Exhibit 10.25  TERMINATION AND
RELEASE OF IRREVOCABLE CONTRACT GUARANTEE  THIS TERMINATION
AND RELEASE OF IRREVOCABLE CONTRACT GUARANTEE (this Release) is made
and entered into as of December 9, 2009, by and among C/R Cobalt
Investment Partnership, L.P., C/R Energy Coinvestment II, L.P., Riverstone
Energy Coinvestment III, L.P., C/R Energy III Cobalt Partnership, L.P.,
Carlyle/Riverstone Global Energy and Power Fund III, L.P., Carlyle Energy
Coinvestment III, L.P., First Reserve Fund XI, L.P., FR XI Onshore AIV, L.P.,
GS Capital Partners VI Fund, L.P., GS Capital Partners VI Offshore Fund, L.P.,
GS Capital Partners V Fund, L.P., GS Capital Partners V Offshore Fund, L.P.,KERN
Energy Partners I LP,KERN
Energy Partners I U.S., LP,KERN Energy Partners II LP, KERN Energy Partners II U.S., LP,
Caisse de Dépôt et Placement du Québec, and The Board of Trustees of the Leland
Stanford Junior University (each a Guarantor and collectively, the Guarantors)
and ENSCO Offshore Company, a Delaware corporation (the Contractor).  WI T N E S S E T H:  WHEREAS, the
Guarantors entered into that certain Irrevocable Contract Guarantee, dated as
of May 5, 2008 (the Guarantee), in favor of the Contractor,
pursuant to which, as a condition to the Contractors entry into that certain
Offshore Daywork Drilling Contract, dated as of May 5, 2008 (the Rig
Agreement),  with Cobalt
International Energy, L.P. (the Operator), the Guarantors guaranteed
certain payment obligations of the Operator to the Contractor under the Rig Agreement
(any and all obligations of each Guarantor under the Guarantee, the Obligations);  WHEREAS, the Operator
is proposing to effect the sale of shares of common stock of a newly formed
corporation, that will wholly own the Operator, to the public in an initial
public offering (the IPO);  WHEREAS, pursuant
to Section 8 of the Guarantee, each Guarantor is required to be released
from the Guarantee and its Obligations upon receipt by the Contractor of
reasonable substitute credit support reasonably acceptable to the Contractor in
the amount of the remaining Obligations of such Guarantor;  WHEREAS, the Operator,
the Contractor and JPMorgan Chase Bank, N.A., as escrow agent, have entered
into an escrow agreement (the Escrow Agreement) pursuant to which the Operator
will deposit $186,000,000 in escrow in accordance with the terms of the Escrow
Agreement (such escrow arrangement, the Substitute Credit Support);  WHEREAS, the
Contractor agrees and acknowledges that the Substitute Credit Support is a reasonable
substitute credit support for the remaining Obligations as required pursuant to
Section 8 of the Guarantee; and  WHEREAS, the
Contractor hereby agrees to release the Guarantors from their Obligations under
the Guarantee and terminate the Guarantee, effective upon the


deposit
of $186,000,000 by the Operator into an escrow account in accordance with the
terms of the Escrow Agreement, on the terms set forth in this Release.  NOW, THEREFORE,
for good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto agree as follows:  1.             Release.  In consideration of and effective upon the
deposit of $186,000,000 by the Operator into an escrow account in accordance
with the terms of the Escrow Agreement, the Contractor (on behalf of itself and
its successors and assigns) hereby fully and forever releases, discharges and
acquits each of the Guarantors (and their respective subsidiaries, affiliates,
past and present officers, directors, partners, attorneys, employees, agents,
and each of their assigns and their respective predecessors and successors in
interest) from the Guarantee and its Obligations (including any and all
obligations, liabilities, claims, demands, actions, covenants, and debts of any
kind or nature arising out of or relating to the Guarantee).  2.             Termination.  The Guarantee is hereby terminated as of the deposit
of $186,000,000 by the Operator into an escrow account in accordance with the
terms of the Escrow Agreement and, upon such termination, the Guarantors shall
have no further liabilities or obligations thereunder.  3.             Entire Agreement.  This Release contains the complete, exclusive
and final agreement between the Contractor and the Guarantors and supersedes
any and all prior agreements, arrangements or understandings between the
Contractor and the Guarantors relating to the subject matter hereof.  No oral understandings, statements, promises
or inducements contrary to the terms of this Release exist.  This Release may be modified only upon the
written agreement of the Contractor and the Guarantors.  4.             Counterparts.  This Release may be executed by facsimile or
in one or more counterparts, all of which together shall constitute one and the
same agreement.  5.             Governing Law.  This Release and the rights and obligations
of the parties hereto shall be governed by and construed and enforced in
accordance with the laws of the State of New York excluding any
conflict-of-laws rule or principle (whether of New York or any other
jurisdiction) that might refer the governance or the construction of this
Release to the law of another jurisdiction.  [REMAINDER OF PAGE INTENTIONALLY BLANK]  2


IN WITNESS
WHEREOF, the parties hereto have caused this Release to be executed as of the
date set forth above.   ENSCO Offshore CompanyBy:
  /s/
  Michael HoweName:
  Michael
  HoweTitle:
  Treasurer  [Signature
Page to Termination and Release of Irrevocable Contract Guarantee]


C/R Cobalt Investment
  Partnership, L.P.By: Carlyle/Riverstone
  Energy Partners II, L.P.,its general partnerBy: C/R Energy GP II,
  LLC, its general partnerBy:
  /s/
  Pierre LapeyreName:
  Pierre
  LapeyreTitle:
  Managing
  DirectorC/R Energy Coinvestment
  II, L.P.By: Carlyle/Riverstone Energy Partners II, L.P.By: C/R Energy GP II, LLCBy:
  /s/
  Pierre LapeyreName:
  Pierre
  LapeyreTitle:
  Managing
  DirectorRiverstone Energy
  Coinvestment III, L.P.By: Riverstone
  Coinvestment GP, LLCBy: Riverstone
  Holdings, LLCBy:
  /s/
  Pierre LapeyreName:
  Pierre
  LapeyreTitle:
  Managing
  Director  4


C/R Energy III Cobalt
  Partnership, L.P.By: Carlyle/Riverstone
  Energy Partners III, L.P.,
  its general partnerBy: C/R Energy GP III,
  LLC, its general partnerBy:
  /s/
  Pierre LapeyreName:
  Pierre
  LapeyreTitle:
  Managing
  DirectorCarlyle/Riverstone
  Global Energy and Power Fund III, L.P.By:Carlyle/Riverstone Energy Partners III, L.P.,
  its general partnerBy: C/R Energy GP III,
  LLC, its general partnerBy:
  /s/
  Pierre LapeyreName:
  Pierre
  LapeyreTitle:
  Managing
  DirectorCarlyle Energy
  Coinvestment III, L.P.By: Carlyle Energy
  Coinvestment III GP, L.L.C.By: TCG Holdings,
  L.L.C.By:
  /s/
  Daniel A. DAnielloName:
  Daniel
  A. DAnielloTitle:
  Managing
  Director  [Signature Page to Termination
and Release of Irrevocable Contract Guarantee]


GS Capital Partners VI
  Fund, L.P.By:
  GSCP VI Advisors, L.L.C.its
  general partnerBy:
  /s/
  Ken PontarelliName:
  Ken
  PontarelliTitle:
  Managing
  DirectorGS Capital Partners VI
  Offshore Fund, L.P.By:
  GSCP VI Offshore Advisors, L.L.C.its
  general partnerBy:
  /s/
  Ken PontarelliName:
  Ken
  PontarelliTitle:
  Managing
  DirectorGS Capital Partners V
  Fund, L.P.By:
  GSCP V Advisors, L.L.C.its
  general partnerBy:
  /s/
  Ken PontarelliName:
  Ken
  PontarelliTitle:
  Managing
  DirectorGS Capital Partners V
  Offshore Fund, L.P.By:
  GSCP V Offshore Advisors, L.L.C.its
  general partnerBy:
  /s/
  Ken PontarelliName:
  Ken
  PontarelliTitle:
  Managing
  Director  [Signature Page to Termination
and Release of Irrevocable Contract Guarantee]


First Reserve Fund XI,
  L.P.By:First Reserve GP XI, L.P.,its general partnerBy:First
  Reserve GP XI, Inc.,its general partnerBy:
  /s/ J. Hardy MurchisonName:
  J. Hardy MurchisonTitle:
  Managing DirectorFR XI Onshore AIV, L.P.By:First Reserve GP XI, L.P.,its general partnerBy:First
  Reserve GP XI, Inc.,its
  general partnerBy:
  /s/ J. Hardy MurchisonName:
  J. Hardy MurchisonTitle:
  Managing Director  [Signature Page to Termination
and Release of Irrevocable Contract Guarantee]


KERN Energy Partners I LPBy:KERN Energy Partners Management Ltd.,its general partnerBy:
  /s/
  Jeff van SteenbergenName:
  Jeff
  van SteenbergenTitle:
  DirectorKERN Energy Partners I U.S., LPBy:KERN Energy Partners Management Ltd.,its general partnerBy:
  /s/
  Jeff van SteenbergenName:
  Jeff
  van SteenbergenTitle:
  DirectorKERN Energy Partners II U.S., LPBy:KERN Energy Partners Management Ltd.,its general partnerBy:
  /s/
  Jeff van SteenbergenName:
  Jeff
  van SteenbergenTitle:
  DirectorKERN Energy Partners II LPBy:KERN Energy Partners Management Ltd.,its general partnerBy:
  /s/
  Jeff van SteenbergenName:
  Jeff
  van SteenbergenTitle:
  Director  [Signature Page to Termination
and Release of Irrevocable Contract Guarantee]


Caisse de Dépôt et Placement du QuébecBy:
  /s/
  Pierre LambertName:
  Pierre
  LambertTitle:
  Directeur
  InvestissementsBy:
  /s/
  Cyrille VittecoqName:
  Cyrille
  VittecoqTitle:
  Vice-President,
  InvestmentsThe Board of Trustees of
  the Leland Stanford Junior UniversityBy: Stanford Management
  Company, a divisionBy:
  /s/ Mark H.
  Heyes, PhD.Name:
  Mark H. Heyes, PhD.Title:
  Director Natural Resources Investments  [Signature Page to Termination
and Release of Irrevocable Contract Guarantee]