Exhibit 4.1

AMENDMENT NO. 2 TO

AMENDED AND RESTATED CREDIT AGREEMENT

THIS AMENDMENT NO. 2 TO AMENDED AND RESTATED CREDIT AGREEMENT (this “Amendment”) dated as of May 4, 2011, is among Plains Exploration & Production Company, a Delaware corporation (the “Borrower”), the several banks and other financial institutions signatories hereto, and JPMorgan Chase Bank, N.A., a national banking association, as Administrative Agent for the Lenders (the “Administrative Agent”).

RECITALS

A. The Borrower, the Lenders and the Administrative Agent are parties to an Amended and Restated Credit Agreement dated as of August 3, 2010 (as amended, modified or supplemented prior to the date hereof, the “Credit Agreement”).

B. The Borrower has requested the Lenders to approve an amendment to the Credit Agreement that extends the maturity date of the loans made under the Credit Agreement and reduces the Applicable Margin.

NOW, THEREFORE, in consideration of the foregoing and the mutual covenants set forth in this Amendment, the Borrower and the Lenders agree as follows:

1. Defined Terms. Unless otherwise defined in this Amendment, capitalized terms used in this Amendment have the meanings assigned to those terms in the Credit Agreement.

2. Amendments to Credit Agreement. The Credit Agreement is hereby amended as follows:

(a) The definition of “Applicable Margin” in Section 1.1 of the Credit Agreement is hereby amended to read as follows:

“Applicable Margin” means, for any day with respect to the commitment fees payable hereunder, or with respect to any Eurodollar Loan or ABR Loan, as the case may be, the rate per annum set forth in the appropriate column below under the caption “Commitment Fee Rate”, “Eurodollar Spread,” or “ABR Spread,” as the case may be, for the Borrowing Base Utilization Percentage then in effect:

(b) The definition of “Maturity Date” in Section 1.1 of the Credit Agreement is hereby amended to read as follows:

“Maturity Date” means May 4, 2016.

3. Conditions to Effectiveness. This Amendment will become effective on the date on which the following conditions have been satisfied or waived:

(a) The Administrative Agent shall have received this Amendment, executed and delivered by the Borrower, the Guarantors, the Administrative Agent and all Lenders;

(b) The representations and warranties of the Borrower in Section 4 of this Amendment shall be true and correct; and

(c) The Administrative Agent shall have received for the account of each Lender executing this Amendment an amendment fee equal to 0.10% of the Commitment of such Lender.

4. Representations and Warranties. The Borrower hereby represents and warrants to the Administrative Agent and each of the Lenders as follows:

(a) This Amendment has been duly authorized by all necessary corporate action and constitutes the binding obligation of the Borrower.

(b) Each of the representations and warranties made by the Borrower and the Guarantors in or pursuant to the Credit Agreement and the other Loan Documents is true and correct in all material respects as of the date hereof, as if made (after giving effect to this Amendment) on and as of such date, except for any representations and warranties made as of a specified date, which were true and correct in all material respects as of such specified date.

(c) After giving effect to this Amendment, no Default or Event of Default has occurred and is continuing as of the date hereof.

(d) Since the date of the most recent audited financial statements of the Borrower and its Subsidiaries delivered to the Lenders pursuant to Section 8.01(a) of the Credit Agreement, there has been no material adverse effect on the business, operations, Property or financial condition of the Borrower and its Restricted Subsidiaries taken as a whole, excluding the effect of events, developments and circumstances affecting the oil and gas exploration and production industry generally.

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5. Flood Insurance Regulation. Notwithstanding any provision in any Mortgage to the contrary, in no event is any Building (as defined in the applicable Flood Insurance Regulation) or Manufactured (Mobile) Home (as defined in the applicable Flood Insurance Regulation) located in a special flood hazard area included in the definition of “Mortgaged Property” or “Deed of Trust Property” in any Security Instrument and no such Building or Manufactured (Mobile) Home shall be encumbered by any such Security Instrument. As used herein, “Flood Insurance Regulations” shall mean (i) the National Flood Insurance Act of 1968 as now or hereafter in effect or any successor statute thereto, (ii) the Flood Disaster Protection Act of 1973 as now or hereafter in effect or any successor statue thereto, (iii) the National Flood Insurance Reform Act of 1994 (amending 42 USC 4001, et seq.), as the same may be amended or recodified from time to time, (iv) the Flood Insurance Reform Act of 2004 and (v) any regulations promulgated under any of the foregoing statutes.

6. Continuing Effect of the Credit Agreement. This Amendment does not constitute a waiver of any provision of the Credit Agreement and, except as expressly provided herein, is not to be construed as a consent to any action on the part of the Borrower that would require a waiver or consent of the Lenders or an amendment or modification to any term of the Loan Documents. The Borrower hereby confirms and ratifies the Credit Agreement as amended hereby and each of the other Loan Documents to which it is a party and acknowledges and agrees that the same continue in full force and effect as amended hereby (as applicable).

7. Reference to the Credit Agreement. Upon the effectiveness of this Amendment, each reference in the Credit Agreement to “this Agreement,” “hereunder,” “herein” or words of like import refer to the Credit Agreement, as amended and affected hereby.

8. Designation as Loan Document. This Amendment is a Loan Document.

9. Counterparts. This Amendment may be executed by all parties hereto in any number of separate counterparts each of which may be delivered in original, facsimile or other electronic (e.g., “.pdf”) form and all of such counterparts taken together constitute one instrument.

10. References. The words “hereby,” “herein,” “hereinabove,” “hereinafter,” “hereinbelow,” “hereof,” “hereunder” and words of similar import when used in this Amendment refer to this Amendment as a whole and not to any particular article, section or provision of this Amendment. References in this Amendment to a section number are to such sections of the Credit Agreement unless otherwise specified.

11. Headings Descriptive. The headings of the several sections of this Amendment are inserted for convenience only and do not in any way affect the meaning or construction of any provision of this Amendment.

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12. Governing Law. This Amendment is governed by and will be construed in accordance with the law of the State of New York.

13. Payment of Expenses. The Borrower shall pay or reimburse the Administrative Agent for all of its out-of-pocket costs and reasonable expenses incurred in connection with this Amendment, any other documents prepared in connection herewith and the transactions contemplated hereby, including, without limitation, the reasonable fees and disbursements of counsel to the Administrative Agent.

14. Final Agreement of the Parties. THIS AMENDMENT, THE CREDIT AGREEMENT AND THE OTHER LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT AMONG THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.

[Signature Pages Follow]

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IN WITNESS WHEREOF, the parties are signing this Amendment as of the date first above written.

Signature Page to Amendment No. 2

Each of the undersigned Guarantors (i) acknowledges, consents and agrees to this Amendment and each of the terms and provisions contained herein, and (ii) agrees that the Loan Documents to which it is a party remain in full force and effect and continue to be the legal, valid and binding obligation of such Person.

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