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                                                                     EXHIBIT 2.2


                            STOCK PURCHASE AGREEMENT


         THIS STOCK PURCHASE AGREEMENT ("Agreement") is dated April 29, 1999 by
and between SHELL OFFSHORE INC., a Delaware corporation ("Shell") having a post
office address of P.O. Box 61933, New Orleans, Louisiana 70161, and APACHE
CORPORATION, a Delaware corporation ("Apache"), the address for which is 2000
Post Oak Boulevard, Suite 100, Houston, Texas 77056-4400. Shell and Apache are
sometimes separately referred to as a "Party" and are sometimes collectively
referred to as "Parties."

         WHEREAS, the Parties and certain affiliates of Shell (collectively, the
"Shall Entities") have entered into an Asset Purchase Agreement dated even
herewith for the sale by the Shell Entities and purchase by Apache of certain
oil and gas properties (the "Asset Purchase Agreement"); and

         WHEREAS, as a portion of the consideration to be paid by Apache
pursuant to the Asset Purchase Agreement, Shell has agreed to acquire and Apache
has agreed to issue shares of common stock of Apache;

         NOW, THEREFORE, in consideration of the mutual promises contained
herein and in the Asset Purchase Agreement, the benefits to be derived by each
Party hereunder and thereunder, and other good and valuable consideration, the
Parties agree as follows:

SECTION 1 - DEFINITIONS

All capitalized terms used herein and not otherwise defined have the meanings
set forth in the Asset Purchase Agreement.

SECTION 2 - PURCHASE AND SALE OF THE SHARES

2.1      PURCHASE AND SALE OF THE SHARES: On the terms and subject to the
         conditions of the Asset Purchase Agreement and this Agreement, at the
         Closing, Apache shall issue and sell to Shell 1,000,000 shares (the
         "Shares") of the common stock, par value $1.25 per share, of Apache
         ("Apache Common Stock") and Shell shall acquire and purchase the Shares
         from Apache.

2.2      CONSIDERATION FOR THE SHARES: The Shares are being issued in connection
         with and as part of the consideration for the acquisition by Apache of
         certain oil and gas properties from Shell pursuant to the Asset
         Purchase Agreement.

2.3      SHARE CERTIFICATE: Apache shall deliver to Shell at the Closing a stock
         certificate representing the Shares in appropriate form.
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SECTION 3 - REPRESENTATIONS AND WARRANTIES OF SHELL

Shell hereby represents and warrants to Apache as of the date hereof and as of
the Closing that:

3.1      Shell is acquiring the Shares for its own account and not as a nominee
         or agent or otherwise for any other person.

3.2      Shell is acquiring the Shares for investment purposes and not with a
         view to, or for resale in connection with, any distribution any of the
         Shares in violation of the Securities Act of 1933, as amended.

3.3      Shell has such knowledge, sophistication and experience in business,
         tax and financial matters that Shell is capable of evaluating and is
         familiar with the merits and risks of an investment in the Shares, can
         bear substantial economic risk of an investment in the Shares for an
         indefinite period of time and can afford a complete loss of such
         investment.

3.4      Shell has received from Apache, and has had the opportunity to review,
         the following documents concerning Apache:

         (i)      Prospectus dated September 21, 1995 relating to 1,350,000
                  shares of Apache Common Stock registered pursuant to a
                  registration statement described in Section 4.1 below,

         (ii)     Prospectus supplement dated April 26, 1999,

         (iii)    Annual Report on Form 10-K for the year ended December 31,
                  1998,

         (iv)     Current Report on Form 8-K dated March 2, 1999 (as amended by
                  Amendment No. 1 on Form 8-K/A filed on March 5, 1999), and

         (v)      Proxy Statement for annual meeting of stockholders to be held
                  on May 6, 1999.

         Shell acknowledges that certain information conveyed to it under item
         (ii) above contains material nonpublic information concerning Apache
         and that the federal securities laws prohibit trading in securities
         while in possession of material nonpublic information, and Shell agrees
         to maintain the confidentiality of such information.

3.5      Shell acknowledges that (i) none of Apache, any affiliate thereof or
         any person representing Apache or any affiliate thereof has made any
         representation to it with respect to Apache or the offering or sale of
         the Shares, other than the information concerning Apache and the
         offering contained in the documents set forth in Section 3.4 or the
         Asset Purchase Agreement, (ii) in making its investment decision Shell
         is not relying upon any information given by Apache or any affiliate
         thereof or any person representing Apache or any affiliate thereof
         other than the information concerning Apache and the offering contained
         in the documents set forth in Section 3.4 and the Asset Purchase
         Agreement and (iii) no representation has been made, and no information
         has been furnished, to Shell in connection with the offering or sale of
         the Shares that was in any way inconsistent with any other information
         with which Shell has been provided.


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3.6      Shell understands the Apache is relying upon the representations and
         warranties contained in this Agreement for purposes of determining
         whether it is appropriate to issue the Shares to Shell.

3.7      Shell is a corporation duly organized, validly existing and in good
         standing under the laws of the State of Delaware. Shell has full power
         and authority to enter into this Agreement and consummate the
         transactions contemplated by this Agreement. This Agreement has been
         duly and validly authorized, executed and delivered on behalf of Shell
         and is a valid and binding agreement of Shell enforceable in accordance
         with its terms, subject as to enforceability to general principles of
         equity and to bankruptcy or other laws affecting the enforcement of
         creditors' rights generally.

SECTION 4 - REPRESENTATIONS AND WARRANTIES OF APACHE

Apache hereby represents and warrants to Shell as of the date hereof and as of
the Closing that:

4.1      Apache has prepared and filed with the Securities and Exchange
         Commission ("Commission") a registration statement on Form S-4 (No.
         33-61669) that covers the registration of the Shares under the
         Securities Act of 1933, as amended ("Securities Act"), and the sale of
         the Shares pursuant to the Asset Purchase Agreement and this Agreement
         in accordance with Rule 415 of the rules and regulations of the
         Commission under the Securities Act, 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, and no stop order suspending the effectiveness of the
         registration statement has been issued by the Commission.

4.2      The Shares have been duly and validly authorized for issuance, offer
         and sale pursuant to this Agreement. The Shares, when issued and
         delivered against payment of the consideration therefor in accordance
         with this Agreement and the Asset Purchase Agreement, will be validly
         issued, fully paid and non-assessable shares of Apache Common Stock.

4.3      On or prior to the date of the Closing, the Shares will have been
         listed for trading on the New York Stock Exchange and the Chicago Stock
         Exchange.

4.4      Apache is a corporation duly organized, validly existing and in good
         standing under the laws of the State of Delaware. Apache has full power
         and authority to enter into this Agreement and consummate the
         transactions contemplated by this Agreement. This Agreement has been
         duly and validly authorized, executed and delivered on behalf of Apache
         and is a valid and binding agreement of Apache enforceable in
         accordance with its terms, subject as to enforceability to general
         principles of equity and to bankruptcy or other laws affecting the
         enforcement of creditors' rights generally.


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SECTION 5 - TRANSFER RESTRICTIONS AND RESALES

5.1      NINETY DAY HOLDING PERIOD: In addition to any restrictions that might
         apply as set forth in other subsections of this Section, Shell agrees
         that during a period of ninety days from the date of this Agreement it
         will not, 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 of the Shares or (ii) enter
         into any swap or any other agreement or transaction that transfers, in
         whole or in part, directly or indirectly, the economic consequence of
         ownership of the Shares, whether any such swap or other transaction is
         to be settled by delivery of the Shares or other securities, in cash or
         otherwise (collectively, the "lock-up"); provided, however, that Apache
         agrees that (x) Apache will, after the date of this Agreement, consult
         with Goldman, Sachs & Co. ("Goldman") on an on-going basis concerning
         the continued need for the lock-up provided for in this subsection and
         (y) promptly following Apache's receipt of advice from Goldman that
         such lock-up is no longer required in connection with Apache's planned
         underwritten public offering of equity securities, Apache will give
         Shell notice that the restrictions set forth in this subsection are
         terminated and such restrictions shall cease.

5.2      RESALES: Shell acknowledges that since it and its affiliates may be
         deemed to be "affiliates" for purposes of Rule 145 promulgated under
         the Securities Act at the time the Shares are issued, such Shares can
         be sold only (i) pursuant to an effective registration statement under
         the Securities Act, (ii) in conformity with the volume, manner of sale
         and other limitations of Rule 145(d) promulgated under the Securities
         Act, or (iii) in reliance upon an exemption from registration that is
         available under the Securities Act.

         Shell also acknowledges and agrees that stop-transfer instructions will
         be given to Apache's transfer agent with respect to the Shares and that
         there will be placed on the certificates representing such Shares, or
         any substitutions therefor, a legend stating in substance as follows:

                  "These shares were issued in a transaction to which Rule 145
                  promulgated under the Securities Act of 1933, as amended (the
                  "Securities Act"), applies. These shares may only be
                  transferred in accordance with the terms of such Rule or as
                  otherwise provided under the Securities Act."

         It is understood and agreed that the legend set forth above shall be
         removed, upon surrender of certificates bearing such legend, by
         delivery of substitute certificates without such legend if Shell shall
         have satisfied Apache that the sale or disposition of the shares
         represented by the surrendered certificates may be effected without
         registration of the offering, sale and delivery of such shares under
         the Securities Act.

SECTION 6 - CONDITIONS PRECEDENT

The Parties' obligations pursuant to this Agreement shall be subject to the
occurrence of the Closing pursuant to the Asset Purchase Agreement, and if the
Asset Purchase Agreement is terminated without the Closing being consummated,
then this Agreement shall terminate simultaneously therewith and be void and of
no further force or effect.


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SECTION 7 - ADMINISTRATIVE PROVISIONS

7.1      PROVISIONS INCORPORATED BY REFERENCE: The following provisions of the
         Asset Purchase Agreement are incorporated by reference into this
         Agreement and shall apply to this Agreement as if set forth in full
         herein; provided that each reference to "PURCHASER" and "SELLER"
         therein shall become a reference to "Apache" and "Shell," respectively,
         herein: Sections 10.1 through 10.7, Sections 10.9, 10.10, 10.11, 10.13
         and 10.14.

7.2      GOVERNING LAW: This Agreement shall be governed and interpreted
         according to the laws of the State of Texas without giving effect to
         principles of conflicts of laws.

                            [signature page follows]


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IN WITNESS WHEREOF, the Parties have executed this Agreement as of the date
first above written.


                                           APACHE CORPORATION

                                           By:  /s/ Lisa A. Floyd
                                              -------------------------------
                                           Name:    Lisa A. Floyd
                                           Title:   VP Business Development


                                           Shell Offshore Inc.

                                           By:  /s/ K. R. Sissell
                                              -------------------------------
                                           Name:    K. R. Sissell
                                           Title:   Attorney-in-Fact


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