Rimrock Energy Receives $250 Million Equity Commitment

August 15, 2007

Rimrock Energy, LLC (“Rimrock” or the “Company”), a private oil and gas company headquartered in Denver, Colorado, today announced equity commitments of $250 million from Bear Stearns Merchant Banking (“BSMB”) and Natural Gas Partners (“NGP”). Rimrock is a newly-formed natural gas exploration and production company focused on onshore unconventional resources in North America, including shale gas, tight gas and coalbed methane. Rimrock was founded in July 2007 by Terrell A. Dobkins, Sanford E. McCormick and Wallace G. Wilson, who have made equity commitments to the Company alongside the investor group.

Terrell A. Dobkins will serve as Chief Executive Officer of Rimrock. With over 30 years of experience in the oil and gas industry, Mr. Dobkins previously served as Vice President of Production at Antero Resources Corporation, where he focused on resource plays in the Barnett Shale, Arkoma Basin and Piceance Basin. Sanford E. McCormick will serve as Chairman of Rimrock. Mr. McCormick has over 40 years of experience in the oil and gas industry, including CEO positions at private and publicly-traded companies. Wallace G. Wilson will serve as Chief Financial Officer of Rimrock. Mr. Wilson has served as Chief Financial Officer of several companies in addition to his 16 years of experience in public accounting.

“We created Rimrock to capitalize on the growing opportunities in unconventional oil and gas in a well-capitalized venture with strong partners,” said Mr. Dobkins. “I feel very fortunate to have such a strong team of professionals, from top to bottom. In addition, BSMB and NGP both have established track records for working closely with management teams to help develop and grow companies, and we look forward to working with them.”