Exhibit 10.12**SUBORDINATED PROMISSORY NOTE**THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANYAPPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE OFFERED OR SOLD UNLESS IT HAS BEEN REGISTEREDUNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS OR UNLESS AN EXEMPTION FROM REGISTRATION ISAVAILABLE AND THEN ONLY IN COMPLIANCE WITH THE RESTRICTIONS ON TRANSFER SET FORTH HEREIN.THIS INSTRUMENT AND THE RIGHTS AND OBLIGATIONS EVIDENCED HEREBY ARE SUBORDINATE IN THE MANNER ANDTO THE EXTENT SET FORTH HEREIN TO THE SENIOR DEBT (AS HEREINAFTER DEFINED); AND EACH HOLDER OF THISINSTRUMENT, BY ITS ACCEPTANCE HEREOF, IRREVOCABLY AGREES TO BE BOUND BY THE SUBORDINATIONPROVISIONS HEREIN. $**50,000,000** July ___, 2007     FOR VALUE RECEIVED, **QUICKSILVER GAS SERVICES LP**, a Delaware limited partnership(“**Payor**”), HEREBY AGREES TO PAY to the order of **QUICKSILVER RESOURCES INC.**, a Delawarecorporation, or its successors and assigns (together with its successors and assigns, the“**Subordinated Creditor**”), in lawful currency of the United States of America, inimmediately available funds, at such location or bank account as the Subordinated Creditor shallfrom time to time designate, the principal amount of ***Fifty Million and 00/100 Dollars($50,000,000)***, together with interest, compounded quarterly, on the unpaid principal balanceoutstanding from time to time from the date hereof until the Maturity Date (as hereinafter defined)at a rate of interest per annum equal to the lesser of (a) the Note Rate (as hereinafter defined)or (b) the Highest Lawful Rate (as hereinafter defined); provided, however, that,notwithstanding the foregoing, in the event the Payor fails to make any payment of any portion ofthe principal of this Note when due and payable (including, without limitation, due to a BlockageEvent), at the request of the Subordinated Creditor, interest on such overdue amount (including,without limitation, interest with respect to such overdue amount to the extent permitted byapplicable law) shall accrue at a rate of interest per annum equal to the lesser of (a) the NoteRate plus two percent (2.00%) and (b) the Highest Lawful Rate. Capitalized terms used in thisSubordinated Promissory Note (this “**Note**”), but not defined herein shall have the meaningsspecified therefor in the Credit Agreement, dated as of July ___, 2007 (as amended, restated,supplemented or otherwise modified from time to time, the “**Credit Agreement**”), among Payor,as the borrower, the Lenders party thereto, Bank of America, N.A., as L/C Issuer thereunder, Bankof America, N.A., as Administrative Agent (or any successor administrative agent appointed pursuantto Article IX of the Credit Agreement, the “**Administrative Agent**”) for the Lendersthereunder, and the other Agents party thereto.     1. Principal. Subject to the subordination provisions contained in Section 7hereof, Payor promises to pay the principal on this Note in equal consecutive quarterlyinstallments of ***$275,000.00***on the last Business Day of each calendar quarter, beginning onMarch 31, 2008, and to pay the entire remaining outstanding principal balance on this Note onJanuary
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*___, 2013*(the “**Maturity Date**”); provided, that, if the final maturitydate of the Senior Debt (as hereinafter defined) is extended to any date later than July___, 2012(such later date being referred to herein as the “**Extended Senior Maturity Date**”), theMaturity Date shall be automatically extended without further action by Payor or the SubordinatedCreditor to the date that is six months after such Extended Senior Maturity Date, and the amount ofthe quarterly installments of principal will be reamortized to create equal quarterly installmentsof the remaining outstanding principal balance on this Note over the remaining term of this Note asextended. Notwithstanding anything to the contrary herein, any amounts paid or prepaid hereundermay not be reborrowed thereafter. Furthermore, notwithstanding anything to the contrary herein,all amounts payable pursuant to this Note (including, without limitation, all principal andinterest payments, and prepayments thereof) may, at the request of the Subordinated Creditor, bepaid, in whole or in part, using Equity Interests of Payor.     2. Interest. Subject to the subordination provisions contained in Section 7hereof, Payor also promises to pay interest on the unpaid principal amount from time to timeoutstanding hereunder from the date hereof until such principal amount is paid in full at theapplicable rate per annum set forth above, which interest shall be payable quarterly on the lastBusiness Day of each calendar quarter, beginning March 31, 2008, and on the Maturity Date,(a) by capitalizing the accrued and unpaid interest on this Note and adding it to the then unpaidprincipal amount hereof, or (b) at the request of the Subordinated Creditor, by wire transfer ofimmediately available funds, in lawful currency of the United States of America, to a bank accountdesignated by the Subordinated Creditor to Payor on or prior to the applicable due date therefor.Interest on this Note will be calculated based on a 360-day year and paid for the actual number ofdays elapsed.     As used herein, the term “**Note Rate**” shall mean a rate of interest per annum equal tothe Adjusted Eurodollar Rate for an Interest Period of three (3) months, plus the Applicable Ratefor Eurodollar Loans for such day as determined pursuant to the terms of the Credit Agreement,regardless of whether such interest rate is in effect for any Borrowings outstanding under theCredit Agreement, plus one percent (1.00%). The Note Rate shall change effective upon each changein the Applicable Rate under the Credit Agreement and shall remain in effect until the next changein the Applicable Rate effected pursuant to the Credit Agreement. Each determination by theSubordinated Creditor of the Note Rate shall, except in cases of manifest error, be final,conclusive and binding. If the Subordinated Creditor determines (which determination shall beconclusive absent manifest error) that adequate and reasonable means do not exist for ascertainingthe Adjusted Eurodollar Rate or the Eurodollar Rate, as applicable, pursuant to the terms of theCredit Agreement, for the Interest Period specified above, then, at the option of the SubordinatedCreditor, and in the Subordinated Creditor’s sole discretion, the Note Rate shall be determined bythe Subordinated Creditor by reference to (a) the Adjusted Eurodollar Rate for such other InterestPeriod as the Subordinated Creditor may select in its sole discretion, or (b) the interest rateapplicable to ABR Loans as provided in the Credit Agreement, in each case, plus the Applicable Ratefor such Type of Loan     3. Prepayments. Subject to the subordination provisions contained in Section7 hereof, this Note may be prepaid in full or in part at any time and from time to time withoutpremium or penalty. The prepayment of any principal amount of this Note shall be made togetherwith all accrued and unpaid interest thereon through the date of prepayment and all
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accrued and unpaid costs and expenses then payable hereunder. In the event of a partialprepayment, the Subordinated Creditor shall record the date and amount of any such prepayments onthe reverse side of this Note, and interest shall cease to accrue on such prepaid principalamounts.     4. Note Events of Default.          (a) The occurrence of any of the following events constitutes an event of default under thisNote (each, a “**Note Event of Default**”):     (i) Payor defaults in the payment of any portion of the principal of, interest on, orother amounts owing under, this Note when due and payable, except to the extent a failure topay is due to a Blockage Event; or     (ii) Payor or any other Person (other than the Subordinated Creditor) fails to performor observe any other term, covenant or agreement contained in this Note, and such defaultshall continue unremedied for a period of thirty (30) days after the earlier to occur of (A)the date upon which a Responsible Officer of the General Partner becomes aware of suchdefault and (B) the date upon which written notice thereof is given to Payor by theSubordinated Creditor; or     (iii) an Event of Default (as defined in the Credit Agreement) shall occur; or     (iv) any representation or warranty at any time made by Payor or any other Person inthis Note shall be, or shall prove to have been, false or misleading in any material respectwhen so made; or     (v) this Note shall cease, for any reason, to be in full force and effect; anyprovision of this Note shall for any reason cease to be valid and binding on or enforceableagainst Payor; the validity or enforceability of this Note is contested by Payor or anyother Person; or Payor denies it has any further liability or obligation under this Note.     (b) Subject to the subordination provisions contained in Section 7 hereof, upon theoccurrence and during the continuance of any Note Event of Default, the Subordinated Creditor shallhave the right, without notice, demand, presentment, notice of nonpayment or nonperformance,protest, notice of protest, notice of intent to accelerate, notice of acceleration or any othernotice or action of any kind, **ALL OF WHICH PAYOR HEREBY EXPRESSLY WAIVES AND RELINQUISHES**, (i) bynotice to Payor, to declare the entire principal amount then outstanding on this Note, and allaccrued and unpaid interest thereon and all other accrued and unpaid amounts hereunder, immediatelydue and payable, whereupon all such principal, interest and other amounts shall become immediatelydue and payable, and the Subordinated Creditor may proceed to enforce the payment of suchprincipal, interest and other amounts, or part thereof, in such manner as the Subordinated Creditormay elect and (ii) to exercise all rights and remedies available to it under this Note or at law orin equity;
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provided, however, subject to the terms hereof, upon the occurrence of any Event of Default definedin clause (h) or (i) of Article VIII of the Credit Agreement (in the case of clause (h) of ArticleVIII of the Credit Agreement, upon the expiration of the sixty (60) day period mentioned therein),the unpaid principal amount of this Note, and all accrued and unpaid interest thereon and all otheraccrued and unpaid amounts hereunder, shall automatically become due and payable without furtheract of the Subordinated Creditor.     5. Ranking. All obligations evidenced hereby shall (a) be subordinated pursuant tothe subordination provisions contained in Section 7 hereof to the prior payment in full ofthe Senior Debt, (b) rank pari passu with all unsubordinated indebtedness of Payor (other than theSenior Debt), and (c) rank senior to any subordinated indebtedness of Payor.     6. Amendment and Restatement. Upon the payment in full of the Senior Debt, Payorhereby agrees, if requested by the Subordinated Creditor, to execute and deliver to theSubordinated Creditor a new note that will amend and restate this Note, which amended and restatednote shall, among other things, include those provisions of the Credit Agreement (including,without limitation, the applicable provisions for determining the interest rate under the CreditAgreement, the covenants contained in Articles VI and VII of the Credit Agreement, the Events ofDefault (as defined in the Credit Agreement) contained in Article VIII of the Credit Agreement andthe applicable defined terms contained in the Credit Agreement that are used in such interest rateprovisions, covenants and Events of Default) as the Subordinated Creditor in its sole discretionshall determine appropriate to include in such amended and restated note, the provisions of theCredit Agreement so included in such amended and restated note to include (a) such modificationsthereto, in the Subordinated Creditor’s sole discretion, necessary to conform such provisions (forexample, definitions) for use in the context of such amended and restated note, and (b) any otherchanges thereto (including, but not limited to, changing the methodology for determining the NoteRate) requested by the Subordinated Creditor and consented to by Payor, such consent not to beunreasonably withheld, conditioned or delayed.     7. Subordination Provisions. (a) The aggregate principal amount owing to theSubordinated Creditor from time to time under this Note, all accrued and unpaid interest thereon(if any), and any and all other Indebtedness evidenced by or otherwise owing in respect of thisNote, whether now or hereafter existing, including, without limitation, all such Indebtednessunder, or in respect of, any and all extensions, modifications, substitutions, amendments,amendments and restatements, renewals, refinancings and refundings of any or all of the foregoingIndebtedness, and any instrument or agreement evidencing, governing or otherwise setting forth theterms of any such Indebtedness or other Indebtedness incurred in any such extension, modification,substitution, amendment, amendment and restatement, renewal, refinancing or refunding, in each casewhether direct or indirect, absolute or contingent, and whether for principal, interest (including,without limitation, interest accruing after the filing of a petition initiating any InsolvencyProceeding (as hereinafter defined), whether or not such interest accrues after the filing of suchpetition for purposes of any applicable Insolvency Laws (as hereinafter defined), or is an allowedclaim in such Insolvency Proceeding), premiums, fees, indemnification obligations, contract causesof action, costs, expenses or otherwise (all such Indebtedness being, collectively, the“**Subordinated Debt**”) is and shall be subordinate and junior in right of payment, to theextent and in the manner hereinafter set forth, to the prior payment in full of all Indebtedness,whether now or hereafter existing, including, without
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limitation, all Lender Indebtedness, under or in respect of: (i) the Credit Agreement, theNotes, the Security Instruments, the other Loan Documents and the Hedging Agreements entered intoby Payor or any of its Subsidiaries with any Lender or Secured Affiliate (the “**Secured HedgingAgreements**”) and (ii) any and all extensions, modifications, substitutions, amendments,amendments and restatements, renewals and refundings of any or all of the foregoing Indebtedness,and any instrument or agreement evidencing, governing or otherwise setting forth the terms of anysuch Indebtedness or other Indebtedness incurred in any such extension, modification, substitution,amendment, amendment and restatement, renewal or refunding, in each case whether direct orindirect, absolute or contingent, and whether for principal, interest (including, withoutlimitation, interest accruing after the filing of a petition initiating any Insolvency Proceeding,whether or not such interest accrues after the filing of such petition for purposes of anyapplicable Insolvency Laws, or is an allowed claim in such Insolvency Proceeding), premiums, fees,indemnification obligations (exclusive of indemnification obligations not then owing which survivethe termination or expiration of the Credit Agreement or the other Loan Documents, to the extentdemand therefor has not been made or threatened as of the date of such termination or expiration),contract causes of action, costs and expenses pursuant to the Loan Documents (all such Indebtednessbeing, collectively, the “**Senior Debt**”). For all purposes of this Note, the Senior Debtshall not be deemed to have been paid in full (“**paid in full**” or “**payment in full**”)until (A) such Senior Debt (exclusive of indemnification obligations not then owing which survivethe termination or expiration of the Credit Agreement or the other Loan Documents, to the extentdemand therefor has not been made or threatened as of the date of such termination or expiration,and Cash Collateralized L/C Obligations) has been indefeasibly paid in full in cash, (B) thetermination of all of the Commitments, and (C) there are no Letters of Credit (exclusive of Lettersof Credit which have been Cash Collateralized) issued under the Loan Documents.          (b) Until all of the Senior Debt shall have been paid in full, subject to the proviso to thissentence and the last sentence of this Section 7(b), no payment or distribution of anyproperty or assets of Payor of any kind or character (including, without limitation, any paymentthat may be payable in respect of, or turnover of funds to be applied to, the Subordinated Debt byreason of any other Indebtedness or obligations of Payor being subordinated to payment of theSubordinated Debt) shall be made by or on behalf of Payor for or on account of any SubordinatedDebt or any purchase, redemption or other acquisition thereof (including, without limitation, byway of set-off, counterclaim or otherwise), and the Subordinated Creditor shall not ask, demand,sue for, take or receive from Payor, directly or indirectly, in cash or other property or byset-off or in any other manner (including, without limitation, from or by way of collateral),payment of all or any of the Subordinated Debt; provided, however, thatnotwithstanding the foregoing or anything to the contrary contained herein or in the LoanDocuments, if no Blockage Event then exists or would result therefrom, Payor (i) may and shall makeany and all regularly scheduled payments in respect of the Subordinated Debt, including any missedpayments (and default interest thereon at the then applicable rate provided herein) that it wasprohibited from making to the Subordinated Creditor during the existence of any Blockage Event, tothe Subordinated Creditor with no further notice, consent or action by the Administrative Agent,the Lenders or the Secured Affiliates, and (ii) may make, at any time and from time to time inwhole or in part, any prepayments of this Note to the Subordinated Creditor with no further notice,consent or action by the Administrative Agent, the Lenders or the Secured Affiliates. Payor andthe Subordinated Creditor (by its acceptance
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hereof) acknowledge and agree that, as of the date of this Note, a Blockage Event of the typedescribed in clause (C) of the definition thereof exists. As used herein, the term “**BlockageEvent**” shall mean (A) an Event of Default exists on the date of any payment on this Note, (B) ajudicial proceeding is pending with respect to any Event of Default on the date of any payment onthis Note, or (C) the Consolidated Leverage Ratio as of the end of the Fiscal Quarter immediatelypreceding the date of any principal payment on this Note is equal to or greater than 3.5 to 1.0 andwould be equal to or greater than 3.5 to 1.0 after giving pro forma effect to any such principalpayment (in each case as calculated pursuant to the following sentence). Notwithstanding anythingto the contrary contained in the Credit Agreement, including in the definitions of ConsolidatedLeverage Ratio, Consolidated Funded Debt or Funded Indebtedness, the Consolidated Leverage Ratiofor purposes of this Section 7(b) only shall be calculated to include any Indebtednessremaining on this Note after giving pro forma effect to any such permitted payment hereunder.Notwithstanding the foregoing or anything to the contrary contained herein, (1) nothing in thisNote shall prevent the occurrence of any Note Event of Default, the acceleration by theSubordinated Creditor of any of the indebtedness hereunder after the acceleration of the SeniorDebt or the giving of any notice by the Subordinated Creditor to Payor with respect thereto, (2)Payor may at all times pay interest hereunder by capitalization of the accrued and unpaid interestas described in Section 2 of this Note, and (3) at the request of the SubordinatedCreditor, Payor may at all times make payments or prepayments, in whole or in part, with respect tothis Note using Equity Interests of Payor and/or using the proceeds from the contemporaneous saleor issuance of Equity Interests of Payor.          (c) In the event of any dissolution, winding up, liquidation, arrangement, reorganization,adjustment, protection, relief or composition of Payor or its debts, whether voluntary orinvoluntary, in any bankruptcy, insolvency, arrangement, reorganization, receivership, relief orother similar action or proceeding under the United States Federal Bankruptcy Code or any otherfederal or state bankruptcy or insolvency laws or any similar Governmental Rule of any otherjurisdiction covering the protection of creditors’ rights or the relief of debtors (collectively,the “**Insolvency Laws**”) or upon an assignment for the benefit of creditors or any othermarshalling of the property, assets and liabilities of Payor or otherwise (each, an “**InsolvencyProceeding**”), the Administrative Agent, for the ratable benefit of the L/C Issuer, Lenders andSecured Affiliates (collectively, the “**Secured Parties**”), shall be entitled to receivepayment in full of all of the Senior Debt (whether or not any or all of the Senior Debt has beendeclared due and payable prior to the date on which such Senior Debt otherwise would have becomedue and payable) before the Subordinated Creditor (or anyone claiming through or on its behalf(including, without limitation, any receiver, trustee or other similar Person) is entitled toreceive or retain any payment or distribution of any kind or character on account of all or any ofthe Subordinated Debt, and, to that end, any payment or distribution of any kind or character(whether in cash, property or securities) that otherwise would be payable or deliverable upon orwith respect to the Subordinated Debt in any such Insolvency Proceeding (including, withoutlimitation, any payment that may be payable in respect of, or turnover of funds to be applied to,the Subordinated Debt by reason of any other Indebtedness or obligations of Payor beingsubordinated to payment of the Subordinated Debt) shall be paid or delivered forthwith directly tothe Administrative Agent, for the account of the Secured Parties, in the same form as so received(with any necessary endorsement or assignment) for application (in the case of cash) to, or to beheld as collateral (in the case of noncash property or securities) for, the payment,
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prepayment and/or cash collateralization of the Senior Debt until all of the Senior Debt shallhave been paid in full.          (d) So long as the Senior Debt shall not have been paid in full, the Subordinated Creditorshall not (i) ask, demand, sue for, take or receive from Payor, directly or indirectly, in cash orother property or by set-off or in any manner (including, without limitation, from or by way ofcollateral), payment of all or any of the Subordinated Debt, except such payments as otherwiseexpressly permitted herein when no Blockage Event has occurred and is continuing, (ii) commence, orjoin with any creditor other than the Administrative Agent in commencing, or directly or indirectlycause Payor to commence, or assist Payor in commencing, any Insolvency Proceeding, or (iii) requestor accept any collateral or other security for all or any portion of the Subordinated Debt. If theSubordinated Creditor, in contravention hereof, shall commence, prosecute or participate in any ofthe actions, suits or proceedings referred to above in this paragraph, then the AdministrativeAgent may intervene and interpose as a defense or plea the terms of this Note in its own name or inthe name of the Subordinated Creditor.          (e) Until such time as all of the Senior Debt has been paid in full, if any InsolvencyProceeding is commenced by or against Payor, the Subordinated Creditor authorizes and empowers theAdministrative Agent to file proofs of claim of the Subordinated Debt on behalf of the SubordinatedCreditor in any statutory or non-statutory proceeding as the agent and attorney-in-fact for theSubordinated Creditor if the Subordinated Creditor fails to file such proofs of claim on or beforethe date that is ten (10) days prior to the date such proofs of claim must be filed by theSubordinated Creditor in accordance with applicable law; provided, however, that(i) the foregoing authorization and empowerment (A) imposes no obligation on the AdministrativeAgent to take any such action, and (B) is granted only for the specific and limited purpose forwhich it is given, and (ii) the Administrative Agent shall have, prior to taking any such action,given 15 days prior written notice (which notice may be given up to 60 days prior to the expirationof the time to file such claim) to the Subordinated Creditor that it intends to file such claim orproof of debt. Notwithstanding anything to the contrary herein, in no event may the AdministrativeAgent, any Lender or any Secured Affiliate vote or take any other action related to any claim withrespect to the Subordinated Debt on behalf of the Subordinated Creditor, and such agency andappointment of attorney-in-fact shall not extend to any such right to vote or take any other actionrelated to any such claim of the Subordinated Creditor, which rights to vote and take action theSubordinated Creditor is hereby authorized to exercise and take.          (f) All payments or distributions upon or with respect to the Subordinated Debt that arereceived by the Subordinated Creditor contrary to the provisions of this Note shall be received intrust for the benefit of the Administrative Agent, shall be segregated from other property or fundsof the Subordinated Creditor and shall be paid or delivered forthwith directly to theAdministrative Agent, for the account of the Secured Parties, in the same form as so received (withany necessary endorsement or assignment), to be applied (in the case of cash) to, or held ascollateral (in the case of noncash property or securities) for, the payment, prepayment and/or cashcollateralization of the Senior Debt until all of the Senior Debt shall have been paid in full.          (g) To the extent that Payor, the Subordinated Creditor or any of their respectivesubsidiaries or any other Credit Party or guarantor of or provider of collateral for the
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Senior Debt shall make any payment on the Senior Debt that is subsequently invalidated,declared to be fraudulent or preferential or set aside or is required to be repaid to a trustee,receiver or any other party under any applicable Insolvency Law or equitable cause (any suchpayment being a “**Voided Payment**”), then to the extent of such Voided Payment, that portionof the Senior Debt that had been previously satisfied by such Voided Payment shall be reinstatedand continue in full force and effect as if such Voided Payment had never been made. To the extentthat the Subordinated Creditor shall have received any payments subsequent to the date of theinitial receipt of such Voided Payment by the Administrative Agent or any of the Secured Partiesand such payments have not been invalidated, declared to be fraudulent or preferential or set asideor required to be repaid to a trustee, receiver or any other party under any applicable InsolvencyLaw or equitable cause, the Subordinated Creditor shall be obligated and hereby agrees that anysuch payment so made or received shall be deemed to have been received in trust for the benefit ofthe Administrative Agent, and the Subordinated Creditor (by its acceptance hereof) hereby agrees topay to the Administrative Agent, upon demand, the full amount so received by the SubordinatedCreditor during such period of time to the extent necessary to fully restore to the Secured Partiesthe amount of such Voided Payment, which amount shall be applied as set forth in the immediatelypreceding paragraph.          (h) The Subordinated Creditor will not:          (i) (A) cancel or otherwise discharge any of the Subordinated Debt (except (1) uponpayment in full of the Senior Debt, (2) by a conversion of all or any part of theSubordinated Debt to a capital contribution to Payor in return for Equity Interests of Payoror (3) as otherwise permitted by the Credit Agreement), or (B) convert or exchange any ofthe Subordinated Debt into or for any other Indebtedness (other than any other SubordinatedDebt);          (ii) sell, assign, pledge, encumber or otherwise dispose of any of the SubordinatedDebt other than the pledge of the instruments and agreements evidencing the SubordinatedDebt to the Global Administrative Agent (as defined in the Parent Credit Agreement) pursuantto the Parent Credit Agreement or any of the other Combined Loan Documents (as defined inthe Parent Credit Agreement) or a transfer or other disposition of such instruments andagreements in connection with a foreclosure under the Parent Credit Agreement or any of theother Combined Loan Documents (as defined in the Parent Credit Agreement); or          (iii) contest, or cause or encourage any other Person to contest, at any time, thevalidity, perfection, priority or enforceability of the subordination provisions of thisNote, the Senior Debt, the agreements evidencing the Senior Debt or the security interestsor the Liens granted to the Administrative Agent or any of the other Secured Partiespursuant thereto.          (i) Subject to the payment in full of the Senior Debt, the Subordinated Creditor shall besubrogated to the rights of the Lenders and the Secured Affiliates to receive payments ordistributions of assets of Payor in respect of the Senior Debt until the Subordinated Debt shall bepaid in full. For the purposes of such subrogation, payments or distributions to theAdministrative Agent, for the account of the Lenders and the Secured Affiliates, of any cash,
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property or securities to which the Subordinated Creditor would be entitled except for theprovisions of this Note shall be deemed, as between Payor and its creditors (other than theLenders, the Secured Affiliates and the Subordinated Creditor), to be a payment by Payor to or onaccount of the Subordinated Debt, it being understood that the provisions of this Section7(i) are, and are intended solely, for the purpose of defining the relative rights of theSubordinated Creditor, on the one hand, and the Administrative Agent, the Lenders and the SecuredAffiliates, on the other hand.          (j) The Lenders or other holders of the Senior Debt may, at any time and from time to time,without any consent of or notice to the Subordinated Creditor or any other holder of theSubordinated Debt and without impairing or releasing the obligations of the Subordinated Creditorhereunder:          (i) change the manner, place or terms of payment of, or change or extend the time ofpayment of, or renew payment or change or extend the time or payment of, or renew or alter,the Senior Debt (including any change in the rate of interest thereon), or amend, supplementor otherwise modify in any manner any Loan Document or other instrument, agreement or otherdocument under which any of the Senior Debt is outstanding;          (ii) sell, exchange, release, not perfect and otherwise deal with any of the propertyor assets of any Person at any time pledged, assigned or mortgaged to secure the SeniorDebt;          (iii) release any Person liable in any manner under or in respect of the Senior Debt;          (iv) exercise or refrain from exercising any rights against Payor, any of the otherCredit Parties or any of their respective Subsidiaries or any other Person;          (v) apply to the Senior Debt any sums from time to time received by or on behalf of theAdministrative Agent or any of the Secured Parties; or          (vi) sell, assign, transfer or exchange any of the Senior Debt.          (k) Each of Payor and the Subordinated Creditor will, if reasonably requested by theAdministrative Agent, further mark their respective books of account in such a manner as shall beeffective to give proper notice of the effect of the subordination provisions of this Note. Each ofPayor and the Subordinated Creditor will, at Payor’s sole expense and at any time and from time totime, promptly execute and deliver all further instruments and documents, and take all furtheractions, that may be necessary or that the Administrative Agent may reasonably deem advisable andmay request in order to protect any right or interest granted or intended to be granted under thesubordination provisions of this Note or to enable the Administrative Agent or any of the otherSecured Parties to exercise and enforce its rights and remedies hereunder.          (l) The Subordinated Creditor shall, upon reasonable request from time to time, from Payor,any Secured Party or any other holder of Senior Debt or any party who intends to extend Senior Debtto Payor, provide to the holder(s) of Senior Debt or any such prospective
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holder(s) of Senior Debt a written acknowledgment by the Subordinated Creditor addressed tosuch holder(s) of Senior Debt to the effect that such holder of Senior Debt is a holder of theSenior Debt entitled to the benefits of this Note, or, in the case of a prospective holder ofSenior Debt, to the effect that the credit to be extended by such prospective holder will be SeniorDebt and that such prospective holder will be entitled to the benefits of this Note.          (m) Payor acknowledges and agrees that the provisions of this Note, including, withoutlimitation, the foregoing subordination provisions are, and are intended to be, an inducement and aconsideration to each Secured Party, whether the Senior Debt held by such Secured Party was createdor acquired before or after the issuance of this Note, to acquire and continue to hold, or tocontinue to hold, such Senior Debt and such Secured Party shall be deemed conclusively to haverelied on the provisions of this Note, including, without limitation, such subordinationprovisions, in acquiring and continuing to hold, or in continuing to hold, such Senior Debt.          (n) The foregoing provisions regarding subordination are and are intended solely for thepurpose of defining the relative rights of the holders of the Senior Debt, on the one hand, and theholders of the Subordinated Debt, on the other hand. Such provisions are for the benefit of theholders of the Senior Debt and shall inure to the benefit of, and shall be enforceable by, theAdministrative Agent, on behalf of itself and the other Secured Parties, directly against theholders of the Subordinated Debt, and no holder of the Senior Debt shall be prejudiced in its rightto enforce the subordination of any of the Subordinated Debt by any act or failure to act by Payoror any Person in custody of its property or assets. The subordination provisions herein shallconstitute a continuing offer to each and every holder of Senior Debt from time to time and suchholders are intended third party beneficiaries hereof. Nothing contained in the foregoingprovisions is intended to or shall impair, as between Payor and the holders of the SubordinatedDebt, the obligations of Payor to such holders.     8. WAIVER. PAYOR HEREBY WAIVES PROMPTNESS, DILIGENCE, PRESENTMENT FOR PAYMENT,DEMAND, NOTICE OF DISHONOR AND PROTEST AND ANY OTHER NOTICE WITH RESPECT TO THIS NOTE.     9. Amendments, Etc. None of the provisions of this Note may be waived, amended,supplemented or otherwise modified except in a writing signed by Payor and the SubordinatedCreditor; provided, however, that, until the Senior Debt has been paid in full, noamendment, waiver or modification of this Note (including, without limitation, the subordinationprovisions hereof), and no consent to any departure herefrom, that would violate Section 7.17 ofthe Credit Agreement shall be effective unless the same shall be in writing and also signed by theAdministrative Agent, and then, in each case, such waiver, modification or consent shall beeffective only in the specific instance and for the specific purpose for which given.     10. No Waiver; Cumulative Remedies. No failure on the part of the SubordinatedCreditor or the Administrative Agent to exercise, and no delay in exercising, any right, power orprivilege hereunder shall operate as a waiver thereof or a consent thereto; nor shall a single orpartial exercise of any such right, power or privilege preclude any other or further exercisethereof or the exercise of any other right, power or privilege. The remedies provided herein arecumulative and are not exclusive of any remedies provided by applicable law or in equity.
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     11. Notices. All notices and other communications provided for herein shall be inwriting and shall be delivered by hand or overnight courier service, mailed by certified orregistered mail or sent by facsimile or electronic mail (e-mail), as follows:       If to Payor: Quicksilver Gas Services LP    c/o Quicksilver Gas Services GP LLC    777 West Rosedale Street, Suite 300    Fort Worth, Texas 76104    Attention: MarLu Hiller    FAX: 817-665-5016    Electronic Mail (E-mail): mhiller@qrinc.com       If to the Subordinated    Creditor: Quicksilver Resources Inc.    777 West Rosedale Street, Suite 300    Fort Worth, Texas 76104    Attention: MarLu Hiller    FAX: 817-665-5016    Electronic Mail (E-mail): mhiller@qrinc.com       If to the Administrative    Agent: Bank of America, N.A.    700 Louisiana Street, 8th Floor    TX4-213-08-14    Houston, Texas 77002    Attention: Ronald E. McKaig    FAX: 713-247-7286    Electronic Mail (E-mail):    ronald.e.mckaig@bankofamerica.com     12. Assignment. This Note shall be binding upon the successors and assigns of Payorand shall inure to the benefit of the Subordinated Creditor and its successors and assigns;provided, however, that Payor shall not assign, delegate or otherwise transfer any of its rights orobligations under this Note without the prior written consent of the Subordinated Creditor.     13. No Credit Support. Payor and the Subordinated Creditor (by its acceptance hereof)acknowledge and agree that this Note is not secured by any mortgage, Lien, pledge, charge,financing statement, security interest, hypothecation, or other security instrument of any type.Payor and the Subordinated Creditor (by its acceptance hereof) further acknowledge and agree thatthis Note is not supported directly or indirectly by any Guarantee of any person or entity. Payorand the Subordinated Creditor (by its acceptance hereof) further agree that Payor will not grant,or cause any other Credit Party to grant any Lien securing this Note or provide any Guarantee forthe payment of this Note until the Senior Debt has been paid in full.     14. Severability. Any provision of this Note which is prohibited or unenforceable inany jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibitionor unenforceability without invalidating the remaining provisions hereof; and any such prohibition
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or unenforceability in any jurisdiction shall not invalidate or render unenforceable suchprovision in any other jurisdiction.     15. Usury Savings Clause. (a) It is the intention of the parties hereto to complywith applicable state and federal usury laws (now or hereafter enacted). Accordingly,notwithstanding any provision to the contrary in this Note, in no event (including, but not limitedto, prepayment or acceleration of the maturity of any obligation) shall this Note require thepayment or permit the collection of interest in excess of the Highest Lawful Rate. If, under anycircumstance whatsoever, any provision of this Note shall provide for the payment or collection ofinterest in excess of the Highest Lawful Rate, then, ipsofacto, the obligation tobe fulfilled shall be reduced to the limit of such validity, and if from any such circumstances theSubordinated Creditor shall ever receive anything of value as interest or deemed interest byapplicable law under this Note or otherwise an amount that would exceed the Highest Lawful Rate,such amount that would be excessive interest shall be applied to the reduction of the principalamount owing under this Note or on account of any other indebtedness of Payor to the SubordinatedCreditor, and not to the payment of interest, or if such excessive interest exceeds the unpaidbalance of principal of this Note and such other indebtedness, such excess shall be refunded toPayor. In determining whether or not the interest paid or payable with respect to any indebtednessof Payor to the Subordinated Creditor, under any specified contingency, exceeds the Highest LawfulRate, Payor and the Subordinated Creditor shall, to the maximum extent permitted by applicable law,(i) characterize any non-principal payment as an expense, fee or premium rather than as interest,(ii) exclude voluntary prepayments and the effects thereof, (iii) amortize, prorate, allocate andspread the total amount of interest throughout the full term of such indebtedness so that interestthereon does not exceed the maximum amount permitted by applicable law, and/or (iv) allocateinterest between portions of such indebtedness, to the end that no such portion shall bear interestat a rate greater than that permitted by applicable law.          (b) If at any time the interest rate hereunder (the “**Stated Rate**”) exceeds the HighestLawful Rate, then the rate at which interest shall accrue hereunder shall automatically be limitedto the Highest Lawful Rate, and shall remain at the Highest Lawful Rate until the total amount ofinterest accrued hereunder equals the total amount of interest that would have accrued but for theoperation of this sentence. Thereafter, interest shall accrue at the Stated Rate unless and untilthe Stated Rate again exceeds the Highest Lawful Rate, in which case the immediately precedingsentence shall apply.     16. Jurisdiction, Etc. (a) THIS NOTE SHALL BE DEEMED TO BE A CONTRACT UNDER THE LAWSOF THE STATE OF TEXAS. Payor hereby irrevocably and unconditionally submits, for itself and itsproperty, to the nonexclusive jurisdiction of the United States District Court for the NorthernDistrict of Texas and of any Texas State court sitting in Tarrant or Dallas County, Texas, and anyappellate court from any thereof, for purposes of any action or proceeding arising out of orrelating to this Note, or for recognition or enforcement of any judgment, and Payor herebyirrevocably and unconditionally agrees that all claims in respect of any such action or proceedingmay be heard and determined in any such court. Payor agrees that a final judgment in any suchaction or proceeding shall be conclusive and may be enforced in other jurisdictions by suit on thejudgment or in any other manner provided by law. Nothing in this Note shall affect any right thatthe Subordinated Creditor may otherwise have to bring any action or proceeding relating to thisNote in the courts of any jurisdiction.
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          (b) Payor irrevocably and unconditionally waives, to the fullest extent it may legally andeffectively do so, any objection that it may now or hereafter have to the laying of venue of anysuit, action or proceeding arising out of or relating to this Note in any such court. Payor herebyirrevocably waives, to the fullest extent permitted by applicable law, the defense of aninconvenient forum to the maintenance of such action or proceeding in any such court.          (c) Payor agrees to not assert any claim against the Subordinated Creditor, any of itsaffiliates or any of their respective directors, officers, attorneys, agents and advisers, forspecial, indirect, consequential or punitive damages arising out of or otherwise relating to thisNote, any of the transactions contemplated herein or the actual or proposed use of the loanevidenced by this Note.     17. Relationship of the Parties. Notwithstanding any business or personalrelationship between Payor and the Subordinated Creditor, or any officer, director or employee ofthe Subordinated Creditor, that may exist or have existed, the relationship between Payor and theSubordinated Creditor under and with respect to this Note is solely that of debtor and creditor,the Subordinated Creditor has no fiduciary or other special relationship with Payor by virtue ofthis Note, Payor and the Subordinated Creditor are not partners or joint venturers, and no term orcondition of any of this Note shall be construed so as to deem the relationship between Payor andthe Subordinated Creditor to be other than that of debtor and creditor.     18. Right of Set-off. Subject to the subordination provisions contained inSection 7 hereof, the Subordinated Creditor is hereby authorized at any time and from timeto time, to the fullest extent permitted by applicable law, to set off and apply any and allindebtedness, obligations or liabilities at any time owing by the Subordinated Creditor to or forthe credit or the account of Payor against any and all of the obligations of Payor now or hereafterexisting under this Note, whether or not the Subordinated Creditor shall have made any demand underthis Note and although such obligations may be unmatured. The rights of the Subordinated Creditorunder this Section 18 are in addition to other rights and remedies (including, withoutlimitation, other rights of set off) which the Subordinated Creditor may have.     19. Costs and Expenses. Subject to the subordination provisions contained inSection 7 hereof, Payor agrees to pay on demand all costs and expenses incurred by theSubordinated Creditor in connection with the preparation, execution, delivery, administration,modification and amendment of this Note, including, without limitation, the reasonable attorneys’fees and expenses of the Subordinated Creditor with respect thereto and with respect to advisingthe Subordinated Creditor as to its rights and responsibilities under this Note. Subject to thesubordination provisions contained in Section 7 hereof, Payor further agrees to pay ondemand all losses, costs and expenses, if any (including attorneys’ fees and expenses), inconnection with the enforcement (whether through negotiations, legal proceedings or otherwise) ofthis Note, including, without limitation, attorneys’ fees and expenses in connection with theenforcement of rights under this Section 19. In addition, Payor shall pay any and allstamp and other taxes payable or determined to be payable in connection with the execution anddelivery of this Note, and agrees to save the Subordinated Creditor harmless from and against anyand all liabilities with respect to or resulting from any delay in paying or omission to pay suchtaxes.
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     20. Representations and Warranties. Payor hereby represents and warrants to theSubordinated Creditor that (a) Payor’s execution, delivery and performance of this Note have beenauthorized by all necessary action; (b) it has the requisite power and authority to execute,deliver and perform its obligations under this Note; (c) this Note has been duly executed anddelivered to the Subordinated Creditor by Payor; and (d) this Note is the legal, valid and bindingobligation of Payor, enforceable against Payor in accordance with its terms, subject to applicablebankruptcy, insolvency, reorganization, moratorium or similar laws affecting the enforceability ofcreditors’ rights generally and by general principles of equity.     21. WAIVER OF JURY TRIAL. PAYOR HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIALBY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS NOTE.     22. GOVERNING LAW. THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,THE LAWS OF THE STATE OF TEXAS, WITHOUT REGARD TO CONFLICTS OF LAW PRINCIPLES THEREOF.     23. ENTIRE AGREEMENT. THIS NOTE REPRESENTS THE FINAL, ENTIRE AGREEMENT BETWEEN THEPARTIES REGARDING THE SUBJECT MATTER HEREOF AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORALAGREEMENTS BETWEEN THE PARTIES.     24. No Recourse. Notwithstanding anything to the contrary in this Note, in no eventshall the Subordinated Creditor have any recourse against the assets of the Subordinated Creditoror any of its Restricted Subsidiaries (as such term is defined in the First Supplemental Indenture,dated as of March 16, 2006, by and among the Subordinated Creditor, the subsidiary guarantorsparties thereto and The Bank of New York, as Trustee (as successor in interest to JPMorgan ChaseBank, National Association), as such First Supplemental Indenture may be amended, modified,restated, supplemented or replaced from time to time, or any comparable term in any otherdocumentation now or hereafter evidencing any Indebtedness of the Subordinated Creditor) for any ofthe Subordinated Debt pursuant to this Note.[Signature on Following Page]
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     IN WITNESS WHEREOF, Payor has caused this instrument to be duly executed and delivered to theSubordinated Creditor by a Responsible Officer of the general partner of Payor on behalf of Payoras of July ___, 2007.           QUICKSILVER GAS SERVICES LP,    a Delaware limited partnership           By: Quicksilver Gas Services GP LLC,      a Delaware limited liability company, its      General Partner               By:                        MarLu Hiller,             Vice President — Treasurer  [Signature Page]

 
**ENDORSEMENT**PAY TO THE ORDER OF