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                                                                    EXHIBIT 99.6





                               APACHE CORPORATION




                           CONVERTIBLE PREFERRED STOCK









                       UNDERWRITING AGREEMENT BASIC TERMS



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                               APACHE CORPORATION


                           Convertible Preferred Stock


                       UNDERWRITING AGREEMENT BASIC TERMS


         Apache Corporation, a Delaware corporation (the "Company"), may issue
and sell from time to time its shares of preferred stock, no par value,
convertible into common stock, $1.25 par value per share (the "Common Stock")
and related rights to purchase its Common Stock (the "Rights") (the "Convertible
Preferred Stock"). Each issue of Convertible Preferred Stock may vary as to
number of shares, liquidation values, dividend rate or rates and timing of
payments thereof, redemption provisions, if any, convertible provisions and any
other variable terms as set forth in the Terms Agreement (as defined below)
relating thereto. The Convertible Preferred Stock may be represented by
depositary shares (the "Depositary Shares") pursuant to a deposit agreement (the
"Deposit Agreement") among the Company, Norwest Bank Minnesota, N.A. (the
"Depositary"), and all holders from time to time of receipts issued thereunder.

         Whenever the Company determines to make an offering of the Convertible
Preferred Stock, the Depositary Shares, if any, and the Common Stock and the
related Rights into which the Convertible Preferred Stock is convertible, the
Company will enter into an agreement (the "Terms Agreement") providing for the
sale of such securities (the "Offered Securities") to, and the purchase and
offering thereof by, one or more underwriters specified in the Terms Agreement
(the "Underwriters", which term shall include any Underwriters substituted
pursuant to Section 10 hereof). The Terms Agreement relating to the Offered
Securities shall specify the names of the Underwriters participating in such
offering, the amount of Offered Securities which each such Underwriter severally
agrees to purchase, the price at which the Offered Securities are to be
purchased by the Underwriters from the Company, the initial public offering
price, the time and place of delivery and payment, such other information as is
indicated in Exhibit A hereto and such other terms as are agreed by the Company
and the Underwriters. In addition, each Terms Agreement shall specify whether
the Company has agreed to grant to the Underwriters an option to purchase
additional Offered Securities to cover over-allotments, if any, and the number
of Offered Securities subject to such option described in Section 2(b) hereof
(the "Option Securities"). As used herein, the term "Offered Securities" shall
include the Option Securities, if any, and the number of firm shares of
Convertible Preferred Stock or Depositary Shares, as the case may be, specified
in the Terms Agreement (the "Firm Securities"); and "Representatives" shall mean
the Underwriter or Underwriters so specified in the Terms Agreement or, if no
Underwriter is so specified, shall mean each Underwriter. The Terms Agreement
may be in the form of an exchange of any standard form of written
telecommunication between the Underwriters and the Company. The offering of the
Offered Securities will be governed by the Terms Agreement, as supplemented
hereby (collectively, this "Agreement"), and this Agreement shall inure to the
benefit of and be binding upon each Underwriter participating in the offering of
the Offered Securities.



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         The Company has prepared and filed with the Securities and Exchange
Commission (the "Commission") a registration statement on Form S-3 (No.
333-75633) for the registration of the Offered Securities, under the Securities
Act of 1933, as amended (the "1933 Act"), and the offering thereof from time to
time in accordance with Rule 415 of the rules and regulations of the Commission
under the 1933 Act (the "1933 Act Regulations"), and has prepared and filed such
amendments thereto as may have been required to the date hereof. Such
registration statement, as amended, has been declared effective by the
Commission. As provided in Section 3(a), a prospectus supplement reflecting the
terms of the Offered Securities, the terms of the offering thereof and the other
matters set forth therein has been prepared and will be filed pursuant to Rule
424 under the 1933 Act. Such prospectus supplement, in the form first filed
after the date of the Terms Agreement pursuant to Rule 424, is herein referred
to as the "Prospectus Supplement". Such registration statement, as amended at
the date of the Terms Agreement, including the exhibits thereto and the
documents incorporated by reference therein, is herein called the "Registration
Statement". Any registration statement filed pursuant to Rule 462(b) of the 1933
Act Regulations is herein referred to as the "Rule 462(b) Registration
Statement," and after such filing the term "Registration Statement" shall
include the Rule 462(b) Registration Statement. The basic prospectus included in
the Registration Statement, as supplemented by the Prospectus Supplement, is
herein called the "Prospectus", except that, if such basic prospectus is amended
or supplemented on or prior to the date on which the Prospectus Supplement is
first filed pursuant to Rule 424, the term "Prospectus" shall refer to the basic
prospectus as so amended or supplemented and as supplemented by the Prospectus
Supplement or, if any revised prospectus shall be provided to the Underwriters
by the Company for their use in connection with the offering of the Offered
Securities which differs from such basic prospectus and Prospectus Supplement
(whether or not required to be filed by the Company pursuant to Rule 424), the
term "Prospectus" shall refer to such revised prospectus (including any
prospectus supplement) from and after the time it is first provided to the
Underwriters for such use, in either case including the documents filed by the
Company with the Commission pursuant to the Securities Exchange Act of 1934, as
amended (the "1934 Act"), that are incorporated by reference therein.

         SECTION 1. Representations and Warranties. The Company represents and
warrants to each Underwriter named in the Terms Agreement as of the date thereof
and as of the Closing Time referred to in Section 2(c) hereof, and as of each
Date of Delivery (if any) referred to in Section 2(b) hereof (in each case, a
"Representation Date"), as follows:

                  (a) The Company has been duly incorporated and is validly
                  existing as a corporation in good standing under the laws of
                  the State of Delaware with corporate power and authority to
                  own, lease and operate its properties and to conduct its
                  business as described in the Prospectus and to enter into and
                  perform its obligations under this Agreement; and the Company
                  is duly qualified as a foreign corporation to transact
                  business and is in good standing in the State of Texas and in
                  each other jurisdiction in which such qualification is
                  required, whether by reason of the ownership or leasing of
                  property or the conduct of business, except where the failure
                  to so qualify and be in good standing would not have a
                  material adverse effect on the condition, financial or
                  otherwise, or the results of operations, business affairs or
                  business prospects of the Company and its subsidiaries
                  considered as one enterprise.



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                  (b) Each "significant subsidiary" of the Company as defined in
                  Rule 405 of Regulation C of the 1933 Act Regulations
                  (collectively, the "Significant Subsidiaries") has been duly
                  incorporated and is validly existing as a corporation in good
                  standing under the laws of the jurisdiction of its
                  incorporation, has corporate power and authority to own, lease
                  and operate its properties and conduct its business as
                  described in the Prospectus and is duly qualified as a foreign
                  corporation to transact business and is in good standing in
                  each jurisdiction in which such qualification is required,
                  whether by reason of the ownership or leasing of property or
                  the conduct of business, except where the failure to so
                  qualify and be in good standing would not have a material
                  adverse effect on the condition, financial or otherwise, or
                  the results of operations, business affairs or business
                  prospects of the Company and its subsidiaries considered as
                  one enterprise; and, except as described in the Prospectus,
                  all of the issued and outstanding capital stock of each
                  Significant Subsidiary has been duly authorized and validly
                  issued, is fully paid and non-assessable and, except for
                  directors' qualifying shares (if applicable), is owned by the
                  Company, directly or through subsidiaries, free and clear of
                  any security interest, mortgage, pledge, lien, encumbrance,
                  claim or equity.

                  (c) The Company meets the requirements for use of Form S-3
                  under the 1933 Act. Each of the Registration Statement and any
                  Rule 462(b) Registration Statement has become effective under
                  the 1933 Act and no stop order suspending the effectiveness of
                  the Registration Statement or any Rule 462(b) Registration
                  Statement has been issued under the 1933 Act and no
                  proceedings for that purpose have been instituted or are
                  pending or, to the knowledge of the Company, are contemplated
                  by the Commission, and any request on the part of the
                  Commission for additional information has been complied with.

                  (d) There are no contracts, agreements or understandings
                  between the Company or any of its subsidiaries, on the one
                  hand, and any person, on the other hand, granting such person
                  the right to require the Company or any of its subsidiaries to
                  file a registration statement under the 1933 Act with respect
                  to any securities (other than contractual obligations by the
                  Company to file registration statements on Form S-8 covering
                  issuances of Common Stock pursuant to its employee or director
                  stock, bonus or compensation plans) or to require the Company
                  or any of its subsidiaries to include such securities in any
                  registration statement filed by the Company under the 1933 Act
                  or in any public offering of securities.

                  (e) At the time the Registration Statement and the Rule 462(b)
                  Registration Statement, if any, became effective and as of
                  each Representation Date, the Registration Statement and the
                  Rule 462(b) Registration Statement, if any, complied and will
                  comply in all material respects with the requirements of the
                  1933 Act and the 1933 Act Regulations and the 1939 Act and the
                  rules and regulations of the Commission promulgated
                  thereunder; the Registration Statement and the Rule 462(b)
                  Registration Statement, if any, each at the time it became
                  effective, did not, and at each time thereafter at which any
                  amendment to the Registration Statement becomes effective or
                  any Annual Report on Form 



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                  10-K is filed by the Company with the Commission and as of
                  each Representation Date, will not, contain an untrue
                  statement of a material fact or omit to state a material fact
                  required to be stated therein or necessary to make the
                  statements therein not misleading; and the Prospectus, as of
                  each Representation Date, does not and will not include an
                  untrue statement of a material fact or omit to state a
                  material fact necessary in order to make the statements
                  therein, in the light of the circumstances under which they
                  were made, not misleading; provided, however, that the
                  representations and warranties in this subsection shall not
                  apply to statements in or omissions from the Registration
                  Statement and the Rule 462(b) Registration Statement, if any,
                  or the Prospectus made in reliance upon and in conformity with
                  information furnished to the Company in writing by the
                  Underwriters expressly for use in the Registration Statement
                  and the Rule 462(b) Registration Statement, if any, or the
                  Prospectus.

                  (f) The documents incorporated by reference in the Prospectus,
                  at the time they were or hereafter are filed with the
                  Commission, complied or when so filed will comply, as the case
                  may be, in all material respects with the requirements of the
                  1934 Act and the rules and regulations of the Commission
                  promulgated thereunder (the "1934 Act Regulations"), and, when
                  read together and with the other information in the
                  Prospectus, did not and will not include an untrue statement
                  of a material fact or omit to state a material fact required
                  to be stated therein or necessary in order to make the
                  statements therein, in the light of the circumstances under
                  which they were or are made, not misleading.

                  (g) The accountants who certified the financial statements
                  included or incorporated by reference in the Registration
                  Statement and the Prospectus are independent public
                  accountants with respect to the Company as required by the
                  1933 Act and the 1933 Act Regulations.

                  (h) The financial statements and any supporting schedules of
                  the Company and its subsidiaries included or incorporated by
                  reference in the Registration Statement and the Prospectus
                  present fairly the consolidated financial position of the
                  Company and its subsidiaries as of the dates indicated and the
                  consolidated results of their operations for the periods
                  specified; except as stated therein, said financial statements
                  have been prepared in conformity with U.S. generally accepted
                  accounting principles applied on a consistent basis; the
                  supporting schedules included or incorporated by reference in
                  the Registration Statement and the Prospectus present fairly
                  the information required to be stated therein; and the pro
                  forma financial statements and the related notes thereto, if
                  any, included or incorporated by reference in the Registration
                  Statement and the Prospectus present fairly the information
                  shown therein, have been prepared in accordance with the
                  Commission's rules and guidelines with respect to pro forma
                  financial statements and have been properly compiled on the
                  bases described therein, and the assumptions used in the
                  preparation thereof are reasonable and the adjustments used
                  therein are appropriate to give effect to the transactions and
                  circumstances referred to therein.



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                  (i) The petroleum engineers who have consented to being named
                  as having reviewed certain reserve data included or
                  incorporated by reference in the Prospectus are independent
                  engineers with respect to the Company and its subsidiaries.

                  (j) This Agreement has been duly authorized, executed and
                  delivered by the Company and, upon execution and delivery by
                  the Underwriters, will be a valid and legally binding
                  agreement of the Company.

                  (k) If the Offered Securities include Depositary Shares, the
                  Deposit Agreement has been duly authorized, executed and
                  delivered by the Company and, assuming due authorization,
                  execution and delivery by the Depositary, constitutes a valid
                  and legally binding obligation of the Company enforceable in
                  accordance with its terms except as enforceability thereof may
                  be limited by bankruptcy, insolvency, reorganization,
                  moratorium and other laws relating to or affecting creditors'
                  rights generally and by general equity principles.

                  (l) The authorized, issued and outstanding capital stock of
                  the Company is as set forth in the Prospectus (except for
                  issuances, if any, described in the Prospectus, pursuant to
                  this Agreement, pursuant to reservations, agreements or
                  employee benefit plans referred to in the Prospectus or
                  pursuant to the exercise of convertible securities or options
                  referred to in the Prospectus); the shares of issued and
                  outstanding capital stock set forth therein have been duly
                  authorized and validly issued and are fully paid and
                  non-assessable; and the Offered Securities conform to all
                  statements relating thereto contained in the Prospectus and
                  such statements conform to the provisions of the instruments
                  defining the same.

                  (m) The Convertible Preferred Stock has been duly and validly
                  authorized for issuance, offer and sale pursuant to this
                  Agreement, the Deposit Agreement, if any, and the applicable
                  Terms Agreement; the Convertible Preferred Stock when issued
                  and delivered against payment therefor as provided for in this
                  Agreement, the Deposit Agreement, if any, and the applicable
                  Terms Agreement, will be validly issued, fully paid and
                  non-assessable; the Depositary Shares, if any, when issued and
                  delivered against payment therefor as provided for in this
                  Agreement, the Deposit Agreement, if any, and the applicable
                  Terms Agreement, will be validly issued by the Depositary; and
                  the holders of the Depositary Shares, if any, will be entitled
                  to the rights specified in the Depositary Receipts and in the
                  Deposit Agreement (subject, in the case of the Deposit
                  Agreement, as to enforcement, bankruptcy, insolvency,
                  reorganization and other laws of general applicability
                  relating to or affecting creditors' rights and to general
                  equity principles); the Convertible Preferred Stock comprising
                  the Offered Securities is convertible into shares of Common
                  Stock in accordance with the terms of the Convertible
                  Preferred Stock; the shares of Common Stock initially issuable
                  upon conversion of the Convertible Preferred Stock comprising
                  the Offered Securities have been duly and validly reserved for
                  issuance, and when issued and delivered pursuant to the terms
                  of the Convertible Preferred Stock, will be validly issued,
                  fully paid and non-assessable; the Rights have been duly and
                  validly authorized 



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                  for issuance by the Company in accordance with the Rights
                  Agreement, dated as of January 31, 1996, between the Company
                  and Norwest Bank Minnesota, N.A.; and the issuance of the
                  Offered Securities will not be subject to any preemptive or
                  similar rights.

                  (n) Since the respective dates as of which information is
                  given in the Registration Statement, any Rule 462(b)
                  Registration Statement and the Prospectus, except as may
                  otherwise be stated therein or contemplated thereby, (1) there
                  has been no material adverse change in the condition,
                  financial or otherwise, or in the results of operations,
                  business affairs or business prospects of the Company and its
                  subsidiaries considered as one enterprise, whether or not
                  arising in the ordinary course of business, and (2) there have
                  been no material transactions entered into by the Company or
                  any of its subsidiaries other than those in the ordinary
                  course of business, and (3) except for regular dividends on
                  the Common Stock and the Company's preferred stock, there has
                  been no dividend or distribution of any kind declared, paid or
                  made by the Company on any class of its capital stock.

                  (o) Neither the Company nor any of its subsidiaries is in
                  violation of its charter or in default in the performance or
                  observance of any material obligation, agreement, covenant or
                  condition contained in any contract, indenture, mortgage, loan
                  agreement, note, lease or other instrument to which it is a
                  party or by which it or any of them or their properties may be
                  bound, where the consequences of such violation or default
                  would have a material adverse effect on the condition,
                  financial or otherwise, or the results of operations, business
                  affairs or business prospects of the Company and its
                  subsidiaries considered as one enterprise; and the execution
                  and delivery of this Agreement and the Terms Agreement and the
                  consummation of the transactions contemplated herein and
                  therein have been duly authorized by all necessary corporate
                  action of the Company and will not conflict with or constitute
                  a breach of, or default under, or result in the creation or
                  imposition of any lien, charge or encumbrance upon any
                  property or assets of the Company or any of its subsidiaries
                  pursuant to, any contract, indenture, mortgage, loan
                  agreement, note, lease or other instrument to which the
                  Company or any of its subsidiaries is a party or by which it
                  or any of them may be bound or to which any of the property or
                  assets of the Company or any subsidiary thereof is subject,
                  nor will such action result in any violation of the provisions
                  of the charter or by-laws of the Company or any law,
                  administrative regulation or administrative or court order or
                  decree, where the consequences of such conflict, breach,
                  creation, imposition, violation or default would have a
                  material adverse effect on the condition, financial or
                  otherwise, or the results of operations, business affairs or
                  business prospects of the Company and its subsidiaries
                  considered as one enterprise.

                  (p) No consent, approval, authorization, order, decree,
                  registration or qualification of or with any court or
                  governmental agency or body is required for the consummation
                  by the Company of the transactions contemplated by this
                  Agreement or in connection with the sale of Offered Securities
                  hereunder, except 



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                  such as have been obtained or rendered, as the case may be, or
                  as may be required under state securities or Blue Sky laws.

                  (q) Except as may be included or incorporated by reference in
                  the Registration Statement and the Prospectus, there is no
                  action, suit or proceeding before or by any court or
                  governmental agency or body, domestic or foreign, now pending
                  or, to the knowledge of the Company, threatened against or
                  affecting the Company or any of its subsidiaries which might,
                  in the opinion of the Company, result in any material adverse
                  change in the condition, financial or otherwise, or in the
                  results of operations, business affairs or business prospects
                  of the Company and its subsidiaries considered as one
                  enterprise, or could reasonably be expected to materially and
                  adversely affect the properties or assets thereof or could
                  reasonably be expected to materially and adversely affect the
                  consummation of this Agreement or the Terms Agreement or any
                  transaction contemplated hereby or thereby.

                  (r) There are no contracts or documents of the Company or any
                  of its subsidiaries which are required to be filed as exhibits
                  to the Registration Statement by the 1933 Act or by the 1933
                  Act Regulations which have not been so filed.

                  (s) Neither the Company nor any of its subsidiaries is in
                  violation of any law, ordinance, governmental rule or
                  regulation or court decree to which it may be subject or has
                  failed to obtain any license, permit, franchise or other
                  governmental authorization necessary to the ownership of its
                  property or to the conduct of its business, which violation or
                  failure would materially adversely affect the condition,
                  financial or otherwise, or the results of operations, business
                  affairs or business prospects of the Company and its
                  subsidiaries considered as one enterprise; and the Company and
                  its subsidiaries own or possess or have obtained all
                  governmental licenses, permits, consents, orders, approvals
                  and other authorizations and have properly filed with the
                  appropriate authorities all notices, applications and other
                  documents necessary to lease or own their respective
                  properties and to carry on their respective businesses as
                  presently conducted, except where the failure to possess such
                  licenses or authorizations or make such filings would not
                  materially adversely affect the condition, financial or
                  otherwise, or the results of operations, business affairs or
                  business prospects of the Company and its subsidiaries
                  considered as one enterprise.

                  (t) The Company and its subsidiaries own or possess, or can
                  acquire on reasonable terms, adequate trademarks, service
                  marks and trade names necessary to conduct the business now
                  operated by them, except as set forth or incorporated by
                  reference in the Registration Statement or except where the
                  failure to own or possess the same would not materially
                  adversely affect the condition, financial or otherwise, or the
                  results of operations, business affairs or business prospects
                  of the Company and its subsidiaries considered as one
                  enterprise, and neither the Company nor any of its
                  subsidiaries has received any notice of infringement of or
                  conflict with asserted rights of others with respect to any
                  trademarks, service marks or trade names which, singly or in
                  the aggregate, if the subject of an 



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                  unfavorable decision, ruling or finding, would materially
                  adversely affect the condition, financial or otherwise, or the
                  results of operations, business affairs or business prospects
                  of the Company and its subsidiaries considered as one
                  enterprise.

                  (u) The Company and its subsidiaries have legal, valid and
                  defensible title to all of their interests in oil and gas
                  properties and to all other real and personal property owned
                  by them and any other real property and buildings held under
                  lease by the Company and its subsidiaries are held by them
                  under valid, subsisting and enforceable leases, in each case
                  free and clear of all mortgages, pledges, liens, security
                  interests, claims, restrictions or encumbrances and defects of
                  any kind, except such as (1) are described in the Prospectus,
                  (2) liens and encumbrances under operating agreements,
                  unitization and pooling agreements, production sales
                  contracts, farm-out agreements and other oil and gas
                  exploration and production agreements, in each case that
                  secure payment of amounts not yet due and payable for the
                  performance of other inchoate obligations and are of a scope
                  and nature customary in connection with similar drilling and
                  producing operations, or (3) those that do not have a material
                  adverse effect on the condition, financial or otherwise, or
                  the results of operations, business affairs or business
                  prospects of the Company and its subsidiaries considered as
                  one enterprise.

                  (v) The information underlying the estimates of oil and gas
                  reserves as described in the Prospectus is complete and
                  accurate in all material respects (or, with regard to any
                  information underlying the estimates prepared by any petroleum
                  engineers retained by the seller of such oil and gas reserves,
                  is, to the best knowledge of the Company after reasonable
                  investigation, complete and accurate in all material
                  respects); other than production of the reserves in the
                  ordinary course of business and intervening product price
                  fluctuations described in the Prospectus, the Company is not
                  aware of any facts or circumstances that would result in a
                  material adverse change in the reserves or the present value
                  of future net cash flows therefrom as described in the
                  Prospectus. Estimates of such reserves and present values
                  comply in all material respects with the applicable
                  requirements of Regulation S-X and Industry Guide 2 under the
                  1933 Act.

                  (w) Neither the Company nor any of its subsidiaries is
                  required to be registered under the Investment Company Act of
                  1940, as amended (the "1940 Act").

                  (x) The Company has complied and will comply with the
                  provisions of Florida H.B. 1771, codified as Section 517.075
                  of the Florida Statutes, 1987, as amended, and all regulations
                  promulgated thereunder relating to issuers doing business in
                  Cuba.

                  (y) The Company has reviewed its operations and that of its
                  subsidiaries and any third parties with which the Company or
                  any of its subsidiaries has a material relationship to
                  evaluate the extent to which the business or operations of the
                  Company or any of its subsidiaries will be affected by the
                  Year 2000 Problem. As a result of such review, the Company has
                  no reason to believe, and does not 



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                  believe, that the Year 2000 Problem will have a material
                  adverse effect on the condition, financial or otherwise, or
                  the results of operations, business affairs or business
                  prospects of the Company and its subsidiaries considered as
                  one enterprise or result in any material loss or interference
                  with the Company's business or operations. The "Year 2000
                  Problem" as used herein means any significant risk that
                  computer hardware or software used in the receipt,
                  transmission, processing, manipulation, storage, retrieval,
                  retransmission or other utilization of data or in the
                  operation of mechanical or electrical systems of any kind will
                  not, in the case of dates or time periods occurring after
                  December 31, 1999, function at least as effectively as in the
                  case of dates or time periods occurring prior to January 1,
                  2000.

                  (z) Except as described in the Registration Statement, (1)
                  neither the Company nor any of its subsidiaries is in
                  violation of any local or foreign laws or regulations relating
                  to pollution or protection of human health, the environment
                  (including, without limitation, ambient air, surface water,
                  groundwater, land surface or subsurface strata) or wildlife,
                  including, without limitation, laws and regulations relating
                  to the release or threatened release of chemicals, pollutants,
                  contaminants, wastes, toxic substances, hazardous substances,
                  petroleum or petroleum products (collectively, "Hazardous
                  Materials") or to the manufacture, processing, distribution,
                  use, treatment, storage, disposal, transport or handling of
                  Hazardous Materials (collectively, "Environmental Laws"),
                  except such violations as would not, singly or in the
                  aggregate, have a material adverse effect on the condition,
                  financial or otherwise, or the results of operations, business
                  affairs or business prospects of the Company and its
                  subsidiaries considered as one enterprise, and (2) to the best
                  of the Company's knowledge, there are no events or
                  circumstances that could reasonably be expected to be the
                  basis of an order for clean-up or remediation, or an action,
                  suit or proceeding by any private party or governmental body
                  or agency, against or affecting the Company or any of its
                  subsidiaries relating to any Hazardous Materials or the
                  violation of any Environmental Laws, which, singly or in the
                  aggregate, could reasonably be expected to have a material
                  adverse effect on the condition, financial or otherwise, or
                  the results of operations, business affairs or business
                  prospects of the Company and its subsidiaries considered as
                  one enterprise.

         Any certificate signed by any director or officer of the Company and
delivered to the Representatives or to counsel for the Underwriters shall be
deemed a representation and warranty by the Company as to the matters covered
thereby.

         SECTION 2.  Purchase and Sale.

         (a) The several commitments of the Underwriters to purchase the Offered
Securities pursuant to this Agreement shall be deemed to have been made on the
basis of the representations and warranties herein contained and shall be
subject to the terms and conditions herein and therein set forth.



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         (b) In addition, on the basis of the representations and warranties
herein contained and subject to the terms and conditions herein set forth, the
Company may grant, if so provided in the Terms Agreement, an option to the
Underwriters named in the Terms Agreement, severally and not jointly, to
purchase up to the number of Option Securities set forth therein at the same
price per share as is applicable to the Offered Securities plus accrued
dividends, if any. Such option, if granted, will expire 30 days after the date
of the Terms Agreement, and may be exercised in whole or in part from time to
time only for the purpose of covering over-allotments which may be made in
connection with the offering and distribution of the Offered Securities upon
notice by the Representatives to the Company setting forth the number of Option
Securities as to which the several Underwriters are then exercising the option
and the time and date of payment and delivery for such Option Securities. Any
such time and date of delivery (a "Date of Delivery") shall be determined by the
Representatives, but shall not be later than seven full business days and not
earlier than two full business days after the exercise of said option, nor in
any event prior to the Closing Time, as hereinafter defined, unless otherwise
agreed upon by the Representatives and the Company. If the option is exercised
as to all or any portion of the Option Securities, each of the Underwriters,
acting severally and not jointly, will purchase the proportion of the total
number of Option Securities then being purchased that the number of Firm
Securities each such Underwriter has agreed to purchase, as set forth in the
Terms Agreement, bears to the total number of Firm Securities, subject to such
adjustments as the Representatives in their discretion shall make to eliminate
any sales or purchases of fractional shares.

         (c) Payment of the purchase price for, and delivery of, the Firm
Securities to be purchased by the Underwriters shall be made at the place set
forth in the Terms Agreement, or at such other place as shall be agreed upon by
the Representatives and the Company, on the third business day (unless postponed
in accordance with the provisions of Section 10) following the date of the Terms
Agreement or such other time as shall be agreed upon by the Underwriters and the
Company (such time and date being referred to as the "Closing Time"). Except as
specified in the Terms Agreement, payment shall be made to the Company by wire
transfer in same day funds to the account of the Company specified in the Terms
Agreement against delivery to the Underwriters for the respective accounts of
the Underwriters of the Firm Securities to be purchased by them. In addition, in
the event that any or all of the Option Securities are purchased by the
Underwriters, payment of the purchase price for, and delivery of certificates
representing, such Option Securities shall be made at such place as shall be
agreed upon by the Representatives and the Company, on each Date of Delivery as
agreed by the Representatives and the Company. The Firm Securities and the
Option Securities, if any, shall be in such denominations and registered in such
names as the Underwriters may request in writing at least two business days
prior to the Closing Time or relevant Date of Delivery, as the case may be. The
Firm Securities and the Option Securities, if any, will be made available for
examination and packaging by the Representatives on or before the first business
day prior to the Closing Time or relevant Date of Delivery, as the case may be.

         SECTION 3.  Covenants of the Company.  The Company covenants with each
Underwriter as follows:

                  (a) Immediately following the execution of the Terms
                  Agreement, the Company will prepare a Prospectus Supplement in
                  form approved by the Representatives setting forth the number,
                  class and designation of the Firm Securities, the names 



                                       11
   12

                  of the Underwriters and the number of the Offered Securities
                  which each severally and not jointly has agreed to purchase,
                  the price per share at which the Offered Securities are to be
                  purchased by the Underwriters from the Company, the initial
                  public offering price, the selling concession and reallowance,
                  if any, any Option Securities, and such other information as
                  the Representatives and the Company deem appropriate in
                  connection with the offering of the Offered Securities. The
                  Company will promptly transmit copies of the Prospectus
                  Supplement to the Commission for filing pursuant to Rule 424
                  of the 1933 Act Regulations and will furnish to the
                  Underwriters named therein as many copies of the Prospectus
                  (including the Prospectus Supplement) as the Representatives
                  shall reasonably request.

                  (b) The Company will comply with the 1933 Act and the 1933 Act
                  Regulations and the 1934 Act and the 1934 Act Regulations so
                  as to permit the completion of the distribution of the Offered
                  Securities as contemplated in this Agreement and in the
                  Prospectus. If, at any time when a prospectus is required by
                  the 1933 Act to be delivered in connection with sales of the
                  Offered Securities, any event shall occur or condition exist
                  as a result of which it is necessary, in the opinion of
                  counsel for the Underwriters or counsel for the Company, to
                  amend or supplement the Prospectus in order that the
                  Prospectus will not include an untrue statement of a material
                  fact or omit to state any material fact necessary in order to
                  make the statements therein not misleading in the light of the
                  circumstances existing at the time the Prospectus is delivered
                  to a purchaser, or if it shall be necessary, in the opinion of
                  either such counsel, to amend or supplement the Registration
                  Statement or the Prospectus in order to comply with the
                  requirements of the 1933 Act or the 1933 Act Regulations, the
                  Company will promptly amend the Registration Statement and the
                  Prospectus, whether by filing documents pursuant to the 1934
                  Act or the 1933 Act or otherwise, as may be necessary to
                  correct such untrue statement or omission or to make the
                  Registration Statement and the Prospectus comply with such
                  requirements.

                  (c) The Company will make generally available to its security
                  holders as soon as practicable, but not later than 90 days
                  after the close of the period covered thereby, an earnings
                  statement (in form complying with the provisions of Rule 158
                  of the 1933 Act Regulations) covering each twelve month period
                  beginning, in each case, not later than the first day of the
                  Company's fiscal quarter next following the "effective date"
                  (as defined in such Rule 158) of the Registration Statement
                  with respect to the sale of Offered Securities.

                  (d) While the Prospectus is required by the 1933 Act to be
                  delivered in connection with sales of the Offered Securities,
                  the Company will give the Representatives notice of its
                  intention to file any additional registration statement with
                  respect to the registration of additional Convertible
                  Preferred Stock, Common Stock and Depositary Shares, if any,
                  any amendment to the Registration Statement (including any
                  filing under Rule 462(b)) or any amendment or supplement to
                  the Prospectus, whether pursuant to the 1934 Act, the 1933 Act
                  or otherwise; will furnish the Underwriters with copies of any
                  such amendment or 



                                       12
   13

                  supplement or other documents proposed to be filed a
                  reasonable time in advance of such proposed filing or use, as
                  the case may be; and will not file any such amendment or
                  supplement or other documents in a form to which the
                  Representatives or counsel to the Underwriters reasonably
                  object.

                  (e) While the Prospectus is required by the 1933 Act to be
                  delivered in connection with sales of the Offered Securities,
                  the Company will notify the Representatives immediately, and
                  promptly confirm the notice in writing, of (i) the
                  effectiveness of any amendment to the Registration Statement,
                  (ii) the transmittal to the Commission for filing of any
                  supplement to the Prospectus or any document to be filed
                  pursuant to the 1934 Act which will be incorporated by
                  reference into the Registration Statement or the Prospectus,
                  (iii) the receipt of any comments from the Commission with
                  respect to the Registration Statement, the Prospectus or the
                  Prospectus Supplement, (iv) any request by the Commission for
                  any amendment to the Registration Statement, or any amendment
                  or supplement to the Prospectus or for additional information,
                  (v) the issuance by the Commission of any stop order
                  suspending the effectiveness of the Registration Statement or
                  the initiation of any proceedings for that purpose and (vi)
                  any change in the rating assigned by any nationally recognized
                  statistical rating organization to any debt securities of the
                  Company or the public announcement by any nationally
                  recognized statistical rating organization that it has under
                  surveillance or review, with possible negative implications,
                  its rating of any debt securities of the Company. The Company
                  will make every reasonable effort to prevent the issuance of
                  any stop order and, if any stop order is issued, to obtain the
                  lifting thereof at the earliest possible moment.

                  (f) Prior to 10:00 A.M, New York City time, on the business
                  day next succeeding the date of this Agreement and from time
                  to time, the Company will deliver to each Underwriter one
                  conformed copy of the Registration Statement (as originally
                  filed) and of each amendment thereto (including exhibits filed
                  therewith or incorporated by reference therein and documents
                  incorporated by reference in the Prospectus) and will also
                  deliver to the Representatives as many conformed copies of the
                  Registration Statement as originally filed and of each
                  amendment thereto (without exhibits) as the Representatives
                  may reasonably request. While the Prospectus is required by
                  the 1933 Act to be delivered in connection with sales of the
                  Offered Securities, the Company will furnish to the
                  Representatives as many copies of the Prospectus (including
                  the Prospectus Supplement) as the Representatives reasonably
                  request.

                  (g) The Company has delivered to each Underwriter, without
                  charge, as many copies of each preliminary Prospectus
                  Supplement as such Underwriter reasonably requested, and the
                  Company hereby consents to the use of such copies for purposes
                  permitted by the 1933 Act.

                  (h) The Company will endeavor, in cooperation with the
                  Underwriters, to qualify the Offered Securities for offering
                  and sale under the applicable securities laws of such states
                  and other jurisdictions of the United States as the
                  Underwriters may 



                                       13
   14

                  designate, and will maintain such qualifications in effect for
                  as long as may be required for the distribution of the Offered
                  Securities; provided, however, that the Company shall not be
                  obligated to file any general consent to service of process or
                  to qualify as a foreign corporation in any jurisdiction in
                  which it is not so qualified. The Company will file such
                  statements and reports as may be required by the laws of each
                  jurisdiction in which the Offered Securities have been
                  qualified as above provided. The Company will promptly advise
                  the Representatives of the receipt by the Company of any
                  notification with respect to the suspension of the
                  qualification of the Offered Securities for sale in any such
                  state or jurisdiction or the initiating or threatening of any
                  proceeding for such purpose.

                  (i) The Company, during the period when the Prospectus is
                  required to be delivered under the 1933 Act or the 1934 Act in
                  connection with sales of the Offered Securities, will file all
                  documents required to be filed with the Commission pursuant to
                  Sections 13, 14 or 15(d) of the 1934 Act within the time
                  periods prescribed by the 1934 Act and the 1934 Act
                  Regulations.

                  (j) If specified in the Terms Agreement, during the 90-day
                  period following the date of the Terms Agreement, the Company
                  will not, without the prior written consent of the
                  Representatives, (i) directly or indirectly, issue, offer,
                  pledge, sell, contract to sell, sell any option or contract to
                  purchase, purchase any option or contract to sell, grant any
                  option, right or warrant to purchase or otherwise transfer or
                  dispose of any share of Convertible Preferred Stock, Common
                  Stock or any Depositary Share or any securities convertible
                  into or exercisable or exchangeable for Convertible Preferred
                  Stock, Common Stock or Depositary Shares or any such
                  substantially similar securities or file any registration
                  statement under the 1933 Act with respect to any of the
                  foregoing or (ii) enter into any swap or any other agreement
                  or any transaction that transfers, in whole or in part,
                  directly or indirectly, the economic consequence of ownership
                  of Convertible Preferred Stock, Common Stock or Depositary
                  Shares, whether any such swap or transaction described in
                  clause (i) or (ii) above is to be settled by delivery of
                  Convertible Preferred Stock, Common Stock or Depositary Shares
                  or such other securities, in cash or otherwise. The foregoing
                  sentence shall not apply to (A) the Offered Securities, (B)
                  any shares of Convertible Preferred Stock or Common Stock or
                  Depositary Shares issued by the Company upon the exercise of
                  an option or warrant or the conversion of a security
                  outstanding on the date hereof and referred to in the
                  Prospectus, (C) any shares of Convertible Preferred Stock or
                  Common Stock or Depositary Shares issued or options to
                  purchase Common Stock granted pursuant to existing employee
                  benefit plans of the Company referred to in the Prospectus,
                  (D) any shares of Convertible Preferred Stock or Common Stock
                  or Depositary Shares issued pursuant to any non-employee
                  director stock plan or dividend reinvestment plan, (E) any
                  shares of Convertible Preferred Stock or Common Stock or
                  Depositary Shares issued pursuant to the Company's existing
                  dividend reinvestment program, (F) the Common Stock, if any,
                  that is the subject of a concurrent public offering, or (G)
                  any shares of 



                                       14
   15

                  Common Stock issuable in connection with any asset purchase or
                  other transaction described in the Prospectus.

                  (k) The Company will reserve and keep available at all times,
                  free of preemptive rights, shares of Common Stock for the
                  purpose of enabling the Company to satisfy any obligations to
                  issue shares of its Common Stock upon conversion of the
                  Convertible Preferred Stock.

                  (l) The Company will use its best efforts to list, subject to
                  notice of issuance, the Offered Securities, including the
                  Common Stock issuable upon conversion of the Convertible
                  Preferred Stock on the New York Stock Exchange.

                  (m) The Company will use the net proceeds received by it from
                  the sale of the Offered Securities in the manner specified in
                  the Prospectus under "Use of Proceeds". (n) If the Company
                  elects to rely upon Rule 462(b), the Company shall file a Rule
                  462(b) Registration Statement with the Commission in
                  compliance with Rule 462(b) and the Company shall at the time
                  of filing either pay the Commission a filing fee for the Rule
                  462(b) Registration Statement or give irrevocable instructions
                  for the payment of such fee pursuant to Rule 111(b) under the
                  1933 Act.

         SECTION 4. Conditions of Underwriters' Obligations. The obligations of
the Underwriters to purchase Offered Securities pursuant to this Agreement are
subject to the accuracy of the representations and warranties on the part of the
Company herein contained, to the accuracy of the statements which the Company's
officers made in any certificate furnished pursuant to the provisions hereof, to
the performance by the Company of all of its covenants and other obligations
hereunder and under the Terms Agreement, and to the following further
conditions:

                  (a) The Registration Statement and any Rule 462(b)
                  Registration Statement have become effective and, at the
                  Closing Time, no stop order suspending the effectiveness of
                  the Registration Statement or any Rule 462(b) Registration
                  Statement shall have been issued under the 1933 Act or
                  proceedings therefor initiated or threatened by the Commission
                  and any request on the part of the Commission for additional
                  information shall have been complied with to the reasonable
                  satisfaction of counsel to the Underwriters. A prospectus
                  containing the Rule 430A Information shall have been filed
                  with the Commission in accordance with Rule 424(b) (or a
                  post-effective amendment providing such information shall have
                  been filed and declared effective in accordance with the
                  requirements of Rule 430A) or, if the Company has elected to
                  rely upon Rule 434, a term sheet shall have been filed with
                  the Commission in accordance with Rule 424(b).

                  (b) At the Closing Time, the Representatives shall have
                  received:


                                       15
   16

                           (1) The favorable opinion, dated as of the Closing
                  Time, of Mayor, Day, Caldwell & Keeton, L.L.P., counsel to the
                  Company, to the effect that:

                           (i) The Company has been duly incorporated and is
                  validly existing as a corporation in good standing under the
                  laws of the State of Delaware.

                           (ii) This Agreement and the Terms Agreement have been
                  duly authorized, executed and delivered by the Company.

                           (iii) The Convertible Preferred Stock has been duly
                  and validly authorized for issuance, offer and sale pursuant
                  to this Agreement, the Deposit Agreement, if any, and the
                  applicable Terms Agreement; the Convertible Preferred Stock,
                  when issued and delivered against payment therefor as provided
                  for in this Agreement, the Deposit Agreement, if any, and the
                  applicable Terms Agreement, will be validly issued, fully paid
                  and non-assessable; the Depositary Shares, if any, when issued
                  and delivered against payment therefor as provided for in this
                  Agreement, the Deposit Agreement, if any, and the applicable
                  Terms Agreement, will be validly issued by the Depositary; and
                  the holders of the Depositary Shares, if any, will be entitled
                  to the rights specified in the Depositary Receipts and in the
                  Deposit Agreement (subject, in the case of the Deposit
                  Agreement, as to enforcement, to bankruptcy, insolvency,
                  reorganization and other laws of general applicability
                  relating to or affecting creditors' rights and to general
                  equity principles); the Convertible Preferred Stock comprising
                  the Offered Securities is convertible into shares of Common
                  Stock in accordance with the terms of the Convertible
                  Preferred Stock; the shares of Common Stock initially issuable
                  upon conversion of the Convertible Preferred Stock comprising
                  the Offered Securities have been duly and validly reserved for
                  issuance, and when issued and delivered pursuant to the terms
                  of the Convertible Preferred Stock, will be validly issued,
                  fully paid and non-assessable; the Rights have been duly and
                  validly authorized for issuance by the Company in accordance
                  with the Rights Agreement, dated as of January 31, 1996,
                  between the Company and Norwest Bank Minnesota, N.A.; and the
                  issuance of the Offered Securities will not be subject to any
                  preemptive or similar rights.

                           (iv) The Offered Securities conform in all material
                  respects to the statements relating thereto in the Prospectus;
                  and the statements in the Prospectus under the caption
                  "Description of Capital Stock" and in the Prospectus
                  Supplement under the headings "Description of Convertible
                  Preferred Stock", "Description of Depositary Shares" and
                  similar headings, insofar as they purport to summarize certain
                  provisions of instruments specifically referred to therein,
                  are fair and correct summaries of such provisions.

                           (v) The Registration Statement, including any Rule
                  462(b) Registration Statement, has been declared effective by
                  the Commission under the 1933 Act and, to the best of such
                  counsel's knowledge, no stop order suspending the
                  effectiveness of the Registration Statement or any Rule 462(b)
                  Registration 



                                       16
   17

                  Statement has been issued under the 1933 Act or proceedings
                  therefor initiated or threatened by the Commission.

                           (vi) The execution and delivery of this Agreement and
                  the Terms Agreement, the issuance of Offered Securities
                  covered by the Terms Agreement, the incurrence of the
                  obligations set forth herein and therein, and the consummation
                  of the transactions herein and therein contemplated do not and
                  will not conflict with or constitute or result in a breach of,
                  or default under, the Company's certificate of incorporation
                  or by-laws, each as in effect at the applicable Closing Time,
                  of the Company.

                           (vii) If the Offered Securities include Depositary
                  Shares, the Deposit Agreement has been duly authorized,
                  executed and delivered by the Company and assuming due
                  authorization, execution and delivery by the Depositary,
                  constitutes a valid and legally binding obligation of the
                  Company enforceable in accordance with its terms except as
                  enforceability thereof may be limited by bankruptcy,
                  insolvency, reorganization, moratorium and other laws relating
                  to or affecting creditors' rights generally and by general
                  equity principles.

                           (viii) The Registration Statement, including any Rule
                  462(b) Registration Statement, and the Prospectus (except for
                  financial statements and engineering reports and other
                  financial or engineering data, as to which such counsel need
                  not express any opinion), as of their respective effective or
                  issue dates, appeared on their face to be appropriately
                  responsive to the requirements of the 1933 Act and the 1933
                  Act Regulations.

                           (ix) The information contained in the Prospectus
                  Supplement under the caption "Certain Federal Income Tax
                  Considerations", to the extent that such information
                  constitutes matters of law, summaries of legal matters or
                  legal conclusions, has been reviewed by such counsel and is
                  correct.

                  In rendering such opinion, counsel for the Company may (i)
                  rely as to matters of fact upon the representations of
                  officers of the Company contained in any certificate delivered
                  to such counsel and certificates of public officials, which
                  certificates shall be attached to or delivered with such
                  opinion and (ii) as to the laws of the State of New York
                  applicable to the enforceability of the Deposit Agreement,
                  upon the opinion of Brown & Wood LLP. Such opinion shall be
                  limited to the General Corporation Law of the State of
                  Delaware, the laws of the State of Texas and the laws of the
                  United States of America.

                           (2) The favorable opinion of Zurab S. Kobiashvili, 
                  General Counsel of the Company, to the effect that:

                           (i) The Company has the corporate power and authority
                  to own, lease and operate its properties and to conduct its
                  business as described in the Prospectus and to enter into and
                  perform its obligations under this Agreement and the Terms
                  Agreement.



                                       17
   18
                           (ii) To the best knowledge and information of such
                  counsel, the Company is duly qualified as a foreign
                  corporation to transact business and is in good standing in
                  the State of Texas and in each other jurisdiction in which
                  such qualification is required, except where the failure to so
                  qualify and be in good standing would not have a material
                  adverse effect on the condition, financial or otherwise, or
                  the results of operations, business affairs or business
                  prospects of the Company and its subsidiaries considered as
                  one enterprise.

                           (iii) Each Significant Subsidiary has been duly
                  incorporated and is validly existing as a corporation in good
                  standing under the laws of the jurisdiction of its
                  incorporation, has corporate power and authority to own, lease
                  and operate its properties and conduct its business as
                  described in the Prospectus, and, to the best of such
                  counsel's knowledge and information, is duly qualified as a
                  foreign corporation to transact business and is in good
                  standing in each jurisdiction in which such qualification is
                  required, except where the failure to so qualify and be in
                  good standing would not have a material adverse effect on the
                  condition, financial or otherwise, or the results of
                  operations, business affairs or business prospects of the
                  Company and its subsidiaries considered as one enterprise; and
                  all of the issued and outstanding capital stock of each
                  Significant Subsidiary has been duly authorized and validly
                  issued, is fully paid and non-assessable, and is owned by the
                  Company, directly or indirectly, free and clear of any
                  mortgage, pledge, lien, encumbrance, claim or equity (except
                  as described in the Prospectus).

                           (iv) The authorized, issued and outstanding capital
                  stock of the Company is as set forth in the Prospectus (except
                  for issuances, if any, described in the Prospectus, pursuant
                  to this Agreement, pursuant to reservations, agreements or
                  employee benefit plans referred to in the Prospectus or
                  pursuant to the exercise of convertible securities or options
                  referred to in the Prospectus); the shares of issued and
                  outstanding capital stock set forth therein have been duly
                  authorized and validly issued and are fully paid and
                  non-assessable; and the Offered Securities conform to all
                  statements relating thereto contained in the Prospectus and
                  such statements conform to the provisions of the instruments
                  defining the same.

   
                           (v) The Convertible Preferred Stock has been duly and
                  validly authorized for issuance, offer and sale pursuant to
                  this Agreement, the Deposit Agreement, if any, and the
                  applicable Terms Agreement; the Convertible Preferred Stock,
                  when issued and delivered against payment therefor as provided
                  for in this Agreement, the Deposit Agreement, if any, and the
                  applicable Terms Agreement, will be validly issued, fully paid
                  and non-assessable; the Depositary Shares, if any, when issued
                  and delivered against payment therefor as provided for in this
                  Agreement, the Deposit Agreement, if any, and the applicable
                  Terms Agreement, will be validly issued by the Depositary; and
                  the holders of the Depositary Shares, if any, will be entitled
                  to the rights specified in the Depositary Receipts and in the
                  Deposit Agreement (subject, in the case of the Deposit
                  Agreement, as to enforcement, bankruptcy, insolvency,
                  reorganization and other laws of general applicability
                  relating to or affecting creditors' rights and to 
    



                                       18
   19

                  general equity principles); the Convertible Preferred Stock
                  comprising the Offered Securities is convertible into shares
                  of Common Stock in accordance with the terms of the
                  Convertible Preferred Stock; the shares of Common Stock
                  initially issuable upon conversion of the Convertible
                  Preferred Stock comprising the Offered Securities have been
                  duly and validly reserved for issuance, and when issued and
                  delivered pursuant to the terms of the Convertible Preferred
                  Stock, will be validly issued, fully paid and non-assessable;
                  the Rights have been duly and validly authorized for issuance
                  by the Company in accordance with the Rights Agreement, dated
                  as of January 31, 1996, between the Company and Norwest Bank
                  Minnesota, N.A.; and the issuance of the Offered Securities
                  will not be subject to any preemptive or similar rights.

                           (vi) If the Offered Securities include Depositary
                  Shares, the Deposit Agreement has been duly authorized,
                  executed and delivered by the Company and assuming due
                  authorization, execution and delivery by the Depositary,
                  constitutes a valid and legally binding obligation of the
                  Company enforceable in accordance with its terms except as
                  enforceability thereof may be limited by bankruptcy,
                  insolvency, reorganization, moratorium and other laws relating
                  to or affecting creditors' rights generally and by general
                  equity principles.

                           (vii) Each document filed pursuant to the 1934 Act
                  and incorporated by reference in the Prospectus (except for
                  financial statements, supporting schedules and other financial
                  or statistical information as to which no opinion need be
                  rendered) appeared on its face to be appropriately responsive
                  when so filed to the requirements of the 1934 Act and the 1934
                  Act Regulations.

                           (viii) Neither the Company nor any of its
                  subsidiaries is required to be registered under the 1940 Act.

                           (ix) No consent, approval, authorization, order,
                  decree, registration or qualification of or with any court or
                  governmental authority or agency is required that has not been
                  obtained in connection with the consummation by the Company of
                  the transactions contemplated by this Agreement, except such
                  as have been obtained or rendered, as the case may be, or as
                  may be required under the 1933 Act, the 1933 Act Regulations,
                  the 1934 Act, the 1934 Act Regulations or state securities
                  laws; and the execution and delivery of this Agreement and the
                  consummation of the transactions contemplated herein and
                  therein have been duly authorized by all necessary corporate
                  action of the Company and, to the best knowledge and
                  information of such counsel, will not conflict with or
                  constitute a breach of, or default under, or result in the
                  creation or imposition of any lien, charge or encumbrance upon
                  any property or assets of the Company or any of its
                  subsidiaries pursuant to, any contract, indenture, mortgage,
                  loan agreement, note, lease or other instrument to which the
                  Company or any of its subsidiaries is a party or by which it
                  or any of them may be bound or to which any of the property or
                  assets of the Company or any such subsidiary is subject, nor
                  will such action result in any violation of the provisions of
                  the charter or by-laws of the Company 



                                       19
   20

                  or any applicable law, administrative regulation or, to the
                  best knowledge and information of such counsel, administrative
                  or court order or decree.

                           (x) Neither the Company nor any of its Significant
                  Subsidiaries is in violation of its charter or by-laws.

                           (xi) To the best knowledge and information of such
                  counsel, neither the Company nor any of its subsidiaries is in
                  violation of any law, ordinance, governmental rule or
                  regulation or court decree to which it may be subject or has
                  failed to obtain any license, permit, franchise or other
                  governmental authorization necessary to the ownership of its
                  property or to the conduct of its business, which violation or
                  failure would materially adversely affect the condition,
                  financial or otherwise, or the results of operations, business
                  affairs or business prospects of the Company and its
                  subsidiaries considered as one enterprise; and, to the best
                  knowledge and information of such counsel, the Company and its
                  subsidiaries own or possess or have obtained all governmental
                  licenses, permits, consents, orders, approvals and other
                  authorizations necessary to lease or own their respective
                  properties and to carry on their respective businesses as
                  presently conducted, except where the failure to obtain such
                  authorizations would not have a material adverse effect on the
                  condition, financial or otherwise, or the results of
                  operations, business affairs or business prospects of the
                  Company and its subsidiaries considered as one enterprise.

                           (xii) To the best of such counsel's knowledge and
                  information, there is no action, suit or proceeding before or
                  by any court or governmental agency or body, domestic or
                  foreign, now pending, or threatened against or affecting, the
                  Company or any of its subsidiaries, which would be reasonably
                  expected to result in any material adverse change in the
                  condition, financial or otherwise, or in the results of
                  operations, business affairs or business prospects of the
                  Company and its subsidiaries considered as one enterprise, or
                  would materially and adversely affect the properties or assets
                  thereof or would materially and adversely affect the
                  consummation of this Agreement and the Terms Agreement or any
                  transaction contemplated hereby or thereby.

                           (xiii) To the best of such counsel's knowledge and
                  information, there are no contracts or other documents
                  required to be described or referred to in the Registration
                  Statement or to be filed as exhibits thereto other than those
                  described or referred to therein or filed or incorporated by
                  reference as exhibits thereto, the descriptions thereof or
                  references thereto are correct in all material respects, and,
                  to the best of such counsel's knowledge and information, no
                  default exists in the due performance or observance of any
                  material obligation, agreement, covenant or conditions
                  contained in any contract, or other documents so described,
                  referred to, filed or incorporated by reference where the
                  consequences of such default would have a material adverse
                  effect on the condition, financial or otherwise, or the
                  results of operations, business affairs or business prospects
                  of the Company and its subsidiaries considered as one
                  enterprise.



                                       20
   21
                           In rendering such opinion, Zurab S. Kobiashvili may
                  rely (i) as to matters of fact upon the representations of
                  officers of the Company contained in any certificate delivered
                  to such counsel and certificates of public officials, (ii) as
                  to matters of law governed by laws other than the General
                  Corporation Law of the State of Delaware, the laws of the
                  State of Texas and the laws of the United States of America,
                  such opinions of counsel admitted to practice in the
                  applicable jurisdictions as Mr. Kobiashvili deems appropriate,
                  and (iii) as to matters related to the capital stock of the
                  Company and each of the Company's Significant Subsidiaries
                  issued prior to March 30, 1993, the opinion of George J.
                  Morgenthaler, former Senior Vice President and General Counsel
                  of the Company, dated March 30, 1993, which certificates and
                  opinions shall be attached to or delivered with such opinion.
                  Such opinion shall be limited to the General Corporation Law
                  of the State of Delaware, the laws of the State of Texas and
                  the laws of the United States of America.

                           (3) The favorable opinion, dated as of the Closing
         Time, of Brown & Wood LLP, counsel for the Underwriters, with respect
         to the matters set forth in clauses (i) to (v), inclusive, and (viii)
         of subsection (b)(1) of this Section.

   
                           (4) In giving their opinions required by subsection
         (b)(1), (b)(2) and (b)(3), respectively, of this Section 4, Mayor, Day,
         Caldwell & Keeton, L.L.P., Zurab S. Kobiashvili and Brown & Wood LLP
         shall each additionally state that in the course of the preparation of
         the Registration Statement and the Prospectus such counsel has
         considered the information set forth therein in light of the matters
         required to be set forth therein, and has participated in conferences
         with officers and representatives of the Company, including its
         independent public accountants, during the course of which the contents
         of the Registration Statement and the Prospectus, and related matters
         were discussed. Such counsel need not independently check the accuracy
         or completeness of, or otherwise verify, and accordingly need not pass
         upon, and accordingly need not assume responsibility for, the accuracy,
         completeness or fairness of the statements contained in the
         Registration Statement or the Prospectus, and such counsel may, in good
         faith, rely as to materiality, to the extent deemed appropriate, upon
         the judgment of officers and representatives of the Company. Such
         counsel shall additionally state that, however, as a result of such
         consideration and participation, nothing has come to such counsel's
         attention which causes such counsel to believe that the Registration
         Statement, at the time it became effective (or, if an amendment to the
         Registration Statement or an Annual Report on Form 10-K has been filed
         by the Company with the Commission subsequent to the effectiveness of
         the Registration Statement, then at the time such amendment became
         effective or at the time of the most recent such filing, as the case
         may be), contained an untrue statement of a material fact or omitted to
         state a material fact required to be stated therein or necessary in
         order to make the statements therein not misleading or that the
         Prospectus or any amendment or supplement thereto, at the time the
         Prospectus was issued, at the time any such amendment or supplement was
         issued, or at the Closing Time, included or includes an untrue
         statement of a material fact or omitted or omits to state a material
         fact necessary in order to make the statements therein, in the light of
         the circumstances under which they were made, not misleading (it being
         understood that such counsel need express no opinion with respect to 
    



                                       21
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         the financial statements and engineering reports and other financial or
         engineering data contained in the Registration Statement (including the
         Prospectus)).


                  (c) At the Closing Time, there shall not have been, since the
                  date of the Terms Agreement or since the respective dates as
                  of which information is given in the Registration Statement
                  and the Prospectus, any material adverse change in the
                  condition, financial or otherwise, or in the results of
                  operations, business affairs or business prospects of the
                  Company and its subsidiaries considered as one enterprise,
                  whether or not arising in the ordinary course of business, and
                  the Representatives shall have received a certificate of the
                  Chief Executive Officer, President or a Vice President and the
                  Treasurer, the Assistant Treasurer, the principal financial
                  officer or principal accounting officer of the Company, dated
                  as of the Closing Time, to the effect that (i) there has been
                  no such material adverse change with respect to the Company
                  and its subsidiaries, (ii) the representations and warranties
                  of the Company contained in Section 1 are true and correct as
                  of the Closing Time, (iii) the Company has performed or
                  complied with all agreements and satisfied all conditions on
                  its part to be performed or satisfied at or prior to the date
                  of such certificate and (iv) no stop order suspending the
                  effectiveness of the Registration Statement or any Rule 462(b)
                  Registration Statement has been issued and no proceedings for
                  that purpose have been initiated or threatened by the
                  Commission. As used in this Section 4(c), the term
                  "Prospectus" means the Prospectus in the form first provided
                  to the applicable Underwriter or Underwriters for use in
                  confirming sales of the Offered Securities.

                  (d)(1) On the date of the Terms Agreement, the Underwriters
                  shall have received a letter from Arthur Andersen LLP, dated
                  as of the date thereof and in form and substance satisfactory
                  to the Underwriters, to the effect that:

                           (i) They are independent accountants with respect to
                  the Company and its subsidiaries within the meaning of the
                  1933 Act, the 1933 Act Regulations, the 1934 Act and the 1934
                  Act Regulations.

                           (ii) It is their opinion that the consolidated
                  financial statements and supporting schedule(s) included or
                  incorporated by reference in the Registration Statement and
                  the Prospectus and audited by them and covered by their
                  opinions therein comply in form in all material respects with
                  the applicable accounting requirements of the 1933 Act, the
                  1933 Act Regulations, the 1934 Act and the 1934 Act
                  Regulations.

                           (iii) They have performed specified procedures, not
                  constituting an audit, including a reading of the latest
                  available interim financial statements of the Company and its
                  indicated subsidiaries, a reading of the minute books of the
                  Company and such subsidiaries since the end of the most recent
                  fiscal year with respect to which an audit report has been
                  issued, inquiries of and discussions with certain officials of
                  the Company and such subsidiaries responsible for financial
                  and accounting matters with respect to the unaudited
                  consolidated financial 



                                       22
   23

                  statements included or incorporated by reference in the
                  Registration Statement and the Prospectus and the latest
                  available interim unaudited financial statements of the
                  Company and its subsidiaries, and such other inquiries and
                  procedures as may be specified in such letter, and on the
                  basis of such inquiries and procedures, nothing came to their
                  attention that caused them to believe that: (A) any material
                  modifications should be made to the unaudited consolidated
                  financial statements of the Company and its subsidiaries
                  included or incorporated by reference in the Registration
                  Statement and the Prospectus for them to be in conformity with
                  generally accepted accounting principles in the United States,
                  (B) the unaudited consolidated financial statements of the
                  Company and its subsidiaries included or incorporated by
                  reference in the Registration Statement and the Prospectus do
                  not comply as to form in all material respects with the
                  applicable accounting requirements of the 1934 Act and the
                  1934 Act Regulations or (C) at a specified date not more than
                  three days prior to the date of such letter, there was any
                  change in the consolidated capital stock, any increase in
                  consolidated long-term debt or any decrease in the
                  consolidated net current assets or consolidated net assets of
                  the Company and its subsidiaries, in each case as compared
                  with the amounts shown on the most recent consolidated balance
                  sheet of the Company and its subsidiaries included or
                  incorporated by reference in the Registration Statement and
                  the Prospectus or, during the period from the date of such
                  balance sheet to a specified date not more than three days
                  prior to the date of such letter, there were any decreases, as
                  compared with the corresponding period in the preceding year,
                  in consolidated revenues or in the total or per-share amounts
                  of income before extraordinary items or of net income of the
                  Company and its subsidiaries, except in all instances for
                  changes, increases or decreases that the Registration
                  Statement and the Prospectus disclose have occurred or may
                  occur or except for such exceptions enumerated in such letter
                  as shall have been agreed to by the Underwriters and the
                  Company.

                           (iv) They have performed specified procedures, not
                  constituting an audit, set forth in their letter, based upon
                  which nothing came to their attention that caused them to
                  believe that the unaudited pro forma consolidated condensed
                  financial statements, if any, included or incorporated by
                  reference in the Registration Statement or the Prospectus do
                  not comply as to form in all material respects with the
                  applicable accounting requirements of Rule 11-02 of Regulation
                  S-X and that the pro forma adjustments have not been properly
                  applied to the historical amounts in the compilation of those
                  statements.

                           (v) In addition to the audit referred to in their
                  opinions and the limited procedures referred to in clauses
                  (iii) and (iv) above, they have carried out certain specified
                  procedures, not constituting an audit, with respect to certain
                  amounts, percentages and financial information which are
                  included or incorporated by reference in the Registration
                  Statement and the Prospectus and which are specified by the
                  Underwriters, and have found such amounts, percentages and
                  financial information to be in agreement with the relevant
                  accounting, financial and other records of the Company and its
                  subsidiaries identified in such letter.



                                       23
   24

                           (2) At the Closing Time, the Underwriters shall have
                  received from Arthur Andersen LLP, a letter, dated as of the
                  Closing Time, to the effect that they reaffirm the statements
                  made in the letter furnished pursuant to subsection (d)(1) of
                  this Section, except that the specified date referred to shall
                  be a date not more than three days prior to the Closing Time.

                  (e) At the date of this Agreement, the Representatives shall
                  have received an agreement substantially in the form of
                  Exhibit B hereto signed by the persons, if any, listed on
                  Schedule A to the Terms Agreement.

                  (f) The Convertible Preferred Stock or, if applicable, the
                  Depositary Shares comprising the Offered Securities at the
                  Closing Time shall have been duly listed, subject to notice of
                  issuance, on the New York Stock Exchange.

                  (g) At the Closing Time, counsel for the Underwriters shall
                  have been furnished with such documents and opinions as they
                  may reasonably require for the purpose of enabling them to
                  pass upon the issuance and sale of the Offered Securities as
                  herein contemplated and related proceedings or in order to
                  evidence the accuracy and completeness of any of the
                  representations and warranties, or the fulfillment of any of
                  the conditions, herein contained; and all proceedings taken by
                  the Company in connection with the issuance and sale of the
                  Offered Securities as herein and in the Terms Agreement
                  contemplated shall be satisfactory in form and substance to
                  the Representatives.

                  (h) In the event that the Terms Agreement provides for Option
                  Securities and the Underwriters exercise their option pursuant
                  to Section 2(b) hereof to purchase all or any portion of the
                  Option Securities, the representations and warranties of the
                  Company contained herein and the statements in any
                  certificates furnished by the Company hereunder shall be true
                  and correct as of each Date of Delivery, and the Underwriters
                  shall have received:

                           (1) Unless the Date of Delivery is the Closing Time,
                  a certificate, dated such Date of Delivery, of the Chief
                  Executive Officer, President or a Vice President and the
                  Treasurer, the Assistant Treasurer, the principal financial
                  officer or principal accounting officer of the Company, in
                  their capacities as such, confirming that the certificate
                  delivered at the Closing Time pursuant to Section 4(c) hereof
                  remains true and correct as of such Date of Delivery.

                           (2) The favorable opinions of Mayor, Day, Caldwell &
                  Keeton, L.L.P., counsel for the Company, and Zurab S.
                  Kobiashvili, General Counsel for the Company, in form and
                  substance satisfactory to counsel for the Underwriters, dated
                  such Date of Delivery, relating to the Option Securities and
                  otherwise substantially to the same effect as the opinions
                  required by subsections (1) and (2) of Section 4(b) hereof.

                           (3) The favorable opinion of Brown & Wood LLP,
                  counsel for the Underwriters, dated such Date of Delivery,
                  relating to the Option Securities and 



                                       24
   25

                  otherwise to the same effect as the opinion required by
                  subsection (3) to Section 4(b) hereof.

                           (4) Unless the Date of Delivery is the Closing Time,
                  a letter from Arthur Andersen LLP, in form and substance
                  satisfactory to the Underwriters and dated such Date of
                  Delivery, substantially the same in scope and substance as the
                  letter furnished to the Underwriters at the Closing Time
                  pursuant to Section 4(d) hereof, except that the "specified
                  date" in the letter shall be a date not more than three days
                  prior to such Date of Delivery.

         If any condition specified in this Section shall not have been
fulfilled when and as required to be fulfilled, this Agreement may be terminated
by the Representatives by notice to the Company at any time at or prior to the
Closing Time, and such termination shall be without liability of any party to
any other party except as provided in Section 5.

         SECTION 5.  Payment of Expenses.  The Company will pay all expenses 
incident to the performance of its obligations under this Agreement, including:

                  (a) the preparation and filing of the Registration Statement,
                  including any Rule 462(b) Registration Statement, and all
                  amendments thereto and the Prospectus and any amendments or
                  supplements thereto;

                  (b) the preparation, filing, reproduction and delivery to the
                  Underwriters of this Agreement; any Agreement among
                  Underwriters and such other documents as may be required in
                  connection with the offering, purchase, sale, issuance or
                  delivery of the Offered Securities;

                  (c) the preparation, printing, issuance and delivery of the
                  Offered Securities, including any stock or other transfer
                  taxes and any stamp or other duties payable upon the sale,
                  issuance or delivery of the Offered Securities;

                  (d) the fees and disbursements of the Company's accountants,
                  counsel and other advisors;

                  (e) except as otherwise provided in the Terms Agreement, the
                  reasonable fees and disbursements of counsel to the
                  Underwriters;

                  (f) the qualification of the Offered Securities under state
                  securities laws in accordance with the provisions of Section
                  3(k) hereof, including filing fees and the reasonable fees and
                  disbursements of counsel for the Underwriters in connection
                  therewith and in connection with the preparation of any Blue
                  Sky or Legal Investment Survey;

                  (g) the printing and delivery to the Underwriters in
                  quantities as hereinabove stated of copies of the Registration
                  Statement and any amendments thereto, and of each preliminary
                  Prospectus Supplement, the Prospectus and 



                                       25
   26

                  any amendments or supplements thereto, and the delivery by the
                  Underwriters of the Prospectus and any amendments or
                  supplements thereto in connection with solicitations or
                  confirmations of sales of the Offered Securities;

                  (h) all fees and disbursements of any transfer and paying
                  agent;

                  (i) any fees charged by nationally recognized statistical
                  rating organizations for the rating of the Offered Securities;

                  (j) the fees and expenses incurred in connection with any
                  listing of Offered Securities on a securities exchange;

                  (k) the fees and expenses incurred with respect to any filing
                  with the National Association of Securities Dealers, Inc.;

                  (l) any out-of-pocket expenses of the Underwriters incurred
                  with the approval of the Company; and

                  (m) the cost of providing any CUSIP or other identification
                  numbers for the Offered Securities.

         If this Agreement is terminated by the Underwriters in accordance with
the provisions of Section 4, 9 or 10, the Company shall reimburse the
Underwriters for all of their out-of-pocket expenses, including the reasonable
fees and disbursements of counsel for the Underwriters.

         SECTION 6.  Indemnification.  (a) The Company agrees to indemnify and 
hold harmless each Underwriter and each person, if any, who controls any
Underwriter within the meaning of Section 15 of the 1933 Act as follows:

         (i) against any and all loss, liability, damage, joint or several, and
         expense whatsoever, as incurred, arising out of any untrue statement or
         alleged untrue statement of a material fact contained in the
         Registration Statement (or any amendment thereto), including any Rule
         462(b) Registration Statement, including information deemed to be part
         of the Registration Statement pursuant to Rule 430A(b) of the 1933 Act
         Regulations, if applicable, or the omission or alleged omission
         therefrom of a material fact required to be stated therein or necessary
         to make the statements therein not misleading or arising out of any
         untrue statement or alleged untrue statement of a material fact
         included in any preliminary Prospectus Supplement or the Prospectus (or
         any amendment or supplement thereto) or the omission or alleged
         omission therefrom of a material fact necessary in order to make the
         statements therein, in the light of the circumstances under which they
         were made, not misleading, unless such untrue statement or omission or
         such alleged untrue statement or omission was made in reliance upon and
         in conformity with written information furnished to the Company by an
         Underwriter expressly for use in the Registration Statement (or any
         amendment thereto) or such preliminary Prospectus Supplement or the
         Prospectus (or any amendment or supplement thereto);

         (ii) against any and all loss, liability, damage, joint or several, and
         expense whatsoever, as incurred, to the extent of the aggregate amount
         paid in settlement of any litigation, or investigation or proceeding by
         any governmental agency or body, commenced or 



                                       26
   27

         threatened, or of any claim whatsoever based upon any such untrue 
         statement or omission, or any such alleged untrue statement or 
         omission; provided that such settlement is effected with the written 
         consent of the Company, which consent shall not be unreasonably 
         withheld; and

         (iii) against any and all expense whatsoever, as incurred (including
         the fees and expenses of counsel chosen by such Underwriter),
         reasonably incurred in investigating, preparing or defending against
         any litigation, or any investigation or proceeding by any governmental
         agency or body, commenced or threatened, or any claim whatsoever based
         upon any such untrue statement or omission, or any such alleged untrue
         statement or omission, to the extent (x) the Company is required to do
         so under Section 6(c) below and (y) that any such expense is not paid
         under (i) or (ii) above.

         (b) Each Underwriter agrees, severally and not jointly, to indemnify
and hold harmless the Company, its directors, each of its officers who signed
the Registration Statement, and each person, if any, who controls the Company
within the meaning of Section 15 of the 1933 Act against any and all loss,
liability, claim, damage and expense described in the indemnity contained in
subsection (a) of this Section, but only with respect to untrue statements or
omissions, or alleged untrue statements or omissions, made in the Registration
Statement (or any amendment thereto), any Rule 462(b) Registration Statement or
any preliminary Prospectus Supplement or the Prospectus (or any amendment or
supplement thereto) in reliance upon and in conformity with written information
furnished to the Company by such Underwriter expressly for use in the
Registration Statement (or any amendment thereto), any Rule 462(b) Registration
Statement or any preliminary Prospectus Supplement or the Prospectus (or any
amendment or supplement thereto).

         (c) Each indemnified party shall give notice as promptly as reasonably
practicable to each indemnifying party of any action commenced against it in
respect of which indemnity may be sought hereunder, but failure to so notify an
indemnifying party shall not relieve it from any liability which it may have
otherwise than on account of this indemnity agreement. If any such claim or
action shall be brought against an indemnified party, and it shall notify the
indemnifying party thereof, the indemnifying party shall be entitled to
participate therein and to the extent that it wishes, jointly with any other
similarly notified indemnifying party, to assume the defense thereof with
counsel reasonably satisfactory to the indemnified party. After notice from the
indemnifying party to the indemnified party of its election to assume the
defense of such claim or action, the indemnifying party shall not be liable to
the indemnified party under this Section for any legal or other expenses
subsequently incurred by the indemnified party in connection with the defense
thereof other than reasonable costs of investigation; provided, however, that
each Underwriter shall have the right to employ counsel to represent jointly the
Underwriters and their respective controlling persons who may be subject to
liability arising out of any claim in respect of which indemnity may be sought
by the Underwriters against the Company under this Section if, in the judgment
of any of the Underwriters, it is advisable for such Underwriter or Underwriters
and controlling persons to be jointly represented by separate counsel, and in
that event the fees and expenses of such separate counsel shall be paid by the
Company. In no event shall the indemnifying parties be liable for the fees and
expenses of more than one counsel (in addition to any local counsel) separate
from their own counsel for all indemnified parties in connection with any one
action or separate but similar or related actions in the same jurisdiction




                                       27
   28

arising out of the same general allegations or circumstances. No indemnifying
party shall, without the prior written consent of the indemnified parties (which
shall not unreasonably be withheld), settle or compromise or consent to the
entry of any judgment with respect to any litigation, or any investigation or
proceeding by any governmental agency or body, commenced or threatened, or any
claim whatsoever in respect of which indemnification or contribution could be
sought under this Section 6 or Section 7 hereof (whether or not the indemnified
parties are actual or potential parties thereto), unless such settlement,
compromise or consent (i) includes an unconditional release of each indemnified
party from all liability arising out of such litigation, investigation,
proceeding or claim and (ii) does not include a statement as to or an admission
of fault, culpability or a failure to act by or on behalf of any indemnified
party.

         (d) For purposes of this Section 6, all references to the Registration
Statement, any preliminary Prospectus Supplement or the Prospectus, or any
amendment or supplement to any of the foregoing, shall be deemed to include,
without limitation, any electronically transmitted copies thereof, including,
without limitation, any copies filed with the Commission pursuant to EDGAR.

         SECTION 7. Contribution. If the indemnification provided for in Section
6 hereof is for any reason unavailable to or insufficient to hold harmless an
indemnified party in respect of any losses, liabilities, claims, damages or
expenses referred to therein, then each indemnifying party shall contribute to
the aggregate amount of such losses, liabilities, claims, damages and expenses
incurred by such indemnified party, as incurred, (i) in such proportion as is
appropriate to reflect the relative benefits received by the Company on the one
hand and the Underwriters on the other hand from the offering of the Offered
Securities pursuant to this Agreement or (ii) if the allocation provided by
clause (i) is not permitted by applicable law, in such proportion as is
appropriate to reflect not only the relative benefits referred to in clause (i)
above but also the relative fault of the Company on the one hand and of the
Underwriters on the other hand in connection with the statements or omissions
which resulted in such losses, liabilities, claims, damages or expenses, as well
as any other relevant equitable considerations. The relative benefits received
by the Company on the one hand and the Underwriters on the other hand in
connection with the offering of the Offered Securities pursuant to this
Agreement shall be deemed to be in the same respective proportions as the total
net proceeds from the offering of the Offered Securities pursuant to this
Agreement (before deducting expenses) received by the Company and the total
commission or underwriting discount received by each Underwriter, in each case
as set forth on the cover of the Prospectus Supplement, bear to the aggregate
initial public offering price of the Offered Securities sold to or through such
Underwriter as set forth on such cover. The relative fault of the Company on the
one hand and the Underwriters on the other hand shall be determined by reference
to, among other things, whether the untrue or alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company or by the Underwriters and the
parties' relative intent, knowledge, access to information and opportunity to
correct or prevent such statement or omission. The Company and the Underwriters
agree that it would not be just and equitable if contribution pursuant to this
Section 7 were determined by pro rata allocation (even if the Underwriters were
treated as one entity for such purpose) or by any other method of allocation
which does not take account of the equitable considerations referred to above in
this Section 7. The aggregate amount of losses, liabilities, claims, damages and
expenses incurred by an indemnified party and referred to above in this Section
7 shall be deemed to include any legal or 



                                       28
   29

other expenses reasonably incurred by such indemnified party in investigating,
preparing or defending against any litigation, or any investigation or
proceeding by any governmental agency or body, commenced or threatened, or any
claim whatsoever based upon any such untrue or alleged untrue statement or
omission or alleged omission. Notwithstanding the provisions of this Section 7,
no Underwriter shall be required to contribute any amount in excess of the
amount by which the total price at which the Offered Securities sold to or
through such Underwriter were offered to the public exceeds the amount of any
damages which such Underwriter has otherwise been required to pay by reason of
such untrue or alleged untrue statement or omission or alleged omission. No
person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the 1933 Act) shall be entitled to contribution from any person who was
not guilty of such fraudulent misrepresentation. For purposes of this Section 7,
each person, if any, who controls an Underwriter within the meaning of Section
15 of the 1933 Act or Section 20 of the 1934 Act shall have the same rights to
contribution as such Underwriter, and each director of the Company, each officer
of the Company who signed the Registration Statement, and each person, if any,
who controls the Company within the meaning of Section 15 of the 1933 Act or
Section 20 of the 1934 Act shall have the same rights to contribution as the
Company. The Underwriters' respective obligations to contribute pursuant to this
Section 7 are several in proportion to the principal amount of Offered
Securities sold to or through each Underwriter and not joint.

         SECTION 8. Representations, Warranties and Agreements to Survive
Delivery. All representations, warranties and agreements contained in this
Agreement or in certificates of officers of the Company submitted pursuant
hereto or thereto shall remain operative and in full force and effect,
regardless of any investigation made by or on behalf of any Underwriter or
controlling person of an Underwriter, or by or on behalf of the Company, and
shall survive each delivery of and payment for any Offered Securities.

         SECTION 9.  Termination.

         (a) The Representatives may terminate this Agreement immediately upon
notice to the Company, at any time at or prior to the Closing Time if (i) there
has been, since the date of the Terms Agreement or since the respective dates as
of which information is given in the Registration Statement, any material
adverse change in the condition, financial or otherwise, or in the results of
operations, business affairs or business prospects of the Company and its
subsidiaries considered as one enterprise, whether or not arising in the
ordinary course of business, or (ii) there shall have occurred any material
adverse change in the financial markets in the United States or any outbreak or
escalation of hostilities or other national or international calamity or crisis
the effect of which is such as to make it, in the judgment of the
Representatives, impracticable to market the Offered Securities or enforce
contracts for the sale of the Offered Securities, or (iii) trading in any
securities of the Company has been suspended by the Commission or a national
securities exchange, or if trading generally on either the American Stock
Exchange or the New York Stock Exchange shall have been suspended, or minimum or
maximum prices for trading have been fixed, or maximum ranges for prices for
securities have been required, by either of said exchanges or by order of the
Commission or any other governmental authority, or if a banking moratorium shall
have been declared by either Federal, New York or Texas authorities or if a
banking moratorium shall have been declared by the relevant authorities in the
country or countries of origin of any foreign currency or currencies in 



                                       29
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which the Offered Securities are denominated or payable, or (iv) a downgrading
shall have occurred in the rating accorded to any debt securities or preferred
stock of the Company by any "nationally recognized statistical rating
organization," as that term is defined by the Commission for purposes of Rule
436(g)(2) under the 1933 Act or such organization shall have publicly announced
that it has under survellience or review, with possible negative implications,
its rating of any debt securities or preferred stock of the Company, or (v)
there shall have come to the attention of the Representatives any facts that
would cause them to reasonably believe that the Prospectus, at the time it was
required to be delivered to a purchaser of the Offered Securities, included an
untrue statement of a material fact or omitted to state a material fact
necessary in order to make the statements therein, in light of the circumstances
existing at the time of such delivery, not misleading. As used in this Section
9, the term "Prospectus" means the Prospectus in the form first provided to the
applicable Underwriter or Underwriters for use in confirming sales of the
related Offered Securities.

         (b) If this Agreement is terminated pursuant to this Section, such
termination shall be without liability of any party to any other party, except
to the extent provided in Section 5. Notwithstanding any such termination, (i)
the covenants set forth in Section 3(b), (d), and (e) with respect to any
offering of Offered Securities shall remain in effect so long as any Underwriter
owns any such Offered Securities purchased from the Company pursuant to this
Agreement and during the period when the Prospectus is required to be delivered
in connection with sales of the Offered Securities and (ii) the covenants set
forth in Section 3(c), (g), (h) and, if applicable, (i), the provisions of
Section 5, the indemnity agreement set forth in Section 6, the contribution
provisions set forth in Section 7 and the provisions of Sections 8, 11, 12 and
13 shall remain in effect.

         SECTION 10. Default. If one or more of the Underwriters shall fail at
the Closing Time or a Date of Delivery to purchase the Firm Securities which it
or they are obligated to purchase under this Agreement (the "Defaulted
Securities"), then the Representatives shall have the right, within 24 hours
thereafter, to make arrangements for one or more of the non-defaulting
Underwriters, or any other underwriters, to purchase all, but not less than all,
of the Defaulted Securities in such amounts as may be agreed upon and upon the
terms herein set forth. If, however, during such 24 hours the Representatives
shall not have completed such arrangements for the purchase of all of the
Defaulted Securities, then:

                  (a) if the amount of Defaulted Securities does not exceed 10%
                  of the amount of Firm Securities to be purchased on such date,
                  each of the non-defaulting Underwriters shall be obligated,
                  severally and not jointly, to purchase the full amount thereof
                  in the proportions that their respective underwriting
                  obligations hereunder bear to the underwriting obligations of
                  all non-defaulting Underwriters, or

                  (b) if the amount of Defaulted Securities exceeds 10% of the
                  number of Firm Securities to be purchased on such date, this
                  Agreement or, with respect to any Date of Delivery which
                  occurs after the Closing Time, the obligation of the
                  Underwriters to purchase and of the Company to sell the Option
                  Securities to be purchased and sold on such Date of Delivery
                  shall terminate without liability on the part of any
                  non-defaulting Underwriter.



                                       30
   31

         No action taken pursuant to this Section 10 shall relieve any
defaulting Underwriter from liability in respect of its default.

         In the event of any such default which does not result in a termination
of this Agreement or, in the case of a Date of Delivery which is after the
Closing Time, which does not result in a termination of the obligation of the
Underwriters to purchase and the Company to sell the relevant Option Securities,
as the case may be, either the Representatives or the Company shall have the
right to postpone the Closing Time or the relevant Date of Delivery, as the case
may be, for a period not exceeding seven days in order to effect any required
changes in the Registration Statement or the Prospectus or in any other
documents or arrangements. As used herein, the term "Underwriter" includes any
person substituted for an Underwriter under this Section 10.

         SECTION 11. Notices. All notices and other communications hereunder
shall be in writing, either delivered by hand, by mail or by telex, telecopier
or telegram, and any such notice shall be effective when received at the address
specified in this Section 11. Notices to the Underwriters shall be directed as
provided in the Terms Agreement. Notices to the Company shall be directed to
Apache Corporation, 2000 Post Oak Boulevard, Suite 100, Houston, Texas
77056-4400, Attention: Vice President and Treasurer, with a copy to: John B.
Clutterbuck, Mayor, Day, Caldwell & Keeton, L.L.P., 700 Louisiana, Suite 1900,
Houston, Texas 77002-2778. Any party to this Agreement may from time to time
designate another address to receive notice pursuant to this Agreement by notice
duly given in accordance with the terms of this Section 11.

         SECTION 12. Parties. This Agreement shall inure to the benefit of and
be binding upon the Underwriters and the Company and their respective
successors. Nothing expressed or mentioned in this Agreement is intended or
shall be construed to give any person, firm or corporation, other than the
parties hereto and their respective successors and the controlling persons and
officers and directors referred to in Sections 6 and 7 and their heirs and legal
representatives, any legal or equitable right, remedy or claim under or in
respect of this Agreement or any provision herein contained. This Agreement and
all conditions and provisions hereof are intended to be for the sole and
exclusive benefit of the parties hereto and their respective successors and said
controlling persons and officers and directors and their heirs and legal
representatives, and for the benefit of no other person, firm or corporation. No
purchaser of Offered Securities from any Underwriter shall be deemed to be a
successor by reason merely of such purchase.

         SECTION 13. Governing Law. This Agreement and all the rights and
obligations of the parties hereto shall be governed by and construed in
accordance with the laws of the State of New York applicable to agreements made
and to be performed in such State.

         SECTION 14.  Counterparts.  Any Terms Agreement may be executed in one
or more counterparts and, if executed in more than one counterpart, the executed
counterparts thereof shall constitute a single instrument.




                                       31
   32
                                                                       EXHIBIT A

                                 TERMS AGREEMENT

                           Convertible Preferred Stock

                                                            ___________ __, 19__

Apache Corporation
2000 Post Oak Boulevard, Suite 100
Houston, Texas 77056-4400
Attention: [Title]


Dear Sirs:

         The undersigned underwriters (the "Underwriters") understand that
Apache Corporation (the "Company") proposes to issue and sell [number of] shares
of its [depositary shares, representing the right to receive its shares of]
convertible preferred stock, no par value, convertible into common stock, $1.25
par value per share and related rights to purchase common stock (the "Offered
Securities"). Subject to the terms and conditions set forth herein or
incorporated by reference herein, the Underwriters offer to purchase, severally
and not jointly, the number of Offered Securities set forth below opposite their
respective names at $___ per share together with accrued dividend thereon from
__________, 19__ to the Closing Time:




                                                              Number of
         Underwriter                                       Firm Securities
         -----------                                       ---------------
                                                         



                                                           ---------------
                                                  Total                  
                                                           ===============


         The Offered Securities shall have the following terms:

Title of the Offered Securities:
Number of Firm Securities to be issued:
Maximum number of Option Securities to be issued:
Current ratings:
Dividend rate:
Dividend payment dates:
Redemption provisions, if any:




                                       A-1
   33

Conversion provisions:
Initial price to public:
Underwriting commission:
Purchase price
Closing Time:
Place of delivery and payment:
Company account for wire transfer of payment:
Lock-up pursuant to Section 3(j) of the
         Underwriting Agreement Basic Terms:         [yes]    [no]
Lock-up pursuant to Section 4(e) of the
         Underwriting Agreement Basic Terms:         [yes]    [no]
         Note:  If yes, see Schedule A hereto.
Securities exchanges, if any, on which application will be made to list the
Offered Securities:

Other terms, if any:

         All the provisions contained in "Apache Corporation-Convertible
Preferred Stock--Underwriting Agreement Basic Terms" (the "Basic Terms"), filed
as an exhibit to the Registration Statement relating to the Offered Securities
and attached hereto as Annex A, are herein incorporated by reference in their
entirety and shall be deemed to be a part of this Terms Agreement to the same
extent as if such provisions had been set forth in full herein. Terms defined in
such document are used herein as therein defined.

         Any notice by the Company to the Underwriters pursuant to this Terms
Agreement shall be sufficient if given in accordance with Section 11 of the
Basic Terms addressed to: [insert name and address of the lead manager or
managers or, if only one underwriter is a party hereto, of such firm] which
shall, for all purposes of this Agreement, be the "Representatives".

                                    Very truly yours,

                                    REPRESENTATIVE[S]


                                          [Acting for themselves and as
                                          Representative[s] of the Underwriters]

Accepted:

APACHE CORPORATION

By:                           
   ----------------------------
         Title:



                                      A-2
   34

                                                                      SCHEDULE A

                 List of Persons and Entities Subject to Lock-Up



                                      A-3
   35


                                                                       EXHIBIT B

               [Form of Lock-Up from Directors, Officers or Other
                     Stockholders Pursuant to Section 4(e)]

                                     , 1999


[NAME OF LEAD UNDERWRITER]
[NAME(S) OF ANY CO-REPRESENTATIVE(S)]
   as Representative(s) of the several
   Underwriters to be named in the
   within-mentioned Underwriting Agreement


         Re:      Proposed Public Offering by Apache Corporation

Dear Sirs:

         The undersigned, a stockholder [and an officer and/or director]1 of
Apache Corporation, a Delaware corporation (the "Company"), understands that
[name of lead underwriter][and [name(s) of co-representative(s), if any]]
propose(s) to enter into an Underwriting Agreement (the "Underwriting
Agreement") with the Company providing for the public offering of preferred
stock convertible into shares (the "Securities") of the Company's common stock,
par value $1.25 per share (the "Common Stock") and related rights to purchase
Common Stock. In recognition of the benefit that such an offering will confer
upon the undersigned as a stockholder [and an officer and/or director]1 of the
Company, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the undersigned agrees with each
underwriter to be named in the Underwriting Agreement that, during a period of
90 days from the date of the Underwriting Agreement, the undersigned will not,
without the prior written consent of [name of lead underwriter], directly or
indirectly, (i) offer, pledge, sell, contract to sell, sell any option or
contract to purchase, purchase any option or contract to sell, grant any option,
right or warrant for the sale of, or otherwise dispose of or transfer any shares
of the Company's Common Stock or any securities convertible into or exchangeable
or exercisable for Common Stock or any such substantially similar securities,
whether now owned or hereafter acquired by the undersigned or with respect to
which the undersigned has or hereafter acquires the power of disposition, or
file any registration statement under the Securities Act of 1933, as amended,
with respect to any of the foregoing or (ii) enter into any swap or any other
agreement or any transaction that transfers, in whole or in part, directly or
indirectly, the economic consequence of ownership of the Common Stock, whether
any such swap or transaction is to be settled by delivery of Common Stock or
other securities, in cash or otherwise.


                                                   Very truly yours,



                                                   Signature: 

                                                   Print Name:

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


(1)     Delete or revise background language as appropriate.

                                      B-1
   36

                                                                         ANNEX A


               [Apache Corporation--Convertible Preferred Stock--
                       Underwriting Agreement Basic Terms]



                                      A-1