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                                                                  EXHIBIT 10.31

            AMENDMENT NO. 1 TO STOCK APPRECIATION RIGHTS AGREEMENT

   AMENDMENT NO. 1 TO STOCK APPRECIATION RIGHTS AGREEMENT (this "Amendment"),
dated as of November 20, 2002, by and between Plains Exploration & Production
Company, a Delaware corporation ("Company"), and Stephen A. Thorington
("Grantee"). Undefined capitalized terms are defined in the Agreement (as
defined below).

   WHEREAS, Company and Grantee entered into the Stock Appreciation Rights
Agreement, dated as of September 3, 2002 (the "Agreement");

   WHEREAS, Company and Grantee desire to enter into this Amendment to change
the Grant Date and the Exercise Price;

   NOW THEREFORE, in consideration of the premises and other good and valuable
consideration, the parties hereby agree as follows:

      1.  The preamble of the Agreement is hereby amended by deleting it in its
   entirety and replacing it with the following:

          "THIS AGREEMENT, entered into as of September 3, 2002, with respect
       to the following grant of Stock Appreciation Rights, such grant to be
       effective on the date (the "Grant Date") on which all of the shares of
       common stock of Plains Exploration & Production Company, a Delaware
       corporation (the "Company"), held by Plains Resources Inc. ("PLX") are
       distributed to PLX's stockholders, by and between the Company and
       Stephen A. Thorington ("Grantee")."

      2.  The first recital of the Agreement is hereby amended by deleting the
   term "2002 Stock Incentive Plan" and replacing it with the following "2002
   Transition Stock Incentive Plan, as amended or restated from time to time".

      3.  Section 1.2 of the Agreement is hereby amended by deleting it in its
   entirety and replacing it with the following:

          "1.2  The "Exercise Price" per SAR is equal to the closing price (on
       a "when issued" basis) per Share on the Grant Date as reported on the
       New York Stock Exchange, which has been determined to be the Fair Market
       Value of a Share on the Grant Date."

      4.  Section 9 of the Agreement is hereby amended by changing the section
   reference therein from "14" to "8".

      5.  Effect on the Agreement.  Except as specifically amended or waived by
   this Amendment, all terms and conditions of the Agreement shall remain in
   full force and effect. The term "Agreement" used in the Agreement shall mean
   the Agreement as amended hereby.

      6.  Counterparts.  This Amendment may be executed in counterparts each of
   which shall be deemed to be an original but all of which shall constitute
   one and the same agreement.

      7.  Governing Law.  This Amendment shall be governed by and construed in
   accordance with the laws of the State of Delaware, without regard to its
   principles of conflicts of law.

                           [Signature Page Follows]

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   IN WITNESS WHEREOF, each of the parties have caused this Amendment to be
executed on its behalf by its officers thereunto duly authorized on the day and
year first written above.


                                              PLAINS EXPLORATION & PRODUCTION
                                              COMPANY

                                              By:      /S/ JAMES C. FLORES
                                                  -----------------------------
                                                         James C. Flores
                                                  Chairman and Chief Executive
                                                             Officer


                                                    /S/ STEPHEN A. THORINGTON
                                                  -----------------------------
                                                      Stephen A. Thorington


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