Registration No. 33-54084) and incorporated herein by reference).
</TABLE>



                                       55

<PAGE>   58





<TABLE>
<CAPTION>
Exhibit
Number                                               Exhibit **
- -------                                              -------
<S>      <C>    <C>
10.6*    --     1982 Stock Option Plan of the Registrant (filed as Exhibit 4.1 to the Registrant's Registration Statement
                on Form S-8 (Registration No. 2-81590) and incorporated herein by reference).

10.7*    --     Amendment No. 1 to the 1982 Stock Option Plan of the Registrant (filed as Exhibit 4.2 to the
                Registrant's Registration Statement on Form S-8 (Registration No. 2-81590) and incorporated herein by
                reference).

10.8*    --     Amendment No. 2 to the 1982 Stock Option Plan of the Registrant (filed as Exhibit 10.11 to the
                Registrant's Annual Report on Form 10-K for the year ended December 31, 1995 and incorporated  herein by
                reference).

10.9*    --     1978 Non-Qualified Stock Option Plan of the Registrant (filed as Exhibit 1.1 to the Registrant's
                Registration Statement on Form S-8 (Registration No. 2-64600) and incorporated herein by reference).

10.10*   --     1978 Non-Qualified Stock Option Plan of the Registrant, as amended July 27, 1978 (filed as Exhibit 1.2
                to the Registrant's Registration Statement on Form S-8 (Registration No. 2-64600) and incorporated
                herein by reference).

10.11*   --     Amendment No. 2 to the 1978 Non-Qualified Stock Option Plan of the Registrant (filed as Exhibit 10.20 to
                the Registrant's Annual Report on Form 10-K for the year ended December 31, 1993 and incorporated herein
                by reference).

10.12*   --     Amendment No. 3 to the 1978 Non-Qualified Stock Option Plan of the Registrant (filed as Exhibit 10.15 to
                the Registrant's Annual Report on Form 10-K for the year ended December 31, 1995 and incorporated herein
                by reference).

10.13*   --     1988 Nonqualified Stock Option Plan for Non-Employee Directors of the Registrant, as amended and
                restated, effective as of January 30, 1996 (filed as Exhibit 10.13 to the Registrant's Annual Report on
                Form 10-K for the year ended December 31, 1996 and incorporated herein by reference).

10.14*   --     Form of Indemnity Agreement entered into between the Registrant and each of the Registrant's directors
                and bylaw officers (filed as Exhibit 10.18 to the  Registrant's Annual Report of Form 10-K for the year
                ended December 31, 1995 and incorporated herein by reference).

10.15    --     Guaranty of the Registrant dated October 28, 1982, guaranteeing certain obligations of Samedan (filed as
                Exhibit 10.12 to the Registrant's Annual Report on Form 10-K for the year ended December 31, 1993 and
                incorporated herein by reference).

10.16    --     Stock Purchase Agreement dated as of July 1, 1996, between Samedan Oil Corporation and Enterprise
                Diversified Holdings Incorporated (filed as Exhibit 2.1 to the Registrant's Current Report on Form
                8-K (Date of Event: July 31, 1996) dated August 13, 1996 and incorporated herein by reference).

10.17    --     Credit Agreement dated as of July 31, 1996 among the Registrant, as borrower, certain commercial lending
                institutions which are or may become a party thereto, as lenders (filed as Exhibit 10.1 to the
                Registrant's Current Report on Form 8-K (Date of Event: July 31, 1996), filed on August 13, 1996 and
                incorporated herein by reference).

10.18    --     First Amendment to Credit Agreement dated as of October 15, 1996 among the  Registrant, as borrower,
                certain commercial lending institutions which are or may become parties thereto, as lenders, and Union
                Bank of Switzerland, Houston Agency, as agents for the lender (filed as Exhibit 4.2 to the Registrant's
                Registration Statement on Form S-3 (No. 333-14275) and incorporated herein by reference).
</TABLE>




                                       56

<PAGE>   59


<TABLE>
<CAPTION>
Exhibit
Number                                               Exhibit **
- -------                                              -------
<S>      <C>    <C>
10.19*   --     Noble Affiliates, Inc. 1992 Stock Option and Restricted Stock Plan, as amended and restated on December
                10, 1996, subject to the approval of stockholders (filed as Exhibit 10.21 to the Registrant's Annual
                Report on Form 10-K for the year ended December 31, 1996 and incorporated herein by reference).

10.20    --     Amended and Restated Credit Agreement dated as of December 24, 1997 among the Registrant, as borrower,
                and Union Bank of Switzerland, Houston agency, as the agent for the lender, and NationsBank of Texas,
                N.A. and Texas Commerce Bank National Association, as managing agents, and Bank of Montreal, CIBC Inc.,
                The First National Bank of Chicago, Royal Bank of Canada, and Societe Generale, Southwest agency, as
                co-agents, and certain commercial lending institutions, as lenders.

21       --     Subsidiaries.

23       --     Consent of Arthur Andersen LLP.

27       --     Financial Data Schedule.
</TABLE>


- ------------------

         *   Management contract or compensatory plan or arrangement required to
             be filed as an exhibit hereto.

         **  Copies of exhibits will be furnished upon prepayment of 25 cents
             per page. Requests should be addressed to the Senior Vice President
             - Finance and Treasurer, Noble Affiliates, Inc., Post Office Box
             1967, Ardmore, Oklahoma 73402.




                                       57





<PAGE>   1

                                                                     EXHIBIT 3.3

                                 AMENDED BY-LAWS
                                       OF
                             NOBLE AFFILIATES, INC.

                                   ARTICLE III

                               DIRECTORS (Cont'd)

                             COMMITTEES OF DIRECTORS

         Section 10. The Board of Directors may designate one or more
committees, each committee to consist of one or more of the regular Directors of
the Corporation. The Board may designate one or more regular Directors as
alternate members of any committee, who may replace any absent or disqualified
member at any meeting of the committee. In the absence or disqualification of a
member of the committee, the member or members present at any meeting and not
disqualified from voting, whether or not such member or members constitute a
quorum, may unanimously appoint another member of the Board of Directors to act
at the meeting in the place of any such absent or disqualified member. Any such
committee, to the extent provided in the resolution of the Board of Directors,
shall have and may exercise all the powers and authority of the Board of
Directors in the management of the business and affairs of the Corporation, and
may authorize the seal of the Corporation to be affixed to all papers which may
require it; provided, no such committee shall have the power or authority in
reference to:

                  (a)      approving or adopting,
 or recommending to the
         stockholders, any action or matter expressly required by the Delaware
         General Corporation Law to be submitted to stockholders for approval;
         or

                  (b)      adopting, amending or repealing any By-law.

Any such committee shall have such name or names as may be determined from time
to time by resolution adopted by the Board of Directors.

         Section 11. Each committee shall keep written minutes of its meetings
and report the same to the Board of Directors when required.


                                   ARTICLE VI

          INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES AND AGENTS

         Section 1. The Corporation shall indemnify to the fullest extent
authorized by law any person made or threatened to be made a party to any action
or proceeding, whether criminal, civil, administrative or investigative, by
reason of the fact that such person, or a person of whom such person is the
legal representative, is or was a director or officer of the Corporation or any
predecessor of the Corporation or serves or served any other enterprise as a
director, officer, employee or agent at the request of the Corporation or any
predecessor of the Corporation. The


<PAGE>   2




Corporation may indemnify any person made or threatened to be made a party to
any action or proceeding, whether criminal, civil, administrative or
investigative, by reason of the fact that such person, or a person of whom such
person is the legal representative, is or was an employee or agent of the
Corporation or any predecessor of the Corporation or serves or served any other
enterprise as a director, officer, employee or agent at the request of the
Corporation or any predecessor of the Corporation.

         Section 2. Notwithstanding the other provisions of this Article VI, to
the extent that a present or former director or officer of the Corporation has
been successful on the merits or otherwise in defense of any action, suit or
proceeding referred to in Section 1 of this Article VI, or in defense of any
claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred by such
person in connection therewith.

         Section 3. The rights conferred on any person by Section 1 of this
Article VI shall not be exclusive of any other right that such person may have
or hereafter acquire under any statute, provision of the Corporation's
Certificate of Incorporation, by-law, agreement, vote of stockholders or
disinterested directors, or otherwise. All rights to indemnification under this
Article VI shall be deemed to be provided by a contract between the Corporation
and the director, officer, employee or agent who serves in such capacity at any
time while these By-laws and other relevant provisions of the Delaware General
Corporation Law and other applicable law, if any, are in effect. Any repeal or
modification thereof shall not affect any rights or obligations then existing.

         Section 4. The Corporation may maintain insurance, at its expense, to
protect itself and any director, officer, employee or agent of the Corporation
or another enterprise against all expenses, liability and loss (including
attorneys' fees, judgments, fines, ERISA excise taxes or penalties and amounts
paid or to be paid in settlement), whether or not the Corporation would have the
power to indemnify such person against such expense, liability or loss under the
applicable provisions of the Delaware General Corporation Law.

         Section 5. The Corporation may, in its discretion, pay the expenses
(including attorneys' fees) incurred in defending any civil, criminal,
administrative or investigative action, suit or proceeding in advance of its
final disposition; provided, however, that expenses (including attorneys' fees)
incurred by a present or former officer or director in defending any civil,
criminal, administrative or investigative action, suit or proceeding shall be
paid by the Corporation in advance of the final disposition of such action, suit
or proceeding upon receipt by the Corporation of an undertaking by or on behalf
of such officer or director to repay all such amounts advanced if it should
ultimately be determined that such person is not entitled to be indemnified by
the Corporation under this Article VI or otherwise. Such expenses (including
attorneys' fees) incurred by present or former employees or agents of the
Corporation other than directors or officers may be so paid upon such terms and
conditions, if any, as the Corporation deems appropriate.

                                        2






<PAGE>   1


                                                                     EXHIBIT 3.4

                                     INDEX

                                    BY-LAWS
                      As Amended through February 3, 1998
                             NOBLE AFFILIATES, INC.
                                                                         Page
                                                                         ----
ARTICLE I                 OFFICES                                          1

ARTICLE II                MEETINGS OF STOCKHOLDERS                         1

ARTICLE III               DIRECTORS                                        4
                            MEETINGS OF THE BOARD OF DIRECTORS             5
                            COMMITTEES OF DIRECTORS                        6
                            COMPENSATION OF DIRECTORS                      6

ARTICLE IV                NOTICES                                          6

ARTICLE V                 OFFICERS                                         7
                            CHAIRMAN OF THE BOARD                          7
                            THE PRESIDENT                                  7
                            THE VICE PRESIDENTS                            8
                            THE SECRETARY AND ASSISTANT SECRETARIES        8
                            THE TREASURER AND ASSISTANT TREASURERS         8

ARTICLE VI                INDEMNIFICATION OF DIRECTORS,
                            OFFICERS, EMPLOYEES AND AGENTS                 9

ARTICLE VII               CERTIFICATES OF STOCK                           10
                            LOST CERTIFICATES                             10
                            TRANSFERS OF STOCK                            10
                            FIXING RECORD DATE                            10
                            REGISTERED STOCKHOLDERS                       11

ARTICLE VIII              GENERAL PROVISIONS                              11
                            DIVIDENDS                                     11
                            ANNUAL STATEMENT                              11
                            CHECKS                                        11
                            FISCAL YEAR                                   11
                            SEAL                                          12

ARTICLE IX                AMENDMENTS                                      12

<PAGE>   2
                             NOBLE AFFILIATES, INC.

                                    BY-LAWS


                                   ARTICLE I

                                    OFFICES

         Section 1.  The registered office of the Corporation shall be 100 West
Tenth Street, City of Wilmington, New Castle County, Delaware.

         Section 2.  The Corporation may also have offices at such other places
both within and without the State of Delaware as the Board of Directors may
from time to time determine or the business of the Corporation may require.


                                   ARTICLE II

                            MEETINGS
 OF STOCKHOLDERS

         Section 1.  All meetings of the stockholders for the election of
Directors shall be held at such place, either within or without the State of
Delaware, as shall be designated from time to time by the Board of Directors
and stated in the notice of the meeting.  Meetings of the stockholders for any
other purpose may be held at such time and place, within or without the State
of Delaware, as shall be stated in the notice of the meeting or in a duly
executed waiver of notice thereof.

         Section 2(a).  Annual meetings of stockholders shall be held on the
fourth Tuesday of April if not a legal holiday, and if a legal holiday, then on
the next secular day following, at 10:00 a.m. or at such other date and time as
shall be designated from time to time by the Board of Directors and stated in
the notice of the meeting, at which they shall elect by a plurality vote a
Board of Directors, and transact such other business as may properly be brought
before the meeting.

         (b).  At the annual meeting of the stockholders, only such business
shall be conducted as shall have been properly brought before the meeting.  To
be properly brought before the annual meeting, business must be (i) specified
in the notice of meeting (or any supplement thereto) given by or at the
direction of the Board of Directors, (ii) otherwise be properly brought before
the meeting by or at the direction of the Board of Directors or (iii) otherwise
(1) be properly requested to be brought before the meeting by a stockholder of
record entitled to vote in the election of directors generally and (2)
constitute a proper subject to be brought before the meeting.  In order for
business (other than the election of directors) to be properly brought before
the annual meeting of stockholders by a stockholder, the business must be
legally proper, and written notice of such stockholder's intent to bring such
matter before the annual meeting of stockholders must be delivered, either by
personal delivery or by United States mail, postage prepaid, to the Secretary
of the Corporation.  Such notice must be received by the Secretary not later
than 60 days in advance of such meeting if such meeting is to be held on a day
which is within 30 days preceding the anniversary of the previous year's annual
meeting, or 90 days in advance of such meeting if such meeting is to be held on
or after the anniversary of the previous year's annual meeting.  A
stockholder's notice to the Secretary shall set forth as to each matter the
stockholder proposes to bring before the annual meeting of stockholders:  (i) a
brief description of the business desired to be brought before the meeting and
the reasons for conducting such business at the meeting, (ii) the name and
address, as they appear on the Corporation's books, of the stockholder
proposing such business, (iii) the class and number of shares of the
Corporation which are owned by such stockholder and (iv) any material interest
of the stockholder in such business.  No business brought by a stockholder
shall be conducted at the annual meeting


(Section 2, as amended July 31, 1984)
(Section 2(b) added January 28, 1992)

<PAGE>   3
                                      -2-

of stockholders except in accordance with the procedures set forth in this
Section 2(b).  The filing of a stockholder notice as required by this Section
2(b) shall not, in and of itself, constitute the bringing of the business
described therein before the annual meeting.  The chairman of the meeting
shall, if the facts warrant, determine that (1) the business proposed to be
brought before the meeting is not a proper subject therefor and/or (2) such
business was not properly brought before the meeting in accordance with the
provisions hereof, and if he should so determine, he shall declare to the
meeting that (1) the business proposed to be brought before the meeting is not
a proper subject thereof and/or (2) such business was not properly brought
before the meeting and shall not be transacted.

         Section 3.  Written notice of the annual meeting stating the place,
date and hour of the meeting shall be given to each stockholder entitled to
vote at such meeting not less than ten nor more than sixty days before the date
of the meeting.

         Section 4.  The officer who has charge of the stock ledger of the
Corporation shall prepare and make, at least ten days before every meeting of
stockholders, a complete list of the stockholders entitled to vote at the
meeting, arranged in alphabetical order, and showing the address of each
stockholder and the number of shares registered in the name of each
stockholder.  Such list shall be open to the examination of any stockholder,
for any purpose germane to the meeting, during ordinary business hours, for a
period of at least ten days prior to the meeting, either at a place within the
city where specified in the notice of the meeting, or, if not so specified, at
the place where the meeting is to be held.  The list shall also be produced and
kept at the time and place of the meeting during the whole time thereof, and
may be inspected by any stockholder who is present.

         Section 5.  Special meetings of the stockholders, for any purpose or
purposes, unless otherwise prescribed by statute or by the Certificate of
Incorporation, may be called by the President and shall be called by the
President or Secretary at the request in writing of a majority of the Board of
Directors, or at the request in writing of stockholders owning a majority in
amount of the entire capital stock of the Corporation issued and outstanding
and entitled to vote.  Such request shall state the purpose or purposes of the
proposed meeting.

         Section 6.  Written notice of a special meeting stating the place,
date and hour of the meeting and the purpose or purposes for which the meeting
is called shall be given not less than ten nor more than sixty days before the
date of the meeting to each stockholder entitled to vote at such meeting.

         Section 7.  Business transacted at any special meeting of stockholders
shall be limited to the purposes stated in the notice.

         Section 8.  The holders of a majority of the stock issued and
outstanding and entitled to vote thereat, present in person or represented by
proxy, shall constitute a quorum at all meetings of the stockholders for the
transaction of business except as otherwise provided by statute or by the
Certificate of Incorporation.  Where a separate vote by a class or classes is
required, a majority of the outstanding shares of such class or classes,
present in person or represented by proxy, shall constitute a quorum entitled
to take action with respect to that vote on that matter.  If, however, such
quorum shall not be present or represented at any meeting of the stockholders,
the stockholders entitled to vote thereat, present in person or represented by
proxy, shall have power to adjourn the meeting from time to time, without
notice other than announcement at the meeting, until a quorum shall be present
or represented.  At such adjourned meeting, at which a quorum shall be present
or represented, any business may be transacted which might have been transacted
at the meeting as originally notified.  If the adjournment is for more than
thirty days, or if after the adjournment, a new record date is fixed for the
adjourned meeting, a notice of the adjourned meeting shall be given to each
stockholder of record entitled to vote at the meeting.





(Sections 3, 6 and 8, as amended October 27, 1987)

<PAGE>   4
                                      -3-

         Section 9.  When a quorum is present at any meeting, the vote of the
holders of a majority of the stock having voting power present in person or
represented by proxy shall decide any question brought before such meeting
(other than the election of directors), unless the question is one upon which,
by express provision of the statutes or of the Certificate of Incorporation, a
different vote is required, in which case such express provision shall govern
and control the decision of such question.  Directors shall be elected by a
plurality of the votes of the shares present in person or represented by proxy
at the meeting and entitled to vote on the election of directors.  Where a
separate vote by a class or classes is required, the affirmative vote of the
majority of shares of such class or classes present in person or represented by
proxy at the meeting shall be the act of such class.

         Section 10.  Each stockholder shall at every meeting of the
stockholders be entitled to one vote in person or by proxy for each share of
the capital stock having voting power held by such stockholder, but no proxy
shall be voted on after three years from its date, unless the proxy provides
for a longer period.

         Section 11(a).  Unless otherwise restricted by the Certificate of
Incorporation, any action required or permitted to be taken at any annual or
special meeting of the stockholders may be taken without a meeting, without
prior notice and without a vote, if a consent or consents in writing, setting
forth the action so taken, shall be signed by the holders of outstanding stock
having not less than the minimum number of votes that would be necessary to
authorize or take such action at a meeting at which all shares entitled to vote
thereon were present and voted and shall be delivered to the Corporation by
delivery to its registered office in Delaware, its principal place of business,
or an officer or agent of the Corporation having custody of the book in which
proceedings of meetings of stockholders are recorded.  Delivery made to the
Corporation's registered office shall be by hand or by certified or registered
mail, return receipt requested.

         (b).  Every written consent shall bear the date of signature of each
stockholder who signs the consent and no written consent shall be effective to
take the corporate action referred to therein unless, within sixty days of the
earliest dated consent delivered in the manner required by this Section to the
Corporation, written consents signed by a sufficient number of holders to take
action are delivered to the Corporation by delivery to its registered office in
Delaware, its principal place of business, or an officer or agent of the
Corporation having custody of the book in which proceedings of meetings of
stockholders are recorded.  Delivery made to the Corporation's registered
office shall be by hand or by certified or registered mail, return receipt
requested.

         (c).  Prompt notice of the taking of the corporate action without a
meeting by less than unanimous written consent shall be given to those
stockholders who have not consented in writing.

         Section 12.  Either the Board of Directors or, in the absence of an
appointment of inspectors by the Board, the Chairman of the Board or the
President shall, in advance of each meeting of the stockholders, appoint one or
more inspectors to act at such meeting and make a written report thereof.  In
connection with any such appointment, one or more persons may, in the
discretion of the body or person making such appointment, be designated as
alternate inspectors to replace any inspector who fails to act.  If no
inspector or alternate is able to act at any meeting of stockholders, the
chairman of such meeting shall appoint one or more inspectors to act at such
meeting.  Each such inspector shall perform such duties as are required by law
and as shall be specified by the Board, the Chairman of the Board, the
President or the chairman of the meeting.  Each such inspector, before entering
upon the discharge of his duties, shall take and sign an oath faithfully to
execute the duties of inspector with strict impartiality and according to the
best of his ability.  Inspectors need not be stockholders.  No director or
nominee for the office of director shall be appointed such an inspector.





(Sections 9 and 11, as amended October 27, 1987)
(Section 12 added January 28, 1992)

<PAGE>   5
                                      -4-

                                  ARTICLE III

                                   DIRECTORS

         Section 1(a).  The number of regular Directors which shall constitute
the whole Board shall be not less than three nor more than fifteen.  Within the
limits above specified, the number of regular Directors shall be determined by
resolution of the Board of Directors or by the stockholders at the annual
meeting.

         (b).  A person shall be eligible to be elected a regular Director
until the annual meeting next succeeding such person's 70th birthday.

         (c).  The regular Directors shall be elected at the annual meeting of
the stockholders, except as provided in Section 2 of this Article, and each
regular Director elected shall hold office until his successor is elected and
qualified.

         (d).  All regular Directors who have served as such for not less than
ten successive years at the time of the annual meeting next succeeding their
70th birthday shall automatically become Directors Emeritus to serve at the
pleasure of the regular Board of Directors.

         (e).  A Director Emeritus shall serve until his or her resignation as
such or until terminated by a majority vote of the regular Board.

         (f).  Directors Emeritus shall be entitled to attend and participate
in all regular or special meetings of the Board of Directors and shall be
entitled to all rights, privileges and perquisites of a regular Director except
that such Director Emeritus shall have no duty or obligation to attend Board
meetings, shall not be counted in determining a quorum, shall not serve on
regular committees of the Board, shall have no vote and shall receive no annual
compensation stipend.

         (g).  Directors need not be stockholders.

         (h).  Subject to the rights of the holders of any class or series of
stock having a preference over the Common Stock as to dividends or upon
liquidation, nominations for the election of directors may be made by the Board
of Directors or by any stockholder entitled to vote for the election of
directors.  Any stockholder entitled to vote for the election of directors at a
meeting (i.e., any stockholder of record) may nominate persons for election as
directors only if written notice of such stockholder's intent to make such
nomination is given, either by personal delivery or by United States mail,
postage prepaid, to the Secretary of the Corporation not later than (i) with
respect to an election to be held at an annual meeting of stockholders, 90 days
in advance of such meeting, and (ii) with respect to an election to be held at
a special meeting of stockholders for the election of directors, the close of
business on the seventh day following the date on which notice of such meeting
is first given to stockholders.  Each such notice shall set forth:  (1) the
name and address of the stockholder who intends to make the nomination of the
person or persons to be nominated; (2) a representation that the stockholder is
a holder of record of stock of the Corporation entitled to vote at such meeting
and intends to appear in person or by proxy at the meeting to nominate the
person or persons specified in the notice; (3) a description of all
arrangements or understandings between the stockholder and each nominee and any
other person or persons (naming such person or persons) pursuant to which the
nomination or nominations are to be made by the stockholder; (4) such other
information regarding each nominee proposed by such stockholder as would have
been required to be included in a proxy statement filed pursuant to the proxy
rules of the Securities and Exchange Commission had each nominee been
nominated, or intended to be nominated, by the Board of Directors; and (5) the
written consent of each nominee to serve as a director of the Corporation if so
elected.  The filing of a stockholder notice as required by this Section 1(h)
shall not, in and of itself, constitute the making of the





(Article III, as amended December 14, 1983)
(Section 1(h) added January 28, 1992)

<PAGE>   6
                                      -5-

nomination(s) described therein.  The chairman of the meeting may refuse to
acknowledge the nomination of any person not made in compliance with the
foregoing procedure.

         Section 2.  Vacancies and newly created directorships resulting from
any increase in the authorized number of regular Directors may be filled by a
majority of the regular Directors then in office, though less than a quorum, or
by a sole remaining regular Director, and the Directors so chosen shall hold
office until the next annual election and until their successors are duly
elected and shall qualify, unless sooner displaced.  If there are no regular
Directors in office, then an election of regular Directors may be held in the
manner provided by statute.  If, at the time of filling any vacancy or any
newly created directorship, the regular Directors then in office shall
constitute less than a majority of the whole Board (as constituted immediately
prior to any such increase), the Court of Chancery may, upon application of any
stockholder or stockholders holding at least ten percent of the total number of
the shares at the time outstanding having the right to vote for such Directors,
summarily order an election to be held to fill any such vacancies or newly
created directorships, or to replace the Directors chosen by the Directors then
in office.

         Section 3.  The business of the Corporation shall be managed by its
regular Board of Directors which may exercise all such powers of the
Corporation and do all such lawful acts and things as are not by statute or by
the Certificate of Incorporation or by these By-laws directed or required to be
exercised or done by the stockholders.

                       MEETINGS OF THE BOARD OF DIRECTORS

         Section 4.  The Board of Directors of the Corporation may hold
meetings, both regular and special, either within or without the State of
Delaware.

         Section 5.  The first meeting of each newly elected Board of Directors
shall be held at such time and place as shall be fixed by the vote of the
stockholders at the annual meeting and no notice of such meeting shall be
necessary to the newly elected Directors in order legally to constitute the
meeting, provided a quorum shall be present.  In the event of the failure of
the stockholders to fix the time or place of such first meeting of the newly
elected Board of Directors, or in the event such meeting is not held at the
time and place so fixed by the stockholders, the meeting may be held at such
time and place as shall be specified in a notice given as hereinafter provided
for special meetings of the Board of Directors, or as shall be specified in a
written waiver signed by all of the regular Directors.

         Section 6.  Regular meetings of the Board of Directors may be held
without notice at such time and at such place as shall from time to time be
determined by the Board.

         Section 7.  Special meetings of the Board may be called by the
President on three days' notice to each Director, either personally or by mail
or by telegram; special meetings shall be called by the President or Secretary
in like manner and on like notice on the written request of two regular
Directors.

         Section 8.  At all meetings of the Board a majority of the regular
Directors shall constitute a quorum for the transaction of business and the act
of a majority of the regular Directors present at any meeting at which there is
a quorum shall be the act of the Board of Directors, except as may be otherwise
specifically provided by statute or by the Certificate of Incorporation.  If a
quorum shall not be present at any meeting of the Board of Directors, the
Directors present thereat may adjourn the meeting from time to time, without
notice other than announcement at the meeting, until a quorum shall be present.

         Section 9.  Unless otherwise restricted by the Certificate of
Incorporation or these By-laws, any action required or permitted to be taken at
any meeting of the Board of Directors or of any committee thereof may be taken
without a meeting, if all regular members of the Board or committee, as the
case may be, consent thereto in writing, and the writing or writings are filed
with the minutes of proceedings of the Board or committee.






<PAGE>   7
                                      -6-

                            COMMITTEES OF DIRECTORS

         Section 10.  The Board of Directors may designate one or more
committees, each committee to consist of one or more of the regular Directors
of the Corporation.  The Board may designate one or more regular Directors as
alternate members of any committee, who may replace any absent or disqualified
member at any meeting of the committee.  In the absence or disqualification of
a member of the committee, the member or members present at any meeting and not
disqualified from voting, whether or not such member or members constitute a
quorum, may unanimously appoint another member of the Board of Directors to act
at the meeting in the place of any such absent or disqualified member. Any such
committee, to the extent provided in the resolution of the Board of Directors,
shall have and may exercise all the powers and authority of the Board of
Directors in the management of the business and affairs of the Corporation, and
may authorize the seal of the Corporation to be affixed to all papers which may
require it; provided, no such committee shall have the power or authority in
reference to:

                 (a)      approving or adopting, or recommending to the
         stockholders, any action or matter expressly required by the Delaware
         General Corporation Law to be submitted to stockholders for approval;
         or

                 (b)      adopting, amending or repealing any By-law.

Any such committee shall have such name or names as may be determined from time
to time by resolution adopted by the Board of Directors.

         Section 11.  Each committee shall keep written minutes of its meetings
and report the same to the Board of Directors when required.

                           COMPENSATION OF DIRECTORS

         Section 12.  All Directors may be paid their expenses, if any, of
attendance at each meeting of the Board of Directors and may be paid a fixed
sum for attendance at each meeting of the Board of Directors.  Regular
Directors may be paid an annual stipend or stated salary as Director.  No such
payment shall preclude any Director from serving the Corporation in any other
capacity and receiving compensation therefor.  Members of special or standing
committees may be allowed like compensation for attending committee meetings.


                                   ARTICLE IV

                                    NOTICES

         Section 1.  Whenever, under the provisions of the statutes or of the
Certificate of Incorporation or of these By-laws, notice is required to be
given to any Director or stockholder, it shall not be construed to mean
personal notice, but such notice may be given in writing, by mail, addressed to
such Director or stockholder, at his address as it appears on the records of
the Corporation, with postage thereon prepaid, and such notice shall be deemed
to be given at the time when the same shall be deposited in the mail. Notice to
Directors may also be given by telegram.

         Section 2.  Whenever any notice is required to be given under the
provisions of the statutes or of the Certificate of Incorporation or of the
By-laws, a waiver thereof in writing, signed by the person or persons entitled
to said notice, whether before or after the time stated therein, shall be
deemed equivalent thereto.


(Section 10, as amended February 3, 1998)


<PAGE>   8
                                      -7-

                                   ARTICLE V

                                    OFFICERS

         Section 1.  The officers of the Corporation shall be chosen by the
Board of Directors and shall be a Chairman of the Board, a President, a Vice
President, a Secretary and a Treasurer.  The Board may designate from time to
time either the Chairman of the Board or the President as the Chief Executive
Officer of the Corporation and may also choose additional Vice Presidents and
one or more Assistant Secretaries and Assistant Treasurers.  Any number of
offices may be held by the same person, unless the Certificate of Incorporation
or these By-laws otherwise provide.

         Section 2.  The Board of Directors at its first meeting after each
annual meeting of stockholders shall choose a Chairman of the Board, a
President, one or more Vice Presidents, a Secretary and a Treasurer.

         Section 3.  The Board of Directors may appoint such other officers and
agents as it shall deem necessary who shall hold their offices for such terms
and shall exercise such powers and perform such duties as shall be determined
from time to time by the Board.

         Section 4.  The salaries of all officers and agents of the Corporation
shall be fixed by the Board of Directors.

         Section 5.  The officers of the Corporation shall hold office until
their successors are chosen and qualify.  Any officer elected or appointed by
the Board of Directors may be removed at any time by the affirmative vote of a
majority of the Board of Directors.  Any vacancy occurring in any office of the
Corporation shall be filled by the Board of Directors.

                             CHAIRMAN OF THE BOARD

         Section 6.  The Chairman of the Board of Directors shall preside at
meetings of the Board of Directors and of the stockholders.  He shall have
general power to execute bonds, mortgages, and other instruments requiring a
seal, under the seal of the Corporation, except where the signing and execution
thereof shall be expressly delegated by the Board of Directors to some other
officer or agent.  When the Board of Directors designates the Chairman as the
Chief Executive Officer of the Corporation he shall have general supervision,
direction and active management of the business of the Corporation and shall
see that all orders and resolutions of the Board of Directors are carried into
effect.  The Chairman shall have such other specific duties as shall be
assigned to him by the Board of Directors from time to time.

                                 THE PRESIDENT

         Section 7.  The President, in the absence or disability of the
Chairman of the Board of Directors, shall preside at meetings of the Board of
Directors and of the stockholders and shall perform the duties and exercise the
powers of the Chairman of the Board of Directors.  He shall have general power
to execute bonds, mortgages and other instruments requiring a seal under the
seal of the Corporation, except where the signing and execution thereof shall
be expressly delegated by the Board of Directors to some other officer or agent
of the Corporation.  When designated as Chief Executive Officer of the
Corporation, the President shall have general supervision, direction and active
management of the business of the Corporation and shall see that all orders and
resolutions of the Board of Directors are carried into effect; otherwise, he
shall be the chief operating officer of the Corporation and shall perform such
other duties as may be prescribed by the Board of Directors or by the Chairman
of the Board of Directors.





(Sections 1, 6 and 7 as amended January 29,1980,
effective December 31, 1979)

<PAGE>   9
                                      -8-

                              THE VICE PRESIDENTS

         Section 8.  In the absence of the President or in the event of his
inability or refusal to act, the Vice President (or in the event more than one
Vice President is elected, the Vice Presidents in the order designated, or in
the absence of any designation, then in the order of their election) shall
perform the duties of the President, and when so acting, shall have all the
powers of and be subject to all the restrictions upon the President.  The Vice
Presidents shall perform such other duties and have such other powers as the
Board of Directors may from time to time prescribe.

                    THE SECRETARY AND ASSISTANT SECRETARIES

         Section 9.  The Secretary shall attend all meetings of the Board of
Directors and all meetings of the stockholders and record all the proceedings
of the meetings of the Corporation and of the Board of Directors in a book to
be kept for that purpose and shall perform like duties for the standing
committees when required.  He shall give, or cause to be given, notice of all
meetings of the stockholders and special meetings of the Board of Directors,
and shall perform such other duties as may be prescribed by the Board of
Directors or President, under whose supervision he shall be.  He shall have
custody of the corporate seal of the Corporation and he, or an Assistant
Secretary, shall have authority to affix the same to any instrument requiring
it and when so affixed, it may be attested by his signature or by the signature
of such Assistant Secretary.  The Board of Directors may give general authority
to any other officer to affix the seal of the Corporation and to attest the
affixing by his signature.

         Section 10.  The Assistant Secretary, or if there be more than one,
the Assistant Secretaries in the order determined by the Board of Directors (or
if there be no such determination, then in the order of their election), shall,
in the absence of the Secretary or in the event of his inability or refusal to
act, perform the duties and exercise the powers of the Secretary and shall
perform such other duties and have such other powers as the Board of Directors
may from time to time prescribe.

                     THE TREASURER AND ASSISTANT TREASURERS

         Section 11.  The Treasurer shall have the custody of the corporate
funds and securities and shall keep full and accurate accounts of receipts and
disbursements in books belonging to the Corporation and shall deposit all
moneys and other valuable effects in the name and to the credit of the
Corporation in such depositories as may be designated by the Board of
Directors.

         Section 12.  He shall disburse the funds of the Corporation as may be
ordered by the Board of Directors, taking proper vouchers for such
disbursements, and shall render to the President and the Board of Directors, at
its regular meetings, or when the Board of Directors so requires, an account of
all his transactions as Treasurer and of the financial condition of the
Corporation.

         Section 13.  If required by the Board of Directors, he shall give the
Corporation a bond (which shall be renewed every six years) in such sum and
with such surety or sureties as shall be satisfactory to the Board of Directors
for the faithful performance of the duties of his office and for the
restoration to the Corporation, in case of his death, resignation, retirement
or removal from office, of all books, papers, vouchers, money and other
property of whatever kind in his possession or under his control belonging to
the Corporation.

         Section 14.  The Assistant Treasurer, or if there shall be more than
one, the Assistant Treasurers in the order determined by the Board of Directors
(or if there be no such determination, then in the order of their election),
shall, in the absence of the Treasurer or in the event of his inability or
refusal to act, perform the duties and exercise the powers of the Treasurer and
shall perform such other duties and have such other powers as the Board of
Directors may from time to time prescribe.






<PAGE>   10
                                      -9-


                                   ARTICLE VI

          INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES AND AGENTS

         Section 1.  The Corporation shall indemnify to the fullest extent
authorized by law any person made or threatened to be made a party to any
action or proceeding, whether criminal, civil, administrative or investigative,
by reason of the fact that such person, or a person of whom such person is the
legal representative, is or was a director or officer of the Corporation or any
predecessor of the Corporation or serves or served any other enterprise as a
director, officer, employee or agent at the request of the Corporation or any
predecessor of the Corporation.  The Corporation may indemnify any person made
or threatened to be made a party to any action or proceeding, whether criminal,
civil, administrative or investigative, by reason of the fact that such person,
or a person of whom such person is the legal representative, is or was an
employee or agent of the Corporation or any predecessor of the Corporation or
serves or served any other enterprise as a director, officer, employee or agent
at the request of the Corporation or any predecessor of the Corporation.

         Section 2.  Notwithstanding the other provisions of this Article VI,
to the extent that a present or former director or officer of the Corporation
has been successful on the merits or otherwise in defense of any action, suit
or proceeding referred to in Section 1 of this Article VI, or in defense of any
claim, issue or matter therein, such person shall be indemnified against
expenses (including attorneys' fees) actually and reasonably incurred by such
person in connection therewith.

         Section 3.  The rights conferred on any person by Section 1 of this
Article VI shall not be exclusive of any other right that such person may have
or hereafter acquire under any statute, provision of the Corporation's
Certificate of Incorporation, by-law, agreement, vote of stockholders or
disinterested directors, or otherwise.  All rights to indemnification under
this Article VI shall be deemed to be provided by a contract between the
Corporation and the director, officer, employee or agent who serves in such
capacity at any time while these By-laws and other relevant provisions of the
Delaware General Corporation Law and other applicable law, if any, are in
effect.  Any repeal or modification thereof shall not affect any rights or
obligations then existing.

         Section 4.  The Corporation may maintain insurance, at its expense, to
protect itself and any director, officer, employee or agent of the Corporation
or another enterprise against all expenses, liability and loss (including
attorneys' fees, judgments, fines, ERISA excise taxes or penalties and amounts
paid or to be paid in settlement), whether or not the Corporation would have
the power to indemnify such person against such expense, liability or loss
under the applicable provisions of the Delaware General Corporation Law.

         Section 5.  The Corporation may, in its discretion, pay the expenses
(including attorneys' fees) incurred in defending any civil, criminal,
administrative or investigative action, suit or proceeding in advance of its
final disposition; provided, however, that expenses (including attorneys' fees)
incurred by a present or former officer or director in defending any civil,
criminal, administrative or investigative action, suit or proceeding shall be
paid by the Corporation in advance of the final disposition of such action,
suit or proceeding upon receipt by the Corporation of an undertaking by or on
behalf of such officer or director to repay all such amounts advanced if it
should ultimately be determined that such person is not entitled to be
indemnified by the Corporation under this Article VI or otherwise.  Such
expenses (including attorneys' fees) incurred by present or former employees or
agents of the Corporation other than directors or officers may be so paid upon
such terms and conditions, if any, as the Corporation deems appropriate.






(Article VI, as amended July 29, 1986 and
as amended February 3, 1998)
(Section 4 added October 27, 1992)


<PAGE>   11
                                      -10-

                                  ARTICLE VII

                             CERTIFICATES OF STOCK

         Section 1.  Every holder of stock in the Corporation shall be entitled
to have a certificate, signed by, or in the name of, the Corporation by the
Chairman of the Board of Directors or the President or a Vice President and the
Treasurer or an Assistant Treasurer, or the Secretary or an Assistant Secretary
of the Corporation, certifying the number of shares owned by him in the
Corporation.

         Section 2.  Where a certificate is countersigned (1) by a transfer
agent other than the Corporation or its employee, or, (2) by a registrar other
than the Corporation or its employee, any other signature on the certificate
may be a facsimile.  In case any officer, transfer agent or registrar who has
signed or whose facsimile signature has been placed upon a certificate shall
have ceased to be such officer, transfer agent or registrar before such
certificate is issued, it may be issued by the Corporation with the same effect
as if he were such officer, transfer agent or registrar at the date of issue.

                               LOST CERTIFICATES

         Section 3.  The Board of Directors may direct a new certificate or
certificates to be issued in place of any certificate or certificates
theretofore issued by the Corporation alleged to have been lost, stolen or
destroyed, upon the making of an affidavit of that fact by the person claiming
the certificate of stock to be lost, stolen or destroyed.  When authorizing
such issue of a new certificate or certificates, the Board of Directors may, in
its discretion and as a condition precedent to the issuance thereof, require
the owner of such lost, stolen or destroyed certificate or certificates, or his
legal representative, to advertise the same in such manner as it shall require
and/or to give the Corporation a bond in such sum as it may direct as indemnity
against any claim that may be made against the Corporation with respect to the
certificate alleged to have been lost, stolen or destroyed.

                               TRANSFERS OF STOCK

         Section 4.  Upon surrender to the Corporation or the transfer agent of
the Corporation of a certificate for shares duly endorsed or accompanied by
proper evidence of succession, assignment or authority to transfer, it shall be
the duty of the Corporation to issue a new certificate to the person entitled
thereto, cancel the old certificate and record the transaction upon its books.

                               FIXING RECORD DATE

         Section 5(a).  In order that the Corporation may determine the
stockholders entitled to notice of or to vote at any meeting of stockholders or
any adjournment thereof, the Board of Directors may fix a record date, which
record date shall not precede the date upon which the resolution fixing the
record date is adopted by the Board of Directors, and which record date shall
not be more than sixty nor less than ten days before the date of such meeting.
A determination of stockholders of record entitled to notice of or to vote at a
meeting of stockholders shall apply to any adjournment of a meeting; provided,
however, that the Board of Directors may fix a new record date for the
adjourned meeting.

         (b).  In order that the Corporation may determine the stockholders
entitled to consent to corporate action in writing without a meeting, the Board
of Directors may fix a record date, which record date shall not precede the
date upon which the resolution fixing the record date is adopted by the Board
of Directors, and which date shall not be more than ten days after the date
upon which the resolution fixing the record date is adopted by the Board of
Directors.





(Section 5 as amended  October 27, 1987)

<PAGE>   12
                                      -11-

         (c).  In order that the Corporation may determine the stockholders
entitled to receive payment of any dividend or other distribution or allotment
of any rights or the stockholders entitled to exercise any rights in respect of
any change, conversion or exchange of stock, or for the purpose of any other
lawful action, the Board of Directors may fix a record date, which record date
shall not precede the date upon which the resolution fixing the record date is
adopted, and which record date shall be not more than sixty days prior to such
action.

                            REGISTERED STOCKHOLDERS

         Section 6.  The Corporation shall be entitled to recognize the
exclusive right of a person registered on its books as the owner of shares to
receive dividends, and to vote as such owner, and to hold liable for calls and
assessments a person registered on its books as the owner of shares, and shall
not be bound to recognize any equitable or other claim to interest in such
share or shares on the part of any other person, whether or not it shall have
express or other notice thereof, except as otherwise provided by the laws of
Delaware.


                                  ARTICLE VIII

                               GENERAL PROVISIONS

                                   DIVIDENDS

         Section 1.  Dividends upon the capital stock of the Corporation,
subject to the provisions of the Certificate of Incorporation, if any, may be
declared by the Board of Directors at any regular or special meeting, pursuant
to law.  Dividends may be paid in cash, in property, or in shares of the
capital stock, subject to the provisions of the Certificate of Incorporation.

         Section 2.  Before payment of any dividend, there may be set aside out
of any funds of the Corporation available for dividends such sum or sums as the
Directors from time to time, in their absolute discretion, think proper as a
reserve or reserves to meet contingencies, or for equalizing dividends, or for
repairing or maintaining any property of the Corporation, or for such other
purpose as the Directors shall think conducive to the interest of the
Corporation, and the Directors may modify or abolish any such reserve in the
manner in which it was created.

                                ANNUAL STATEMENT

         Section 3.  The Board of Directors shall present at each annual
meeting, and at any special meeting of the stockholders when called for by vote
of the stockholders, a full and clear statement of the business and condition
of the Corporation.

                                     CHECKS

         Section 4.  All checks or demands for money and notes of the
Corporation shall be signed by such officer or officers or such other person or
persons as the Board of Directors may from time to time designate.

                                  FISCAL YEAR

         Section 5.  The fiscal year of the Corporation shall be fixed by
resolution of the Board of Directors.

<PAGE>   13
                                      -12-

                                      SEAL

         Section 6.  The corporate seal shall have inscribed thereon the name
of the Corporation, the year of its organization and the words "Corporate Seal,
Delaware".  The seal may be used by causing it or a facsimile thereof to be
impressed or affixed or reproduced or otherwise.


                                   ARTICLE IX

                                   AMENDMENTS

         Section 1.  These By-laws may be altered, amended or repealed or new
By-laws may be adopted by the stockholders or by the Board of Directors, when
such power is conferred upon the Board of Directors by the Certificate of
Incorporation, at any regular meeting of the stockholders or of the Board of
Directors or at any special meeting of the stockholders or of the Board of
Directors if notice of such alteration, amendment, repeal or adoption of new
By-laws be contained in the notice of such special meeting.



<PAGE>   1
                                                                   EXHIBIT 10.20




                              U.S. $300,000,000
                                      
                                      
                    AMENDED AND RESTATED CREDIT AGREEMENT,
                                      
                                      
                        dated as of December 24, 1997
                                      
                                      
                                    among
                                      
                                      
                           NOBLE AFFILIATES, INC.,
                               as the Borrower,
                                      
                                     and
                                      
                                      
                  UNION BANK OF SWITZERLAND, Houston Agency,
                         as the Agent for the Lenders
                                      
                                     and
                                      
                                      
                        NATIONSBANK OF TEXAS, N.A. and
                  TEXAS COMMERCE BANK NATIONAL ASSOCIATION,
                              as Managing Agents
                                      
                                     and
                                      
                                      
                              BANK OF MONTREAL,
                                  CIBC INC.,
                     THE FIRST NATIONAL BANK OF CHICAGO,
                          ROYAL BANK OF CANADA, and
                     SOCIETE GENERALE, SOUTHWEST AGENCY,
                                 as Co-Agents
                                      
                                     and
                                      
                                      
                   CERTAIN COMMERCIAL LENDING INSTITUTIONS,
                                as the Lenders

<PAGE>   2



                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                                      PAGE
                                                                                                                      ----
<S>      <C>                                                                                                           <C>
I        DEFINITIONS AND ACCOUNTING TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
         1.1       Defined Terms  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
         1.2       Use of Defined Terms   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
         1.3       Cross-References   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
         1.4       Accounting and Financial Determinations  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18

II       THE FACILITY, BORROWING PROCEDURES AND NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.1       The Facility   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.1.1     Description of the Facility  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.1.2     Availability of Facility   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.2       Competitive Bid Advances   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.2.1     Competitive Bid Option   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.2.2     Competitive Bid Quote Request  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
         2.2.3     Invitation for Competitive Bid Quotes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20
         2.2.4     Submission and Contents of Competitive Bid Quotes  . . . . . . . . . . . . . . . . . . . . . . . .  20
         2.2.5     Notice to the Borrower   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21
         2.2.6     Acceptance and Notice by the Borrower  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21
         2.2.7     Allocation by the Agent  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
         2.2.8     Administration Fees  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
         2.2.9     Reduction  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
         2.3       Reduction
 of Commitment Amount   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
         2.4       Base Rate Loans and Eurodollar Loans   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
         2.5       Borrowing Procedures for Loans   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
         2.5.1     Domestic Loans   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
         2.5.2     Eurodollar Loans   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
         2.6       Continuation and Conversion Elections  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
         2.7       Funding  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
         2.8       Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24

III      REPAYMENTS, PREPAYMENTS, INTEREST AND FEES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
         3.1       Repayments and Prepayments   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
         3.2       Interest Provisions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
         3.2.1     Rates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
         3.2.2     Post-Maturity Rates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
         3.2.3     Payment Dates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25
         3.3       Fees   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         3.3.1     Facility Fee   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         3.3.2     Agent's Fee  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         3.3.3     Payment Office   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
</TABLE>






                                       i

<PAGE>   3

<TABLE>
<S>      <C>                                                                                                           <C>
         IV        CERTAIN EURODOLLAR AND OTHER PROVISIONS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         4.1       Eurodollar Lending Unlawful  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         4.2       Deposits Unavailable or Eurodollar Interest Rate Unascertainable   . . . . . . . . . . . . . . . .  26
         4.3       Increased Eurodollar Borrowing Costs, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         4.4       Funding Losses   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         4.5       Increased Capital Costs  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         4.6       Taxes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
         4.7       Special Fees in Respect of Reserve Requirements  . . . . . . . . . . . . . . . . . . . . . . . . .  29
         4.8       Payments, Computations, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
         4.9       Sharing of Payments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
         4.10      Use of Proceeds  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31
         4.11      Replacement of Lender on Account of Increased Costs, Eurodollar Lending Unlawful, Reserve
                   Requirements, Taxes, Certain Dissents, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . .  31
         4.12      Maximum Interest   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31

V        CONDITIONS TO BORROWING  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  32
         5.1       Initial Borrowing  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  32
         5.1.1     Resolutions, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.1.2     Delivery of Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.1.3     Opinion of Counsel   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.1.4     Fee Letters, Closing Fees, Expenses, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.1.5     Material Adverse Change  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.1.6     Other Documents  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.2       All Borrowings   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.2.1     Compliance with Warranties, No Default, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         5.2.2     Borrowing Request and Competitive Bid Quote Request  . . . . . . . . . . . . . . . . . . . . . . .  34
         5.2.3     Satisfactory Legal Form  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34

VI       REPRESENTATIONS AND WARRANTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
         6.1       Organization, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
         6.2       Due Authorization, Non-Contravention, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
         6.3       Government Approval, Regulation, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.4       Validity, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.5       Financial Information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.6       No Material Adverse Change   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.7       Litigation, Labor Controversies, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.8       Subsidiaries   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         6.9       Taxes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         6.10      Pension and Welfare Plans  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         6.11      Environmental Warranties and Compliance  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         6.12      Regulations G, T, U and X  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
</TABLE>






                                       ii

<PAGE>   4
                               TABLE OF CONTENTS
                                  (CONTINUED)

<TABLE>
<CAPTION>
                                                                                                                     PAGE
                                                                                                                     ----
<S>      <C>                                                                                                           <C>
         6.13      Accuracy of Information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         6.14      Use of Proceeds  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         6.15      Existing Liens   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37

VII      COVENANTS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37
         7.1       Affirmative Covenants  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37
         7.1.1     Financial Information, Reports, Notices, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . .  37
         7.1.2     Compliance with Laws, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  38
         7.1.3     Maintenance of Properties  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  38
         7.1.4     Insurance  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.1.5     Books and Records  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.1.6     Conduct of Business  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.2       Negative Covenants   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.2.1     Business Activities  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.2.2     Liens  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         7.2.3     Financial Covenants  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
         7.2.4     Restricted Payments, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
         7.2.5     Indebtedness   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
         7.2.6     Consolidation, Merger, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
         7.2.7     Transactions with Affiliates   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
         7.2.8     Negative Pledges, Restrictive Agreements, etc.   . . . . . . . . . . . . . . . . . . . . . . . . .  41

VIII     EVENTS OF DEFAULT  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1       Listing of Events of Default   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.1     Non-Payment of Obligations   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.2     Breach of Warranty   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.3     Non-Performance of Certain Covenants and Obligations   . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.4     Non-Performance of Other Covenants and Obligations   . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.5     Default on Other Indebtedness  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
         8.1.6     Judgments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         8.1.7     Pension Plans  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         8.1.8     Change in Control  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         8.1.9     Bankruptcy, Insolvency, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         8.2       Action if Bankruptcy   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         8.3       Action if Other Event of Default   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44

 IX      THE AGENT, THE MANAGING AGENTS AND THE CO-AGENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
         9.1       Actions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
         9.2       Funding Reliance, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
         9.3       Exculpation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
         9.4       Successor  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
</TABLE>






                                      iii

<PAGE>   5
                               TABLE OF CONTENTS
                                  (CONTINUED)

<TABLE>
<CAPTION>
                                                                                                                     PAGE
                                                                                                                     ----
<S>      <C>                                                                                                           <C>
         9.5       Loans by the Agents  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
         9.6       Credit Decisions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
         9.7       Copies, etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46

X        MISCELLANEOUS PROVISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
         10.1      Waivers, Amendments, etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
         10.2      Notices  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
         10.3      Payment of Costs, Expenses and Taxes   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  48
         10.4      Indemnification  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  48
         10.5      Survival   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.6      Severability   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.7      Headings   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.8      Execution in Counterparts, Effectiveness, etc.   . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.9      Governing Law; Entire Agreement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.10     Successors and Assigns   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
         10.11     Sale and Transfer of Loans and Notes; Participations in Loans and
                   Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
         10.11.1   Assignments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
         10.11.2   Participations   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  51
         10.12     Other Transactions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  51
         10.13     Sale and Purchase of Loans   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  51
         10.14     Forum Selection and Consent to Jurisdiction  . . . . . . . . . . . . . . . . . . . . . . . . . . .  52
         10.15     Waiver of Jury Trial   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  53
</TABLE>






                                       iv

<PAGE>   6
                               TABLE OF CONTENTS
                                  (CONTINUED)

<TABLE>
<CAPTION>                                                      
                                                                        PAGE
                                                                        ----  
<S>              <C>   <C>                                              <C>
SCHEDULE I       -     Disclosure Schedule
SCHEDULE IIA     -     Schedule of Commitments
SCHEDULE IIB     -     Schedule of Outstandings and Commitments

EXHIBIT  2.2.1   -     Form of Competitive Bid Note
EXHIBIT  2.2.2   -     Form of Competitive Bid Quote Request
EXHIBIT  2.2.3   -     Form of Invitation for Competitive Bid Quotes
EXHIBIT  2.2.4   -     Form of Competitive Bid Quote
EXHIBIT  2.5     -     Form of Borrowing Request
EXHIBIT  2.6     -     Form of Continuation/Conversion Notice
EXHIBIT  2.8     -     Form of Revolving Note
EXHIBIT  5.1.4   -     Form of Opinion of Counsel to the Borrower
EXHIBIT  10.11   -     Form of Lender Assignment Agreement
</TABLE>






                                       v


<PAGE>   7
                     AMENDED AND RESTATED CREDIT AGREEMENT

         THIS AMENDED AND RESTATED CREDIT AGREEMENT, dated as of December 24,
1997 (as may be amended, restated, supplemented or otherwise modified from time
to time, this "Agreement"), is among NOBLE AFFILIATES, INC., a Delaware
corporation (the "Borrower"), UNION BANK OF SWITZERLAND, Houston Agency
("UBS"), as administrative agent (UBS in such capacity, together with any
successor(s) thereto in such capacity, the "Agent"), NATIONSBANK OF TEXAS, N.A.
("NB") and TEXAS COMMERCE BANK NATIONAL ASSOCIATION ("TCB"), as managing agents
(NB and TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), BANK OF MONTREAL
("BOM"), CIBC INC.  ("CIBC"), THE FIRST NATIONAL BANK OF CHICAGO ("First
Chicago"), ROYAL BANK OF CANADA ("RBC") and SOCIETE GENERALE, SOUTHWEST AGENCY
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co-Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders").

                              W I T N E S S E T H:

         WHEREAS, the Borrower, the Agent, the Managing Agents, the Co-Agents
and the Lenders have heretofore entered into that certain Credit Agreement
dated July 31, 1996, as amended pursuant to that certain First Amendment to
Credit Agreement dated October 15, 1996 (as amended, the "Original Credit
Agreement"), pursuant to which the Lenders have agreed to make available to the
Borrower a term loan facility and revolving credit facility with a competitive
bid loan subfacility;

         WHEREAS, the Borrower intends to repay all indebtedness evidenced by
and outstanding under the Original Credit Agreement as of the Effective Date
(the "Prior Indebtedness");

         WHEREAS, the Borrower has asked that the Lenders modify their
respective commitments under the Original Credit Agreement such that on the
Effective Date each Lender shall be obligated hereunder, subject to the terms
hereof, to the Commitment stated on Schedule IIA for such Lender;

         WHEREAS, the term loan facility and all the term loans thereunder have
been fully repaid and the parties hereto intend to reduce the revolving credit
facility; and

         WHEREAS, the parties hereto intend and have agreed to amend and
restate the Credit Agreement in its entirety as and pursuant to this Agreement.


<PAGE>   8
         NOW, THEREFORE, the parties hereto agree as follows:

                                   ARTICLE I

                        DEFINITIONS AND ACCOUNTING TERMS

         SECTION 1.1      Defined Terms.  The following terms (whether or not
underscored) when used in this Agreement, including its preamble and recitals,
shall, except where the context otherwise requires, have the following meanings
(such meanings to be equally applicable to the singular and plural forms
thereof):

         "Absolute Rate" means, with respect to a Competitive Bid Loan made by
a particular Lender for the relevant Absolute Rate Interest Period, the rate of
interest per annum (rounded to the nearest 1/100 of 1%) offered by such Lender
and accepted by the Borrower pursuant to Section 2.2.6(ii).

         "Absolute Rate Advance" means a borrowing hereunder consisting of the
aggregate amount of the several Absolute Rate Loans made by some or all of the
Lenders to the Borrower at the same time and for the same Absolute Rate
Interest Period.

         "Absolute Rate Auction" means a solicitation of Competitive Bid Quotes
setting forth Absolute Rates pursuant to Section 2.2.

         "Absolute Rate Interest Period" means, with respect to an Absolute
Rate Advance or an Absolute Rate Loan, a period of not less than 14 and not
more than 90 days commencing on a Business Day selected by the Borrower
pursuant to this Agreement.  If such Absolute Rate Interest Period would end on
a day which is not a Business Day, such Absolute Rate Interest Period shall end
on the next succeeding Business Day.

         "Absolute Rate Loan" means a Loan which bears interest at an Absolute
Rate.

         "Affiliate" of any Person means any other Person which, directly or
indirectly, controls, is controlled by or is under common control with such
Person (excluding any trustee under, or any committee with responsibility for
administering, any Plan).  A Person shall be deemed to be "controlled by" any
other Person if such other Person possesses, directly or indirectly, power (a)
to vote 10% or more of the securities (on a fully diluted basis) having
ordinary voting power for the election of directors or managing general
partners; or (b) to direct or cause the direction of the management and
policies of such Person whether by contract or otherwise.

         "Agent" is defined in the preamble and includes each other Person as
shall have subsequently been appointed as the successor Agent pursuant to
Section 9.4.





                                       2

<PAGE>   9
         "Agent Fee Letter" is defined in Section 3.3.2.

         "Agreement" means, on any date, this Credit Agreement as originally in
effect on the Effective Date and as thereafter from time to time amended,
supplemented, amended and restated, or otherwise modified and in effect on such
date.

         "Applicable Facility Fee Rate" means the number of basis points per
annum (based on a year of 360 days) set forth below based on the Applicable
Rating Level and the Total Debt to Capitalization Ratio on such date:



<TABLE>
<CAPTION>
================================================================================
                                                50% <
           Applicable                         Debt/Cap        Debt/Cap
           Rating Level                         > 60%       < or = to 50%
           ------------                       --------      -------------
           <S>                                  <C>              <C>
- --------------------------------------------------------------------------------
           Level I                              12.5             12.5
- --------------------------------------------------------------------------------
           Level II                             15.0             12.5
- --------------------------------------------------------------------------------
           Level III                            20.0             20.0
- --------------------------------------------------------------------------------
           Level IV                             25.0             25.0
================================================================================
</TABLE>


; provided, however, that at any time that Moody's and S&P have split ratings
of two or more rating differentials, then the Applicable Facility Fee Rate will
be determined using the following formula:

         M + S = R
         -----
           2

where (i) "M" is the number of basis points per annum determined in accordance
with the above chart using an Applicable Rating Level equal to the Moody's
Rating Level at the time of such determination and the Total Debt to
Capitalization Ratio at the time of such determination, (ii) "S" is the number
of basis points per annum determined in accordance with the above chart using
an Applicable Rating Level equal to the S&P's Rating Level at the time of such
determination and the Total Debt to Capitalization Ratio at the time of such
determination and (iii) "R" is the Applicable Facility Fee Rate.  Changes in
the Facility Fee Rate will occur automatically without prior notice.  The Agent
will give notice promptly to the Borrower and the Lenders of changes in the
Facility Fee Rate.

         "Applicable Margin" means on any date and with respect to each
Eurodollar Loan or Eurodollar Bid Rate Advance the number of basis points per
annum set forth below based on the Applicable Rating Level and the Total Debt
to Capitalization Ratio on such date:





                                       3

<PAGE>   10

<TABLE>
<CAPTION>
================================================================================
            Applicable
            ----------
           Rating Level       50% < Debt/Cap < 60%     Debt/Cap < or = to 50%
           ------------       ------------------       ----------------------
           <S>                        <C>                      <C>
- --------------------------------------------------------------------------------
           Level I                    22.5                     17.5
- --------------------------------------------------------------------------------
           Level II                    35                      22.5
- --------------------------------------------------------------------------------
           Level III                  42.5                      30
- --------------------------------------------------------------------------------
           Level IV                    50                      37.5
================================================================================
</TABLE>


; provided, however, that if Moody's and S&P have split ratings of two or more
rating differentials, then the Applicable Margin will be determined using the
following formula:

         M + S = A
         -----
           2

where (i) "M" is the number of basis points per annum determined in accordance
with the above chart using an Applicable Rating Level equal to the Moody's
Rating Level at the time of such determination and the Total Debt to
Capitalization Ratio at the time of such determination, (ii) "S" is the number
of basis points per annum determined in accordance with the above chart using
an Applicable Rating Level equal to the S&P's Rating Level at the time of such
determination and the Total Debt to Capitalization Ratio at the time of such
determination and (iii) "A" is the Applicable Margin.

Changes in the Applicable Margin will occur automatically without prior notice.
The Agent will give notice promptly to the Borrower and the Lenders of changes
in the Applicable Margins.

         "Applicable Rating Level" means at any time that Moody's and S&P have
the equivalent rating or split ratings of not more than one rating
differential, of the Borrower's senior unsecured long-term debt, the level set
forth in the chart below under the heading "Applicable Rating Level" opposite
the rating under the heading "Moody's" or "S&P" which is the higher of the two
if split ratings or opposite the ratings under the headings "Moody's" and "S&P"
if equivalent; provided that at any time that Moody's and S&P have split
ratings of more than one rating differential, there shall be no Applicable
Rating Level for purposes of this Agreement.



<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
Applicable Rating Level             Moody's                      S&P
- -----------------------             -------                      ---
    <S>                           <C>                       <C>
- --------------------------------------------------------------------------------
    Level I                       > or = to Baa1            > or = to>BBB+
- --------------------------------------------------------------------------------
    Level II                           Baa2                      BBB
- --------------------------------------------------------------------------------
    Level III                          Baa3                      BBB-
- --------------------------------------------------------------------------------
    Level IV                      < or = to Ba1             < or = to BB+
- --------------------------------------------------------------------------------
</TABLE>






                                       4

<PAGE>   11
For example, if the Moody's rating is Baa1 and the S&P rating is BBB, Level I
shall apply.

         For purposes of the foregoing, (i) "equal to or more than" means a 
rating equal to or more favorable than; "equal to or less than" means a rating
equal to or less favorable than; "more than" means a rating greater than; "less
than" means a rating less than; (ii) if ratings for the Borrower's senior
unsecured long-term debt shall not be available from S&P or Moody's, Level IV
shall be deemed applicable; (iii) if determinative ratings shall change (other
than as a result of a change in the rating system used by any applicable Rating
Agency) such that a change in Applicable Rating Level would result, such change
shall effect a change in Applicable Rating Level as of the day on which it is
first announced by the applicable Rating Agency, and any change in the
Applicable Margin or percentage used in calculating fees due hereunder shall
apply commencing on the effective date of such change and ending on the date
immediately preceding the effective date of the next such change; and (iv) if
the rating system of any of the Rating Agencies shall change prior to the date
all obligations hereunder have been paid and the Commitments canceled, the
Borrower and the Lenders shall negotiate in good faith to amend the references
to specific ratings in this definition to reflect such changed rating system,
and pending such amendment, if no Applicable Rating Level is otherwise
determinable based upon the foregoing, Level IV shall apply.

         "Assignee Lender" is defined in Section 10.11.1.

         "Authorized Officer" means, relative to the Borrower, those of its
officers whose signatures and incumbency shall have been certified to the Agent
and the Lenders pursuant to Section 5.1.1.

         "Base Rate" means, on any date and with respect to all Base Rate
Loans, a fluctuating rate of interest per annum equal to the higher of (a) the
rate of interest most recently announced by UBS at its Domestic Office as its
base rate for Dollar loans; and (b) the Federal Funds Rate most recently
determined by the Agent plus  1/2%.  The Base Rate is not necessarily intended
to be the lowest rate of interest determined by the UBS in connection with
extensions of credit.  Changes in the rate of interest on that portion of any
Loans maintained as Base Rate Loans will take effect simultaneously with each
change in the Base Rate.  The Agent will give notice promptly to the Borrower
and the Lenders of changes in the Base Rate.

         "Base Rate Loan" means a Loan bearing interest at a fluctuating rate
determined by reference to the Base Rate.

         "Borrower" is defined in the preamble, and includes its permitted
successors and assigns.

         "Borrowing" means any extension of credit (as opposed to any
continuation or conversion thereof) made by the Lenders by way of Competitive
Bid Advances and Revolving Loans.

         "Borrowing Date" means a date on which a Borrowing is made hereunder.





                                       5

<PAGE>   12
         "Borrowing Request" means a loan request and certificate duly executed
by an Authorized Officer of the Borrower, substantially in the form of Exhibit
2.5 hereto.

         "Business Day" means (a) any day which is neither a Saturday or Sunday
nor a legal holiday on which banks are authorized or required to be closed in
New York, New York; and (b) relative to the making, continuing, prepaying or
repaying of any Eurodollar Borrowing, any day on which dealings in Dollars are
carried on in the London and New York Eurodollar interbank market.

         "Capitalization" means the sum, at any time outstanding and without
duplication, of (i) Debt plus (ii) Stockholders' Equity.

         "Capitalized Lease Liabilities" means all monetary obligations of the
Borrower or any of its Subsidiaries under any leasing or similar arrangement
which, in accordance with GAAP, would be classified as capitalized leases, and,
for purposes of this Agreement and each other Loan Document, the amount of such
obligations shall be the capitalized amount thereof, determined in accordance
with GAAP, and the stated maturity thereof shall be the date of the last
payment of rent or any other amount due under such lease prior to the first
date upon which such lease may be terminated by the lessee without payment of a
penalty.

         "CERCLA" means the Comprehensive Environmental Response, Compensation
and Liability Act of 1980, as amended.

         "Change in Control" means (a) the acquisition by any Person, or two or
more Persons acting in concert, of beneficial ownership (within the meaning of
Rule 13d-3 of the Securities and Exchange Commission under the Securities
Exchange Act of 1934) of 30% or more of the outstanding shares of voting stock
of the Borrower; or (b) the failure of the Borrower to own, free and clear of
all Liens or encumbrances (other than non-consensual Liens or encumbrances
which are not material or which are fully discharged or with respect to
obligations which are fully bonded, in either case within thirty (30) days
after the imposition of such Lien or encumbrance) at least 100% of the
outstanding shares of voting stock of SOC on a fully diluted basis.

         "Co-Agents" is defined in the preamble.

         "Code" means the Internal Revenue Code of 1986, as amended, reformed
or otherwise modified from time to time.

         "Commitment" means, relative to any Lender, such Lender's obligation
to make Revolving Loans pursuant to Section 2.1.1.

         "Commitment Amount" means, on any date, $300,000,000, as such amount
may be reduced from time to time pursuant to Section 2.3.





                                       6

<PAGE>   13
         "Commitment Termination Date" means the earliest of (a) the fifth
anniversary of the Effective Date; (b) the date on which the Commitment Amount
is terminated in full or reduced to zero pursuant to Section 2.3; and (c) the
date on which any Commitment Termination Event occurs.  Upon the occurrence of
any event described in clause (b) or (c), the Commitments shall terminate
automatically and without any further action.

         "Commitment Termination Event" means (a) the occurrence of any Default
described in clauses (a) through (d) of Section 8.1.9 with respect to the
Borrower or any Significant Subsidiary; or (b) the occurrence and continuance
of any other Event of Default and either (i) the declaration of the Loans to be
due and payable pursuant to Section 8.3, or (ii) in the absence of such
declaration, the giving of notice by the Agent, acting at the direction of the
Required Lenders, to the Borrower that the Commitments have been terminated.

         "Competitive Bid Advance" means a borrowing hereunder consisting of
the aggregate amount of the (i) several Eurodollar Bid Rate Advances or (ii)
several Absolute Rate Advances, made by some or all of the Lenders to the
Borrower at the same time, at the same interest basis, and for the same
Interest Period.

         "Competitive Bid Borrowing Notice" is defined in Section 2.2.6.

         "Competitive Bid Fee Letter" is defined in Section 2.2.8.

         "Competitive Bid Loan" means a Eurodollar Bid Rate Loan or an Absolute
Rate Loan, as the case may be.

         "Competitive Bid Margin" means the margin above, at or below the
applicable Eurodollar Rate offered for a Eurodollar Bid Rate Loan, expressed as
a percentage (rounded to the nearest 1/100 of 1%) to be added or subtracted
from such Eurodollar Rate.

         "Competitive Bid Note" means a promissory note in substantially the
form of Exhibit 2.2.1 hereto, with appropriate insertions, duly executed and
delivered to the Agent by the Borrower for the account of a Lender and payable
to the order of such Lender, including any amendment, modification, renewal or
replacement of such promissory note.

         "Competitive Bid Quote" means a Competitive Bid Quote substantially in
the form of Exhibit 2.2.4 hereto completed and delivered by a Lender to the
Agent in accordance with Section 2.2.4.

         "Competitive Bid Quote Request" means a Competitive Bid Quote Request
substantially in the form of Exhibit 2.2.2 hereto completed and delivered by
the Borrower to the Agent in accordance with Section 2.2.2.





                                       7

<PAGE>   14
         "Continuation/Conversion Notice" means a notice of continuation or
conversion and certificate duly executed by an Authorized Officer of the
Borrower, substantially in the form of Exhibit 2.6 hereto.

         "Controlled Group" means all members of a controlled group of
corporations and all members of a controlled group of trades or businesses
(whether or not incorporated) under common control which, together with the
Borrower, are treated as a single employer under Section 414(b) or 414(c) of
the Code or Section 4001 of ERISA.

         "Debt" means the consolidated Indebtedness of the Borrower and its
Subsidiaries.

         "Default" means any Event of Default or any Unmatured Event of
Default.

         "Default Margin" means 2%.

         "Disclosure Schedule" means the Disclosure Schedule attached hereto as
Schedule I, as it may be amended, supplemented or otherwise modified from time
to time by the Borrower with the written consent of the Agent and the Required
Lenders.

         "Dollar" and the sign "$" mean lawful money of the United States.

         "Domestic Office" means, relative to any Lender, the office of such
Lender designated as such below its signature hereto or designated in the
Lender Assignment Agreement or such other office of a Lender (or any successor
or assign of such Lender) within the United States as may be designated from
time to time by notice from such Lender, as the case may be, to each other
Person party hereto.  A Lender may have separate Domestic Offices for purposes
of making, maintaining or continuing, as the case may be, Base Rate Loans.

         "EBITDA" means, for any period, the sum of (i) the consolidated net
income of the Borrower and its Subsidiaries for such period before non-cash
non-recurring items, gains or losses on dispositions of assets and the
cumulative effect of changes in accounting principles plus (ii) to the extent
included in the determination of such income, the consolidated charges for such
period for interest, depreciation, depletion and amortization plus (or, if
there is a benefit from income taxes, minus) (iii) to the extent included in
the determination of such income, the amount of the provision for or benefit
from income taxes; provided that in determining such consolidated net income,
such consolidated charges and such provision for or benefit from income taxes,
there shall be excluded therefrom (to the extent otherwise included therein)
the net income (but not loss) of, charges for interest, depreciation, depletion
and amortization of, and such provision for (but not benefit from) income taxes
of, any Person which is subject to any contractual restriction which prevents
the payment of dividends or the making of distributions on the capital stock or
other ownership interests of such Person to the extent of such contractual
restrictions.





                                       8

<PAGE>   15
         "EDC" means Energy Development Corporation, a New Jersey corporation,
and its permitted successors and assigns.

         "Effective Date" means the date this Agreement becomes effective
pursuant to Section 10.8.

         "Environmental Law"  means any federal, state, or local statute, or
rule or regulation promulgated thereunder, any judicial or administrative order
or judgment to which the Borrower or any Subsidiary is party or which are
applicable to the Borrower or any Subsidiary (whether or not by consent), and
any provision or condition of any governmental permit, license or other
operating authorization, relating to protection of the environment, persons or
the public welfare from actual or potential exposure for the effects of
exposure to any actual or potential release, discharge, spill or emission
(whether past or present) of, or regarding the manufacture, processing,
production, gathering, transportation, importation, use, treatment, storage or
disposal of, any chemical, raw material, pollutant, contaminant or toxic,
corrosive, hazardous, or non-hazardous substance or waste, including petroleum.

         "Equatorial Guinea Project" means the participation by the Borrower
and/or its Subsidiaries in the construction of a methanol plant in Equatorial
Guinea, which participation shall not exceed a 50% equity interest in the
aggregate.

         "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended, and any successor statute of similar import, together with the
regulations thereunder, in each case as in effect from time to time.
References to sections of ERISA also refer to any successor sections.

         "Eurodollar Auction" means a solicitation of Competitive Bid Quotes
setting forth Competitive Bid Margins pursuant to Section 2.2.

         "Eurodollar Bid Rate" means, with respect to a Loan made by a given
Lender for the relevant Eurodollar Interest Period, the sum of (i) the
Eurodollar Rate and (ii) the Competitive Bid Margin offered by such Lender and
accepted by the Borrower pursuant to Section 2.2.6(i).

         "Eurodollar Bid Rate Advance" means a Competitive Bid Advance which
bears interest at a Eurodollar Bid Rate.

         "Eurodollar Bid Rate Loan" means a Competitive Bid Loan which bears
interest at a Eurodollar Bid Rate.

         "Eurodollar Borrowing" means a borrowing hereunder consisting of the
aggregate amount of the (i) several Eurodollar Loans or (ii) several Eurodollar
Bid Rate Loans, made by all or some of the Lenders to the Borrower, at the same
time, at the same interest rate and for the same Interest Period.





                                       9

<PAGE>   16
         "Eurodollar Loan" means a Loan bearing interest, at all times during
an Interest Period applicable to such Loan, at a fixed rate of interest
determined by reference to the Eurodollar Rate.

         "Eurodollar Office" means, relative to any Lender, the office of such
Lender designated as such below its signature hereto or designated in the
Lender Assignment Agreement or such other office of a Lender as designated from
time to time by notice from such Lender to the Borrower and the Agent, whether
or not outside the United States, which shall be making or maintaining
Eurodollar Loans of such Lender hereunder.

         "Eurodollar Rate" means, relative to any Interest Period for
Eurodollar Loans, the rate of interest equal to the average of the offered
quotations appearing on Telerate Page 3750 or if such Telerate Page shall not
be available, on the LIBO page on the Reuters Screen (or any page that can
reasonably be considered a replacement page) at approximately 11:00 a.m.,
London time, (or as soon thereafter as practicable) on the day two Business
Days prior to the first day of such Interest Period for dollar deposits having
a term comparable to such Interest Period.  If none of such Telerate Page 3750
or Reuters Screen LIBO page (or replacement page) is available, then the
"Eurodollar Rate" shall mean, with respect to any Interest Period for any
applicable Eurodollar Loan, the rate per annum determined by the Agent to be
the average of the rates quoted by the Reference Banks at approximately 10:00
a.m., New York time, (or as soon thereafter as practicable) on the day two
Business Days prior to the first day of such Interest Period for the offering
by such Reference Banks to leading banks in the interbank market of U.S. dollar
deposits having a term comparable to such Interest Period and in an amount
comparable to the principal amount of the Eurodollar Loan of such respective
Reference Bank to which such Interest Period relates.  If any Reference Bank
does not furnish a timely quotation, the Agent shall determine the relevant
interest rate on the basis of the quotation or quotations furnished by the
remaining Reference Bank or Banks.

         "Event of Default" is defined in Section 8.1.

         "Facility" is defined in Section 2.1.1.

         "Federal Funds Rate" means, for any day, the average rate quoted to
the Agent at approximately 11:00 a.m. (New York City time) on such day (or, if
such day is not a Business Day, on the next preceding Business Day) for
overnight Federal Funds transactions arranged by New York Federal Funds brokers
selected by the Agent.

         "Fee Letter" means the Agent Fee Letter or the Competitive Bid Fee
Letter, as the case may be.

         "Fiscal Quarter" means any quarter of a Fiscal Year.





                                       10

<PAGE>   17
         "Fiscal Year" means any period of twelve consecutive calendar months
ending on December 31; references to a Fiscal Year with a number corresponding
to any calendar year (e.g., the "1988 Fiscal Year") refer to the Fiscal Year
ending on December 31 occurring during such calendar year.

         "Fixed Rate Borrowing" means a borrowing hereunder consisting of the
aggregate amount of the (i) several Eurodollar Bid Rate Loans, or (ii) several
Absolute Rate Loans, or (iii) several Eurodollar Loans, made by all or some of
the Lenders to the Borrower at the same time and for the same Interest Period.

         "F.R.S. Board" means the Board of Governors of the Federal Reserve
System or any successor thereto.

         "GAAP" is defined in Section 1.4.

         "Guaranteed Liability" means any agreement, undertaking or arrangement
by which any Person guarantees, endorses or otherwise becomes or is
contingently liable upon (by direct or indirect agreement, contingent or
otherwise, to provide funds for payment, to supply funds to, or otherwise to
invest in, a debtor, or otherwise to assure a creditor against loss) the
Indebtedness, obligation or any other liability (other than guaranties of trade
payables and guaranties of performance obligations) of any other Person (other
than by endorsements of instruments in the course of collection), or guarantees
the payment of dividends or other distributions upon the shares of any other
Person.  The amount of any Person's obligation under any Guaranteed Liability
shall (subject to any limitation set forth therein) be deemed to be the
outstanding principal amount (or maximum principal amount, if larger) of the
debt, obligation or other liability (other than guaranties of trade payables
and guaranties of performance obligations) guaranteed thereby.

         "Hazardous Material" means:  i) any "hazardous substance", as defined
by CERCLA; ii) any "hazardous waste", as defined by the Resource Conservation
and Recovery Act, as amended; iii) any petroleum, crude oil or any fraction
thereof; iv) any hazardous, dangerous or toxic chemical, material, waste or
substance within the meaning of any Environmental Law; v) any radioactive
material, including any naturally occurring radioactive material, and any
source, special or by-product material as defined in 42 U.S.C. Section  2011
et. seq., and any amendments or reauthorizations thereof; vi)
asbestos-containing materials in any form or condition; or vii) polychlorinated
biphenyls in any form or condition.

         "Hedging Obligations" means, with respect to any Person, all
liabilities of such Person under derivative contracts, including interest rate
or commodity swap agreements, interest rate or commodity cap agreements and
interest rate or commodity collar agreements, and all similar agreements or
arrangements.

         "herein", "hereof", "hereto", "hereunder" and similar terms contained
in this Agreement or any other Loan Document refer to this Agreement or such
other Loan Document, as the case may be, as a whole and not to any particular
Section, paragraph or provision of this Agreement or such other Loan Document.





                                       11

<PAGE>   18
         "Impermissible Qualification" means, relative to the opinion or
certification of any independent public accountant as to any financial
statement of the Borrower, any qualification or exception to such opinion or
certification (a) which is of a "going concern" or similar nature; (b) which
relates to the limited scope of examination of matters relevant to such
financial statement; or (c) which relates to the treatment or classification of
any item in such financial statement and which, as a condition to its removal,
would require an adjustment to such item the effect of which would be to cause
the Borrower to be in default of any of its obligations under Section 7.2.4.

         "including" means including without limiting the generality of any
description preceding such term.

         "Indebtedness" of any Person means, without duplication: (a) all
obligations of such Person for borrowed money and all obligations of such
Person evidenced by bonds, debentures, notes or other similar instruments; (b)
all obligations, contingent or otherwise, relative to (i) banker's acceptances
issued for the account of such Person and (ii) the face amount of all letters
of credit, whether or not drawn, to the extent that such letters of credit
support the payment of financial obligations; (c) all obligations of such
Person as lessee under leases which have been or should be, in accordance with
GAAP, recorded as Capitalized Lease Liabilities; (d) whether or not so included
as liabilities in accordance with GAAP, all obligations of such Person to pay
the deferred purchase price of property or services (except accounts payable
arising in the ordinary course of business), and indebtedness (excluding
prepaid interest thereon) secured by a Lien on property owned or being
purchased by such Person (including indebtedness arising under conditional
sales or other title retention agreements), whether or not such indebtedness
shall have been assumed by such Person or is limited in recourse; and (e) all
Guaranteed Liabilities of such Person in respect of any of the foregoing.  For
all purposes of this Agreement, the Indebtedness of any Person shall include
the Indebtedness of any partnership or joint venture in which such Person is a
general partner or a joint venturer unless such Indebtedness by its terms is
expressly non-recourse to such general partner or joint venturer.

         "Indemnified Liabilities" is defined in Section 10.4.

         "Indemnified Parties" is defined in Section 10.4.

         "Interest Period" means, relative to any Fixed Rate Borrowings, (a)
with respect to Eurodollar Borrowings, the period beginning on (and including)
the date on which such Eurodollar Borrowing is made or continued as, or
converted into, a Eurodollar Borrowing pursuant to Section 2.5 or 2.6 and shall
end on (but exclude) the day which numerically corresponds to such date one,
two, three or six months thereafter (or, if such month has no numerically
corresponding day, on the last Business Day of such month), as the Borrower may
select in its relevant notice pursuant to Section 2.5, or (b) with respect to
Absolute Rate Advances, as the period as the Borrower may select pursuant to
Section 2.2; provided, however, that (a) the Borrower shall not be permitted to
select Interest Periods to be in effect at any one time which have expiration
dates occurring on more than five different dates; (b) Interest Periods
commencing on the same date for Loans or Competitive Bid Advances comprising
part of the same Borrowing shall be of the same duration; (c) if such Interest





                                       12

<PAGE>   19
Period would otherwise end on a day which is not a Business Day, such Interest
Period shall end on the next following Business Day (unless, if such Interest
Period applies to Eurodollar Loans, such next following Business Day is the
first Business Day of a calendar month, in which case such Interest Period
shall end on the Business Day next preceding such numerically corresponding
day); and (d) no Interest Period may end later than the date set forth in
clause (a) of the definition of "Commitment Termination Date".

         "Interests" is defined in Section 10.13.

         "Invitation for Competitive Bid Quotes" is defined in Section 2.2.3.

         "Law" means any law (including, without limitation, any zoning law or
ordinance or any Environmental Law), statute, rule, regulation, ordinance,
order, directive, code, interpretation, judgment, decree, injunction, writ,
determination, award, permit, license, authorization, direction, requirement or
decision of and agreement with or by any government or governmental department,
commission, board, court, authority, agency, official or officer, domestic or
foreign.

         "Lender Assignment Agreement" means a Lender Assignment Agreement
substantially in the form of Exhibit 10.11 hereto.

         "Lenders" means the financial institutions listed on the signature
pages hereto and their respective successors and assigns in accordance with
Section 10.11 (including any commercial lending institution becoming a party
hereto pursuant to a Lender Assignment Agreement) or otherwise by operation of
law.

         "Lien" means any security interest, mortgage, pledge, hypothecation,
assignment, deposit arrangement, encumbrance, lien (statutory or otherwise),
charge against or interest in property to secure payment of a debt or
performance of an obligation or other priority arrangement of any kind or
nature whatsoever.

         "Loan" means, as the context may require, either a Revolving Loan or a
Competitive Bid Loan.

         "Loan Advances" means the Loans of the same Type and, in the case of
Fixed Rate Loans, having the same Interest Period made by all Lenders on the
same Business Day and pursuant to the same Borrowing Request in accordance with
Section 2.1.

         "Loan Documents" means this Agreement, each of the Notes, each
Competitive Bid Quote Request, each Borrowing Request, each Committed Borrowing
Notice, each Fee Letter, together in each case with all exhibits, schedules and
attachments thereto, and all other agreements and instruments from time to time
executed and delivered by the Borrower or any of its Subsidiaries pursuant to
or in connection with any of the foregoing.

         "Managing Agents" is defined in the preamble.





                                       13

<PAGE>   20
         "Material Adverse Effect" means a material adverse effect on (i) the
business, property, financial condition or results of operations of the
Borrower and its Subsidiaries (taken as a whole) or (ii) the ability of the
Borrower to perform its payment obligations under any of the Loan Documents.

         "Moody's" means Moody's Investors Service, Inc. and any successor
thereto that is a nationally-recognized rating agency.

         "Moody's Rating Level" means at any time a determination thereof is to
be made, the level shown under the heading "Applicable Rating Level" opposite
the Borrower's then rating of its senior unsecured long-term debt shown in the
column "Moody's" in the definition of Applicable Rating Level; provided that at
any time that the Borrower does not have a rating of its senior unsecured
long-term debt by Moody's, the Moody's Rating Level shall be deemed to be Level
IV.

         "Noble Gas" means Noble Gas Marketing, Inc., a Delaware corporation,
and its permitted successors and assigns.

         "Noble Trading" means Noble Trading, Inc., a Delaware corporation, and
its permitted successors and assigns.

         "Note" means, as the context may require, either a Revolving Note or a
Competitive Bid Note; and "Notes" means some or all of the foregoing.

         "Obligations" means all obligations (monetary or otherwise) of the
Borrower arising under or in connection with this Agreement, the Notes and each
other Loan Document.

         "Organic Document" means, relative to the Borrower, its certificate of
incorporation, its by-laws and all shareholder agreements, voting trusts and
similar arrangements applicable to any of its authorized shares of capital
stock.

         "Original Credit Agreement" is defined in the first recital.

         "Participant" is defined in Section 10.11.

         "Payment Date" is defined in Section 3.2.4.





                                       14

<PAGE>   21
         "Payment Office" means:

                 Union Bank of Switzerland, New York Branch
                 299 Park Avenue
                 New York, New York 10171

                 Attention:       James Broadus
                 Phone:           (212) 821-3227
                 Facsimile:       (212) 821-3259

                 Payment instructions:     via Fed Wire to ABA 0260 0843 9 
                                           (UBS, New York Branch
                                           Att:  Loan Servicing)
                 Reference:       NOBLE AFFILIATES

         "PBGC" means the Pension Benefit Guaranty Corporation and any entity
succeeding to any or all of its functions under ERISA.

         "Pension Plan" means a "pension plan", as such term is defined  in
section 3(2) of ERISA, which is subject to Title IV of ERISA (other than a
multiemployer plan as defined in section 4001(a)(3) of ERISA), and to which the
Borrower or any corporation, trade or business that is, along with the
Borrower, a member of a Controlled Group, may have liability, including any
liability by reason of having been a substantial employer within the meaning of
section 4063 of ERISA at any time during the preceding five years, or by reason
of being deemed to be a contributing sponsor under section 4069 of ERISA.

         "Percentage" means, relative to any Lender, the percentage set forth
in Schedule II attached hereto or set forth in the most recent Lender
Assignment Agreement executed by such Lender, as such percentage may be
adjusted from time to time pursuant to Lender Assignment Agreements executed by
such Lender and its Assignee Lenders and delivered pursuant to Section 10.11.

         "Person" means any natural person, corporation, partnership, firm,
association, trust, government, governmental agency or any other entity,
whether acting in an individual, fiduciary or other capacity.

         "Plan" means any Pension Plan or Welfare Plan.

         "Prior Indebtedness" is defined in the fourth recital.

         "Quarterly Payment Date" means the last day of each March, June,
September, and December or, if any such day is not a Business Day, the next
succeeding Business Day.

         "Rating Agency" means either of S&P or Moody's.





                                       15

<PAGE>   22
         "Reference Banks" means each of the Agent and any two Lenders selected
by UBS in its sole discretion.

         "Release" means a "release", as such term is defined in CERCLA.

         "Required Lenders" means Lenders in the aggregate holding at least 67%
of the aggregate unpaid principal amount of the outstanding Borrowings (other
than Competitive Bid Loans) and if no Borrowings (other than Competitive Bid
Loans) are outstanding, Lenders having at least 67% of the then Total
Commitment.

         "Resource Conservation and Recovery Act" means the Resource
Conservation and Recovery Act, 42 U.S.C. Section 690, et seq., as in effect
from time to time.

         "Restricted Indebtedness" means, at the time of determination and
after giving effect to any Indebtedness incurred or to be incurred in
connection with such determination and to any substantially contemporaneous use
of the proceeds thereof to repay other Indebtedness, the sum of (i) the
aggregate principal amount of the Indebtedness of the Borrower and its
Significant Subsidiaries then secured (or to be secured in connection with such
determination) by Liens permitted under Section 7.2.2(n) plus (ii) the
aggregate principal amount of the Indebtedness of the Significant Subsidiaries
then outstanding (or to be incurred in connection with such determination)
other than Indebtedness  of the Significant Subsidiaries permitted by Section
7.2.5(i).

         "Restricted Indebtedness Basket" means, at the time of determination,
an amount equal to 5% of the Borrower's consolidated tangible net worth as
reported in the Borrower's consolidated financial statements most recently
delivered to the Lenders.

         "Revolving Loan" is defined in Section 2.1.1.

         "Revolving Note" means a promissory note of the Borrower payable to
any Lender, in the form of Exhibit 2.8 hereto (as such promissory note may be
amended, endorsed or otherwise modified from time to time), evidencing the
aggregate Indebtedness of the Borrower to such Lender resulting from
outstanding Revolving Loans, and also means all other promissory notes accepted
from time to time in substitution therefor or renewal thereof.

         "S&P" means Standard & Poor's Ratings Group and any successor thereto
that is a nationally-recognized rating agency.

         "S&P's Rating Level" means at any time a determination thereof is to
be made, the level shown under the heading "Applicable Rating Level" opposite
the Borrower's then rating of its senior unsecured long-term debt shown in the
column "S&P's" in the definition of Applicable Rating Level; provided that at
any time that the Borrower does not have a rating of its senior unsecured
long-term debt by S&P, the S&P Rating Level shall be deemed to be Level IV.





                                       16

<PAGE>   23
         "Significant Subsidiary" means (a) SOC, EDC and each other Subsidiary
of the Borrower (other than Noble Gas or Noble Trading) that (i) accounts for
at least 5% of the consolidated revenues of the Borrower and its Subsidiaries
for any consecutive four quarter period ending on the last day of a fiscal
quarter, or (ii) has assets which represent at least 5% of the consolidated
assets of the Borrower and its Subsidiaries as of the last day of any fiscal
quarter of the Borrower immediately preceding the date as of which any such
determination is made, all of which, with respect to clauses (a)(i) and (ii),
shall be as reflected on the financial statements of the Borrower and its
Subsidiaries for such period, or as of such date, as the case may be; or (b)
Noble Gas or Noble Trading, or both, as the case may be, to the extent that
Noble Gas or Noble Trading or both, as the case may be, (i) has consolidated
net income of at least 10% of the consolidated net income of the Borrower and
its Subsidiaries for any consecutive four quarter period ending on the last day
of a fiscal quarter, or (ii) has consolidated tangible net worth of at least 5%
of the consolidated tangible net worth of the Borrower and its Subsidiaries as
of the last day of any fiscal quarter of the Borrower immediately preceding the
date as of which any such determination is made, all of which, with respect to
clauses (b)(i) and (ii), shall be as reflected on the financial statements of
the Borrower and its Subsidiaries for such period, or as of such date.

         "SPV" means any Subsidiary of the Borrower that is not a Significant
Subsidiary and that is designated by the Borrower in a written notice to the
Agent as an SPV; provided that the Borrower shall not designate as an SPV any
Subsidiary of the Borrower that has any operations at the time of such
designation or any Subsidiary of the Borrower that owns, directly or
indirectly, in whole or in part, any other Subsidiary of the Borrower at the
time of such designation.

         "SOC" means Samedan Oil Corporation, a Delaware corporation, and its
permitted successors and assigns.

         "Solvent" means, with respect to any Person at any time, a condition
under which: a) the fair saleable value of such Person's assets is, on the date
of determination, greater than the total amount of such Person's liabilities
(including contingent and unliquidated liabilities) at such time; b) such
Person is able to pay all of its liabilities as such liabilities mature; and c)
such Person does not have unreasonably small capital with which to conduct its
business.  For purposes of this definition (i) the amount of a Person's
contingent or unliquidated liabilities at any time shall be that amount which,
in light of all the facts and circumstances then existing, represents the
amount which can reasonably be expected to become an actual or matured
liability; (ii) the "fair saleable value" of an asset shall be the amount which
may be realized within a reasonable time either through collection or sale of
such asset at its regular market value; and (iii) the "regular market value" of
an asset shall be the amount which a capable and diligent business person could
obtain for such asset from an interested buyer who is willing to purchase such
asset under ordinary selling conditions.

         "Stated Maturity Date" means the fifth anniversary of the Effective
Date.

         "Stockholders' Equity" means, as of the time of any determination
thereof is to be made, the sum of the Borrower's capital stock (which shall
exclude treasury stock and any capital stock subject to mandatory redemption by
the issuer at the option of the holder thereof) and additional paid-in





                                       17

<PAGE>   24
capital, plus retained earnings (minus accumulated deficit), all as shown on
the consolidated balance sheet of the Borrower and its Subsidiaries and based
on GAAP.

         "Subsidiary" means, with respect to any Person, (a) any corporation of
which more than 50% of the outstanding capital stock having ordinary voting
power to elect a majority of the board of directors of such corporation
(irrespective of whether at the time capital stock of any other class or
classes of such corporation shall or might have voting power upon the
occurrence of any contingency) is at the time directly or indirectly owned by
such Person, by such Person and one or more other Subsidiaries of such Person,
or by one or more other Subsidiaries of such Person, (b) any partnership of
which such Person, such Person and one or more other Subsidiaries of such
Person, or one or more other Subsidiaries of such Person is a general partner
and (c) any limited liability company in which such Person, such Person and one
or more other Subsidiaries of such Person, or one or more other Subsidiaries of
such Person is a member or manager.

         "Taxes" is defined in Section 4.6.

         "Total Commitment" means the aggregate of all the Lenders'
Commitments.

         "Total Debt to Capitalization Ratio" means the ratio of (a) total Debt
to (b) total Capitalization.

         "Total Interest Expense" means with respect to any period for which a
determination thereof is to be made, the sum, without duplication, of (i) the
aggregate amount of all interest accrued (whether or not paid) on all
Indebtedness of the Borrower and its Subsidiaries on a consolidated basis plus
(ii) the portion of any Capitalized Lease Liabilities allocable to interest
expense in accordance with GAAP.

         "Type" means, relative to any Loan, the portion thereof, if any, being
maintained as a Base Rate Loan or a Eurodollar Loan.

         "UBS" is defined in the preamble, and includes its successors and
assigns.

         "United States" or "U.S." means the United States of America, its
fifty States and the District of Columbia.

         "Unmatured Event of Default" means any condition, occurrence or event
which, after notice or lapse of time or both, would constitute an Event of
Default.

         "Welfare Plan" means a "welfare plan", as such term is defined in
section 3(1) of ERISA.

         SECTION 1.2      Use of Defined Terms.  Unless otherwise defined or
the context otherwise requires, terms for which meanings are provided in this
Agreement shall have such meanings when used in the Disclosure Schedule and in
each Note, Borrowing Request, Competitive Bid Quote Request, Competitive Bid
Borrowing Notice, Continuation/Conversion Notice, Loan Document,





                                       18

<PAGE>   25
notice and other communication delivered from time to time in connection with
this Agreement or any other Loan Document.

         SECTION 1.3      Cross-References.  Unless otherwise specified,
references in this Agreement and in each other Loan Document to any Article or
Section are references to such Article or Section of this Agreement or such
other Loan Document, as the case may be, and, unless otherwise specified,
references in any Article, Section or definition to any clause are references
to such clause of such Article, Section or definition.

         SECTION 1.4      Accounting and Financial Determinations.  Unless
otherwise specified, all accounting terms used herein or in any other Loan
Document shall be interpreted, all accounting determinations and computations
hereunder or thereunder (including under Section 7.2.4) shall be made, and all
financial statements required to be delivered hereunder or thereunder shall be
prepared in accordance with, those generally accepted accounting principles
("GAAP") applied in the preparation of the financial statements referred to in
Section 6.5.


                                   ARTICLE II

                  THE FACILITY, BORROWING PROCEDURES AND NOTES

         SECTION 2.1      The Facility.

         SECTION 2.1.1    Description of the Facility.  The Lenders grant to
the Borrower a revolving credit facility (the "Facility") pursuant to which,
and upon the terms and subject to the conditions herein set out and provided
that no Default or Unmatured Default has occurred and is continuing from time
to time on any Business Day occurring prior to the Commitment Termination Date,
each Lender severally agrees to make revolving loans in U.S. Dollars (relative
to such Lender, its "Revolving Loans") to the Borrower equal to such Lender's
Percentage of the aggregate amount of Revolving Loans requested by the Borrower
to be made on such day (the commitment of each Lender described in this Section
2.1.1 is herein referred to as its "Commitment").  In addition, each Lender
may, in its sole discretion, make bids to make Competitive Bid Loans in U.S.
Dollars to the Borrower in accordance with Section 2.2.  No Lender shall be
permitted or required to make (i) any Revolving Loan or Competitive Bid Loan
if, after giving effect thereto, the aggregate outstanding principal amount of
all Revolving Loans plus Competitive Bid Loans of all Lenders would exceed the
Commitment Amount, and (ii) any Revolving Loan if, after giving effect thereto,
the aggregate amount of all Revolving Loans of such Lender would exceed the
Lender's Percentage of the Commitment Amount.  Subject to clause (i) in the
immediately preceding sentence, any Lender may make Competitive Bid Loans in
excess of such Lender's Percentage of the Commitment.

         SECTION 2.1.2    Availability of Facility.  Subject to the terms of
this Agreement, the Facility is available to the Borrower from the date of this
Agreement to the Commitment Termination Date, and the Borrower may borrow,
repay and reborrow under the Facility at any time prior to the Commitment
Termination Date.





                                       19

<PAGE>   26
         SECTION 2.2      Competitive Bid Advances.

         SECTION 2.2.1    Competitive Bid Option.  In addition to Loans
pursuant to Section 2.1, but subject to the terms and conditions of this
Agreement (including, without limitation, the limitation set forth in Section
2.1.1 as to the maximum aggregate principal amount of all outstanding Loans
hereunder), the Borrower may, as set forth in this Section 2.2, request the
Lenders, prior to the Commitment Termination Date, to make offers to make
Competitive Bid Advances to the Borrower.  Each Lender may, but shall have no
obligation to, make such offers and the Borrower may, but shall have no
obligation to, accept any such offers in the manner set forth in this Section
2.2.

         SECTION 2.2.2    Competitive Bid Quote Request.  The Borrower may
request offers to make Competitive Bid Loans under Section 2.2 by transmitting
to the Agent by telex or telecopy a Competitive Bid Quote Request so as to be
received no later than (i) 10:00 a.m. (New York time) at least four Business
Days prior to the Borrowing Date proposed therein, in the case of a Eurodollar
Auction or (ii) 10:00 a.m. (New York time) at least one Business Day prior to
the Borrowing Date proposed therein, in the case of an Absolute Rate Auction.
The Competitive Bid Quote Request shall specify (i) the proposed Borrowing
Date, which shall be a Business Day, for the proposed Competitive Bid Advance;
(ii) the aggregate principal amount of such Competitive Bid Advance; (iii)
whether the Competitive Bid Quotes requested are to set forth a Competitive Bid
Margin or an Absolute Rate, or both; and (iv) the Interest Period applicable
thereto (which may not end after the Commitment Termination Date).

         The Borrower may request offers to make Competitive Bid Loans for more
than one Interest Period and for a Eurodollar Auction and an Absolute Rate
Auction in a single Competitive Bid Quote Request.  No Competitive Bid Quote
Request shall be given within three Business Days (or upon reasonable prior
notice to the Lenders, such other number of days as the Borrower and the Agent
may agree) of any other Competitive Bid Quote Request.  Each Competitive Bid
Quote Request shall be in a minimum amount of $10,000,000 (and in integral
multiples of $1,000,000 in excess thereof).  A Competitive Bid Quote Request
that does not conform substantially to the format of Exhibit 2.2.2 hereto shall
be rejected, and the Agent shall promptly notify the Borrower of such rejection
by telex or telecopy.

         SECTION 2.2.3    Invitation for Competitive Bid Quotes.  Promptly and
in any event before 1:00 p.m. (New York time) on the same Business Day of
receipt of a Competitive Bid Quote Request that is not rejected pursuant to
Section 2.2.2, the Agent shall send to each of the Lenders by telex or telecopy
an Invitation for Competitive Bid Quotes, substantially in the form of Exhibit
2.2.3 attached hereto, which shall constitute an invitation by the Borrower to
each Lender to submit Competitive Bid Quotes offering to make the Competitive
Bid Loans to which such Competitive Bid Quote Request relates in accordance
with Section 2.2.4.

         SECTION 2.2.4    Submission and Contents of Competitive Bid Quotes.
(a) Each Lender may, in its sole discretion, but is under no obligation to,
submit a Competitive Bid Quote containing





                                       20

<PAGE>   27
an offer or offers to make Competitive Bid Loans in response to any Invitation
for Competitive Bid Quotes.  Each Competitive Bid Quote must comply with the
requirements of this Section 2.2.4 and must be submitted to the Agent by
telecopy (except in the case of UBS) at its offices specified in Section 10.2
not later than (i) in the case of a Eurodollar Auction, (A) with respect to
UBS, 12:45 p.m. (New York time), at least three Business Days prior to the
proposed Borrowing Date and (B) with respect to each other Lender, 1:00 p.m.
(New York time), at least three Business Days prior to the proposed Borrowing
Date, or (ii) in the case of an Absolute Rate Auction, (A) with respect to UBS,
9:45 a.m. (New York time) on the proposed Borrowing Date and (B) with respect
to each other Lender, 10:00 a.m. (New York time) on the proposed Borrowing Date
(or, with respect to clauses (i) and (ii) and upon reasonable prior notice to
the Lenders, such other time and date as the Borrower and the Agent may agree,
provided that UBS shall submit its Competitive Bid Quote fifteen minutes before
the time that the other Lenders are required to submit their Competitive Bid
Quotes).

         (b)     Each Competitive Bid Quote shall in any case specify: (i) the
proposed Borrowing Date, which shall be the same as that set forth in the
applicable Invitation for Competitive Bid Quotes; (ii) the principal amount of
the Competitive Bid Loan for which each such offer is being made, which
principal amount (1) may be greater than, less than or equal to the Commitment
of the quoting Lender, (2) must be at least $10,000,000 and an integral
multiple of $1,000,000, and (3) may not exceed the principal amount of
Competitive Bid Loans for which offers were requested; (iii) in the case of a
Eurodollar Auction, the Competitive Bid Margin offered for each such
Competitive Bid Loan; (iv) the minimum or maximum amount, if any, of any
Competitive Bid Loan which may be accepted by the Borrower and/or the limit, if
any, as to the aggregate principal amount of Competitive Bid Loans from such
Lender which may be accepted by the Borrower; (v) in the case of an Absolute
Rate Auction, the Absolute Rate offered for each such Competitive Bid Loan;
(vi) the applicable Interest Period; and (vii) the identity of the quoting
Lender.

         (c)     The Agent shall reject any Competitive Bid Quote that (i) is
not substantially in the form of Exhibit 2.2.4 hereto or does not specify all
of the information required by Section 2.2.4(ii); (ii) contains qualifying,
conditional or similar language, other than any such language contained in
Exhibit 2.2.4 hereto; (iii) proposes terms other than or in addition to those
set forth in the applicable Invitation for Competitive Bid Quotes; or (iv)
arrives after the time set forth in Section 2.2.4(i).  If any Competitive Bid
Quote shall be rejected pursuant to this Section 2.2.4(iii), then the Agent
shall notify the relevant Lender of such rejection as soon as practical.

         SECTION 2.2.5    Notice to the Borrower.  The Agent shall promptly
notify the Borrower of the terms (i) of any Competitive Bid Quote submitted by
a Lender that is in accordance with Section 2.2.4 and (ii) of any Competitive
Bid Quote that is in accordance with Section 2.2.4 and amends, modifies or is
otherwise inconsistent with a previous Competitive Bid Quote submitted by such
Lender with respect to the same Competitive Bid Quote Request.  Any such
subsequent Competitive Bid Quote shall be disregarded by the Agent unless such
subsequent Competitive Bid Quote specifically states that it is submitted
solely to correct a manifest error in such former Competitive Bid Quote.  The
Agent's notice to the Borrower shall specify the aggregate principal amount of
Competitive Bid Loans for which offers have been received for each Interest
Period





                                       21

<PAGE>   28
specified in the related Competitive Bid Quote Request and the respective
principal amounts and Competitive Bid Margins or Absolute Rates, as the case
may be, so offered.

         SECTION 2.2.6    Acceptance and Notice by the Borrower.  Subject to
the receipt of the notice from the Agent referred to in Section 2.2.5, not
later than (i) 3:00 p.m. (New York time) at least three Business Days prior to
the proposed Borrowing Date, in the case of a Eurodollar Auction or (ii) 11:00
a.m. (New York time) on the proposed Borrowing Date, in the case of an Absolute
Rate Auction, the Borrower shall notify the Agent of its acceptance or
rejection of the offers so notified to it pursuant to Section 2.2.5; provided,
however, that the failure by the Borrower to give such notice to the Agent
shall be deemed to be a rejection of all such offers.  In the case of
acceptance, such notice (a "Competitive Bid Borrowing Notice") shall be
irrevocable and shall specify the aggregate principal amount of offers for each
Interest Period that are accepted.  The Borrower may accept or reject any
Competitive Bid Quote in whole or in part (subject to the terms of Section
2.2.4(b)(iv)); provided that (a) the aggregate principal amount of each
Competitive Bid Advance may not exceed the applicable amount set forth in the
related Competitive Bid Quote Request; (b) acceptance of offers for any
Competitive Bid Advance with otherwise identical terms may only be made on the
basis of ascending Competitive Bid Margins or Absolute Rates, as the case may
be; (c) the Borrower may not accept any offer of the type described in Section
2.2.4(c) or that otherwise fails to comply with the requirements of this
Agreement for the purpose of obtaining a Competitive Bid Loan under this
Agreement; and (d) after giving effect to such Competitive Bid Advance, the sum
of the aggregate principal amount of all outstanding Revolving Loans plus all
Competitive Bid Advances shall not exceed the Commitment Amount.

         SECTION 2.2.7    Allocation by the Agent.  If offers are made by two
or more Lenders with the same Competitive Bid Margins or Absolute Rates, as the
case may be, for a greater aggregate principal amount than the amount in
respect of which offers are permitted to be accepted for the related Interest
Period, the principal amount of Competitive Bid Loans in respect of which such
offers are accepted shall be allocated by the Agent among such Lenders as
nearly as possible (in such multiples, not greater than $1,000,000, as the
Agent may deem appropriate) in proportion to the aggregate principal amount of
such offers; provided, however, that no Lender shall be allocated a portion of
any Competitive Bid Advance which is less than the minimum amount which such
Lender has indicated that it is willing to accept.  Allocations by the Agent of
the amounts of Competitive Bid Loans shall be conclusive in the absence of
manifest error.  The Agent shall promptly, but in any event on the same
Business Day in the case of Eurodollar Bid Rate Advances, and by 12:00 p.m.
(New York time) in the case of Absolute Rate Advances, notify each Lender of
its receipt of a Competitive Bid Borrowing Notice and the aggregate principal
amount of such Competitive Bid Advance allocated to each participating Lender.

         SECTION 2.2.8    Administration Fees.  The Borrower hereby agrees to
pay to the Agent for its sole account administration fees for Competitive Bid
Quote Requests in such amounts as heretofore agreed upon by the Borrower and
the Agent in a fee letter dated December 24, 1997, as amended from time to time
(the "Competitive Bid Fee Letter").





                                       22

<PAGE>   29
         SECTION 2.2.9    Reduction.  While any Competitive Bid Advances are
outstanding, each Lender's Commitment shall be reduced by, and deemed used in
the amount of its pro rata share (based on its respective Percentage of the
Commitment Amount) of the outstanding amount of such Competitive Bid Advances.

         SECTION 2.3      Reduction of Commitment Amount.  The Borrower may,
from time to time on any Business Day occurring after the time of the initial
Borrowing hereunder, voluntarily reduce the amount of the Commitment Amount;
provided, however, that all such reductions shall require at least three
Business Days' prior notice to the Agent and be permanent, and any partial
reduction of the Commitment Amount shall be in a minimum amount of $25,000,000
and in an integral multiple of $5,000,000.

         SECTION 2.4      Base Rate Loans and Eurodollar Loans.  Subject to the
terms and conditions set forth in Article V, each Loan shall be either a
Eurodollar Loan or a Base Rate Loan as the Borrower may request, it being
understood that Loans made to the Borrower on any date may be either Eurodollar
Loans or Base Rate Loans or a combination thereof.  As to any Eurodollar Loan,
each Lender may, if it so elects, fulfill its commitment to make such
Eurodollar Loan by causing its Eurodollar Office to make such Eurodollar Loan;
provided, however, that in such event the obligation of the Borrower to repay
such Eurodollar Loan nevertheless shall be to such Lender and shall be deemed
to be held by such Lender for the account of such Eurodollar Office.

         SECTION 2.5      Borrowing Procedures for Loans.  The Borrower shall
give the Agent prior written or telegraphic notice pursuant to a Borrowing
Request (in substantially the form of Exhibit 2.5 hereto) of each proposed
Borrowing or continuation, and as to whether such Borrowing or continuation is
to be of Base Rate Loans or Eurodollar Loans, as follows:

         SECTION 2.5.1    Domestic Loans.  The Agent shall receive written or
telegraphic notice from the Borrower on or before 2:00 p.m. New York time one
Business Day prior to the date of such Borrowing and amount of such Borrowing
(which shall be in a minimum amount of $10,000,000 and an integral multiple of
$1,000,000), and the Agent shall advise each Lender thereof promptly
thereafter.  Not later than 10:00 a.m., New York time, on the date specified in
such notice for such Borrowing, each Lender shall provide to the Agent at the
Payment Office, same day or immediately available funds covering such Lender's
Percentage of the requested Base Rate Loan.  Upon fulfillment of the applicable
conditions set forth in Article V with respect to such Base Rate Loan, the
Agent shall make available to the Borrower the proceeds of each Base Rate Loan
(to the extent received from the Lenders) by wire transfer of such proceeds to
such account(s) as the Borrower shall have specified in the Borrowing Request.

         SECTION 2.5.2    Eurodollar Loans.  The Agent shall receive written or
telegraphic notice pursuant to a Borrowing Request from the Borrower on or
before 10:00 a.m. New York time, at least three (3) Business Days prior to the
date requested for each proposed Borrowing or continuation of a Eurodollar
Loan, of the date of such Borrowing or continuation, as the case may be, the
amount of such Borrowing or continuation, as the case may be (which shall be in
a minimum amount of $10,000,000 and an integral multiple of $1,000,000), and
the duration of the initial Euro-





                                       23

<PAGE>   30
dollar Interest Period with respect thereto, and the Agent shall advise each
Lender thereof promptly thereafter.  Not later than 10:00 a.m., New York time,
on the date specified in such notice for such Borrowing, each Lender shall
provide to the Agent at the Payment Office, same day or immediately available
funds covering such Lender's Percentage of the requested Eurodollar Loan.  Upon
fulfillment of the applicable conditions set forth in Article V with respect to
such Eurodollar Loan, the Agent shall make available to the Borrower the
proceeds of each Eurodollar Loan (to the extent received from the Lenders) by
wire transfer of such proceeds to such account(s) as the Borrower shall have
specified in the Borrowing Request.

         SECTION 2.6      Continuation and Conversion Elections.  By delivering
a Continuation/Conversion Notice to the Agent on or before 10:00 a.m., New York
time, on a Business Day, the Borrower may from time to time irrevocably elect,
on not less than three nor more than five Business Days' notice that all, or
any portion in an aggregate minimum amount of $10,000,000 and an integral
multiple of $1,000,000 of any Borrowings be, (i) in the case of Base Rate
Loans, converted into Eurodollar Loans, or (ii) in the case of Eurodollar
Loans, be converted into a Base Rate Loan or continued as a Eurodollar Loan of
such Type (in the absence of delivery of a Continuation/Conversion Notice with
respect to any Eurodollar Loan at least three Business Days before the last day
of the then current Interest Period with respect thereto, such Eurodollar Loan
shall, on such last day, automatically convert to a Base Rate Loan); provided,
however, that (i) each such conversion or continuation shall be pro rated among
the applicable outstanding Loans of all Lenders, and (ii) no portion of the
outstanding principal amount of any Loans may be continued as, or be converted
into, Eurodollar Loans when any Default has occurred and is continuing.

         SECTION 2.7      Funding.  Each Lender may, if it so elects, fulfill
its obligation to make, continue or convert Eurodollar Loans hereunder by
causing one of its foreign branches or Affiliates (or an international banking
facility created by such Lender) to make or maintain such Eurodollar Loan;
provided, however, that such Eurodollar Loan shall nonetheless be deemed to
have been made and to be held by such Lender, and the obligation of the
Borrower to repay such Eurodollar Loan shall nevertheless be to such Lender for
the account of such foreign branch, Affiliate or international banking
facility.  In addition, the Borrower hereby consents and agrees that, for
purposes of any determination to be made for purposes of Sections 4.1, 4.2, 4.3
or 4.4, it shall be conclusively assumed that each Lender elected to fund all
Eurodollar Loans by purchasing, as the case may be, Dollar deposits in its
Eurodollar Office's interbank eurodollar market.

         SECTION 2.8      Notes.  Each Lender's Revolving Loans shall be
evidenced by a Revolving Note, payable to the order of such Lender in a maximum
principal amount equal to such Lender's Percentage of the original applicable
Commitment Amount.  Each Lender's Competitive Bid Loans shall be evidenced by a
Competitive Bid Note, each payable to the order of such Lender in a maximum
principal amount of $300,000,000.  The Borrower hereby irrevocably authorizes
each Lender to make (or cause to be made) appropriate notations on the grid
attached to such Lender's Notes (or on any continuation of such grid), which
notations, if made, shall evidence, inter alia, the date of, the outstanding
principal of, and the interest rate and Interest Period applicable to the
Revolving Loans or Competitive Bid Loans evidenced thereby.  Such notations
shall be conclusive





                                       24

<PAGE>   31
and binding on the Borrower absent manifest error; provided, however, that the
failure of any Lender to make any such notations shall not limit or otherwise
affect any Obligations of the Borrower.


                                  ARTICLE III

                   REPAYMENTS, PREPAYMENTS, INTEREST AND FEES

         SECTION 3.1      Repayments and Prepayments.  The Borrower shall repay
in full the unpaid principal amount of each Loan upon the Stated Maturity Date
or of each Competitive Bid Loan on the last day of its applicable Interest
Period.  Prior thereto, the Borrower

         (a)     may, from time to time on any Business Day, make a voluntary
prepayment, in whole or in part, of the outstanding principal amount of any
Loans; provided, however, that (i) any such prepayment shall be applied to the
Lenders among Loans having the same Type and, if applicable, having the same
Interest Period; (ii) no such prepayment of any Competitive Bid Loan may be
made on any day other than the last day of the Interest Period for such Loan;
(iii) all such voluntary prepayments shall require at least three Business
Days' prior written notice to the Agent; and (iv) all such voluntary partial
prepayments shall be in an minimum amount of $10,000,000 and an integral
multiple of $5,000,000; and

         (b)     shall, immediately upon any acceleration of the Stated
Maturity Date of any Loans pursuant to Section 8.2 or Section 8.3, repay all
Loans, unless, pursuant to Section 8.3, only a portion of all Loans is so
accelerated.

Each prepayment of Loans shall be applied, to the extent of such prepayment, in
the inverse order of maturity.  Each prepayment of any Loans made pursuant to
this Section shall be without premium or penalty, except as may be required by
Section 4.4.  No voluntary prepayment of principal of any Revolving Loans shall
cause a reduction in the Commitment Amount.

         SECTION 3.2      Interest Provisions.  Interest on the outstanding
principal amount of Loans shall accrue and be payable in accordance with this
Section 3.2.

         SECTION 3.2.1    Rates.  Pursuant to an appropriately delivered
Borrowing Request or Continuation/Conversion Notice, the Borrower may elect
that Loans comprising a Borrowing accrue interest at a rate per annum: (a) on
that portion maintained from time to time as a Base Rate Loan, equal to the sum
of the Base Rate from time to time in effect; and (b) on that portion
maintained as a Eurodollar Loan, during each Interest Period applicable
thereto, equal to the sum of the Eurodollar Rate for such Interest Period plus
the Applicable Margin.  All Eurodollar Borrowings shall bear interest from and
including the first day of the applicable Interest Period to (but not
including) the last day of such Interest Period at the interest rate determined
as applicable to such Eurodollar Borrowing.





                                       25

<PAGE>   32
         SECTION 3.2.2    Post-Maturity Rates.  After the date any principal
amount of any Loan is due and payable (whether on the Stated Maturity Date,
upon acceleration or otherwise), or after any other monetary Obligation of the
Borrower shall have become due and payable, the Borrower shall pay, but only to
the extent permitted by law, interest (after as well as before judgment) on
such amounts at a rate per annum equal to the Base Rate plus the Default
Margin.

         SECTION 3.2.3    Payment Dates.  Interest accrued on each Borrowing
shall be payable, without duplication on the following dates (each a "Payment
Date"): (a) on the Stated Maturity Date therefor; (b) on the date of any
payment or prepayment, in whole or in part, of principal outstanding on such
Loan on the amount of such principal prepaid or repaid; (c) with respect to
Base Rate Loans, on each Quarterly Payment Date occurring after the Effective
Date; (d) with respect to Eurodollar Borrowings, on the last day of each
applicable Interest Period (and, if such Interest Period shall exceed 90 days,
on the 90th day of such Interest Period); (e) with respect to any portion of
Base Rate Loans converted into Eurodollar Loans on a day when interest would
not otherwise have been payable pursuant to clause (c), on the date of such
conversion; and (f) on that portion of any Borrowings the Stated Maturity Date
of which is accelerated pursuant to Section 8.2 or Section 8.3, immediately
upon such acceleration; and (g) with respect to Competitive Bid Loans, as
otherwise provided by the relevant Competitive Bid Quote Request.  Interest
accrued on Borrowings or other monetary Obligations arising under this
Agreement or any other Loan Document after the date such amount is due and
payable (whether on the Stated Maturity Date, upon acceleration or otherwise)
shall be payable upon demand.

         SECTION 3.3      Fees.  The Borrower agrees to pay the fees set forth
in this Section 3.3.  All such fees shall be non-refundable.

         SECTION 3.3.1    Facility Fee.  The Borrower agrees to pay to the
Agent for the account of each Lender, a facility fee in an amount equal to the
product of the Applicable Facility Fee Rate times such Lender's Percentage
times the Commitment Amount as it may be reduced from time to time, pursuant to
reductions under Section 2.3.

         SECTION 3.3.2    Agent's Fee.  The Borrower agrees to pay to the Agent
for its own account, all fees (including any fees pursuant to Section 2.2.8)
pursuant to that certain fee letter agreement dated December 24, 1997, between
the Borrower and the Agent, as amended from time to time (the "Agent Fee
Letter").

         SECTION 3.3.3    Payment Office.  The Borrower shall make all payments
to the Agent at the Payment Office.





                                       26

<PAGE>   33
                                   ARTICLE IV

                    CERTAIN EURODOLLAR AND OTHER PROVISIONS

         SECTION 4.1      Eurodollar Lending Unlawful.  If any Lender shall
determine (which determination shall, upon notice thereof to the Borrower and
the Lenders, be conclusive and binding on the Borrower) that the introduction
of or any change in or in the interpretation of any law makes it unlawful, or
any central bank or other governmental authority asserts that it is unlawful,
for such Lender to make, continue or maintain any Borrowing as, or to convert
any Borrowing into, a Eurodollar Borrowing, the obligations of such Lender to
make, continue, maintain or convert any such Borrowings shall, upon such
determination, forthwith be suspended until such Lender shall notify the Agent
that the circumstances causing such suspension no longer exist, and all
Eurodollar Borrowings shall automatically convert into Base Rate Loans at the
end of the then current Interest Periods with respect thereto or sooner, if
required by such law or assertion; provided, however, that the obligation of
such Lender to make, continue, maintain or convert any such Eurodollar
Borrowings shall remain unaffected if such Lender can designate a different
Eurodollar Office for the making, continuance, maintenance or conversion of
Eurodollar Borrowings and such designation will not, in the sole discretion of
such Lender, be otherwise disadvantageous to such Lender.

         SECTION 4.2      Deposits Unavailable or Eurodollar Interest Rate
Unascertainable.  If the Agent shall have determined that, by reason of
circumstances affecting the Agent's relevant market, adequate means do not
exist for ascertaining the interest rate applicable hereunder to Eurodollar
Borrowings, then, upon notice from the Agent to the Borrower and the Lenders,
the obligations of all Lenders under Section 2.6 and Section 2.8 to make or
continue any Borrowings as, or to convert any Borrowings into, Eurodollar
Borrowings shall forthwith be suspended until the Agent shall notify the
Borrower and the Lenders that the circumstances causing such suspension no
longer exist.

         SECTION 4.3      Increased Eurodollar Borrowing Costs, etc.  The
Borrower agrees to reimburse each Lender for any increase in the cost to such
Lender of, or any reduction in the amount of any sum receivable by such Lender
in respect of, making, continuing or maintaining (or of its obligation to make,
continue or maintain) any Borrowings as, or of converting (or of its obligation
to convert) any Borrowings into, Eurodollar Borrowings.  Such Lender shall
promptly notify the Agent and the Borrower in writing of the occurrence of any
such event, such notice to state, in reasonable detail, the reasons therefor
and the additional amount required fully to compensate such Lender for such
increased cost or reduced amount; provided, however, that such Lender shall
designate a different Eurodollar Office if such designation will avoid the need
for, or reduce the amount of, such compensation and will not, in the sole
discretion of such Lender, be otherwise disadvantageous to such Lender.  Such
additional amounts shall be payable by the Borrower directly to such Lender
within fifteen days of its receipt of such notice, and such notice shall be
rebuttable presumptive evidence of the amount payable by the Borrower.

         SECTION 4.4      Funding Losses.  In the event any Lender shall incur
any loss or expense (including any loss or expense incurred by reason of the
liquidation or reemployment of deposits or





                                       27

<PAGE>   34
other funds acquired by such Lender to make, continue or maintain any portion
of the principal amount of any Borrowing as, or to convert any portion of the
principal amount of any Borrowing into, a Eurodollar Borrowing) as a result of
(a) any conversion or repayment or prepayment of the principal amount of any
Eurodollar Borrowings on a date other than the scheduled last day of the
Interest Period applicable thereto, whether pursuant to Section 3.1 or
otherwise, (b) any Borrowings not being made as Eurodollar Borrowings in
accordance with the Borrowing Request or Competitive Bid Quote Request, as the
case may be, therefor, or (c) any Borrowings not being continued as, or
converted into, Eurodollar Borrowings in accordance with the
Continuation/Conversion Notice therefor, then, upon the written notice of such
Lender to the Borrower (with a copy to the Agent), the Borrower shall, within
fifteen days of its receipt thereof, pay directly to such Lender such amount as
will (in the reasonable determination of such Lender) reimburse such Lender for
such loss or expense.  Such written notice (which shall include calculations in
reasonable detail) shall be rebuttable presumptive evidence of the amount
payable by the Borrower.

         SECTION 4.5      Increased Capital Costs.  If any change in, or the
introduction, adoption, effectiveness, interpretation, reinterpretation or
phase-in of, any law or regulation, directive, guideline, decision or request
(whether or not having the force of law) of any court, central bank, regulator
or other governmental authority affects or would affect the amount of capital
required or expected to be maintained by any Lender or any Person controlling
such Lender, and such Lender determines (in its sole discretion) that the rate
of return on its or such controlling Person's capital as a consequence of its
Commitments or the Borrowings made by such Lender is reduced to a level below
that which such Lender or such controlling Person could have achieved but for
the occurrence of any such circumstance, then, in any such case upon notice
from time to time by such Lender to the Borrower, the Borrower shall pay
directly to such Lender, within fifteen days, additional amounts sufficient to
compensate such Lender or such controlling Person for such reduction in rate of
return; provided, however, that such Lender shall designate a different
Domestic or Eurodollar Office if such designation will avoid the need for, or
reduce the amount of, such compensation and will not, in the sole discretion of
such Lender, be otherwise disadvantageous to such Lender.  A statement of such
Lender as to any such additional amount or amounts (including calculations
thereof in reasonable detail) shall be rebuttable presumptive evidence of the
amount payable by the Borrower.  In determining such amount, such Lender may
use any reasonable method of averaging and attribution that it (in its sole
discretion) shall deem applicable.

         SECTION 4.6      Taxes.  All payments by the Borrower of principal of,
and interest on, the Borrowings and all other amounts payable hereunder shall
be made free and clear of and without deduction for any present or future
income, excise, stamp or franchise taxes and other taxes, fees, duties,
withholdings or other charges of any nature whatsoever imposed by any taxing
authority, but excluding franchise taxes and taxes imposed on or measured by
any Lender's net income or receipts (such non-excluded items being called
"Taxes").  In the event that any withholding or deduction from any payment to
be made by the Borrower hereunder is required in respect of any Taxes pursuant
to any applicable law, rule or regulation, then the Borrower will, within
fifteen days (a) pay directly to the relevant authority the full amount
required to be so withheld or deducted; (b) promptly forward to the Agent an
official receipt or other documentation satisfactory to the Agent evidencing





                                       28

<PAGE>   35
such payment to such authority; and (c) pay to the Agent for the account of the
Lenders such additional amount or amounts as is necessary to ensure that the
net amount actually received by each Lender will equal the full amount such
Lender would have received had no such withholding or deduction been required.

         If any Taxes are directly asserted against the Agent or any Lender
with respect to any payment received by the Agent or such Lender hereunder, the
Agent or such Lender may pay such Taxes and the Borrower will promptly pay such
additional amounts (including any penalties, interest or expenses) as is
necessary in order that the net amount received by such person after the
payment of such Taxes (including any Taxes on such additional amount) shall
equal the amount such person would have received had not such Taxes been
asserted; provided that the Borrower will not be obligated to pay such
additional amounts to the Agent or such Lender to the extent that such
additional amounts shall have been incurred as a consequence of the Agent's or
such Lender's gross negligence or willful misconduct, as the case may be.

         If the Borrower fails to pay any Taxes when due to the appropriate
taxing authority or fails to remit to the Agent, for the account of the
respective Lenders, the required receipts or other required documentary
evidence, the Borrower shall indemnify the Lenders for any incremental Taxes,
interest or penalties that may become payable by any Lender as a result of any
such failure.  For purposes of this Section 4.6, a distribution hereunder by
the Agent or any Lender to or for the account of any Lender shall be deemed a
payment by the Borrower.

         Each Lender that is organized under the laws of a jurisdiction other
than the United States shall, prior to the due date of any payments under the
Notes, execute and deliver to the Borrower and the Agent, on or about the first
scheduled Payment Date in each Fiscal Year, one or more (as the Borrower or the
Agent may reasonably request) United States Internal Revenue Service Forms 4224
or Forms 1001 or such other forms or documents (or successor forms or
documents), appropriately completed, as may be applicable to establish the
extent, if any, to which a payment to such Lender is exempt from withholding or
deduction of Taxes, and shall (but only so long as such Lender remains lawfully
able to do so) deliver to the Borrower  and the Agent additional copies of such
forms on or before the date that such forms expire or become obsolete or after
the occurrence of an event requiring a change in the most recent form so
delivered by it and such amendments thereto as may be reasonably requested by
the Borrower or the Agent, in each case certifying that such Lender is entitled
to benefits under an income tax treaty to which the United States is a party
which reduces the rate of withholding tax on payments of interest or fees or
certifying that the income receivable pursuant to this Agreement is effectively
connected with the conduct of a trade or business in the United States.  If the
form provided by a Lender at the time such Lender first becomes a party to this
Agreement indicates a United States withholding tax rate in excess of zero,
withholding tax at such rate shall be considered excluded from the definition
of "Taxes".  For any period with respect to which a Lender has failed to
provide the Borrower and the Agent with the forms required pursuant to this
paragraph, if any (other than if such failure is due to a change in treaty, law
or regulation occurring subsequent to the date on which a form originally was
required to be provided), such Lender shall not be entitled to indemnification
under this Section 4.6 with respect to Taxes imposed





                                       29

<PAGE>   36
by the United States which Taxes would not have been imposed but for such
failure to provide such form; provided, however, that should a Lender, which is
otherwise exempt from or subject to a reduced rate of withholding tax, become
subject to Taxes because of its failure to deliver a form required hereunder,
the Borrower shall take such steps as the Lender shall reasonably request to
assist the Lender to recover such Taxes.

         If the Borrower is required to pay additional amounts to or for the
account of any Lender pursuant to this Section 4.6, then such Lender will
change the jurisdiction of its applicable Eurodollar or Domestic Office so as
to eliminate or reduce any such additional payment which may thereafter accrue
if such change, in the sole discretion of such Lender, is not otherwise
disadvantageous to such Lender.  No Lender shall be entitled to receive any
greater payment under this Section 4.6 as a result of the designation by such
Lender of a different applicable Eurodollar or Domestic Office after the date
hereof, unless such designation is made with the Borrower's prior written
consent or by reason of the provisions of Sections 4.1, 4.3 or 4.5 requiring
such Lender to designate a different applicable Eurodollar or Domestic Office
under certain circumstances or at a time when the circumstances giving rise to
such greater payment did not exist.

         SECTION 4.7      Special Fees in Respect of Reserve Requirements.
With respect to Eurodollar Borrowings, the Borrower agrees to pay to each
Lender on appropriate Payment Dates, as additional interest, such amounts as
will compensate such Lender for any cost to such Lender, from time to time, of
any reserve, special deposit, special assessment or similar capital
requirements against assets of, deposits with or for the account of, or credit
extended by, such Lender which are imposed on, or deemed applicable by, such
Lender, from time to time, under or pursuant to (i) any Law, treaty, regulation
or directive now or hereafter in effect (including, without limitation,
Regulation D of the Board of Governors of the Federal Reserve System but
excluding any reserve requirement included in the definition of Eurodollar Rate
in Section 1.1), (ii) any interpretation or application thereof by any
governmental authority, agency or instrumentality charged with the
administration thereof or by any court, central bank or other fiscal, monetary
or other authority having jurisdiction over the Eurodollar Borrowings or the
office of such Lender where its Eurodollar Borrowings are lodged, or (iii) any
requirement imposed or requested by any court, governmental authority, agency
or instrumentality or central bank, fiscal, monetary or other authority,
whether or not having the force of law.  A written notice as to the amount of
any such cost or any change therein (including calculations, in reasonable
detail, showing how such Lender computed such cost or change) shall be promptly
furnished by such Lender to the Borrower and shall be rebuttable presumptive
evidence of such cost or change.  The Borrower will not be responsible for
paying any amounts pursuant to this Section 4.7 accruing prior to 180 days
prior to the receipt by the Borrower of the written notice referred to in the
preceding sentence.  Within fifteen (15) days after such certificate is
furnished to the Borrower, the Borrower will pay directly to such Lender such
additional amount or amounts as will compensate such Lender for such cost or
change.

         SECTION 4.8      Payments, Computations, etc.  Unless otherwise
expressly provided, all payments by the Borrower pursuant to this Agreement,
the Notes or any other Loan Document shall be made by the Borrower to the Agent
for the pro rata account of the Lenders entitled to receive such





                                       30

<PAGE>   37
payment.  All such payments required to be made to the Agent shall be made,
without setoff, deduction or counterclaim, not later than 11:00 a.m., New York
time, on the date due, in same day or immediately available funds, to such
account as the Agent shall specify from time to time by notice to the Borrower.
Funds received after that time shall be deemed to have been received by the
Agent on the next succeeding Business Day.  The Agent shall promptly remit in
same day funds to each Lender its share, if any, of such payments received by
the Agent for the account of such Lender.  All interest and fees shall be
computed on the basis of the actual number of days (including the first day but
excluding the last day) occurring during the period for which such interest or
fee is payable over a year comprised of 360 days (or, in the case of interest
on a Base Rate Loan, 365 days or, if appropriate, 366 days).  Whenever any
payment to be made shall otherwise be due on a day which is not a Business Day,
such payment shall (except as otherwise required by clause (c) of the
definition of the term "Interest Period" with respect to Eurodollar Loans) be
made on the next succeeding Business Day and such extension of time shall be
included in computing interest and fees, if any, in connection with such
payment.

         SECTION 4.9      Sharing of Payments.  If any Lender shall obtain any
payment or other recovery (whether voluntary, involuntary, by application of
setoff or otherwise) on account of any Loan (other than pursuant to the terms
of Sections 4.3, 4.4 and 4.5) in excess of its pro rata share of payments then
or therewith obtained by all Lenders, such Lender shall purchase from the other
Lenders such participations in Loans made by them as shall be necessary to
cause such purchasing Lender to share the excess payment or other recovery
ratably with each of them; provided, however, that if all or any portion of the
excess payment or other recovery is thereafter recovered from such purchasing
Lender, the purchase shall be rescinded and each Lender which has sold a
participation to the purchasing Lender shall repay to the purchasing Lender the
purchase price to the ratable extent of such recovery together with an amount
equal to such selling Lender's ratable share (according to the proportion of
(a) the amount of such selling Lender's required repayment to the purchasing
Lender to (b) the total amount so recovered from the purchasing Lender) of any
interest or other amount paid or payable by the purchasing Lender in respect of
the total amount so recovered.  The Borrower agrees that any Lender so
purchasing a participation from another Lender pursuant to this Section 4.9
may, to the fullest extent permitted by law, exercise all its rights of payment
with respect to such participation as fully as if such Lender were the direct
creditor of the Borrower in the amount of such participation.  If under any
applicable bankruptcy, insolvency or other similar law, any Lender receives a
secured claim in lieu of a set off to which this Section 4.9 applies, such
Lender shall, to the extent practicable, exercise its rights in respect of such
secured claim in a manner consistent with the rights of the Lenders entitled
under this Section to share in the benefits of any recovery on such secured
claim.

         SECTION 4.10     Use of Proceeds.  The Borrower shall apply the
proceeds of each Borrowing in accordance with the fourth recital; without
limiting the foregoing, no proceeds of any Borrowing will be used to acquire
any equity security of a class which is registered pursuant to Section 12 of
the Securities Exchange Act of 1934 or any "margin stock", as defined in F.R.S.
Board Regulation U.





                                       31

<PAGE>   38
         SECTION 4.11     Replacement of Lender on Account of Increased Costs,
Eurodollar Lending Unlawful, Reserve Requirements, Taxes, Certain Dissents,
etc.  If any Lender shall claim the inability to make or maintain Eurodollar
Borrowings pursuant to Section 4.1 above, if any Lender is owed increased costs
under Section 4.5 above, if any payment to any Lender by the Borrower is
subject to any withholding tax pursuant to Section 4.6 above, or if any Lender
is owed any cost or expense pursuant to Section 4.7 above, the Borrower shall
have the right, if no Event of Default or Unmatured Event of Default then
exists, to replace such Lender with another bank or financial institution
provided that (i) if it is not a Lender or an Affiliate thereof, such bank or
financial institution shall be reasonably acceptable to the Agent and (ii) such
bank or financial institution shall unconditionally purchase, in accordance
with Section 10.11 hereof, all of such Lender's rights and obligations under
this Agreement and the Notes and the appropriate pro rata share of such
Lender's Notes and Commitments, without recourse or expense to, or warranty by,
such Lender being replaced for a purchase price equal to the aggregate
outstanding principal amount of the Notes payable to such Lender, plus any
accrued but unpaid interest on such Notes plus accrued but unpaid fees in
respect of such Lender's Borrowings and Percentage of the Commitments hereunder
to the date of such purchase on a date therein specified.  The Borrower shall
be obligated to pay, simultaneously with such purchase and sale, the increased
costs, amounts, expenses and taxes under Sections 4.1, 4.5, 4.6, and 4.7 above,
all breakage fees payable under Section 4.4 and all other costs, fees and
expenses payable to such Lender hereunder and under the Loan Documents, to the
date of such purchase as well as all other Obligations due and payable to or
for the benefit of such Lender; provided, that if such bank or financial
institution fails to purchase such rights and obligations, the Borrower shall
continue to be obligated to pay the increased costs, amounts, expenses and
taxes under Sections 4.1, 4.5, 4.6, and 4.7 above to such Lender.

         SECTION 4.12     Maximum Interest.  It is the intention of the parties
hereto to conform strictly to applicable usury laws and, anything herein to the
contrary notwithstanding, the obligations of the Borrower to each Lender under
this Agreement shall be subject to the limitation that payments of interest
shall not be required to the extent that receipt thereof would be contrary to
provisions of law applicable to such Lender limiting rates of interest which
may be charged or collected by such Lender.  Accordingly, if the transactions
contemplated hereby would be usurious under applicable law (including the
Federal and state laws of the United States of America, or of any other
jurisdiction whose laws may be mandatorily applicable) with respect to a Lender
then, in that event, notwithstanding anything to the contrary in this
Agreement, it is agreed as follows: (a) the provisions of this Section 4.12
shall govern and control; (b) the aggregate of all consideration which
constitutes interest under applicable law that is contracted for, charged or
received under this Agreement, or under any of the other aforesaid agreements
or otherwise in connection with this Agreement by such Lender shall under no
circumstances exceed the maximum amount of interest allowed by applicable law
(such maximum lawful interest rate, if any, with respect to such Lender herein
called the "Highest Lawful Rate"), and any excess shall be credited to the
Borrower by such Lender (or, if such consideration shall have been paid in
full, such excess refunded to the Borrower); (c) all sums paid, or agreed to be
paid, to such Lender for the use, forbearance and detention of the Indebtedness
of the Borrower to such Lender hereunder shall, to the extent permitted by
applicable law, be amortized, prorated, allocated and spread throughout the
full term of such Indebtedness until payment in full





                                       32

<PAGE>   39
so that the actual rate of interest is uniform throughout the full term
thereof; and (d) if at any time the interest provided pursuant to Section 4.1
together with any other fees payable pursuant to this Agreement and deemed
interest under applicable law, exceeds that amount which would have accrued at
the Highest Lawful Rate, the amount of interest and any such fees to accrue to
such Lender pursuant to this Agreement shall be limited, notwithstanding
anything to the contrary in this Agreement to that amount which would have
accrued at the Highest Lawful Rate, but any subsequent reductions, as
applicable, shall not reduce the interest to accrue to such Lender pursuant to
this Agreement below the Highest Lawful Rate until the total amount of interest
accrued pursuant to this Agreement and such fees deemed to be interest equals
the amount of interest which would have accrued to such Lender if a varying
rate per annum equal to the interest provided pursuant to Section 3.2 had at
all times been in effect, plus the amount of fees which would have been
received but for the effect of this Section 4.12.   For purposes of Article
5069-1.04, Vernon's Texas Civil Statutes, as amended, to the extent, if any,
applicable to a Lender, the Borrower agrees that the Highest Lawful Rate shall
be the "indicated (weekly) rate ceiling" as defined in said Article, provided
that such Lender may also rely, to the extent permitted by applicable laws, on
alternative maximum rates of interest under other laws applicable to such
Lender if greater.  Tex. Rev. Civ. Stat. Ann. Art. 5069, Ch. 15 (which
regulates certain revolving credit loan accounts and revolving tri-party
accounts) shall not apply to this Agreement or the Notes.


                                   ARTICLE V

                            CONDITIONS TO BORROWING

         SECTION 5.1      Initial Borrowing.  The obligations of the Lenders to
fund the initial Borrowing shall be subject to the prior satisfaction, or
waiver in writing by the Agent (with the consent of Required Lenders) of each
of the conditions precedent set forth in this Section 5.1.

         SECTION 5.1.1    Resolutions, etc.  The Agent shall have received from
the Borrower a certificate, dated the date of the initial Borrowing, of its
Secretary or Assistant Secretary as to (a) resolutions of its Board of
Directors then in full force and effect authorizing the execution, delivery and
performance of this Agreement, the Notes and each other Loan Document to be
executed by it; and (b) the incumbency and signatures of those of its officers
authorized to act with respect to this Agreement, the Notes and each other Loan
Document executed by it, upon which certificate each Lender may conclusively
rely until it shall have received a further certificate of the Secretary of the
Borrower canceling or amending such prior certificate.

         SECTION 5.1.2    Delivery of Notes.  The Agent shall have received,
for the account of each Lender, its Notes duly executed and delivered by the
Borrower.

         SECTION 5.1.3    Opinion of Counsel.  The Agent shall have received a
favorable opinion, dated the date hereof and addressed to the Agent and all
Lenders, from Thompson & Knight, P.C., counsel to the Borrower, substantially
in the form of Exhibit 5.1.4 hereto.





                                       33

<PAGE>   40
         SECTION 5.1.4    Fee Letters, Closing Fees, Expenses, etc.  The Agent
shall have received the Competitive Bid Fee Letter and the Agent Fee Letter
described in Sections 2.2.8 and 3.3.2, respectively, duly executed by the
Borrower.  The Agent shall also have received for its own account, or for the
account of each Lender, as the case may be, all fees, costs and expenses due
and payable pursuant to Sections 3.3.2 and 10.3, if then invoiced.

         SECTION 5.1.5    Material Adverse Change.  There shall have been no
material adverse change in the consolidated business, condition (financial or
otherwise), operations, performance or properties of any of the Borrower and
its consolidated Subsidiaries taken as a whole from June 30, 1997, except as
disclosed in Item 5.1.5 ("Material Adverse Change") of the Disclosure Schedule.

         SECTION 5.1.6    Other Documents.  Such other documents as the Agent
or any Lender may have reasonably requested.

         SECTION 5.2      All Borrowings.  The obligation of each Lender to
fund any Borrowing (including the initial Borrowing) shall be subject to the
satisfaction of each of the conditions precedent set forth in this Section 5.2.

         SECTION 5.2.1    Compliance with Warranties, No Default, etc.  Both
before and after giving effect to any Borrowing (but, if any Default of the
nature referred to in Section 8.1.5 shall have occurred with respect to any
other Indebtedness, without giving effect to the application, directly or
indirectly, of the proceeds thereof) the following statements shall be true and
correct (a) the representations and warranties set forth in Article VI
(excluding, however, except in the case of the initial Borrowing, those
contained in Section 6.6 and Section 6.7) shall be true and correct with the
same effect as if then made (unless stated to relate solely to an early date,
in which case such representations and warranties shall be true and correct as
of such earlier date); and (b) no Default shall have then occurred and be
continuing, and neither the Borrower nor any of its Subsidiaries are in
material violation of any law or governmental regulation or court order or
decree.

         SECTION 5.2.2    Borrowing Request and Competitive Bid Quote Request.
The Agent shall have received a Borrowing Request or a Competitive Bid Quote
Request for such Borrowing.  Each of the delivery of a Borrowing Request or a
Competitive Bid Borrowing Notice and the acceptance by the Borrower of the
proceeds of such Borrowing shall constitute a representation and warranty by
the Borrower that on the date of such Borrowing (both immediately before and
after giving effect to such Borrowing and the application of the proceeds
thereof) the statements made in Section 5.2.1 are true and correct.

         SECTION 5.2.3    Satisfactory Legal Form.  All documents executed or
submitted pursuant hereto by or on behalf of the Borrower or any of its
Subsidiaries shall be satisfactory in form and substance to the Agent and its
counsel; the Agent and its counsel shall have received all information,
approvals, opinions, documents or instruments as the Agent or its counsel may
reasonably request.





                                       34

<PAGE>   41

                                   ARTICLE VI

                         REPRESENTATIONS AND WARRANTIES

         In order to induce the Lenders and the Agent to enter into this
Agreement and to make Loans hereunder, the Borrower represents and warrants
unto the Agent and each Lender as set forth in this Article VI.

         SECTION 6.1      Organization, etc.  The Borrower and each of its
Subsidiaries is a corporation, partnership, limited partnership or limited
liability company validly organized and existing and in good standing under the
laws of the State of its incorporation, is duly qualified to do business and is
in good standing as a foreign entity in each jurisdiction where the nature of
its business requires such qualification, and has full power and authority and
holds all requisite governmental licenses, permits and other approvals to enter
into and perform its Obligations under this Agreement, the Notes and each other
Loan Document to which it is a party and to conduct its business substantially
as currently conducted by it (except where the failure to be so qualified to do
business or be in good standing or to hold any such licenses, permits and other
approvals will not have a Material Adverse Effect.

         SECTION 6.2      Due Authorization, Non-Contravention, etc.  The
execution, delivery and performance by the Borrower of this Agreement, the
Notes and each other Loan Document executed or to be executed by it, and the
Borrower's participation in any transaction contemplated herein are within the
Borrower's powers, have been duly authorized by all necessary corporate action,
and do not (a) contravene the Borrower's Organic Documents; (b) contravene any
contractual restriction, law or governmental regulation or court decree or
order binding on or affecting the Borrower; or (c) result in, or require the
creation or imposition of, any Lien on any of the Borrower's properties.

         SECTION 6.3      Government Approval, Regulation, etc.  No
authorization or approval or other action by, and no notice to or filing with,
any governmental authority or regulatory body or other Person is required for
the due execution, delivery or performance by the Borrower of this Agreement,
the Notes or any other Loan Document to which it is a party, or for the
Borrower's participation in any transaction contemplated herein, except as have
been obtained.  Neither the Borrower nor any of its Subsidiaries is an
"investment company" within the meaning of the Investment Company Act of 1940,
as amended, or a "holding company", or a "subsidiary company" of a "holding
company", or an "affiliate" of a "holding company" or of a "subsidiary company"
of a "holding company", within the meaning of the Public Utility Holding
Company Act of 1935, as amended.

         SECTION 6.4      Validity, etc.  This Agreement constitutes, and the
Notes and each other Loan Document executed by the Borrower will, on the due
execution and delivery thereof, constitute, the legal, valid and binding
obligations of the Borrower enforceable in accordance with their respective
terms except as (i) enforceability thereof may be limited by bankruptcy,
insolvency or similar laws





                                       35

<PAGE>   42
affecting creditor's rights generally and (ii) rights of acceleration and the
availability of equitable remedies may be limited by equitable principles of
general applicability.

         SECTION 6.5      Financial Information.  The balance sheets of the
Borrower and each of its Subsidiaries as at June 30, 1997 and the related
statements of earnings and cash flow, copies of which have been furnished to
the Agent and each Lender, have been prepared in accordance with GAAP
consistently applied, and present fairly the consolidated financial condition
of the corporations covered thereby as at the dates thereof and the results of
their operations for the periods then ended except as disclosed in Item 6.5
("Financial Information") of the Disclosure Schedule.

         SECTION 6.6      No Material Adverse Change.  As of the Effective
Date, since the date of the financial statements described in Section 6.5,
there has been no material adverse change in the financial condition,
operations, assets, business or properties of the Borrower and its Subsidiaries
(on a consolidated basis), except as disclosed in Item 5.1.5 ("Material Adverse
Change") of the Disclosure Schedule.

         SECTION 6.7      Litigation, Labor Controversies, etc.  As of the
Effective Date, there is no pending or, to the knowledge of the Borrower,
threatened litigation, action, proceeding, or labor controversy affecting the
Borrower or any of its Subsidiaries, or any of their respective properties,
businesses, assets or revenues, which could reasonably be expected to have a
Material Adverse Effect or which purports to affect the legality, validity or
enforceability of, and the rights and remedies of the Agent and the Lenders
under, this Agreement, the Notes or any other Loan Document, except as
disclosed in Item 6.7 ("Litigation") of the Disclosure Schedule.

         SECTION 6.8      Subsidiaries.  As of the Effective Date, the Borrower
has no Subsidiaries, except those Subsidiaries which are identified in Item 6.8
("Subsidiaries") of the Disclosure Schedule.

         SECTION 6.9      Taxes.  The Borrower and each of its Subsidiaries has
filed all tax returns and reports required by law to have been filed by it and
has paid all taxes and governmental charges thereby shown to be owing, except
any such taxes or charges which are being diligently contested in good faith by
appropriate proceedings and for which adequate reserves in accordance with GAAP
shall have been set aside on its books except such returns and taxes for
jurisdictions other than the United States with respect to which the failure to
file and pay such taxes would not have a Material Adverse Effect.

         SECTION 6.10     Pension and Welfare Plans.  During the
twelve-consecutive-month period prior to the date of the execution and delivery
of this Agreement and prior to the date of any Borrowing hereunder, no steps
have been taken to terminate any Pension Plan, and no contribution failure has
occurred with respect to any Pension Plan sufficient to give rise to a Lien
securing an amount in excess of $1,000,000 under section 302(f) of ERISA.  No
condition exists or event or transaction has occurred with respect to any
Pension Plan which might result in the incurrence by the Borrower or any member
of the Controlled Group of any material liability, fine or penalty.





                                       36

<PAGE>   43
Except as disclosed in Item 6.10 ("Employee Benefit Plans") of the Disclosure
Schedule, neither the Borrower nor any member of the Controlled Group has any
contingent liability with respect to any post-retirement benefit under a
Welfare Plan, other than liability for continuation coverage described in Part
6 of Title I of ERISA.

         SECTION 6.11     Environmental Warranties and Compliance.  The
liabilities and costs of Borrower and its consolidated Subsidiaries related to
compliance with applicable Environmental Laws (as in effect on the date on
which this representation is made or deemed made) could not reasonably be
expected to have a Material Adverse Effect.

         SECTION 6.12     Regulations G, T, U and X.  None of the Borrower and
its Subsidiaries are engaged in the business of extending credit for the
purpose of purchasing or carrying margin stock, and no proceeds of any Loans
will be used for a purpose which violates, or would be inconsistent with,
F.R.S. Board Regulation G, T, U or X.  Terms for which meanings are provided in
F.R.S. Board Regulation G, T, U or X or any regulations substituted therefor,
as from time to time in effect, are used in this Section with such meanings.

         SECTION 6.13     Accuracy of Information.  No certificate, statement
or other information delivered herewith or hereto by or on behalf of the
Borrower in writing to the Agent  or any Lender in connection with the
negotiation of this Agreement or in connection with any transaction
contemplated hereby contains any untrue statement of a fact or omits to state
any fact known to the Borrower or its Subsidiaries necessary to make the
statements contained herein or therein not misleading as of the date made or
deemed made, except to the extent that any untrue statement or omission could
not reasonably be expected to have a Material Adverse Effect.

         SECTION 6.14     Use of Proceeds.  The proceeds of each Borrowing
shall be used for the general corporate purposes of the Borrower and its
Subsidiaries; without limiting the foregoing, no proceeds of any Borrowing will
be used to acquire any equity security of a class which is registered pursuant
to Section 12 of the Securities Exchange Act of 1934 or any "margin stock", as
defined in F.R.S. Board Regulation U.

         SECTION 6.15     Existing Liens.  None of the assets of the Borrower
or any Subsidiary of the Borrower is subject to any Lien except the Liens
permitted under Section 7.2.2.


                                  ARTICLE VII

                                   COVENANTS

         SECTION 7.1      Affirmative Covenants.  The Borrower agrees with the
Agent and each Lender that, until all Commitments have terminated and all
Obligations have been paid and performed in full, the Borrower will perform the
obligations set forth in this Section 7.1.





                                       37

<PAGE>   44
         SECTION 7.1.1    Financial Information, Reports, Notices, etc.  The
Borrower will furnish, or will cause to be furnished, to each Lender and the
Agent copies of the following financial statements, reports, notices and
information:

         (a)     as soon as available and in any event within 45 days after the
end of each of the first three Fiscal Quarters of each Fiscal Year of the
Borrower, consolidated balance sheets of the Borrower and its Subsidiaries as
of the end of such Fiscal Quarter and consolidated statements of earnings and
cash flow of the Borrower and its Subsidiaries for such Fiscal Quarter and for
the period commencing at the end of the previous Fiscal Year and ending with
the end of such Fiscal Quarter, certified by the chief financial Authorized
Officer of the Borrower;

         (b)     as soon as available and in any event within 90 days after the
end of each Fiscal Year of the Borrower, a copy of the annual audit report for
such Fiscal Year for the Borrower and its Subsidiaries, including therein
consolidated balance sheets of the Borrower and its Subsidiaries as of the end
of such Fiscal Year and consolidated statements of earnings and cash flow of
the Borrower and its Subsidiaries for such Fiscal Year, in each case certified
(without any Impermissible Qualification) in a manner acceptable to the Agent
and the Required Lenders by independent public accountants of recognized
national standing;

         (c)     as soon as available and in any event within 60 days after the
end of each Fiscal Quarter, a certificate, executed by the chief financial
Authorized Officer of the Borrower, showing (in reasonable detail and with
appropriate calculations and computations in all respects satisfactory to the
Agent) compliance with the financial covenants set forth in Section 7.2.3;

         (d)     promptly, and in any event within three Business Days after an
officer of the Borrower or any of its Subsidiaries becomes aware of the
existence of the occurrence of each Default, a statement of the chief executive
officer or the chief financial Authorized Officer of the Borrower setting forth
details of such Default and the action which the Borrower has taken and
proposes to take with respect thereto;

         (e)     promptly, and in any event within three Business Days after an
officer of the Borrower or any of its Subsidiaries becomes aware of (x) the
occurrence of any adverse development with respect to any litigation, action,
proceeding, or labor controversy described in Section 6.7 which would have or
reasonably be expected to have a Material Adverse Effect, or (y) the
commencement of any material labor controversy, litigation, action, proceeding
of the type described in Section 6.7 which would have or reasonably be expected
to have a Material Adverse Effect, notice thereof and copies of all
documentation relating thereto requested by the Agent or any Lender;

         (f)     promptly after the sending or filing thereof, copies of all
reports and registration statements which the Borrower or any of its
Subsidiaries files with the Securities and Exchange Commission or any national
securities exchange;





                                       38

<PAGE>   45
         (g)     immediately upon becoming aware of the institution of any
steps by the Borrower or any other Person to terminate any Pension Plan, or the
failure to make a required contribution to any Pension Plan if such failure is
sufficient to give rise to a Lien under section 302(f) of ERISA, or the taking
of any action with respect to a Pension Plan which could result in the
requirement that the Borrower furnish a bond or other security to the PBGC or
such Pension Plan, or the occurrence of any event with respect to any Pension
Plan which could result in the incurrence by the Borrower of any liability,
fine or penalty, or any increase in the contingent liability of the Borrower
with respect to any post-retirement Welfare Plan benefit which would have or
could reasonably be expected to have a Material Adverse Effect, notice thereof
and copies of all documentation relating thereto; and

         (h)     such other information respecting the condition or operations,
financial or otherwise, of the Borrower or any of its Subsidiaries as any
Lender through the Agent may from time to time reasonably request.

         SECTION 7.1.2    Compliance with Laws, etc.  The Borrower will, and
will cause each of its Subsidiaries to, comply in all material respects with
all applicable laws, rules, regulations and orders, such compliance to include
(without limitation): (a) the maintenance and preservation of its corporate
existence and qualification as a foreign corporation, (b) the payment, before
the same become delinquent, of all taxes, assessments and governmental charges
imposed upon it or upon its property except to the extent being diligently
contested in good faith by appropriate proceedings and for which adequate
reserves in accordance with GAAP shall have been set aside on its books and (c)
all Environmental Laws; except; in each case, where the failure to so comply
would not have or would not reasonably be expected to have a Material Adverse
Effect.

         SECTION 7.1.3    Maintenance of Properties.  The Borrower will, and
will cause each of its Subsidiaries to, maintain, preserve, protect and keep
its properties in good repair, working order and condition, and make necessary
and proper repairs, renewals and replacements so that its business carried on
in connection therewith may be properly conducted at all times unless the
Borrower determines in good faith that the continued maintenance of any of its
properties is no longer economically desirable or unless failure to so
preserve, maintain, protect or keep its properties would not reasonably be
expected to have a Material Adverse Effect.

         SECTION 7.1.4    Insurance.  The Borrower will, and will cause each of
its Subsidiaries to, maintain or cause to be maintained with responsible
insurance companies insurance with respect to its properties and business
against such casualties and contingencies and of such types and in such amounts
as is customary in the case of similar businesses in similar locations.

         SECTION 7.1.5    Books and Records.  The Borrower will, and will cause
each of its Subsidiaries to, keep books and records which accurately reflect,
in accordance with GAAP, all of its business affairs and transactions and
permit the Agent or its representatives, at reasonable times and intervals and
upon reasonable prior notice to the Borrower, to visit all of its offices, to
discuss its financial matters with its officers and employees and to examine
any of its books or other





                                       39

<PAGE>   46
corporate records; provided, however, that prior notice to the Borrower shall
not be required if an Event of Default has occurred or is continuing.

         SECTION 7.1.6    Conduct of Business.  Borrower will, and will cause
each Subsidiary to, cause all material properties and businesses to be
regularly conducted, operated, maintained and developed in a good and
workmanlike manner, as would a prudent operator and in accordance with all
applicable federal, state and local laws, rules and regulations, except for any
failure to so operate, maintain and develop that could not reasonably be
expected to have a Material Adverse Effect.

         SECTION 7.2      Negative Covenants.  The Borrower agrees with the
Agent and each Lender that, until all Commitments have terminated and all
Obligations have been paid and performed in full, the Borrower will perform the
obligations set forth in this Section 7.2.

         SECTION 7.2.1    Business Activities.  The Borrower will not, and will
not permit any of its Subsidiaries to, engage in any business activity if, as a
result thereof, the Borrower and its Subsidiaries taken as a whole would no
longer be principally engaged in the business of oil, gas and energy
exploration, development, production, processing and marketing and such
activities as may be incidental or related thereto.

         SECTION 7.2.2    Liens.  The Borrower will not, and will not permit
any of its Subsidiaries to, create, incur, assume or suffer to exist any Lien
upon any of its property, revenues or assets, whether now owned or hereafter
acquired, except:  (a) Liens securing payment of the Obligations, granted
pursuant to any Loan Document; (b) Liens granted prior to the Effective Date to
secure payment of Indebtedness; (c) Liens for taxes, assessments or other
governmental charges or levies not at the time delinquent or thereafter payable
without penalty or being diligently contested in good faith by appropriate
proceedings and for which adequate reserves in accordance with GAAP shall have
been set aside on its books; (d) Liens of carriers, warehousemen, mechanics,
materialmen and landlords incurred in the ordinary course of business for sums
not overdue or being diligently contested in good faith by appropriate
proceedings and for which adequate reserves in accordance with GAAP shall have
been set aside on its books; (e) Liens incurred in the ordinary course of
business in connection with workmen's compensation, unemployment insurance or
other forms of governmental insurance or benefits, or to secure performance of
tenders, statutory obligations, leases and contracts (other than for borrowed
money) entered into in the ordinary course of business or to secure obligations
on surety or appeal bonds; (f) judgment Liens in existence less than 30 days
after the entry thereof or with respect to which execution has been stayed or
the payment of which is covered in full (subject to a customary deductible) by
insurance maintained with responsible insurance companies and (g) Liens on cash
or cash-equivalents securing Hedging Obligations of the Borrower or any of its
Subsidiaries not in excess in the aggregate of $5,000,000 for all such cash and
cash equivalents; (h) any Lien existing on any asset of any Person at the time
such Person becomes a Subsidiary and not created in contemplation of such
event; (i) any Lien existing on any asset prior to the acquisition thereof by
the Borrower or a Subsidiary and not created in contemplation of such
acquisition; (j) Liens in favor of the United States of America or any state
thereof or any department, agency, instrumentality or political subdivision of
any such jurisdiction





                                       40

<PAGE>   47
to secure partial, progress, advance or other payments pursuant to any contract
or statute; (k) Liens required by any contract or statute in order to permit
the Borrower or a Subsidiary to perform any contract or subcontract made by it
with or at the request of the United States of America, any state or any
department, agency or instrumentality or political subdivision of either; (l)
Liens securing Debt owing by any Subsidiary to the Borrower; (m) Liens under
operating agreements, unitization agreements, pooling orders, and similar
arrangements; (n) in addition to those Liens permitted above, Liens securing
Indebtedness which do not encumber or attach to any equity interest in a
Significant Subsidiary so long as the time each such Lien attaches, Restricted
Indebtedness does not exceed the Restricted Indebtedness Basket; and (o) any
extension, renewal or replacement (or successive extensions, renewals or
replacements), in whole or in part, of any Lien referred to in the foregoing
clauses of this Section or of any Debt secured thereby; provided that the
principal amount of Debt secured thereby shall not exceed the principal amount
of Debt so secured at the time of such extension, renewal or replacement and
that such extension, renewal or replacement Lien shall be limited to all or
part of substantially the same property subject of the Lien extended, renewed
or replaced (plus improvements on such property).

         SECTION 7.2.3    Financial Covenants.  The Borrower will not and will
not permit any of its Subsidiaries to:

         (a)     EBITDA to Total Interest Expense.  Permit the ratio of EBITDA
to Total Interest Expense for any consecutive period of four fiscal quarters
ending on the last day of a fiscal quarter to be less than 4.0:1.0.

         (b)     Total Debt to Capitalization.  Permit the Total Debt to
Capitalization Ratio, expressed as a percentage, to exceed 60% at any time.

         SECTION 7.2.4    Restricted Payments, etc.  On and at all times after
the Effective Date, the Borrower will not declare, pay or make any dividend or
distribution (in cash, property or obligations) on any shares of any class of
capital stock (now or hereafter outstanding) of the Borrower or on any
warrants, options or other rights with respect to any shares of any class of
capital stock (now or hereafter outstanding) of the Borrower (other than
dividends or distributions payable in its common stock or warrants to purchase
its common stock or splitups or reclassifications of its stock into additional
or other shares of its common stock) or apply, or permit any of its
Subsidiaries to apply, any of its funds, property or assets to the purchase,
redemption, sinking fund or other retirement of, or agree or permit any of its
Subsidiaries to purchase or redeem, any shares of any class of capital stock
(now or hereafter outstanding) of the Borrower, or warrants, options or other
rights with respect to any shares of any class of capital stock (now or
hereafter outstanding) of the Borrower, if, after giving effect thereto, an
Event of Default shall have occurred and be continuing.

         SECTION 7.2.5    Indebtedness.  The Borrower will not permit any of
its Significant Subsidiaries to contract, create, incur or assume any
Indebtedness, except (i) Indebtedness of a Significant Subsidiary owed to the
Borrower or a Subsidiary of the Borrower, (ii) Indebtedness incurred or to be
incurred by one or more of the Borrower or Samedan of North Africa, Inc. or any





                                       41

<PAGE>   48
SPV in connection with the construction of the Equatorial Guinea Project, which
Indebtedness shall not exceed $175,000,000 in the aggregate at any time
outstanding, or (iii) other Indebtedness if at the time of incurrence thereof,
and after giving effect thereto Restricted Indebtedness does not exceed the
Restricted Indebtedness Basket.

         SECTION 7.2.6    Consolidation, Merger, etc.  The Borrower will not,
and will not permit any of its Subsidiaries to, liquidate or dissolve,
consolidate with, or merge into or with, any other corporation, or purchase or
otherwise acquire all or substantially all of the assets of any Person (or of
any division thereof) except (a) any such Subsidiary may liquidate or dissolve
voluntarily into, and may merge with and into, the Borrower or any other
Subsidiary, and the assets or stock of any Subsidiary may be purchased or
otherwise acquired by the Borrower or any other Subsidiary; and (b) so long as
no Default has occurred and is continuing or would occur after giving effect
thereto, the Borrower or any of its Subsidiaries may purchase all or
substantially all of the assets of any Person, or acquire such Person by merger
(as long as the Borrower or such Subsidiary is the surviving entity).

         SECTION 7.2.7    Transactions with Affiliates.  The Borrower will not,
and will not permit any of its Subsidiaries to, enter into, or cause, suffer or
permit to exist any arrangement or contract with any of its other Affiliates
unless such arrangement or contract is on an "arms length" basis and is an
arrangement or contract of the kind which would be entered into by a prudent
Person in the position of the Borrower or such Subsidiary with a Person which
is not one of its Affiliates.

         SECTION 7.2.8    Negative Pledges, Restrictive Agreements, etc.  The
Borrower will not, and will not permit any of its Subsidiaries to, enter into
any agreement (excluding this Agreement, any other Loan Document and any
agreement governing any Indebtedness not prohibited under this Agreement)
prohibiting the creation or assumption of any Lien upon its properties,
revenues or assets, whether now owned or hereafter acquired, or the ability of
the Borrower to amend or otherwise modify this Agreement or any other Loan
Document.  The Borrower will not and will not permit any of its Subsidiaries to
enter into any agreement prohibiting the ability of any Subsidiary to make any
payments, directly or indirectly, to the Borrower by way of dividends,
advances, repayments of loans or advances, reimbursements of management and
other intercompany charges, expenses and accruals or other returns on
investments, or any other agreement or arrangement which restricts the ability
of any such Subsidiary to make any payment, directly or indirectly, to the
Borrower.





                                       42

<PAGE>   49
                                  ARTICLE VIII

                               EVENTS OF DEFAULT

         SECTION 8.1      Listing of Events of Default.  Each of the following
events or occurrences described in this Section 8.1 shall constitute an "Event
of Default".

         SECTION 8.1.1    Non-Payment of Obligations.  The Borrower shall
default in the payment or prepayment when due of any principal of or interest
on any Loan or Competitive Bid Loan, or the Borrower shall default (and such
default shall continue unremedied for a period of five days) in the payment
when due of any fee or of any other Obligation.

         SECTION 8.1.2    Breach of Warranty.  Any representation or warranty
of the Borrower made or deemed to be made hereunder or in any other Loan
Document executed by it or any certificates delivered pursuant to Article V is
or shall be incorrect in any material respect when made or deemed made.

         SECTION 8.1.3    Non-Performance of Certain Covenants and Obligations.
The Borrower shall default in the due performance and observance of any of its
obligations under Section 7.2.2, 7.2.3, 7.2.6 or 7.2.8; provided that the
imposition of any non-consensual Lien that is not permitted to exist pursuant
to Section 7.2.2 shall not be deemed to constitute an Event of Default
hereunder until thirty (30) days after the date of such imposition.

         SECTION 8.1.4    Non-Performance of Other Covenants and Obligations.
The Borrower shall default in the due performance and observance of any other
provision contained herein (not constituting an Event of Default under the
preceding provisions of this Section 8.1) or any other Loan Document executed
by it, and such default shall continue unremedied for a period of 30 days after
notice thereof shall have been given to the Borrower by the Agent or any
Lender.

         SECTION 8.1.5    Default on Other Indebtedness.  A default shall occur
in the payment when due (subject to any applicable grace period), whether by
acceleration or otherwise, of any Indebtedness (other than Indebtedness
described in Section 8.1.1) of the Borrower or any of its Subsidiaries having a
principal amount, individually or in the aggregate, in excess of $25,000,000,
or a default shall occur in the performance or observance of any obligation or
condition with respect to such Indebtedness if the effect of such default is to
accelerate the maturity of any such Indebtedness or such default shall continue
unremedied for any applicable period of time sufficient to permit the holder or
holders of such Indebtedness, or any trustee or agent for such holders, to
cause such Indebtedness to become due and payable prior to its expressed
maturity.

         SECTION 8.1.6    Judgments.  Any judgment or order for the payment of
money in excess of $25,000,000 shall be rendered against the Borrower or any of
its Significant Subsidiaries if such excess is not fully covered by valid and
collectible insurance in respect thereof, the payment of which is not being
disputed or contested by the insurer or the insurers, and either (i) proper or





                                       43

<PAGE>   50
valid enforcement or levying proceedings shall have been commenced by any
creditor upon such judgment or order or (ii) such judgment or order shall
continue unsatisfied and unstayed for a period of thirty (30) consecutive days.

         SECTION 8.1.7    Pension Plans.  Any of the following events shall
occur with respect to any Pension Plan (a) the institution of any steps by the
Borrower, any member of its Controlled Group or any other Person to terminate a
Pension Plan if, as a result of such termination, the Borrower or any such
member could be required to make a contribution to such Pension Plan, or could
reasonably expect to incur a liability or obligation to such Pension Plan, in
excess of $25,000,000; or (b) a contribution failure occurs with respect to any
Pension Plan sufficient to give rise to a Lien securing an amount in excess of
$1,000,000 under section 302(f) of ERISA.

         SECTION 8.1.8    Change in Control.  Any Change in Control shall
occur.

         SECTION 8.1.9    Bankruptcy, Insolvency, etc.  The Borrower or any of
its Significant Subsidiaries shall (a) become insolvent or generally fail to
pay, or admit in writing its inability or unwillingness to pay, debts as they
become due; (b) apply for, consent to, or acquiesce in, the appointment of a
trustee, receiver, sequestrator or other custodian for the Borrower or any of
its Significant Subsidiaries or any substantial portion of the property of any
thereof, or make a general assignment for the benefit of creditors; (c) in the
absence of such application, consent or acquiescence, permit or suffer to exist
the appointment of a trustee, receiver, sequestrator or other custodian for the
Borrower or any of its Significant Subsidiaries or for a substantial part of
the property of any thereof, and such trustee, receiver, sequestrator or other
custodian shall not be discharged within 60 days, provided that the Borrower,
each Significant Subsidiary hereby expressly authorizes the Agent and each
Lender to appear in any court conducting any relevant proceeding during such
60-day period to preserve, protect and defend their rights under the Loan
Documents; (d) permit or suffer to exist the commencement of any bankruptcy,
reorganization, debt arrangement or other case or proceeding under any
bankruptcy or insolvency law, or any dissolution, winding up or liquidation
proceeding, in respect of the Borrower or any of its Significant Subsidiaries,
and, if any such case or proceeding is not commenced by the Borrower or such
Subsidiary, such case or proceeding shall be consented to or acquiesced in by
the Borrower or such Significant Subsidiary or shall result in the entry of an
order for relief or shall remain for 60 days undismissed, provided that the
Borrower, each Significant Subsidiary hereby expressly authorizes the Agent and
each Lender to appear in any court conducting any such case or proceeding
during such 60-day period to preserve, protect and defend their rights under
the Loan Documents; or (e) take any corporate action authorizing, or in
furtherance of, any of the foregoing.

         SECTION 8.2      Action if Bankruptcy.  If any Event of Default
described in Section 8.1.9 shall occur with respect to the Borrower or any
Significant Subsidiary, the Commitments (if not theretofore terminated) shall
automatically terminate and the outstanding principal amount of all outstanding
Borrowings and all other Obligations shall automatically be and become
immediately due and payable, without notice or demand.





                                       44

<PAGE>   51
         SECTION 8.3      Action if Other Event of Default.  If any Event of
Default (other than any Event of Default described in Section 8.1.9 with
respect to the Borrower or any Significant Subsidiary) shall occur for any
reason, whether voluntary or involuntary, and be continuing, the Agent, upon
the direction of the Required Lenders, shall by notice to the Borrower declare
all or any portion of the outstanding principal amount of the Borrowings and
other Obligations to be due and payable and/or the Commitments (if not
theretofore terminated) to be terminated, whereupon the full unpaid amount of
such Loans and other Obligations which shall be so declared due and payable
shall be and become immediately due and payable, without further notice, demand
or presentment, as the case may be, and/or the Commitments shall terminate.


                                   ARTICLE IX

                THE AGENT, THE MANAGING AGENTS AND THE CO-AGENTS

         SECTION 9.1      Actions.  Each Lender hereby (i) appoints UBS as the
Agent under this Agreement, the Notes and each other Loan Document, (ii)
acknowledges each of NB and TCB as a Managing Agent under this Agreement, the
Notes and each other Loan Document, and (iii) acknowledges each of BOM, CIBC,
First Chicago, RBC and SocGen as a Co-Agent under this Agreement, the Notes and
each other Loan Document.  Each Lender authorizes the Agent to act on behalf of
such Lender under this Agreement, the Notes and each other Loan Document and,
in the absence of other written instructions from the Required Lenders received
from time to time by the Agent (with respect to which the Agent agrees that it
will comply, except as otherwise provided in this Section or as otherwise
advised by counsel), to exercise such powers hereunder and thereunder as are
specifically delegated to or required of the Agent by the terms hereof and
thereof, together with such powers as may be reasonably incidental thereto.
Each Lender acknowledges that none of the Managing Agents and the Co-Agents
have any duties or obligations under this Agreement in connection with their
capacity as a Managing Agent or a Co-Agent, as the case may be.  Each Lender
hereby indemnifies (which indemnity shall survive any termination of this
Agreement) each of the Agent, the Managing Agents and the Co-Agents, pro rata
according to such Lender's Percentage, whether or not related to any singular,
joint or concurrent negligence of the Agent, the Managing Agents and the
Co-Agents, from and against any and all liabilities, obligations, losses,
damages, claims, costs or expenses of any kind or nature whatsoever which may
at any time be imposed on, incurred by, or asserted against, the Agent, any
Managing Agent or any Co-Agent in any way relating to or arising out of this
Agreement, the Notes and any other Loan Document, including reasonable
attorneys' fees, and as to which the Agent, such Managing Agent or such Co-
Agent is not reimbursed by the Borrower; provided, however, that no Lender
shall be liable for the payment of any portion of such liabilities,
obligations, losses, damages, claims, costs or expenses which are determined by
a court of competent jurisdiction in a final proceeding to have resulted solely
from the Agent's, such Managing Agent's or such Co- Agent's gross negligence or
wilful misconduct.  None of the Agent, the Managing Agents and the Co-Agents
shall be required to take any action hereunder, under the Notes or under any
other Loan Document, or to prosecute or defend any suit in respect of this
Agreement, the Notes or any other Loan Document, unless it is indemnified





                                       45

<PAGE>   52
hereunder to its satisfaction.  If any indemnity in favor of the Agent, any
Managing Agent or any Co-Agent shall be or become inadequate, in the Agent's,
such Managing Agent's or such Co-Agent's determination, as the case may be, the
Agent, such Managing Agent or such Co-Agent, as the case may be, may call for
additional indemnification from the Lenders and cease to do the acts
indemnified against hereunder until such additional indemnity is given.
Notwithstanding any provision to the contrary contained elsewhere in this
Agreement or in any other Loan Document, none of the Agent, the Managing Agents
and the Co-Agents shall have any duties or responsibilities, except as
expressly set forth herein, nor shall any of the Agent, the Managing Agents and
the Co-Agents have or be deemed to have any fiduciary relationship with any
Lender, and no implied covenants, functions, responsibilities, duties,
obligations or liabilities shall be read into this Agreement or any other Loan
Document or otherwise exist against any of the Agent, the Managing Agents and
the Co-Agents.

         SECTION 9.2      Funding Reliance, etc.  Unless the Agent shall have
been notified by telephone, confirmed in writing, by any Lender by 5:00 p.m.,
New York time, on the day prior to a Borrowing (except with respect to a
Borrowing comprised of Base Rate Loans, in which case notice shall be given no
later than 12:00 noon, New York time, on the date of the proposed Borrowing)
that such Lender will not make available the amount which would constitute its
Percentage of such Borrowing on the date specified therefor, the Agent may
assume that such Lender has made such amount available to the Agent and, in
reliance upon such assumption, make available to the Borrower a corresponding
amount.  If and to the extent that such Lender shall not have made such amount
available to the Agent, such Lender and the Borrower severally agree to repay
the Agent forthwith on demand such corresponding amount together with interest
thereon, for each day from the date the Agent made such amount available to the
Borrower to the date such amount is repaid to the Agent, at the Federal Funds
Rate.

         SECTION 9.3      Exculpation.  None of the Agent, the Managing Agents,
the Co-Agents and their respective directors, officers, employees or agents
shall be liable to any Lender for any action taken or omitted to be taken by it
under this Agreement or any other Loan Document, or in connection herewith or
therewith, except for its own wilful misconduct or gross negligence, nor
responsible for any recitals or warranties herein or therein, nor for the
effectiveness, enforceability, validity or due execution of this Agreement or
any other Loan Document, nor to make any inquiry respecting the performance by
the Borrower of its obligations hereunder or under any other Loan Document.
Any such inquiry which may be made by the Agent, any Managing Agent or any
Co-Agent shall not obligate it to make any further inquiry or to take any
action.  Each of the Agent, the Managing Agents and the Co-Agents shall be
entitled to rely upon advice of counsel concerning legal matters and upon any
notice, consent, certificate, statement or writing which the Agent, such
Managing Agent or such Co-Agent believes to be genuine and to have been
presented by a proper Person.

         SECTION 9.4      Successor.  Any of the Agent, the Managing Agents and
the Co-Agents may resign as such at any time upon at least 30 days' prior
notice to the Borrower and all Lenders.  If the Agent at any time shall resign,
the Required Lenders may appoint another Lender as the successor





                                       46

<PAGE>   53
Agent which shall thereupon become the Agent hereunder.  If no successor Agent
shall have been so appointed by the Required Lenders, and shall have accepted
such appointment, within 30 days after the retiring Agent's giving notice of
resignation, then the retiring Agent may, on behalf of the Lenders, appoint a
successor Agent, which shall be one of the Lenders or a commercial banking
institution organized under the laws of the U.S. (or any State thereof) or a
U.S. branch or agency of a commercial banking institution, and having a
combined capital and surplus of at least $500,000,000.  Upon the acceptance of
any appointment as the Agent hereunder by a successor Agent, such successor
Agent shall be entitled to receive from the retiring Agent such documents of
transfer and assignment as such successor Agent may reasonably request, and
shall thereupon succeed to and become vested with all rights, powers,
privileges and duties of the retiring Agent, and the retiring Agent shall be
discharged from its duties and obligations under this Agreement.  After a
retiring Agent's, Managing Agent's or Co-Agent's resignation hereunder as
Agent, Managing Agent or Co-Agent, the provisions of (a)this Article IX shall
inure to its benefit as to any actions taken or omitted to be taken by it while
it was the Agent under this Agreement, and Section 10.4 (and, with respect to
the Agent, Section 10.3) shall continue to inure to its benefit.

         SECTION 9.5      Loans by the Agents.  Each of the Agent, the Managing
Agents and the Co-Agents shall have the same rights and powers with respect to
(x) the Loans made by it or any of its Affiliates, and (y) the Notes held by it
or any of its Affiliates as any other Lender and may exercise the same as if it
were not the Agent, a Managing Agent or a Co-Agent, as the case may be.  Each
of the Agent, the Managing Agents and the Co-Agents and its Affiliates may
accept deposits from, lend money to, and generally engage in any kind of
business with the Borrower or any Subsidiary or Affiliate of the Borrower as if
it were not the Agent, a Managing Agent or a Co-Agent hereunder, as the case
may be.

         SECTION 9.6      Credit Decisions.  Each Lender acknowledges that it
has made its own credit decision to extend its Commitments hereunder (i)
independently of each of the Agent, the Managing Agents, the Co-Agents and each
other Lender, and (ii) based on such Lender's review of the financial
information of the Borrower, this Agreement, the other Loan Documents (the
terms and provisions of which being satisfactory to such Lender) and such other
documents, information and investigations as such Lender has deemed
appropriate.  Each Lender also acknowledges that it will continue to make its
own credit decisions as to exercising or not exercising from time to time any
rights and privileges available to it under this Agreement or any other Loan
Document (i) independently of each of the Agent, the Managing Agents, the
Co-Agents and each other Lender, and (ii) based on such other documents,
information and investigations as it shall deem appropriate at any time.

         SECTION 9.7      Copies, etc.  The Agent shall give prompt notice to
each Lender of each notice or request required or permitted to be given to the
Agent by the Borrower pursuant to the terms of this Agreement (unless
concurrently delivered to the Lenders by the Borrower).  The Agent will
distribute to each Lender each document or instrument received for its account
and copies of all other communications received by the Agent from the Borrower
for distribution to the Lenders by the Agent in accordance with the terms of
this Agreement."





                                       47

<PAGE>   54
                                   ARTICLE X

                            MISCELLANEOUS PROVISIONS

         SECTION 10.1     Waivers, Amendments, etc.  The provisions of this
Agreement and of each other Loan Document may from time to time be amended,
modified or waived, if such amendment, modification or waiver is in writing and
consented to by the Borrower and the Required Lenders; provided, however, that
no such amendment, modification or waiver which would: (a) modify any
requirement hereunder that any particular action be taken by all the Lenders or
by the Required Lenders shall be effective unless consented to by each Lender;
(b) modify this Section 10.1, change the definition of "Required Lenders",
increase any Commitment Amount or the Percentage of any Lender, reduce any fees
described in Article III, change the schedule of reductions to the Commitments
provided for in Section 2.3, release any collateral security except as
otherwise specifically provided in any Loan Document or extend any Commitment
Termination Date, shall be made without the consent of each Lender; (c) extend
the due date for, or reduce the amount of, any scheduled repayment or
prepayment of principal of or interest on any Loan (or  reduce the principal
amount of or rate of interest on any Loan) shall be made without the consent of
the holder of that Note evidencing such Loan; or (d) affect adversely the
interests, rights or obligations of the Agent as Agent, any Managing Agent as
Managing Agent or any Co-Agent as Co-Agent shall be made without the consent of
such Agent, Managing Agent or Co-Agent.

No failure or delay on the part of the Agent, any Lender or the holder of any
Note in exercising any power or right under this Agreement or any other Loan
Document shall operate as a waiver thereof, nor shall any single or partial
exercise of any such power or right preclude any other or further exercise
thereof or the exercise of any other power or right.  No notice to or demand on
the Borrower in any case shall entitle it to any notice or demand in similar or
other circumstances.  No waiver or approval by the Agent, any Lender or the
holder of any Note under this Agreement or any other Loan Document shall,
except as may be otherwise stated in such waiver or approval, be applicable to
subsequent transactions.  No waiver or approval hereunder shall require any
similar or dissimilar waiver or approval thereafter to be granted hereunder.

         SECTION 10.2     Notices.  All notices and other communications
provided to any party hereto under this Agreement or any other Loan Document
shall be in writing or by facsimile and addressed, delivered or transmitted to
such party at its address or facsimile number set forth below its signature
hereto or set forth in the Lender Assignment Agreement or at such other address
or facsimile number as may be designated by such party in a notice to the other
parties.  Any notice, if mailed and properly addressed with postage prepaid or
if properly addressed and sent by pre- paid courier service, shall be deemed
given when received; any notice, if transmitted by facsimile, shall be deemed
given when transmitted and receipt is confirmed.

         SECTION 10.3     Payment of Costs, Expenses and Taxes.  The Borrower
agrees to pay on demand all reasonable out- of-pocket costs and expenses of (i)
the Agent (including, without limitation, the reasonable fees and out-of-pocket
expenses of Messrs. Mayer, Brown & Platt and of





                                       48

<PAGE>   55
local counsel, if any, who may be retained by said counsel) in connection with
the preparation, negotiation, execution, delivery, syndication and
administration of this Agreement and of each other Loan Document, including
schedules and exhibits, and any amendments, waivers, consents, supplements or
other modification to this Agreement or any other Loan Document and (ii) the
Agent and the Lenders in connection with the enforcement by the Lenders or the
Agent of, or the protection of rights under, this Agreement, the Notes and each
other Loan Document.  The Agent and each Lender agree to the extent feasible,
and to the extent a conflict of interest does not exist in the reasonable
opinion of the Agent or any Lender, to use one law firm in each jurisdiction in
connection with the foregoing, to the extent they seek reimbursement for the
expenses thereof from the Borrower.  Each Lender agrees to reimburse the Agent
on demand for such Lender's pro rata share (based upon its respective
Percentage) of any such costs or expenses not paid by the Borrower.  In
addition, the Borrower agrees to pay, and to save the Agent and the Lenders
harmless from all liability for, any stamp or other taxes which may be payable
in connection with the execution or delivery of this Agreement, the Borrowings
hereunder, or the issuance of the Notes, or of any other instruments or
documents provided for herein or delivered or to be delivered hereunder or in
connection herewith.

         SECTION 10.4     Indemnification.  In consideration of the execution
and delivery of this Agreement by each Lender and the extension of the
Commitments, the Borrower hereby indemnifies, exonerates and holds the Agent,
each Managing Agent, each Co-Agent and each Lender and each of their respective
officers, directors, employees and agents (collectively, the "Indemnified
Parties"), whether or not related to any negligence of the Indemnified Parties,
free and harmless from and against any and all actions, causes of action,
suits, losses, costs, liabilities and damages, and expenses incurred in
connection therewith (irrespective of whether any such Indemnified Party is a
party to the action for which indemnification hereunder is sought), including
reasonable attorneys' fees and disbursements (collectively, the "Indemnified
Liabilities"), incurred by the Indemnified Parties or any of them as a result
of, or arising out of, or relating to (a) any transaction financed or to be
financed in whole or in part, directly or indirectly, with the proceeds of any
Loan; (b) the entering into and performance of this Agreement and any other
Loan Document by any of the Indemnified Parties; (c)any investigation,
litigation or proceeding related to any acquisition or proposed acquisition by
the Borrower or any of its Significant Subsidiaries of all or any portion of
the stock or assets of any Person, whether or not the Agent, such Managing
Agent, such Co-Agent or such Lender is party thereto; any investigation,
litigation or proceeding related to any environmental cleanup, audit,
compliance or other matter relating to the protection of the environment or the
Release by the Borrower or any of its Significant Subsidiaries of any Hazardous
Material; or (d) the presence on or under, or the escape, seepage, leakage,
spillage, discharge, emission, discharging or releases from, any real property
owned or operated by the Borrower or any Subsidiary thereof of any Hazardous
Material (including any losses, liabilities, damages, injuries, costs, expenses
or claims asserted or arising under any Environmental Law), regardless of
whether caused by, or within the control of, the Borrower or such Subsidiary,
except for any such Indemnified Liabilities arising for the account of a
particular Indemnified Party by reason of the relevant Indemnified Party's
gross negligence or wilful misconduct.  If and to the extent that the foregoing
undertaking may be unenforceable for any





                                       49

<PAGE>   56
reason, the Borrower hereby agrees to make the maximum contribution to the
payment and satisfaction of each of the Indemnified Liabilities which is
permissible under applicable law."

         SECTION 10.5     Survival.  The obligations of the Borrower under
Sections 4.3, 4.4, 4.5, 4.6, 10.3 and 10.4, and the obligations of the Lenders
under Section 9.1, shall in each case survive any termination of this
Agreement, the payment in full of all Obligations and the termination of all
Commitments.

         SECTION 10.6     Severability.  Any provision of this Agreement or any
other Loan Document which is prohibited or unenforceable in any jurisdiction
shall, as to such provision and such jurisdiction, be ineffective to the extent
of such prohibition or unenforceability without invalidating the remaining
provisions of this Agreement or such Loan Document or affecting the validity or
enforceability of such provision in any other jurisdiction.

         SECTION 10.7     Headings.  The various headings of this Agreement and
of each other Loan Document are inserted for convenience only and shall not
affect the meaning or interpretation of this Agreement or such other Loan
Document or any provisions hereof or thereof.

         SECTION 10.8     Execution in Counterparts, Effectiveness, etc.  This
Agreement may be executed by the parties hereto in several counterparts, each
of which shall be executed by the Borrower and the Agent and be deemed to be an
original and all of which shall constitute together but one and the same
agreement.  This Agreement shall become effective when counterparts hereof
executed on behalf of the Borrower and each Lender (or notice thereof
satisfactory to the Agent) shall have been received by the Agent and notice
thereof shall have been given by the Agent to the Borrower and each Lender.

         SECTION 10.9     Governing Law; Entire Agreement.  THIS AGREEMENT, THE
NOTES AND EACH OTHER LOAN DOCUMENT SHALL EACH BE DEEMED TO BE A CONTRACT MADE
UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT
GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAWS.  This Agreement, the Notes
and the other Loan Documents constitute the entire understanding among the
parties hereto with respect to the subject matter hereof and supersede any
prior agreements, written or oral, with respect thereto.

         SECTION 10.10    Successors and Assigns.  This Agreement shall be
binding upon and shall inure to the benefit of the parties hereto and their
respective successors and assigns; provided, however, that: (a) the Borrower
may not assign or transfer its rights or obligations hereunder without the
prior written consent of the Agent and all Lenders; and (b) the rights of sale,
assignment and transfer of the Lenders are subject to Section 10.11.

         SECTION 10.11    Sale and Transfer of Loans and Notes; Participations
in Loans and Notes.  Each Lender may assign, or sell participations in, its
Loans and Commitments to one or more other Persons in accordance with this
Section 10.11.





                                       50

<PAGE>   57
         SECTION 10.11.1  Assignments.  Any Lender, (a) with the written
consents of the Borrower and the Agent (which consents shall not be
unreasonably delayed or withheld, may at any time assign and delegate to one or
more commercial banks or other financial institutions, and (b) with notice to
the Borrower and the Agent, but without the consent of the Borrower or the
Agent, may assign and delegate to any of its Affiliates or to any other Lender
(each Person described in either of the foregoing clauses as being the Person
to whom such assignment and delegation is to be made, being hereinafter
referred to as an "Assignee Lender"), all or any fraction of such Lender's
total Loans and Commitments (which assignment and delegation shall be of a
constant, and not a varying, percentage of all the assigning Lender's Loans and
Commitments and which shall be of equal pro rata shares of the Facility) in a
minimum aggregate amount of $10,000,000; provided, however, that any such
Assignee Lender will comply, if applicable, with the provisions contained in
the last sentence of Section 4.6 and further, provided, however, that, the
Borrower and the Agent shall be entitled to continue to deal solely and
directly with such Lender in connection with the interests so assigned and
delegated to an Assignee Lender until (c) written notice of such assignment and
delegation, together with payment instructions, addresses and related
information with respect to such Assignee Lender, shall have been given to the
Borrower and the Agent by such Lender and such Assignee Lender, (d) such
Assignee Lender shall have executed and delivered to the Borrower and the Agent
a Lender Assignment Agreement, accepted by the Agent, and (e) the processing
fees described below shall have been paid.

         From and after the date that the Agent accepts such Lender Assignment
Agreement, (x) the Assignee Lender thereunder shall be deemed automatically to
have become a party hereto and to the extent that rights and obligations
hereunder have been assigned and delegated to such Assignee Lender in
connection with such Lender Assignment Agreement, shall have the rights and
obligations of a Lender hereunder and under the other Loan Documents, and (y)
the assignor Lender, to the extent that rights and obligations hereunder have
been assigned and delegated by it in connection with such Lender Assignment
Agreement, shall be released from its obligations hereunder and under the other
Loan Documents.  Within five Business Days after its receipt of notice that the
Agent has received an executed Lender Assignment Agreement, the Borrower shall
execute and deliver to the Agent (for delivery to the relevant Assignee Lender)
new Notes evidencing such Assignee Lender's assigned Loans and Commitments and,
if the assignor Lender has retained Loans and Commitments hereunder,
replacement Notes in the principal amount of the Loans and Commitments retained
by the assignor Lender hereunder (such Notes to be in exchange for, but not in
payment of, those Notes then held by such assignor Lender).  Each such Note
shall be dated the date of the predecessor Notes.  The assignor Lender shall
mark the predecessor Notes "exchanged" and deliver them to the Borrower.
Accrued interest on that part of the predecessor Notes evidenced by the new
Notes, and accrued fees, shall be paid as provided in the Lender Assignment
Agreement.  Accrued interest on that part of the predecessor Notes evidenced by
the replacement Notes shall be paid to the assignor Lender.  Accrued interest
and accrued fees shall be paid at the same time or times provided in the
predecessor Notes and in this Agreement.  Such assignor Lender or such Assignee
Lender must also pay a processing fee to the Agent upon delivery of any Lender
Assignment Agreement in the amount of $2,000.  Any attempted assignment and
delegation not made in accordance with this Section 10.11.1 shall be null and
void.





                                       51

<PAGE>   58
         SECTION 10.11.2  Participations.  Any Lender may at any time sell to
one or more commercial banks or other Persons (each of such commercial banks
and other Persons being herein called a "Participant") participating interests
in any of the Loans, Commitments, or other interests of such Lender hereunder;
provided, however, that (a) no participation contemplated in this Section 10.11
shall relieve such Lender from its Commitments or its other obligations
hereunder or under any other Loan Document, (b) such Lender shall remain solely
responsible for the performance of its Commitments and such other obligations,
(c) the Borrower and the Agent shall continue to deal solely and directly with
such Lender in connection with such Lender's rights and obligations under this
Agreement and each of the other Loan Documents, (d) no Participant, unless such
Participant is an Affiliate of such Lender, or is itself a Lender, shall be
entitled to require such Lender to take or refrain from taking any action
hereunder or under any other Loan Document, except that such Lender may agree
with any Participant that such Lender will not, without such Participant's
consent, take any actions of the type described in clause (b) or (c) of Section
10.1, and (e) the Borrower shall not be required to pay any amount under
Section 4.6 that is greater than the amount which it would have been required
to pay had no participating interest been sold.  The Borrower acknowledges and
agrees that each Participant, for purposes of Sections 4.3, 4.4, 4.5, 4.6, 4.7,
4.8, 4.9 and 10.4, shall be considered a Lender; provided that this sentence
shall not obligate Borrower to pay more under such Sections that it would be
obligated to pay had no such participation been granted.

         SECTION 10.12    Other Transactions.  Nothing contained herein shall
preclude the Agent or any other Lender from engaging in any transaction, in
addition to those contemplated by this Agreement or any other Loan Document,
with the Borrower or any of its Affiliates in which the Borrower or such
Affiliate is not restricted hereby from engaging with any other Person.

         SECTION 10.13    Sale and Purchase of Loans.  On the Effective Date,
the aggregate principal balance of the Prior Indebtedness outstanding is
$200,000,000 as shown on Schedule IIB and each Lender represents and warrants
for itself that its outstanding loans under the Original Credit Agreement as of
the Effective Date is as set forth in the second column of Schedule IIB.
Lenders hereby sell, assign, transfer and convey, and Lenders hereby purchase
and accept so much of the Prior Indebtedness and all of the rights, titles,
benefits, interests, privileges, claims, liens, security interests, and
obligations existing and to exist (collectively the "Interests") such that each
Lender's Percentage of the outstanding loans and commitments under the Original
Credit Agreement as amended and restated by this Agreement shall be as set
forth in Schedule IIA as of the Effective Date.  The foregoing assignment,
transfer and conveyance are without recourse to the Lenders and without any
warranties whatsoever as to title, enforceability, collectibility,
documentation or freedom from liens or encumbrances, in whole or in part, other
than the warranty by each Lender that it has not sold, transferred, conveyed or
encumbered such Interests.  If as a result thereof, a Lender's Percentage of
the outstanding Loans under this Agreement is less than its outstanding loans
under the Original Credit Agreement on the Effective Date, the difference set
forth in the last column of Schedule IIB shall be remitted to such Lender by
the Agent upon receipt of funds from the other Lenders shown in the last column
of Schedule IIB on the Effective Date.  Each Lender so acquiring a part of such
outstanding loans assumes its Percentage of the outstanding Loans, Commitments,





                                       52

<PAGE>   59
rights, titles, interests, privileges, claims, liens, security interests,
benefits and obligations under this Agreement and the other Loan Documents and
any Lender so acquiring an interest in such outstanding Loans may be paid a
cost of funds with respect thereto as mutually agreed between the Borrower and
such Lender.  Lenders are proportionately released from the obligations assumed
by Lenders so acquiring such obligations and, to that extent, the Lenders so
released shall have no further obligation under the Original Credit Agreement,
as amended and restated hereby.  The Borrower hereby represents and warrants
that it has no defenses, offsets or counterclaims to the Prior Indebtedness or
its obligations or rights under this Agreement, including, without limitation,
the Interests being assigned pursuant to this Section 10.13.  The promissory
notes evidencing the Prior Indebtedness shall be appropriately endorsed and
delivered by the holders thereof to the Agent and retained by the Agent until
the Obligations shall have been paid in full, all Letters of Credit have
expired or been canceled and the Commitments have been canceled.

         SECTION 10.14    Forum Selection and Consent to Jurisdiction.  ANY
LITIGATION BASED HEREON, OR ARISING OUT OF, UNDER, OR IN CONNECTION WITH, THIS
AGREEMENT OR ANY OTHER LOAN DOCUMENT, OR ANY COURSE OF CONDUCT, COURSE OF
DEALING, STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF THE AGENT, THE
LENDERS OR THE BORROWER SHALL BE BROUGHT AND MAINTAINED EXCLUSIVELY IN THE
COURTS OF THE STATE OF NEW YORK OR IN THE UNITED STATES DISTRICT COURT FOR THE
SOUTHERN DISTRICT OF NEW YORK; PROVIDED, HOWEVER, THAT ANY SUIT SEEKING
ENFORCEMENT AGAINST ANY COLLATERAL OR OTHER PROPERTY MAY BE BROUGHT, AT THE
AGENT'S OPTION, IN THE COURTS OF ANY JURISDICTION WHERE SUCH COLLATERAL OR
OTHER PROPERTY MAY BE FOUND.  THE BORROWER, THE AGENT, AND EACH LENDER HEREBY
EXPRESSLY AND IRREVOCABLY SUBMIT TO THE JURISDICTION OF THE COURTS OF THE STATE
OF NEW YORK AND OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT
OF NEW YORK FOR THE PURPOSE OF ANY SUCH LITIGATION AS SET FORTH ABOVE AND
IRREVOCABLY AGREE TO BE BOUND BY ANY JUDGMENT RENDERED THEREBY IN CONNECTION
WITH SUCH LITIGATION.  THE BORROWER, THE AGENT, AND EACH LENDER FURTHER
IRREVOCABLY CONSENT TO THE SERVICE OF PROCESS BY REGISTERED MAIL, POSTAGE
PREPAID, OR BY PERSONAL SERVICE WITHIN OR WITHOUT THE STATE OF NEW YORK.  THE
BORROWER, THE AGENT, AND EACH LENDER HEREBY EXPRESSLY AND IRREVOCABLY WAIVES,
TO THE FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY HAVE OR
HEREAFTER MAY HAVE TO THE LAYING OF VENUE OF ANY SUCH LITIGATION BROUGHT IN ANY
SUCH COURT REFERRED TO ABOVE AND ANY CLAIM THAT ANY SUCH LITIGATION HAS BEEN
BROUGHT IN AN INCONVENIENT FORUM.  TO THE EXTENT THAT THE BORROWER HAS OR
HEREAFTER MAY ACQUIRE ANY IMMUNITY FROM JURISDICTION OF ANY COURT OF FROM ANY
LEGAL PROCESS (WHETHER THROUGH SERVICE OR NOTICE, ATTACHMENT PRIOR TO JUDGMENT,
ATTACHMENT IN AID OF EXECUTION OR OTHERWISE) WITH RESPECT TO





                                       53

<PAGE>   60
ITSELF OR ITS PROPERTY, THE BORROWER HEREBY IRREVOCABLY WAIVES SUCH IMMUNITY IN
RESPECT OF ITS OBLIGATIONS UNDER THIS AGREEMENT AND THE OTHER LOAN DOCUMENTS.

         SECTION 10.15    Waiver of Jury Trial.  THE AGENT, THE LENDERS AND THE
BORROWER HEREBY KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVE ANY RIGHTS THEY
MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION BASED HEREON, OR
ARISING OUT OF, UNDER, OR IN CONNECTION WITH, THIS AGREEMENT OR ANY OTHER LOAN
DOCUMENT, OR ANY COURSE OF CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER
VERBAL OR WRITTEN) OR ACTIONS OF THE AGENT, THE LENDERS OR THE BORROWER.  THE
BORROWER ACKNOWLEDGES AND AGREES THAT IT HAS RECEIVED FULL AND SUFFICIENT
CONSIDERATION FOR THIS PROVISION (AND EACH OTHER PROVISION OF EACH OTHER LOAN
DOCUMENT TO WHICH IT IS A PARTY) AND THAT THIS PROVISION IS A MATERIAL
INDUCEMENT FOR THE AGENT AND THE LENDERS ENTERING INTO THIS AGREEMENT AND EACH
SUCH OTHER LOAN DOCUMENT.





                                       54

<PAGE>   61
         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their respective officers thereunto duly authorized as of the
day and year first above written.

                            NOBLE AFFILIATES, INC.


                            By:                                             
                               ---------------------------------------------
                            Name:       William D. Dickson
                            Title:      Vice President Finance and Treasurer

                            Address:    110 West Broadway
                                        Ardmore, Oklahoma  73401

                            Facsimile No.:      405/221-1386

                            Telephone No.:      405/223-4110

                            Attention:          William D. Dickson






                                      S-1

<PAGE>   62
                                                        

                      UNION BANK OF SWITZERLAND, Houston Agency, Individually 
                      as a Lender and as the Agent


                      By:                                             
                          --------------------------------------------
                      Name:       Finley Biggerstaff
                      Title:      Assistant Vice President


                      By:                                             
                          --------------------------------------------
                      Name:       Evans Swann
                      Title:      Managing Director

                      Domestic
                      Office:             1100 Louisiana, Suite 4500
                                          Houston, Texas  77002

                      Facsimile No.:      (713) 655-6555

                      Attention:          Finley Biggerstaff
                      Telephone:          (713) 655-6500

                      Eurodollar
                      Office:             1100 Louisiana, Suite 4500
                                          Houston, Texas  77002

                      Facsimile No.:      (713) 655-6555

                      Attention:          Finley Biggerstaff
                      Telephone:          (713) 655-6500






                                      S-2

<PAGE>   63
                                                        
                              NATIONSBANK OF TEXAS, N.A, Individually as a 
                              Lender and as Managing Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:       Dale T. Wilson
                              Title:      Vice President

                              Domestic
                              Office:             901 Main Street, 14th Floor
                                                  Dallas, Texas  75202

                              Facsimile No.:      (214) 508-1215

                              Attention:          Betty Canales
                              Telephone:          (214) 508-1225

                              Eurodollar
                              Office:             901 Main Street, 14th Floor
                                                  Dallas, Texas  75202

                              Facsimile No.:      (214) 508-1215

                              Attention:          Betty Canales
                              Telephone:          (214) 508-1225

                              Send copies to:     303 West Wall Street
                                                  Midland, Texas  79701-4761

                              Facsimile No.:      (915) 685-2009

                              Attention:          Dale Wilson
                              Telephone:          (915) 685-2193






                                      S-3

<PAGE>   64
                        
                              TEXAS COMMERCE BANK NATIONAL ASSOCIATION, 
                              Individually as a Lender and as Managing Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:       Dale Hurd
                              Title:      Senior Vice President

                              Domestic
                              Office:             2200 Ross Ave., 3rd Floor
                                                  Dallas, Texas   75201

                              Facsimile No.:      (214) 965-2389

                              Attention:          Dale Hurd
                              Telephone:          (214) 965-2583


                              Eurodollar
                              Office:             2200 Ross Ave., 3rd Floor
                                                  Dallas, Texas   75201

                              Facsimile No.:      (214) 965-2389

                              Attention:          Dale Hurd
                              Telephone:          (214) 965-2583






                                      S-4

<PAGE>   65


                              BANK OF MONTREAL, Individually as a Lender and 
                              as Co-Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             115 S. LaSalle, 11W
                                                  Chicago, Illinois 60603

                              Facsimile No.:      (312) 750-4326

                              Attention:          Charla Chase
                              Telephone:          (312) 750-4326

                              Eurodollar
                              Office:             115 S. LaSalle,11W
                                                  Chicago, Illinois 60603

                              Facsimile No.:      (312) 750-6061

                              Attention:          Charla Chase
                              Telephone:          (312) 750-4326

                              Send copies to:     700 Louisiana, Suite 4400
                                                  Houston, Texas 77002

                              Facsimile No.:      (713) 223-4007

                              Attention:          Robert L. Roberts
                              Telephone:          (713) 546-9754






                                      S-5

<PAGE>   66

        
                              CIBC INC., Individually as a Lender and as 
                              Co-Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             2727 Paces Ferry Rd.
                                                  Suite 1200
                                                  Atlanta, Georgia   30339

                              Facsimile No.:      (270) 319-4950

                              Attention:          Joan Moseley
                              Telephone:          (270) 319-4828

                              Eurodollar
                              Office:             2727 Paces Ferry Rd.
                                                  Suite 1200
                                                  Atlanta, Georgia   30339

                              Facsimile No.:      (270) 319-4950

                              Attention:          Joan Moseley
                              Telephone:          (270) 319-4828

                              Send copies to:     909 Fannin, Suite 1200
                                                  Houston, TX 77010

                              Facsimile No.:      (713) 658-9922

                              Attention:          Brian Myers
                              Telephone:          (713) 658-5230






                                      S-6

<PAGE>   67


                              THE FIRST NATIONAL BANK OF CHICAGO, Individually 
                              as a Lender and as Co-Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             One First National Plaza
                                                  0634, 1FNP, 10
                                                  Chicago, IL   60670

                              Facsimile No.:      (312) 732-4840

                              Attention:          John Beirne
                              Telephone:          (312) 732-3659

                              Eurodollar
                              Office:             One First National Plaza
                                                  0634, 1FNP, 10
                                                  Chicago, IL   60670

                              Facsimile No.:      (312) 732-4840

                              Attention:          John Beirne
                              Telephone:          (312) 732-3659

                              Send copies to:     1100 Louisiana, Suite 3200
                                                  Houston, TX 77002

                              Facsimile No.:      (713) 654-7370

                              Attention:          Ron Dierker
                              Telephone:          (713) 654-7341






                                      S-7

<PAGE>   68


                              ROYAL BANK OF CANADA, Individually as a Lender 
                              and as Co-Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:       Linda M. Stephens
                              Title:      Manager

                              Domestic
                              Office:          1 Financial Square
                                               New York, NY  10005-3531
                                               
                              Facsimile No.:   (212) 428-2372
                                               
                              Attention:       Linda Smith, Loan Administrator
                              Telephone:       (212) 428-6323
                                               
                              Eurodollar       
                              Office:          1 Financial Square
                                               New York, NY  10005-3531
                                               
                              Facsimile No.:   (212) 428-2372
                                               
                              Attention:       Linda Smith, Loan Administrator
                              Telephone:       (212) 428-6323
                                               





                                      S-8

<PAGE>   69


                              SOCIETE GENERALE, SOUTHWEST AGENCY, Individually 
                              as a Lender and as Co-Agent


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             2001 Ross Ave., Suite 4800
                                                  Dallas, Texas   75201

                              Facsimile No.:      (214) 979-1104

                              Attention:          Louis P. LaVille
                              Telephone:          (214) 979-2762

                              Eurodollar
                              Office:             2001 Ross Ave., Suite 4800
                                                  Dallas, Texas   75201

                              Facsimile No.:      (214) 754-0171

                              Attention:          Ralph Saheb
                              Telephone:          (214) 979-2764






                                      S-9

<PAGE>   70


                              BANK OF AMERICA NATIONAL TRUST AND SAVINGS 
                              ASSOCIATION, as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:       Ronald E. McKaig
                              Title:      Vice President

                              Domestic
                              Office:             Bank of America NT&SA
                                                  231 South LaSalle
                                                  Chicago, IL 60697

                              Facsimile No.:      (510) 603-8264
                              Attention:          Leeann Denbow
                              Telephone:          (510) 675-7040

                              With a copy to:     Bank of America

                              Address:            333 Clay Street, Suite 4550
                                                  Houston, TX  77002

                              Facsimile No.:      (713) 651-4841
                              Attention:          Ronald E. McKaig
                              Telephone:          (713) 651-4881

                              Eurodollar
                              Office:             Bank of America NT&SA
                                                  231 South LaSalle
                                                  Chicago, IL 60697

                              Facsimile No.:      (510) 603-8264
                              Attention:          Leeann Denbow
                              Telephone:          (510) 675-7040

                              With a copy to:     Bank of America

                              Address:            333 Clay Street, Suite 4550
                                                  Houston, TX  77002

                              Facsimile No.:      (713) 651-4841
                              Attention:          Ronald E. McKaig
                              Telephone:          (713) 651-4881






                                      S-10

<PAGE>   71
                                                
                              THE BANK OF NEW YORK, as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             The Energy Industries Division
                                                  One Wall Street, 19th Floor
                                                  New York, New York   10286

                              Facsimile No.:      (212) 635-7923

                              Attention:          Raymond Palmer
                              Telephone:          (212) 635-7834

                              Eurodollar
                              Office:             Eurodollar/Cayman Funding Area
                                                  101 Barclay Street
                                                  New York, New York   10286

                              Facsimile No.:      (212) 635-7923

                              Attention:          Carol Tafuro
                              Telephone:          (212) 635-7550






                                      S-11

<PAGE>   72


                              BANQUE PARIBAS, as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             1200 Smith Street, Suite 3100
                                                  Houston, Texas  77002

                              Facsimile No.:      (713) 659-5305

                              Attention:
                              Telephone:

                              Eurodollar
                              Office:             1200 Smith Street, Suite 3100
                                                  Houston, Texas  77002

                              Facsimile No.:      (713) 659-6915

                              Attention:
                              Telephone:






                                      S-12

<PAGE>   73


                              FIRST UNION NATIONAL BANK f/k/a FIRST UNION 
                              NATIONAL BANK OF NORTH CAROLINA, as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             301 South College Street
                                                  Charlotte, N.C.  28288

                              Facsimile No.:      (704) 374-6249

                              Attention:          Michael Kolosowsky
                              Telephone:          (704) 383-8225

                              Eurodollar
                              Office:             301 South College Street
                                                  Charlotte, N.C.  28288

                              Facsimile No.:      (704) 374-6249

                              Attention:          Michael Kolosowsky
                              Telephone:          (704) 383-8225

                              Send copies to:     1001 Fannin Street, Suite 2255
                                                  Houston, TX 77002

                              Facsimile No.:      (713) 650-6354

                              Attention:          Russell Clingman
                              Telephone:          (713) 650-3619






                                      S-13

<PAGE>   74

        
                              MELLON BANK, N.A., as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:
                              Title:

                              Domestic
                              Office:             Three Mellon Bank Center
                                                  Room 153-1203
                                                  Pittsburgh, PA  15258

                              Facsimile No.:      (412) 236-2027

                              Attention:          Jennifer Ratay
                              Telephone:          (412) 234-5767

                              Eurodollar
                              Office:             Three Mellon Bank Center
                                                  Room 153-1203
                                                  Pittsburgh, PA  15258

                              Facsimile No.:      (412) 236-2027

                              Attention:          Jennifer Ratay
                              Telephone:          (412) 234-5767

                              Send copies to:     One Mellon Bank Center
                                                  Room 151-4425
                                                  Pittsburgh, PA 15258

                              Facsimile No.:      (412) 236-1840

                              Attention:          Richard A. Matthews
                              Telephone:          (412) 234-9759






                                     S-14

<PAGE>   75


                              LIBERTY BANK AND TRUST COMPANY
                              OF OKLAHOMA CITY, N.A., as a Lender


                              By:                                             
                                 ---------------------------------------------
                              Name:       Laura Christofferson
                              Title:      Vice President

                              Domestic
                              Office:             100 North Broadway
                                                  Oklahoma City, OK  73102

                              Facsimile No.:      (405) 231-6788

                              Attention:          Laura Christofferson
                              Telephone:          (405) 231-6853

                              Eurodollar
                              Office:             100 North Broadway
                                                  Oklahoma City, OK  73102

                              Facsimile No.:      (405) 231-6788

                              Attention:          Laura Christofferson
                              Telephone:          (405) 231-6853






                                      S-15

<PAGE>   76
         For purposes of selling, assigning, transferring and conveying its
respective Interests, the undersigned have caused this Agreement to be executed
by their respective officers thereunto duly authorized as of the date and year
first above written.

                                        THE SUMITOMO BANK, LIMITED, HOUSTON 
                                        AGENCY


                                        By:                                   
                                           -----------------------------------
                                        Name:
                                        Title:






                                      S-16

<PAGE>   77
         For purposes of selling, assigning, transferring and conveying its
respective Interests, the undersigned have caused this Agreement to be executed
by their respective officers thereunto duly authorized as of the date and year
first above written.

                                    THE SANWA BANK LTD., DALLAS AGENCY


                                    By:                                   
                                       -----------------------------------
                                    Name:
                                    Title:






                                      S-17

<PAGE>   78
         For purposes of selling, assigning, transferring and conveying its
respective Interests, the undersigned have caused this Agreement to be executed
by their respective officers thereunto duly authorized as of the date and year
first above written.


                                      CREDIT LYONNAIS, NEW YORK BRANCH


                                      By:                                   
                                         -----------------------------------
                                      Name:
                                      Title:






                                      S-18

<PAGE>   79
         For purposes of selling, assigning, transferring and conveying its
respective Interests, the undersigned have caused this Agreement to be executed
by their respective officers thereunto duly authorized as of the date and year
first above written.


                                        THE FUJI BANK, LIMITED - HOUSTON 
                                        AGENCY, as a Lender


                                        By:                                   
                                           -----------------------------------
                                        Name:
                                        Title:






                                      S-19

<PAGE>   80
                                                                      SCHEDULE I

                              DISCLOSURE SCHEDULE


ITEM 5.1.5                Material Adverse Change.  None.

ITEM 6.5                  Financial Information.  None.

ITEM 6.7                  Litigation.  None.

ITEM 6.8                  Existing Subsidiaries.


<TABLE>
<CAPTION>
                                       State or Jurisdiction of
                 Name                        Organization                          Ownership %
                 ----                        ------------                          -----------
  <S>                                          <C>               <C>
  Samedan Oil Corporation                      Delaware           100% owned by Noble Affiliates, Inc.

  Samedan Oil of Canada, Inc.                  Delaware           100% owned by Samedan Oil Corporation

  Samedan of North Africa, Inc.                Delaware           100% owned by Samedan Oil Corporation

  Samedan North Sea, Inc.                      Delaware           100% owned by Samedan Oil Corporation

  Samedan Oil of Indonesia, Inc.               Delaware           100% owned by Samedan Oil Corporation

  Samedan Pipe Line Corporation                Delaware           100% owned by Samedan Oil Corporation

  Samedan Royalty Corporation                  Delaware           100% owned by Samedan Oil Corporation

  Samedan of Tunisia, Inc.                     Delaware           100% owned by Samedan Oil Corporation

  Samedan - NEEI Exploration Company           Oklahoma           50% general partnership interest owned by
                                                                  Samedan Oil Corporation

  Temin 1987 Partnership                       Oklahoma           50% general partnership interest owned by
                                                                  Samedan Oil Corporation

  Comin 1989 Partnership                       Oklahoma           50% general partnership interest owned by
                                                                  Samedan Royalty Corporation
</TABLE>


<PAGE>   81

<TABLE>
<CAPTION>
                                       State or Jurisdiction of
                 Name                        Organization                          Ownership %
                 ----                        ------------                          -----------
  <S>                                       <C>                  <C>
  Shipride Partnership                         Oklahoma           50% general partnership interest owned by
                                                                  Samedan Royalty Corporation

  Samedan of Papua New Guinea, Inc.            Delaware           100% owned by Samedan Oil Corporation

  Noble Gas Marketing, Inc.                    Delaware           100% owned by Noble Affiliates, Inc.

  Noble Gas Pipeline, Inc.                     Delaware           100% owned by Noble Gas Marketing, Inc.

  Noble Trading, Inc.                          Delaware           100% owned by Noble Affiliates, Inc.

  NPM, Inc.                                    Delaware           100% owned by Noble Affiliates, Inc.

  Samedan LPG                               Cayman Islands        100% owned by Samedan of North Africa, Inc.

  Energy Development Corporation              New Jersey          100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Energy Development Corporation               Delaware           100% owned (direct or indirect) by Noble
  (Argentina), Inc.                                               Affiliates, Inc.

  Energy Development Corporation               Delaware           100% owned (direct or indirect) by Noble
  (China), Inc.                                                   Affiliates, Inc.

  Energy Development Corporation               Delaware           100% owned (direct or indirect) by Noble
  (HIPS), Inc.                                                    Affiliates, Inc.

  Energy Development Corporation               Delaware           100% owned (direct or indirect) by Noble
  (Peru), Inc.                                                    Affiliates, Inc.

  EDC (Tunisia), Inc.                          Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC Ecuador Ltd.                             Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC Senegal Ltd.                             Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC Australia Ltd.                           Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC Portugal Ltd.                            Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.
</TABLE>


<PAGE>   82

<TABLE>
<CAPTION>
                                       State or Jurisdiction of
                 Name                        Organization                          Ownership %
                 ----                        ------------                          -----------
  <S>                                         <C>                 <C>
  Gasdel Pipeline System, Inc.                New Jersey          100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Producers Service, Inc.                     New Jersey          100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  HGC, Inc.                                    Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Pelto Oil Company, Inc.                     New Jersey          100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC (UK) Ltd.                                Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Brabant Petroleum, Ltd.                         CFC             100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Industrial Scotland Energy Ltd.                 CFC             100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Brabant Oil Ltd.                                CFC             100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Brabant Oilex Ltd.                              CFC             100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Brabant Petroleum USA Company                 Kansas            100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  Burnside Overseas Exploration                   CFC             100% owned (direct or indirect) by Noble
  Limited                                                         Affiliates, Inc.

  Norman                                          CFC             100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.

  EDC Marketing Company                        Delaware           100% owned (direct or indirect) by Noble
                                                                  Affiliates, Inc.
</TABLE>


ITEM 6.10         Employee Benefit Plans. Noble Affiliates, Inc. and
Samedan Oil Corporation provide subsidized health care and life insurance
benefits to their early retirees (retirees who have completed at least twenty
years of service or retirees who have attained age 55 and completed at least
five years of service) for the period of their retirement prior to attaining
age 65.

<PAGE>   83
                                                                    SCHEDULE IIA


                            SCHEDULE OF COMMITMENTS



<TABLE>
<CAPTION>
                                                               COMMITMENT                     COMMITMENT
NAME OF LENDER                                                 $ MILLIONS                     PERCENTAGE
- --------------                                                 ----------                     ----------
<S>                                                             <C>                         <C>

Union Bank of Switzerland, Houston Agency                        $33.0000                    11.00000%

NationsBank of Texas, N.A.                                       $27.5000                     9.16667%

Texas Commerce Bank National Association                         $27.5000                     9.16667%

Bank of America                                                  $21.8750                     7.29167%

Bank of Montreal                                                 $21.8750                     7.29167%

The Bank of New York                                             $21.8750                     7.29167%

Banque Paribas                                                   $21.8750                     7.29167%

CIBC Inc.                                                        $21.8750                     7.29167%

The First National Bank of Chicago                               $21.8750                     7.29167%

Royal Bank of Canada                                             $21.8750                     7.29167%

Societe Generale, Southwest Agency                               $21.8750                     7.29167%

First Union National Bank                                        $15.1250                     5.04167%

Liberty Bank and Trust Company
  of Oklahoma City, N.A.                                         $12.5000                     4.16667%

Mellon Bank, N.A.                                                $ 9.3750                     3.12500%
                                                                 --------                  -----------

                          TOTAL                                  $300.000                  100.000000%
                                                                 ========                  ===========
</TABLE>


<PAGE>   84
                                                                    SCHEDULE IIB

                    SCHEDULE OF OUTSTANDINGS AND COMMITMENTS



<TABLE>
<CAPTION>
                                                 EXISTING FACILITY                   REVISED FACILITY
                                                                                                                   BALANCE TO BE
                                        COMMITMENT OUTSTANDINGS    COMMITMENT COMMITMENT   OUTSTANDINGS COMMITMENT    FUNDED/       
           NAME OF LENDER               PERCENTAGE  $ MILLIONS    $ MILLIONS  PERCENTAGE    $ MILLIONS $ MILLIONS    (RECEIVED)     
<S>                                      <C>         <C>           <C>        <C>            <C>        <C>          <C>        
Union Bank of Switzerland, Houston Agency  9.37500%   18.7500       37.5000    11.00000%      22.0000    33.0000       3.2500       
NationsBank of Texas, N.A.                 7.81250%   15.6250       31.2500     9.16667%      18.3333    27.5000       2.7083       
Texas Commerce Bank National Association   7.81250%   15.6250       31.2500     9.16667%      18.3333    27.5000       2.7083       
Bank of America                            6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
Bank of Montreal                           6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
The Bank of New York                       6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
Banque Paribas                             6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
CIBC Inc.                                  6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
The First National Bank of Chicago         6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
Royal Bank of Canada                       6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
Societe Generale, Southwest Agency         6.25000%   12.5000       25.0000     7.29167%      14.5833    21.8750       2.0833       
First Union National Bank                  4.37500%    8.7500       17.5000     5.04167%      10.0833    15.1250       1.3333       
Liberty Bank and Trust Company of                                                                                                   
Oklahoma City, N.A.                        1.87500%    3.7500        7.5000     4.16667%       8.3333    12.5000       4.5833       
Mellon Bank N.A.                           3.12500%    6.2500       12.5000     3.12500%       6.2500     9.3750       0.0000       
Credit Lyonnais New York Branch            3.12500%    6.2500       12.5000     0.000000%      0.0000     0.0000      (6.2500)      
The Fuji Bank, Limited - Houston Agency    6.25000%   12.5000       25.0000     0.00000%       0.0000     0.0000     (12.5000)      
The Sanwa Bank Ltd., Dallas Agency         3.12500%    6.2500       12.5000     0.000000%      0.0000     0.0000      (6.2500)      
The Sumitomo Bank, Limited, Houston 
Agency                                     3.12500%    6.2500       12.5000     0.000000%      0.0000     0.0000      (6.2500)      
                                                                                                                                    
Totals                                   100.00000%  200.0000      400.0000   100.000000%    200.0000   300.0000       0.0000       
                                         ==========  ========      ========   ===========    ========   ========     ========       
</TABLE>
                                          

<PAGE>   85
                                                                   EXHIBIT 2.2.1
                                                  
                              COMPETITIVE BID NOTE              

$300,000,000                                                  December 24, 1997

         FOR VALUE RECEIVED, the undersigned, NOBLE AFFILIATES, INC., a
Delaware corporation (the "Borrower"), promises to pay to the order of
_____________________ (the "Lender") on ___________, 2002, the aggregate unpaid
principal amount of all Competitive Bid Loans shown on the schedule attached
hereto (and any continuation thereof) made by the Lender to the Borrower
pursuant to Section 2.2 of the Amended and Restated Credit Agreement, dated as
of December 24, 1997 (as may be amended, supplemented, restated or otherwise
modified from time to time, the "Credit Agreement"), among Noble Affiliates,
Inc., a Delaware corporation (the "Borrower"), Union Bank of Switzerland,
Houston Agency ("UBS"), as administrative agent (UBS in such capacity, together
with any successor(s) thereto in such capacity, the "Agent"), NationsBank of
Texas, N.A. ("NB") and Texas Commerce Bank National Association ("TCB"), as
managing agents (NB and TCB in such capacities, together with any successor(s)
thereto in such capacities, collectively called the "Managing Agents"), Bank of
Montreal ("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago
("First Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest
Agency ("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in
such capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co- Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders").

         The Borrower also promises to pay interest on the unpaid principal
amount hereof from time to time outstanding from the date hereof until maturity
(whether by acceleration or otherwise) and, after maturity, until paid, at the
rates per annum and on the dates specified in the Credit Agreement.

         Payments of both principal and interest are to be made in lawful money
of the United States of America in same day or immediately available funds to
the account designated by the Agent pursuant to the Credit Agreement.

         This Competitive Bid Note is one of the Notes referred to in, and
evidences Indebtedness under, the Credit Agreement, to which reference is made
for a description of the security for this Competitive Bid Note and for a
statement of the terms and conditions on which the Borrower is permitted and
required to make prepayments and repayments of principal of the Indebtedness
evidenced by this Note and on which such Indebtedness may be declared to be
immediately due and payable.  Unless otherwise defined, terms used herein have
the meanings provided in the Credit Agreement.

         This Note represents an extension and renewal of the outstanding
principal amount of, and a replacement and substitution for, a certain
Competitive Bid Note of the undersigned dated July 31, 1996, (the "Prior Note")
payable to the order of the Lender.  The indebtedness evidenced by

<PAGE>   86
the Prior Note is a continuing indebtedness and nothing contained herein shall
be construed to constitute a novation of the Prior Note or to deem paid the
Prior Note.

         All parties hereto, whether as makers, endorsers, or otherwise,
severally waive presentment for payment, demand, protest and notice of
dishonor.

         THIS NOTE SHALL BE DEEMED A CONTRACT TO BE MADE UNDER AND GOVERNED BY
THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO PRINCIPLES
OF CONFLICTS OF LAW.

                                            NOBLE AFFILIATES, INC.


                                            By:                               
                                               -------------------------------
                                                Title:




<PAGE>   87
                  COMPETITIVE BID LOANS AND PRINCIPAL PAYMENTS



<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------------------
           Amount of                             Amount of                Unpaid   
          Competitive                            Principal               Principal
         Bid Loan Made                            Repaid                  Balance  
      -------------------      Interest     ---------------------  --------------------   
      Absolute   Eurodollar   Period (if    Absolute   Eurodollar  Absolute  Eurodollar          Notation
Date  Rate       Rate         applicable)   Rate       Rate        Rate      Rate       Total    Made By 
- ----  --------   ----------   -----------   --------   ----------  --------  ---------- -----    --------
<S>   <C>        <C>          <C>           <C>        <C>         <C>       <C>        <C>      <C>
                                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
</TABLE>



<PAGE>   88
                                                                   EXHIBIT 2.2.2

                         COMPETITIVE BID QUOTE REQUEST

                                                         _______________, 19____

To:      Union Bank of Switzerland, Houston Agency, (the "Agent")

From:    Noble Affiliates, Inc. (the "Borrower")

Re:      Amended and Restated Credit Agreement, dated as of December 24, 1997
         (as may be amended, supplemented, restated or otherwise modified from
         time to time, the "Credit Agreement"), among Noble Affiliates, Inc., a
         Delaware corporation (the "Borrower"), Union Bank of Switzerland,
         Houston Agency ("UBS"), as administrative agent (UBS in such capacity,
         together with any successor(s) thereto in such capacity, the "Agent"),
         NationsBank of Texas, N.A. ("NB") and Texas Commerce Bank National
         Association ("TCB"), as managing agents (NB and TCB in such
         capacities, together with any successor(s) thereto in such capacities,
         collectively called the "Managing Agents"), Bank of Montreal ("BOM"),
         CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
         Chicago"), Royal Bank of Canada ("RBC") and Societe Generale,
         Southwest Agency ("SocGen"), as co-agents (BOM, CIBC, First Chicago,
         RBC and SocGen in such capacities, together with any successor(s)
         thereto in such capacities, collectively called the "Co-Agents"), and
         certain commercial lending institutions as are or may become parties
         hereto (collectively, the "Lenders")

         We hereby give notice pursuant to Section 2.2.2 of the Credit
Agreement that we request Competitive Bid Quotes for the following proposed
Competitive Bid Advance(s):

Borrowing Date: _________________, 19___



<TABLE>
Principal Amount(1)                         Interest Period(2)
- -------------------                         ------------------
<S>                                         <C>
$

</TABLE>


         Such Competitive Bid Quotes should offer [a Competitive Bid Margin]
[an Absolute Rate].

<PAGE>   89
         Upon acceptance by the undersigned of any or all of the Competitive
Bid Advances offered by Lenders in response to this request, the undersigned
shall be deemed to affirm as of the Borrowing Date thereof the representations
and warranties made in the Credit Agreement to the extent specified in Article
V thereof.  Capitalized terms used herein have the meanings assigned to them in
the Credit Agreement.

                                         NOBLE AFFILIATES, INC.


                                         By:                                
                                            --------------------------------
                                         Title:                             
                                               -----------------------------


- -------------------------
(1)       Amount must be at least $10,000,000 and an integral multiple of
         $1,000,000.
(2)      One, two, three or six months (Eurodollar Auction) or at least 14 and
         up to 90 days (Absolute Rate Auction), subject to the provisions of
         the definition of Interest Period.

<PAGE>   90
                                                                   EXHIBIT 2.2.3

                     INVITATION FOR COMPETITIVE BID QUOTES



                                                    _____________________, 19___


To:      [Name of Lender]

Re:      Invitation for Competitive Bid Quotes to
         Noble Affiliates, Inc. (the "Borrower")

         Pursuant to Section 2.2.3 of the Amended and Restated Credit
Agreement, dated as of December 24, 1997 (as may be amended, supplemented,
restated or otherwise modified from time to time, the "Credit Agreement"),
among Noble Affiliates, Inc., a Delaware corporation (the "Borrower"), Union
Bank of Switzerland, Houston Agency ("UBS"), as administrative agent (UBS in
such capacity, together with any successor(s) thereto in such capacity, the
"Agent"), NationsBank of Texas, N.A. ("NB") and Texas Commerce Bank National
Association ("TCB"), as managing agents (NB and TCB in such capacities,
together with any successor(s) thereto in such capacities, collectively called
the "Managing Agents"), Bank of Montreal ("BOM"), CIBC Inc. ("CIBC"), the First
National Bank of Chicago ("First Chicago"), Royal Bank of Canada ("RBC") and
Societe Generale, Southwest Agency ("SocGen"), as co-agents (BOM, CIBC, First
Chicago, RBC and SocGen in such capacities, together with any successor(s)
thereto in such capacities, collectively called the "Co- Agents"), and certain
commercial lending institutions as are or may become parties hereto
(collectively, the "Lenders"), we are pleased on behalf of the Borrower to
invite you to submit Competitive Bid Quotes to the Borrower for the following
proposed Competitive Bid Advance(s):

Borrowing Date:  ______________, 19___


<TABLE>
Principal Amount                            Interest Period
- ----------------                            ---------------
<S>                                         <C>
$

</TABLE>


         Such Competitive Bid Quotes should offer [a Competitive Bid Margin]
[an Absolute Rate].  Your Competitive Bid Quote must comply with Section 2.2.4
of the Credit Agreement and the foregoing.  Capitalized terms used herein have
the meanings assigned to them in the Credit Agreement.

<PAGE>   91
         Please respond to this invitation by no later than [10:00 a.m.] [1:00
p.m,.] New York time on _________, 19____.

                                            UNION BANK OF SWITZERLAND, HOUSTON 
                                            AGENCY, as Agent



                                            By:                               
                                               -------------------------------
                                               Authorized Officer


<PAGE>   92
                                                                   EXHIBIT 2.2.4

                             COMPETITIVE BID QUOTE


                                                       __________________, 19___

To:      Union Bank of Switzerland, Houston Agency, as Agent
         Attn: ___________________

Re:      Competitive Bid Quote to Noble Affiliates, Inc. (the "Borrower")

         In response to your invitation on behalf of the Borrower dated
________, 199_, we hereby make the following Competitive Bid Quote pursuant to
Section 2.2.4 of the Credit Agreement hereinafter referred to and on the
following terms:

1.       Quoting Lender: _________________________________________
2.       Person to contact at Quoting Lender: _____________________________
3.       Borrowing Date: ____________, 19__(1)
4.       We hereby offer to make Competitive Bid Loan(s) in the following
         principal amounts, for the following Interest Periods and at the
         following rates:


<TABLE>
<CAPTION>
Principal         Interest       [Competitive         [Absolute    Minimum
Amount(2)         Period(3)      Bid Margin(4)]       Rate(5)]     Amount(6)
- ---------         ---------      --------------       ---------    --------- 
<S>               <C>            <C>                  <C>          <C>
$
</TABLE>




- -----------------------------------

(1)      As specified in the related Invitation For Competitive Bid Quotes.
(2)      Principal amount bid for each Interest Period may not exceed the
         principal amount requested.  Bids must be made for at least
         $10,000,000 and an integral multiple of $1,000,000.
(3)      One, two, three or six months or at least 14 and up to 90 days, as
         specified in the related Invitation For Competitive Bid Quotes.
(4)      Competitive Bid Margin over or under the Eurodollar Rate determined
         for the applicable Interest Period.  Specify percentage (rounded to
         the nearest 1/100 of 1%) and specify whether "PLUS" or "MINUS".
(5)      Specify rate of interest per annum (rounded to the nearest 1/100 of
         1%).
(6)      Specify minimum or maximum amount, if any, which the Borrower may
         accept and/or the limit, if any, as to the aggregate principal amount
         of the Competitive Bid Loans of the quoting Lender which the Borrower
         may accept (see Section 2.2.4(b)(iv)).

<PAGE>   93
         We understand and agree that the offer(s) set forth above, subject to
the satisfaction of the applicable conditions set forth in the Amended and
Restated Credit Agreement, dated as of December 24, 1997 (as may be amended,
supplemented, restated or otherwise modified from time to time, the "Credit
Agreement"), among Noble Affiliates, Inc., a Delaware corporation (the
"Borrower"), Union Bank of Switzerland, Houston Agency ("UBS"), as
administrative agent (UBS in such capacity, together with any successor(s)
thereto in such capacity, the "Agent"), NationsBank of Texas, N.A.  ("NB") and
Texas Commerce Bank National Association ("TCB"), as managing agents (NB and
TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), Bank of Montreal
("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest Agency
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co-Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders"),
irrevocably obligates us to make the Competitive Bid Loan(s) for which any
offer(s) are accepted, in whole or in part.  Capitalized terms used herein and
not otherwise defined herein shall have their meanings as defined in the Credit
Agreement.

                                               Very truly yours,

                                               [NAME OF BANK]



Dated:                  , 19                   By:                          
       -----------------    ---                   --------------------------
                                                  Authorized Officer





                                       2

<PAGE>   94
                                                                     EXHIBIT 2.5

                               BORROWING REQUEST


Union Bank of Switzerland, Houston Agency
1100 Louisiana St., Suite 4500
Houston, Texas  77002

Attention:  [Name]
            [Title]

                             NOBLE AFFILIATES, INC.


Gentlemen and Ladies:

         This Borrowing Request is delivered to you pursuant to Section 2.5 of
the Amended and Restated Credit Agreement, dated as of December 24, 1997 (as
may be amended, supplemented, restated or otherwise modified from time to time,
the "Credit Agreement"), among Noble Affiliates, Inc., a Delaware corporation
(the "Borrower"), Union Bank of Switzerland, Houston Agency ("UBS"), as
administrative agent (UBS in such capacity, together with any successor(s)
thereto in such capacity, the "Agent"), NationsBank of Texas, N.A. ("NB") and
Texas Commerce Bank National Association ("TCB"), as managing agents (NB and
TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), Bank of Montreal
("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest Agency
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co-Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders").
Unless otherwise defined herein or the context otherwise requires, terms used
herein have the meanings provided in the Credit Agreement.

         The Borrower hereby requests that a Revolving Loan be made in the
aggregate principal amount of $__________ on __________, 19___ as a [Eurodollar
Loan having an Interest Period of _______ months] [Base Rate Loan].

         The Borrower hereby acknowledges that, pursuant to Section 5.2.2 of
the Credit Agreement, each of the delivery of this Borrowing Request and the
acceptance by the Borrower of the proceeds of the Loans requested hereby
constitute a representation and warranty by the Borrower that, on the date of
such Loans, and before and after giving effect thereto and to the application
of the proceeds therefrom, all statements set forth in Section 5.2.1 are true
and correct in all material respects.

<PAGE>   95
'         The Borrower agrees that if prior to the time of the Borrowing
requested hereby any matter certified to herein by it will not be true and
correct at such time as if then made, it will immediately so notify the Agent.
Except to the extent, if any, that prior to the time of the Borrowing requested
hereby the Agent shall receive written notice to the contrary from the
Borrower, each matter certified to herein shall be deemed once again to be
certified as true and correct at the date of such Borrowing as if then made.

         Please wire transfer the proceeds of the Borrowing to the accounts of
the following persons at the financial institutions indicated respectively:


<TABLE>
<CAPTION>
                      Person to be Paid           
Amount to be      --------------------------      Name, Address, etc.
Transferred       Name           Account No.      of Transferee Lender
- -----------       ----           -----------      --------------------
<S>               <C>            <C>              <C>
$                                                 
 -----------      ------------   ----------       --------------------
                                                  --------------------
                                                  Attention: 
                                                             ---------
$                                                 
 -----------      ------------   -----------      --------------------
                                                  --------------------
                                                  Attention: 
                                                             ---------
Balance of        The Borrower                    
such proceeds                    -----------      --------------------
                                                  --------------------
                                                  Attention: 
                                                             ---------
</TABLE>
                                          



         The Borrower has caused this Borrowing Request to be executed and
delivered, and the certification and warranties contained herein to be made, by
its duly Authorized Officer this ___ day of ___________, 19___.



                                            NOBLE AFFILIATES, INC.



                                            By                       
                                               ----------------------
                                               Title:






                                       2

<PAGE>   96
                                                                    EXHIBIT 2.6

                         CONTINUATION/CONVERSION NOTICE


Union Bank of Switzerland, Houston Agency
1100 Louisiana St., Suite 4500
Houston, Texas  77002

Attention:  [Name]
            [Title]

                             NOBLE AFFILIATES, INC.


Gentlemen and Ladies:

         This Continuation/Conversion Notice is delivered to you pursuant to
Section 2.6 of the  Amended and Restated Credit Agreement, dated as of December
24, 1997 (as may be amended, supplemented, restated or otherwise modified from
time to time, the "Credit Agreement"), among Noble Affiliates, Inc., a Delaware
corporation (the "Borrower"), Union Bank of Switzerland, Houston Agency
("UBS"), as administrative agent (UBS in such capacity, together with any
successor(s) thereto in such capacity, the "Agent"), NationsBank of Texas, N.A.
("NB") and Texas Commerce Bank National Association ("TCB"), as managing agents
(NB and TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), Bank of Montreal
("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest Agency
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co-Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders").
Unless otherwise defined herein or the context otherwise requires, terms used
herein have the meanings provided in the Credit Agreement.

         The Borrower hereby requests that on ____________, 19___,

                 (1)      $___________ of the presently outstanding principal
         amount of the Revolving Loans originally made on __________, 19___
         [and $__________ of the presently outstanding principal amount of the
         Revolving Loans originally made on __________, 19___],

<PAGE>   97
                 (2)      and all presently being maintained as (*)[Base Rate
         Loans] [Eurodollar Loans],

                 (3)      be [converted into] [continued as],

                 (4)      (**)[Eurodollar Loans having an Interest Period of
         ______ months] [Base Rate Loans].

The Borrower hereby:

                 (a)      certifies and warrants that no Default or Event of
         Default has occurred and is continuing; and

                 (b)      agrees that if prior to the time of such continuation
         or conversion any matter certified to herein by it will not be true
         and correct at such time as if then made, it will immediately so
         notify the Agent.

Except to the extent, if any, that prior to the time of the continuation or
conversion requested hereby the Agent shall receive written notice to the
contrary from the Borrower, each matter certified to herein shall be deemed to
be certified at the date of such continuation or conversion as if then made.

         The Borrower has caused this Continuation/Conversion Notice to be
executed and delivered, and the certification and warranties contained herein
to be made, by its Authorized Officer this ___ day of _________, 19___.


                                     NOBLE AFFILIATES, INC.


                                     By                          
                                        -------------------------
                                        Title:






- -------------------------

*        Select appropriate interest rate option.

**       Insert appropriate interest rate option.

                                       2

<PAGE>   98
                                                                     EXHIBIT 2.8


                                 REVOLVING NOTE

$___________                                                    ________________

         FOR VALUE RECEIVED, the undersigned, NOBLE AFFILIATES, INC., a
Delaware corporation (the "Borrower"), promises to pay to the order of
______________________ (the "Lender") on _________, 2002 the principal sum of
__________________ DOLLARS ($___________) or, if less, the aggregate unpaid
principal amount of all Revolving Loans shown on the schedule attached hereto
(and any continuation thereof) made by the Lender pursuant to that certain
Amended and Restated Credit Agreement, dated as of December 24, 1997 (as may be
amended, supplemented, restated or otherwise modified from time to time, the
"Credit Agreement"), among Noble Affiliates, Inc., a Delaware corporation (the
"Borrower"), Union Bank of Switzerland, Houston Agency ("UBS"), as
administrative agent (UBS in such capacity, together with any successor(s)
thereto in such capacity, the "Agent"), NationsBank of Texas, N.A. ("NB") and
Texas Commerce Bank National Association ("TCB"), as managing agents (NB and
TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), Bank of Montreal
("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest Agency
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co-Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders").

         The Borrower also promises to pay interest on the unpaid principal
amount hereof from time to time outstanding from the date hereof until maturity
(whether by acceleration or otherwise) and, after maturity, until paid, at the
rates per annum and on the dates specified in the Credit Agreement.

         Payments of both principal and interest are to be made in lawful money
of the United States of America in same day or immediately available funds to
the account designated by the Agent pursuant to the Credit Agreement.

         This Note is one of the Revolving Notes referred to in, and evidences
Indebtedness incurred under, the Credit Agreement, to which reference is made
for a description of the security for this Note and for a statement of the
terms and conditions on which the Borrower is permitted and required to make
prepayments and repayments of principal of the Indebtedness evidenced by this
Note and on which such Indebtedness may be declared to be immediately due and
payable.  Unless otherwise defined, terms used herein have the meanings
provided in the Credit Agreement.

<PAGE>   99
         This Note represents an extension and renewal of the outstanding
principal amount of, and a replacement and substitution for, a certain
Revolving Note of the undersigned dated July 31, 1996, (the "Prior Note")
payable to the order of the Lender.  The indebtedness evidenced by the Prior
Note is a continuing indebtedness and nothing contained herein shall be
construed to constitute a novation of the Prior Note or to deem paid the Prior
Note.

         All parties hereto, whether as makers, endorsers, or otherwise,
severally waive presentment for payment, demand, protest and notice of
dishonor.

         THIS NOTE SHALL BE DEEMED TO BE A CONTRACT MADE UNDER AND GOVERNED BY
THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO PRINCIPLES
OF CONFLICTS OF LAW.

                                          NOBLE AFFILIATES, INC.

                                          By                          
                                            --------------------------
                                            Title:






                                       2

<PAGE>   100
                     REVOLVING LOANS AND PRINCIPAL PAYMENTS


<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------------------
         Amount of                                 Amount of              Unpaid  
         Revolving                                 Principal             Principal
         Loan Made                                  Repaid                Balance 
      ----------------------   Interest     ---------------------  --------------------   
        Base      Eurodollar   Period (if     Base     Eurodollar    Base    Eurodollar          Notation
Date    Rate        Rate      applicable)     Rate        Rate       Rate       Rate    Total     Made By
- ----  --------   -----------  -----------   --------   ----------  --------  ---------- -----    --------
<S>   <C>        <C>          <C>           <C>        <C>         <C>       <C>        <C>      <C>
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
                                                                                                         
- ---------------------------------------------------------------------------------------------------------
</TABLE>






                                       3

<PAGE>   101
                                                                 EXHIBIT 5.1.4


                      [Opinion of Counsel to the Borrower]

<PAGE>   102
                                                                 EXHIBIT 10.11

                          LENDER ASSIGNMENT AGREEMENT

To:      Noble Affiliates, Inc.,
         as Borrower




To:      Union Bank of Switzerland, Houston Agency,
         as Agent


                             NOBLE AFFILIATES, INC.

Gentlemen and Ladies:

         We refer to clause (d) of Section 10.11.1 of the Amended and Restated
Credit Agreement, dated as of December 24, 1997 (as may be amended,
supplemented, restated or otherwise modified from time to time, the "Credit
Agreement"), among Noble Affiliates, Inc., a Delaware corporation (the
"Borrower"), Union Bank of Switzerland, Houston Agency ("UBS"), as
administrative agent (UBS in such capacity, together with any successor(s)
thereto in such capacity, the "Agent"), NationsBank of Texas, N.A. ("NB") and
Texas Commerce Bank National Association ("TCB"), as managing agents (NB and
TCB in such capacities, together with any successor(s) thereto in such
capacities, collectively called the "Managing Agents"), Bank of Montreal
("BOM"), CIBC Inc. ("CIBC"), the First National Bank of Chicago ("First
Chicago"), Royal Bank of Canada ("RBC") and Societe Generale, Southwest Agency
("SocGen"), as co-agents (BOM, CIBC, First Chicago, RBC and SocGen in such
capacities, together with any successor(s) thereto in such capacities,
collectively called the "Co- Agents"), and certain commercial lending
institutions as are or may become parties hereto (collectively, the "Lenders")
and Union Bank of Switzerland, Houston Agency, as agent (the "Agent") for the
Lenders.  Unless otherwise defined herein or the context otherwise requires,
terms used herein have the meanings provided in the Credit Agreement.

         This agreement is delivered to you pursuant to clause (d) of Section
10.11.1 of the Credit Agreement and also constitutes notice to each of you,
pursuant to clause (c) of Section 10.11.1 of the Credit Agreement, of the
assignment and delegation to _______________ (the "Assignee") of ___% of the
Loans and Commitments of _____________ (the "Assignor") outstanding under the
Credit Agreement on the date hereof.  After giving effect to the foregoing
assignment and delegation, the Assignor's and the Assignee's Percentages for
the purposes of the Credit Agreement are set forth opposite such Person's name
on the signature pages hereof.

<PAGE>   103
         [Add paragraph dealing with accrued interest and fees with respect to
Loans assigned, if applicable.]

         The Assignee hereby acknowledges and confirms that it has received a
copy of the Credit Agreement and the exhibits related thereto, together with
copies of the documents which were required to be delivered under the Credit
Agreement as a condition to the making of the Loans thereunder.  The Assignee
further confirms and agrees that in becoming a Lender and in making its
Commitments and Loans under the Credit Agreement, such actions have and will be
made without recourse to, or representation or warranty by the Agent.

         Except as otherwise provided in the Credit Agreement, effective as of
the date of acceptance hereof by the Agent

         (a)     the Assignee (i) shall be deemed automatically to have become
a party to the Credit Agreement, have all the rights and obligations of a
"Lender" under the Credit Agreement and the other Loan Documents as if it were
an original signatory thereto to the extent specified in the second paragraph
hereof; and (ii) agrees to be bound by the terms and conditions set forth in
the Credit Agreement and the other Loan Documents as if it were an original
signatory thereto; and

         (b)     the Assignor shall be released from its obligations under the
Credit Agreement and the other Loan Documents to the extent specified in the
second paragraph hereof.

         The Assignor and the Assignee hereby agree that the [Assignor]
[Assignee] will pay to the Agent the processing fee referred to in Section
10.11.1 of the Credit Agreement upon the delivery hereof.

         The Assignee hereby advises each of you of the following
administrative details with respect to the assigned Loans and Commitments and
requests the Agent to acknowledge receipt of this document:

                 (A)      Address for Notices:
                                  Institution Name:
                                  Attention:
                                  Domestic Office:
                                  Telephone:
                                  Facsimile:
                                  Telex (Answerback):
                                  LIBOR Office:





                                       2

<PAGE>   104
                                  Telephone:
                                  Facsimile:
                                  Telex (Answerback):

                 (B)      Payment Instructions:

         The Assignee agrees to furnish the tax form required by Section 4.6
(if so required) of the Credit Agreement no later than the date of acceptance
hereof by the Agent.

         This Agreement may be executed by the Assignor and Assignee in
separate counterparts, each of which when so executed and delivered shall be
deemed to be an original and all of which taken together shall constitute one
and the same agreement.

Adjusted Percentage                                           [ASSIGNOR]

Revolving Loan
  Commitment
          and
Revolving Loans:                    __%

                                                 By:                          
                                                    --------------------------
                                                    Title:
                                                     
Percentage                                                    [ASSIGNEE]
                                                     
Revolving Loan                                       
  Commitment                                         
     and                                             
Revolving Loans:                    __%              
                                                     
                                                 By:                           
                                                    ---------------------------
                                                    Title:
Accepted and Acknowledged                            
this __ day of _______, 19__                         
                                                     
                                                     
- -------------------------,                           
  as Agent

By:----------------------
   Title:





                                       3

<PAGE>   105





                               [T & K LETTERHEAD]



                               December 24, 1997



Union Bank of Switzerland
Houston Agency,
   As Agent for the Several Lenders
NationsBank of Texas, N.A.,
Texas Commerce Bank National Association,
Bank of Montreal,
CIBC Inc.,
The First National Bank of Chicago,
Royal Bank of Canada,
Societe Generale, Southwest Agency,
and Certain Lending Institutions
c/o Union Bank of Switzerland
1100 Louisiana
Houston, Texas  77002

Ladies and Gentlemen:

         We have acted as counsel to Noble Affiliates, Inc., a Delaware
corporation ("Borrower"), in connection with the $300,000,000 Amended and
Restated Credit Agreement dated as of December 11, 1997 (the "Agreement") among
Borrower and Union Bank of Switzerland, Houston Agency, as the Agent for the
Lenders, NationsBank of Texas, N.A. and Texas Commerce Bank National
Association, as Managing Agents, and Bank of Montreal, CIBC Inc., The First
National Bank of Chicago, Royal Bank of Canada and Societe Generale, Southwest
Agency, as Co-Agents, and certain additional Lenders named therein, providing
for Borrower's issuance and delivery to you on this date of its Notes.  This
opinion letter is delivered to you pursuant to Section 5.1.3 of the Agreement.
Capitalized terms used but not otherwise defined herein shall have the meanings
given to them in the Agreement.

         In our capacity as counsel for Borrower, we have examined executed
originals or telecopies of executed originals of the Agreement and the initial
Notes under the Agreement (the "Loan Documents") and all other certificates,
instruments or documents that have been executed and delivered to you by
Borrower today in connection with the Agreement.  We have also examined and
relied upon originals or copies, certified or otherwise authenticated to our


<PAGE>   106
Union Bank of Switzerland
December 24, 1997
Page 2                     


satisfaction, of such corporate records of Borrower, certificates of officers
of Borrower, certificates and letters of public officials, and other
instruments and documents as we have deemed necessary to require as a basis for
the opinions hereinafter expressed.  In such examination, we have assumed the
genuineness and authenticity of all documents submitted to us as originals
(other than the Loan Documents), the conformity with genuine and authentic
originals of all documents submitted to us as copies, and the genuineness of
all signatures (other than the signatures on behalf of Borrower on the Loan
Documents).

         Where facts material to the opinions hereinafter expressed were not
independently established by us, we have relied upon the representations and
warranties made to you by Borrower in the Loan Documents and upon oral and
written statements of and information furnished by officers of Borrower and its
Subsidiaries, where we deemed such reliance appropriate under the
circumstances.  We have necessarily assumed the accuracy and complete-ness of
such representations, warranties, statements and other information.

         Based on the foregoing and on the assumptions hereinafter set forth,
and subject to the exceptions, limitations and qualifications hereinafter
expressed, it is our opinion that:

         1.      Borrower is a duly incorporated and validly existing
corporation in good standing under the laws of the State of Delaware and has
the corporate power and authority to own its property and assets and to
transact the business in which it is engaged.  Borrower is duly qualified and
is authorized to do business and is in good standing as a foreign corporation
in the State of Oklahoma. Borrower has the corporate power to execute, deliver
and carry out the terms and provisions of each of the Loan Documents to which
it is a party and has taken all necessary corporate action to authorize the
execution, delivery and performance by it of each of such Loan Documents.

         2.      The execution, delivery and performance by Borrower of the
Agreement and each other Loan Document executed by it are within its corporate
powers, have been duly authorized by all necessary corporate action, and do not
(i) contravene Borrower's Organic Documents; (ii) to the knowledge of the
undersigned, contravene any contractual restriction, law or governmental
regulation or court decree or order binding on or affecting Borrower; or (iii)
to the knowledge of the undersigned, result in, or require the creation or
imposition of, any Lien on any of Borrower's properties.

         3.      No authorization or approval or other action by, and no notice
to or filing with, any governmental authority or regulatory body pursuant to
any law or any rule or order of general application is required for the due
execution, delivery or performance by Borrower of any Loan Document to which it
is a party, except as has been obtained or made.

<PAGE>   107
Union Bank of Switzerland
December 24, 1997
Page 3                     


         4.      Neither Borrower nor any of its Subsidiaries is an "investment
company" within the meaning of the Investment Company Act of 1940, as amended,
or a "holding company," or a "subsidiary company" of a "holding company," or an
"affiliate" of a "holding company" or of a "subsidiary company" of a "holding
company," within the meaning of the Public Utility Holding Company Act of 1935,
as amended.

         5.      Each of the Loan Documents to which Borrower is a party has
been duly executed and delivered by Borrower.  Assuming solely for purposes of
this opinion that the internal laws of the State of Texas were to govern the
Loan Documents, the Loan Documents constitute the legal, valid and binding
obligations of Borrower enforceable in accordance with their respective terms,
except as enforcement thereof may be limited by applicable bankruptcy,
insolvency, reorganization or other similar laws affecting creditors' rights
generally and equitable principles of general applicability.

         6.      To the knowledge of the undersigned, there is no pending or
threatened litigation, action, proceeding, or labor controversy affecting
Borrower or any of its Subsidiaries, properties, businesses, assets or
revenues, which purports to affect the legality, validity or enforceability of,
or the rights and remedies of the Agent and the Lenders under, the Agreement or
any other Loan Document.

         The opinions expressed above are based in part upon the assumptions,
and are subject to the exceptions, limitations and qualifications, set forth
below:

         (a)     Whenever any opinion expressed herein with respect to any
matter is qualified by the phrase "to the knowledge of the undersigned," such
phrase (A) indicates that (i) no information has come to the attention of any
attorney of this firm who has devoted substantive attention to the transactions
contemplated in the Agreement that has given any such person actual knowledge
concerning such matter different from that expressed in such opinion; (ii)
except as otherwise stated herein, we have not undertaken any independent
investigation with respect to such matter but have relied on representations
made by Borrower in the Loan Documents and on information otherwise provided to
us by it; and (iii) no inference that any such person has actual knowledge
concerning such matters should be drawn from the fact of our representation of
Borrower and its Subsidiaries or our expression of such opinion; and (B) does
not encompass the actual knowledge of any attorney of this firm who obtained
such knowledge in his capacity as a director of Borrower.  We wish to advise
you that Harold F. Kleinman, a shareholder of this firm, is a director of
Borrower.

<PAGE>   108
Union Bank of Switzerland
December 24, 1997
Page 4



         (b)     Except as expressly set forth herein, we have made no
independent investigation as to the accuracy or completeness of any
representation, warranty, data or other information, written or oral, made or
furnished in or in connection with the Loan Documents, or otherwise.

         (c)     We do not purport to be experts as to the laws of any
jurisdiction other than the State of Texas and the United States of America,
and we express no opinion herein with respect to the laws of any such other
jurisdiction, except insofar as the matters covered by the foregoing opinions
may involve or be governed by or construed under the General Corporation Law of
the State of Delaware.  Our opinion regarding the General Corporation Law of
the State of Delaware is confined to our reading thereof without application of
judicial or administration interpretations thereof.  Insofar as the matters
covered by the opinions expressed in paragraph 5 above may involve or be
governed by or construed under the laws of any jurisdiction other than the
State of Texas, we have necessarily assumed, without knowing, and without
making any investigation to determine, that such laws are the same as those of
the State of Texas and that the courts of any such other jurisdiction would
construe and apply such laws in the same manner as would the courts of the
State of Texas.

         (d)     In rendering certain of the opinions expressed above, we have
assumed that you (i) are duly authorized to execute and deliver (or accept),
and have duly executed and delivered (or accepted), the Loan Documents required
to be executed and delivered (or accepted) by you and (ii) will fund the Loans
to the extent required to be funded by you under the Agreement.

         (e)     We express no opinion concerning (i) any right of any Agent,
Co-Agent or any Lender or any other person to be indemnified against (or
released from the consequences of) its own negligence; (ii) the enforceability
of any obligations of any party other than Borrower; (iii) the effectiveness or
enforceability of provisions regarding exclusive jurisdiction or venue; or (iv)
the effectiveness or enforceability of any waiver of the right to trial by
jury.

         This opinion letter is to be limited in its use to reliance by you and
your counsel in consummating the Agreement.  No other person or entity (other
than Assignee Lenders) may rely or claim reliance on any opinion expressed
herein except with our express written consent.

<PAGE>   109
Union Bank of Switzerland
December 24, 1997
Page 5


We assume no obligation to supplement this opinion if, after the date hereof,
any applicable law changes or we become aware of any facts that might change
the opinions set forth herein.

                                  Respectfully submitted,

                                  THOMPSON & KNIGHT,
                                  A Professional Corporation



                                  By:  /s/ Robert D. Campbell
                                       -----------------------------------
                                       Robert D. Campbell,
                                       Attorney




<PAGE>   1
                                                                     EXHIBIT 21


                                  SUBSIDIARIES


<TABLE>
<CAPTION>
                                                     State or Jurisdiction of
                                                     ------------------------
               Name                                       Organization             Ref
               ----                                       ------------             ---
<S>                                                        <C>                     <C>
Samedan Oil Corporation                                   Delaware                 (1)
Samedan Oil of Canada, Inc.                               Delaware                 (3)
Samedan of North Africa, Inc.                             Delaware                 (3)
Samedan North Sea, Inc.                                   Delaware                 (3)
Samedan Oil of Indonesia, Inc.                            Delaware                 (3)
Samedan Pipe Line Corporation                             Delaware                 (3)
Samedan Royalty Corporation                               Delaware                 (3)
Samedan of Tunisia, Inc.                                  Delaware                 (3)
Samedan of Papua New Guinea, Inc.                         Delaware                 (3)
Noble Gas Marketing, Inc.                                 Delaware                 (1)
Noble Gas Pipeline, Inc.                                  Delaware                 (2)
Noble Trading, Inc.                                       Delaware                 (1)
NPM, Inc.                                                 Delaware                 (1)
Samedan LPG                                                 CFC*                   (4)
Samedan Methanol                                            CFC*                   (5)
Energy Development Corporation                           New Jersey                (3)
Energy Development Corporation (Argentina), Inc.          Delaware                 (6)
Energy Development Corporation (China), Inc.              Delaware                 (6)
Energy Development Corporation (HIPS), Inc.               Delaware                 (6)
Energy Development Corporation (Peru), Inc.               Delaware                 (6)
EDC (Tunisia), Inc.                                       Delaware                 (6)
EDC Ecuador Ltd.                                          Delaware                 (6)
EDC Senegal Ltd.                                          Delaware                 (6)
EDC Australia Ltd.                                        Delaware                 (6)
EDC Portugal Ltd.                                         Delaware                 (6)
Gasdel Pipeline System Incorporated                      New Jersey                (6)
Producers Services, Inc.                                 New Jersey                (6)
HGC, Inc.                                                 Delaware                 (6)
Pelto Oil Company, Inc.                                  New Jersey                (6)
EDC (UK) Ltd                                              Delaware                 (6)
Brabant Petroleum Limited                                   CFC*                   (6)
Industrial Scotland
 Energy Ltd.                             CFC*                   (6)
Brabant Oil Ltd.                                            CFC*                   (6)
Brabant Oilex Ltd.                                          CFC*                   (6)
Brabant Petroleum USA Company                             Kansas                   (6)
Burnside Overseas Exploration Limited                       CFC*                   (6)
EDC Marketing Company                                       CFC*                   (6)
</TABLE>


(1) 100% owned by Noble Affiliates, Inc. (Registrant)
(2) 100% owned by Noble Gas Marketing, Inc.
(3) 100% owned by Samedan Oil Corporation
(4) 100% owned by Samedan of North Africa, Inc.
(5) 100% owned by Samedan LPG.
(6) 100% owned by Energy Development Corporation

* Controlled Foreign Corporation






<PAGE>   1



                                                                      EXHIBIT 23




                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the incorporation of our
report dated January 30, 1998 included on page 29 of the Company's 1997 Form
10-K, into the previously filed registration Statements on Form S-3 (File No.
333-18929) and on Form S-8 (File Nos. 333-39299, 2-64600, 2-81590, 33-32692,
2-66654 and 33-54084).


                                        ARTHUR ANDERSEN LLP


Oklahoma City, Oklahoma
 March 16, 1998





<TABLE> <S> <C>

<ARTICLE> 5
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               DEC-31-1997
<CASH>                                          55,075
<SECURITIES>                                         0
<RECEIVABLES>                                  162,667
<ALLOWANCES>                                         0
<INVENTORY>                                      2,805
<CURRENT-ASSETS>                               258,634
<PP&E>                                       2,807,027
<DEPRECIATION>                             (1,260,601)
<TOTAL-ASSETS>                               1,875,484
<CURRENT-LIABILITIES>                          217,020
<BONDS>                                        644,967
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       194,743
<OTHER-SE>                                     633,664
<TOTAL-LIABILITY-AND-EQUITY>                 1,875,484
<SALES>                                        761,145
<TOTAL-REVENUES>                             1,116,623
<CGS>                                                0
<TOTAL-COSTS>                                  905,930
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              53,008
<INCOME-PRETAX>                                157,685
<INCOME-TAX>                                    58,407
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    99,278
<EPS-PRIMARY>                                     1.75
<EPS-DILUTED>                                     1.73
        

</TABLE>