Exhibit 10.8
EXTENSION AGREEMENT
     This Extension Agreement is executed as of December 3, 2008 by and between
Quicksilver Resources Inc. (“QRI”) and Quicksilver Gas Services LP (“KGS”).
Capitalized terms not otherwise defined herein shall have the same meaning
ascribed to such term in that certain Omnibus Agreement dated August 10, 2007
executed between KGS and QRI.
     A. Pursuant to Section 2.3 of the Omnibus Agreement, QRI is required to
provide KGS a notice and offer for sale regarding its acquisition of midstream
assets in the Quicksilver Counties within 120 days of the consummation of such
acquisition (the “Offer”).
     B. Pursuant to that certain Purchase and Sale Agreement dated July 3, 2008
and closed on August 8, 2008, QRI acquired certain oil and gas assets in the
Alliance Airport area of Tarrant and Denton Counties, Texas which includes
midstream assets (the “Alliance Midstream Assets”).
     C. QRI and KGS desire to extent the time period and the date by which QRI
must provide to KGS the Offer regarding its acquisition of the Alliance
Midstream Assets.
     NOW, THEREFORE, in consideration of the mutual premises and covenants
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree to extend
the deadline by which QRI shall provide the Offer to KGS to be no later than
March 31, 2009.
     EXECUTED as of the date first written above.

            QUICKSILVER RESOURCES INC.
      By:   /s/ Philip Cook         Name:   Philip Cook        Title:   Sr. Vice
President and CFO        QUICKSILVER GAS SERVICES LP
      By:   QUICKSILVER GAS SERVICES GP LLC,
its general partner             By:   /s/ Thomas F. Darden         Name:  
Thomas F. Darden        Title:   President and CEO