This FIRST SUPPLEMENTAL INDENTURE, dated as of July 31, 2009 (this “First SupplementalIndenture”), between QUICKSILVER RESOURCES INC., a Delaware corporation (the “Company”) and THEBANK OF NEW YORK MELLON TRUST COMPANY, N.A., a national banking association duly organized andexisting under the laws of the United States of America (as successor in interest to JPMorgan ChaseBank, National Association (the “Initial Trustee”)), as trustee (the “Trustee”).W I T N E S S E T H     WHEREAS, the Company and the Initial Trustee executed and delivered an Indenture, dated as ofNovember 1, 2004 (the “Original Indenture”), pursuant to which the Company has issued $150,000,000of aggregate principal amount of 1.875% Convertible Subordinated Debentures Due 2024 (the“Notes”);     WHEREAS, the Original Indenture is incorporated herein by this reference and the OriginalIndenture, as supplemented by this First Supplemental Indenture, is herein called the “Indenture”;     WHEREAS, in the fourth quarter of 2006, the Trustee assumed and succeeded to all of the rightsand obligations of the Initial Trustee under the Original Indenture, as supplemented on or beforesuch date;     WHEREAS, Section 10.02 of the Original Indenture provides that, subject to certain conditions,the Company and the Trustee may amend or supplement the Indenture with the consent of the holdersof at least a majority in aggregate principal amount of the Notes at the time outstanding;     WHEREAS, pursuant to the Company’s Consent Solicitation Statement dated July 22, 2009, theconsent of the holders of not less than a majority in aggregate principal amount of the Notesoutstanding has been obtained to amend the definition of “Designated Subsidiary” contained inSection 1.01 of the Indenture as set forth below;     WHEREAS, the Board has approved the amendment to the Indenture to be effected pursuant to thisFirst Supplemental Indenture; and     WHEREAS, all conditions necessary to authorize the execution and delivery of this FirstSupplemental Indenture and make it a valid and binding obligation of the Company, in accordancewith its terms, have been done or performed.     NOW THEREFORE, in consideration of the foregoing, the Company and the Trustee mutuallycovenant and agree for the equal and ratable benefit of the holders of the Notes as follows:ARTICLE 1     Section 1.01. Effect. This Supplemental Indenture is supplemental to the Indenture anddoes and shall be deemed to form a part of, and shall be construed in connection with and as partof, the Indenture for any and all purposes.     Section 1.02. Effective Time. This Supplemental Indenture shall become effectiveimmediately upon its execution and delivery by the Company and the Trustee.ARTICLE 2     Section 2.01. Amendment. The definition of “Designated Subsidiary” contained inSection 1.01 of the Indenture is hereby amended to read in its entirety as follows:     “**Designated Subsidiary**” of the Company means any existing or future, direct orindirect, Subsidiary of the Company whose assets constitute 15% or more of the Company’stotal assets on a consolidated basis, *provided*that any entity designated as an“Unrestricted Subsidiary” under the Company’s outstanding Senior Notes due August 1, 2015,Senior Notes due January 1, 2016 or Senior Subordinated Notes due April 1, 2016 or anyrefinancings or replacements thereof shall be excluded from
 

 
the definition of “**Designated Subsidiary**” for purposes of Section 6.01(h). For purposesof Section 6.01(i) and (j) hereof, “**Designated Subsidiary**” shall also mean any group of twoor more Subsidiaries that, taken as a whole, would constitute a “**Designated Subsidiary**.”ARTICLE 3     Section 3.01. Ratification of Indenture. Except as specifically modified herein, theIndenture and the Notes are in all respects ratified and confirmed (mutatis mutandis) and shallremain in full force and effect in accordance with their terms.     Section 3.02. Defined Terms. All capitalized terms used but not defined herein shallhave the same respective meanings ascribed to them in the Indenture.     Section 3.03. Trustee. Except as otherwise expressly provided herein, no duties,responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee byreason of this First Supplemental Indenture. This First Supplemental Indenture is executed andaccepted by the Trustee subject to all of the terms and conditions set forth in the Indenture withthe same force and effect as if those terms and conditions were repeated at length herein and madeapplicable to the Trustee with respect hereto.     Section 3.04. Governing Law. THIS FIRST SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY,AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.     Section 3.05. Counterparts. The parties may sign any number of copies of this FirstSupplemental Indenture. Each signed copy shall be an original, but all of them together representthe same agreement.     Section 3.06. Headings. The headings herein are inserted for convenience of referenceonly and are not intended to be part of, or to affect the meaning or interpretation of, this FirstSupplemental Indenture.     Section 3.07. Recitals by the Company. The recitals hereto are statements only of theCompany and shall not be considered statements of or attributable to the Trustee.
 

 
     IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental Indenture to beduly executed as of the date first above written.         QUICKSILVER RESOURCES INC.           By: /s/ Phililp Cook             Name: Philip Cook      Title: Senior Vice President — Chief Financial Officer           THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.,as Trustee           By: /s/ Julie Hoffman-Ramos             Name: Julie Hoffman-Ramos      Title: Assistant Treasurer