Exhibit D

Joint Filing Statement

     We, the undersigned, hereby express our agreement that the attached Schedule 13D is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934. This agreement may be terminated with respect to the obligations to jointly file future amendments to such statement on Schedule 13D as to any of the undersigned upon such person giving written notice thereof to each of the other persons signatory hereto, at the principal office thereof.

Dated: August 24, 2007

Quicksilver Resources Inc.
By:	/s/ Thomas F. Darden
Name:	Thomas F. Darden
Title:	Chairman of the Board
Quicksilver Gas Services Holdings LLC
By:	/s/ Thomas F. Darden
Name:	Thomas F. Darden
Title:	President and Chief Executive Officer

Cowtown Gas Processing L.P.
	By: Cowtown Pipeline Management, Inc., its general partner
	By:	/s/ Thomas F. Darden
	Name:	Thomas F. Darden
	Title:	Chairman of the Board
Cowtown Pipeline L.P.
	By: Cowtown Pipeline Management, Inc., its general partner
	By:	/s/ Thomas F. Darden
	Name:	Thomas F. Darden
	Title:	Chairman of the Board

Cowtown Pipeline Management, Inc.
By:	/s/ Thomas F. Darden
Name:	Thomas F. Darden
Title:	Chairman of the Board

Cowtown Pipeline Funding, Inc.
By:	/s/ Thomas F. Darden
Name:	Thomas F. Darden
Title:	Chairman of the Board
Quicksilver Gas Services GP LLC
By:	/s/ Thomas F. Darden
Name:	Thomas F. Darden
Title:	President and Chief Executive Officer