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          “**Guarantor**” means each Material Subsidiary listed on Exhibit L(except QR Canada and Foreign Subsidiaries) under the heading “MaterialSubsidiaries” and each Subsidiary that is required to execute a Guaranty pursuant toSection 5.15.          B.      The definition of “**Permitted Investments**” contained in Section 1.1 of theU.S. Credit Agreement is hereby amended by (i) deleting the word “and” at the end of subsection (r)thereof; (ii) replacing the period at the end of subsection (s) thereof with “;”; and(iii) inserting the following subsections (t), (u), (x) and (y) following subsection (s) thereof:          “(t)      all Investments by the Canadian Borrower in Canadian Newco, including,without limitation, any farm-out agreement or similar contract entered into betweenthe Canadian Borrower and Canadian Newco so long as (i) the Equity Interests ofCanadian Newco owned by the Borrower have been pledged to the Global AdministrativeAgent pursuant to a Pledge Agreement in accordance with, and as and to the extentrequired by (A) Sections 5.15 and 5.17, (B) Sections 5.9 and5.10 of the Canadian Credit Agreement, and (C) the other terms andconditions of the Loan Documents, and (ii) Canadian Newco has provided a Guarantyand Debenture in accordance with, and as and to the extent required by (A)Sections 5.9 and 5.10 of the Canadian Credit Agreement, and (B) theother terms and conditions of the Loan Documents;          (u)      the Investment by the Borrower in the Common Shares of Canadian Newco;          (x)      the Investment by the Canadian Borrower in the Series 1 Preferred Shares ofCanadian Newco; and          (y)      the Investment by the Borrower in common units of BreitBurn Operating,L.P., a Delaware limited partnership, approved by the Combined Lenders pursuant toan agreement dated as of October 25, 2007.”          C.      Section 1.1 of the U.S. Credit Agreement is hereby amended by inserting the followingdefinition of “**Canadian Newco**” in appropriate alphabetical order:          “**Canadian Newco**” means 1373159 Alberta Ltd., an Alberta, Canadacorporation and a Wholly-Owned Subsidiary of the Borrower.          D.      Exhibit L to the U.S. Credit Agreement is hereby amended by replacing Exhibit L to the U.S.Credit Agreement with Exhibit L to this Amendment.          **II.**      **Amendments to Canadian Credit Agreement**.          A.      The definition of “**Guarantor**” contained in Section 1.1 of the Canadian CreditAgreement is hereby amended in its entirety to read as follows:          “**Guarantor**” means collectively (i) the Parent, (ii) Canadian Newco,(iii) each Material Subsidiary, and (iv) each U.S. Material Subsidiary that now or
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hereafter executes and delivers a U.S. Material Subsidiary Guaranty, includingeach Material Subsidiary and each U.S. Material Subsidiary that is required toexecute a Guaranty pursuant to Section 5.9.          B.      The definition of “**Guaranty**” contained in Section 1.1 of the Canadian CreditAgreement is hereby amended in its entirety to read as follows          “**Guaranty**” means collectively (i) the Parent Guaranty, (ii) theCanadian Newco Guaranty, (iii) each Material Subsidiary Guaranty, and (iv) each U.S.Material Subsidiary Guaranty. The term “**Guaranties**” shall include each andevery Guaranty executed and delivered by the Parent, Canadian Newco, each MaterialSubsidiary and each U.S. Material Subsidiary.          C.      Section 1.1 of the Canadian Credit Agreement is hereby amended by inserting the followingdefinitions of “**Canadian Newco**” and “**Canadian Newco Guaranty**” in appropriatealphabetical order:          “**Canadian Newco**” means 1373159 Alberta Ltd., an Alberta, Canadacorporation and a Wholly-Owned Subsidiary of the Parent.          “**Canadian Newco Guaranty**” means a Guaranty executed and delivered byCanadian Newco in favor of the Global Administrative Agent and substantially in theform of the Parent Guaranty, as such Guaranty is amended, supplemented, restated orotherwise modified from time to time in accordance with the terms of this Agreementand the other Loan Documents.          **III.**      **Effectiveness**. This Amendment shall become effective as of the date (the“**Effective Date**”) when the Global Administrative Agent shall have received:          A.      Counterparts hereof duly executed by the U.S. Borrower, the Canadian Borrower, the GlobalAdministrative Agent, the Canadian Administrative Agent and the Majority Lenders (or, in the caseof any party as to which an executed counterpart shall not have been received, telegraphic, telex,or other written confirmation from such party of execution of a counterpart hereof by such party).          B.      The U.S. Borrower and the Canadian Borrower shall have satisfied all of the conditions setforth in the Combined Loan Documents, including, without limitation, Section 5.15 of the U.S.Credit Agreement and Section 5.9 of the Canadian Credit Agreement, with respect to the creation ofCanadian Newco and the permissibility of Investments by the Canadian Borrower in Canadian Newco,including, without limitation, the following:          (i)      the Global Administrative Agent shall have received counterparts of a PledgeAgreement, dated as of the Effective Date, duly executed and delivered by the U.S. Borrower,together with the following:               (a)      to the extent the Equity Interests are certificated, certificatesrepresenting 100% of the outstanding Equity Interests of Canadian Newco owned by theU.S. Borrower (except that, with respect to security for the
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Obligations, such certificates representing Equity Interests shall be limitedto 65% of the total combined voting power of all classes of voting Equity Interestsof Canadian Newco owned by the U.S. Borrower and 100% of all non-voting EquityInterests of Canadian Newco owned by the U.S. Borrower), and powers and instrumentsof transfer, endorsed in blank, with respect to such certificates; and               (b)      all documents and instruments, including Uniform Commercial Code FinancingStatements (Form UCC-1), required by law or reasonably requested by the GlobalAdministrative Agent to be filed, registered or recorded to create or perfect theLiens intended to be created under such Pledge Agreement;          (ii)      the Global Administrative Agent shall have received counterparts of a PledgeAgreement, dated as of the Effective Date, duly executed and delivered by the CanadianBorrower, together with the following:               (a)      to the extent the Equity Interests are certificated, certificatesrepresenting 100% of the outstanding Equity Interests of Canadian Newco owned by theCanadian Borrower, and powers and instruments of transfer, endorsed in blank, withrespect to such certificates; and               (b)      all documents and instruments, including Personal Property Security Actfilings, required by law or reasonably requested by the Global Administrative Agentto be filed, registered or recorded to create or perfect the Liens intended to becreated under such Pledge Agreement;          (iii)      the Global Administrative Agent shall have received counterparts of the CanadianNewco Guaranty (as defined in the Canadian Credit Agreement), duly executed and delivered byCanadian Newco; and          (iv)      the Global Administrative Agent shall have received counterparts of a Debentureduly executed and delivered by Canadian Newco, which Debenture shall create a floatingcharge in favor of the Global Administrative Agent for the benefit of the Canadian Lenderson substantially all of the Borrowing Base Properties (as defined in the Canadian CreditAgreement) or proposed Borrowing Base Properties owned by Canadian Newco, and a Lien in andto all of Canadian Newco’s present and after-acquired personal property, together with suchother documents or instruments as the Global Administrative Agent may reasonably request.          C.      The Global Administrative Agent shall have received UCC Searches, all dated reasonablyclose to the Effective Date, requested by the Global Administrative Agent and in form and substancereasonably satisfactory to the Global Administrative Agent.          D.      The Global Administrative Agent shall have received a certificate of an Authorized Officerof Canadian Newco dated as of the Effective Date, certifying:          (i)      that attached to such certificate is (a) a true and complete copy of the OrganicDocuments of Canadian Newco, as in effect on the date of such certificate,
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(b) a true and complete copy of a certificate from the applicable GovernmentalAuthority of the jurisdiction of Canadian Newco’s organization to the effect that suchentity is validly existing in such jurisdiction, and (c) a true and complete copy of acertificate from the appropriate Governmental Authority of each jurisdiction (withoutduplication) to the effect that Canadian Newco is duly qualified to transact business insuch jurisdiction as a foreign entity, if the failure to be so qualified would reasonably beexpected to have a Material Adverse Effect;          (ii)      that attached to such certificate is a true and complete copy of resolutions dulyadopted by the board of directors of Canadian Newco, authorizing the execution, delivery andperformance of such of the Combined Loan Documents to which Canadian Newco is or is intendedto be a party;          (iii)      that attached thereto is (a) a true and complete copy of a certificate of statusfrom the applicable Governmental Authority of the jurisdiction of Canadian Newco’sorganization as to the existence and the good standing of Canadian Newco, dated as of arecent date, and (b) a true and complete copy of a certificate from the appropriateGovernmental Authority of each jurisdiction (without duplication) to the effect thatCanadian Newco is in good standing in such jurisdiction as a foreign entity, if the failureto be so qualified would reasonably be expected to have a Material Adverse Effect; and          (iv)      as to the incumbency and specimen signature of each Authorized Officer of CanadianNewco executing such of the Combined Loan Documents to which Canadian Newco is or isintended to be a party.          E.      The Global Administrative Agent shall have received opinions, dated the Effective Date,addressed to the Global Administrative Agent, the Canadian Administrative Agent and all Lenders,from (i) McCarthy Tétrault LLP, counsel to Canadian Newco, (ii) Jones Day, U.S. counsel to the U.S.Borrower, and (iii) the General Counsel of the U.S. Borrower, in each case in form and substancereasonably satisfactory to the Global Administrative Agent, such opinions covering such mattersrelating to the U.S. Borrower, Canadian Newco and the execution and delivery of the Combined LoanDocuments to which each is or is intended to be a party pursuant to Section III.B of thisAmendment, as applicable, as the Global Administrative Agent shall reasonably request.          **IV.**      **Reaffirmation of Representations and Warranties**. To induce the Combined Lendersand the Global Administrative Agent to enter into this Amendment, the U.S. Borrower and theCanadian Borrower hereby reaffirm, as of the date hereof, the following:          (i)      The representations and warranties of each Loan Party (as such term is defined inthe U.S. Credit Agreement and the Canadian Credit Agreement, and including, withoutlimitation, Canadian Newco, collectively, the “**Combined Loan Parties**”) set forth inthe Combined Loan Documents to which it is a party are true and correct on and as of thedate hereof (or, if stated to have been made expressly as of an earlier date, were true andcorrect in all material respects as of such date and, except to
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the extent waived in writing by the Combined Lenders, the Required Lenders, theMajority Lenders, the U.S. Lenders or the U.S. Required Lenders, as applicable).          (ii)      Each of the Combined Loan Parties (a) is a corporation, partnership or limitedliability company duly incorporated or organized (as applicable), validly existing and ingood standing under the laws of its jurisdiction of incorporation or organization, (b) hasall corporate, partnership or limited liability company power (as applicable) and allmaterial governmental licenses, authorizations, consents and approvals required to carry onits businesses as now conducted and as proposed to be conducted, and (c) is duly qualifiedto transact business as a foreign corporation, partnership or limited liability company ineach jurisdiction where a failure to be so qualified would reasonably be expected to have aMaterial Adverse Effect.          (iii)      The execution, delivery and performance of this Amendment and the other CombinedLoan Documents by each Combined Loan Party (to the extent each Combined Loan Party is aparty to this Agreement and such Combined Loan Documents) (a) are within such Combined LoanParty’s corporate powers, (b) when executed will be duly authorized by all necessarycorporate action, (c) require no action by or in respect of, or filing with, anyGovernmental Authority (other than (i) actions or filings pursuant to the Exchange Act and(ii) actions or filings that have been taken or made and are in full force and effect) and(d) do not contravene, or constitute a default under, any provision of applicableGovernmental Rule (including, without limitation, Regulation U) or of the articles orcertificate of incorporation, bylaws, regulations, partnership agreement or comparablecharter documents of any Combined Loan Party or of any agreement, judgment, injunction,order, decree or other instrument binding upon any Combined Loan Party or result in thecreation or imposition of any Lien on any Borrowing Base Property or Collateral other thanthe Liens securing the Combined Obligations.          (iv)      This Amendment and each other Combined Loan Document constitutes, or when executedand delivered will constitute, valid and binding obligations of each Combined Loan Partywhich is a party thereto, enforceable against each such Combined Loan Party which executesthe same in accordance with its terms except as the enforceability thereof may be limited by(i) bankruptcy, insolvency, reorganization, moratorium, or similar Governmental Rulesaffecting creditors’ rights generally, and (ii) equitable principles of generalapplicability (whether enforcement is sought by proceedings at law or in equity).          (v)      Neither a Default nor an Event of Default has occurred and will exist under eitherCombined Credit Agreement after giving effect to the transactions contemplated by thisAmendment or the other Combined Loan Documents. Neither the U.S. Borrower or any of itsSubsidiaries nor the Canadian Borrower or any of its Subsidiaries is in default under, norhas any event or circumstance occurred which, but for the expiration of any applicable graceperiod or the giving of notice, or both, would constitute a default under, any MaterialAgreement to which the U.S. Borrower or any of its Subsidiaries or the Canadian Borrower orany of its Subsidiaries is a party or by which the U.S. Borrower or any of its Subsidiariesor the Canadian Borrower or any of its
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Subsidiaries is bound which default would reasonably be expected to have a MaterialAdverse Effect. The U.S. Borrower is in compliance with the financial covenants set forthin Article VI of the U.S. Credit Agreement.          (vi)      No event or events have occurred since December 31, 2006 which individually or inthe aggregate would reasonably be expected to have a Material Adverse Effect.          **V.**      **Defined Terms**. Terms used herein when defined in the U.S. Credit Agreement(including, to the extent applicable, after giving effect to this Amendment) shall have the samemeanings herein unless the context otherwise requires.          **VI.**      **Reaffirmation of Combined Credit Agreements**. This Amendment shall be deemed to bean amendment to the Combined Credit Agreements, and the Combined Credit Agreements, as amendedhereby, are hereby ratified, approved and confirmed in each and every respect. All references tothe Combined Credit Agreements herein and in any other document, instrument, agreement or writingshall hereafter be deemed to refer to the Combined Credit Agreements as amended hereby.          **VII.**      **Governing Law**. **THIS AMENDMENT SHALL BE CONSTRUED IN ACCORDANCE WITH THE LAWS OFTHE STATE OF TEXAS.**          **NOTWITHSTANDING THE FOREGOING SENTENCE AND AFTER GIVING EFFECT TO THE TEXTUAL AMENDMENTSCONTAINED IN****SECTIONS I****AND****II****OF THIS AMENDMENT, (i) THE U.S. CREDIT AGREEMENT (ASAMENDED HEREBY) SHALL CONTINUE TO BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWSPECIFIED IN SECTION 10.****9(a)****OF THE U.S. CREDIT AGREEMENT, AND (ii) THE CANADIAN CREDIT AGREEMENT(AS AMENDED HEREBY) SHALL CONTINUE TO BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWSPECIFIED IN SECTION 10.****9(a)****OF THE CANADIAN CREDIT AGREEMENT.**          **VIII.**      **Severability of Provisions**. Any provision of this Amendment held to be invalid,illegal or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to theextent of such invalidity, illegality or unenforceability without affecting the validity, legalityand enforceability of the remaining provisions hereof; and the invalidity of a particular provisionin a particular jurisdiction shall not invalidate such provision in any other jurisdiction.          **IX.**      **Counterparts**. This Amendment may be executed in counterparts (and by differentparties hereto on different counterparts), each of which shall constitute an original, but all ofwhich when taken together shall constitute a single contract. Delivery of an executed counterpartof a signature page of this Amendment by telecopy (or other electronic transmission acceptable tothe Global Administrative Agent) shall be effective as delivery of a manually executed counterpartof this Amendment.          **X.**      **Headings**. Article and Section headings used herein are for convenience ofreference only, are not part of this Amendment and shall not affect the construction of, or betaken into consideration in interpreting, this Amendment.
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          **XI.**      **Successors and Assigns**. This Amendment shall be binding upon and inure to thebenefit of the parties hereto and their respective successors and assigns permitted hereby(including any Affiliate of an Issuing Bank that issues any Letter of Credit), except that neitherthe U.S. Borrower nor the Canadian Borrower may assign or otherwise transfer any of its rights orobligations hereunder without the prior written consent of the Global Administrative Agent, eachIssuing Bank and each Combined Lender (and any attempted assignment or transfer by either the U.S.Borrower or the Canadian Borrower without such consent shall be null and void).          **XII.**      **No Oral Agreements**. **THIS AMENDMENT, THE COMBINED CREDIT AGREEMENTS, AS AMENDEDHEREBY, AND THE OTHER COMBINED LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN AND AMONG THEPARTIES WITH RESPECT TO THE SUBJECT MATTER HEREOF AND THEREOF AND MAY NOT BE CONTRADICTED BYEVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NOUNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.**          **XIII.**      **Loan Document****. This Amendment constitutes a “Loan Document,” a “Canadian LoanDocument” and a “Combined Loan Document” under and as defined in the U.S. Credit Agreement, and a“Loan Document,” a “U.S. Loan Document” and a “Combined Loan Document” under and as defined in theCanadian Credit Agreement.***[Signature Pages to Follow]*
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          IN WITNESS WHEREOF, the U.S. Borrower, the Canadian Borrower, the undersigned CombinedLenders, the Global Administrative Agent and the Canadian Administrative Agent have executed thisAmendment as of the date first above written.       **U.S. BORROWER**       **QUICKSILVER RESOURCES INC.,**  a Delaware corporation, as U.S. Borrower       By: /s/ MarLu Hiller         MarLu Hiller, Vice President – Treasurer       **CANADIAN BORROWER**       **QUICKSILVER RESOURCES CANADA INC.**,  an Alberta, Canada corporation, as Canadian