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Exhibit 4.1
 AMENDMENT NO. 4
  RECITALS
    ARTICLE I.
DEFINITIONS
 Section 1.01 Terms Defined Above
 Section 1.02 Terms Defined in the Credit Agreement
 Section 1.03 Other Definitional Provisions .




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ARTICLE II.
AMENDMENT TO CREDIT AGREEMENT
 Section 2.01 Amendments to Credit Agreement.
 Section 5.06(d)
 Production Reports
 Section 6.06
  Investments
  provided




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Section 6.14
 Limitation on Speculative Hedging
 ARTICLE III.
REPRESENTATIONS AND WARRANTIES
 Section 3.01 Borrowers Representations and Warranties




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Section 3.02 Guarantors Representations and Warranties
 ARTICLE IV.
CONDITIONS
  Section 4.01 Documents; Certificates




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Section 4.02 No Default
 Section 4.03 Representations
 Section 4.04 Fees.
 ARTICLE V.
MISCELLANEOUS
 Section 5.01 Effect on Loan Documents; Acknowledgments
     
        Section 5.02 Reaffirmation of the Guaranty
 Section 5.03 Counterparts
 Section 5.04 Successors and Assigns
 Section 5.05 Invalidity
 Section 5.06 Governing Law .
 Section 5.07 Entire Agreement THIS AGREEMENT, THE CREDIT AGREEMENT AS AMENDED BY THIS
AGREEMENT, THE NOTES, AND THE OTHER LOAN DOCUMENTS CONSTITUTE THE ENTIRE UNDERSTANDING AMONG THE
PARTIES HERETO WITH RESPECT TO THE SUBJECT MATTER HEREOF AND SUPERSEDE ANY PRIOR AGREEMENTS,
WRITTEN OR ORAL, WITH RESPECT THERETO.
 THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.




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MARINER ENERGY, INC.By:
    /s/ John H. KarnesJohn H. KarnesSenior Vice President and Chief Financial OfficerMARINER ENERGY RESOURCES, INC.By:
    /s/ John H. KarnesJohn H. KarnesSenior Vice President and Chief Financial OfficerMARINER LP LLC, a Delaware
limited liability companyBy:
    Mariner Energy, Inc., its sole memberBy:
    /s/ John H. KarnesJohn H. KarnesSenior Vice President and Chief Financial OfficerUNION BANK OF CALIFORNIA, N.A.,
as Administrative Agent, as Issuing Lender, and as a
LenderBy:
    /s/ Damien MeiburgerDamien Meiburger, Senior Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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LENDERS:
BNP PARIBASBy:
    /s/ Russell OttsName:
    Russell OttsTitle:
    Vice PresidentBy:
    /s/ Betsy JocherName:
    Betsy JocherTitle:
    Director Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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JPMORGAN CHASE BANK, N.A.By:
    /s/ Jo Linda PapadakisName:
    Jo Linda PapadakisTitle:
    Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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NATIXISBy:
    /s/ Louis P. Laville, IIIName:
    Louis P. Laville, IIITitle:
    Managing DirectorBy:
    /s/ Daniel PayerName:
    Daniel PayerTitle:
    Director Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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CAYLON NEW YORK BRANCHBy:
    /s/ Michael D. WillisName:
    Michael D. WillisTitle:
    DirectorBy:
    /s/ Dennis E. PetitoName:
    Dennis E. PetitoTitle:
    Managing Director Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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GUARANTY BANKBy:
    /s/ David M. ButlerName:
    David M. ButlerTitle:
    Vice President




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AMEGY BANK NATIONAL ASSOCIATIONBy:
    /s/ Kenneth R. Batson, IIIName:
    Kenneth R. Batson, IIITitle:
    Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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DZ BANK AG DEUTSCHE ZENTRAL-
GENOSSENSCHAFTSBANK FRANKFURT AM 
MAIN, NEW YORK BRANCHBy:
    /s/ Scott B. LamoreauxName:
    Scott B. LamoreauxTitle:
    First Vice PresidentBy:
    /s/ Paul J. BowlesName:
    Paul J. BowlesTitle:
    Assistant Treasurer Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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CITICORP USA, INC.By:
    /s/ John F. MillerName:
    John F. MillerTitle:
    Vice PresidentBy:Name:Title: Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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WELLS FARGO BANK, NATIONAL ASSOCIATIONBy:
    /s/ Terence C. DSouzaName:
    Terence C. DSouzaTitle:
    Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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COMERICA BANKBy:
    /s/ John StrongName:
    John StrongTitle:
    Assistant Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)




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BMO CAPITAL MARKETS FINANCING, INC.
(f / k / a / HARRIS NESBITT FINANCING, INC.)By:

/s/
Mary Lou AllenName:
    Mary Lou AllenTitle:
    Vice President Signature Page to Amendment No. 4
(Mariner Energy, Inc. and Mariner Energy Resources, Inc.)