North Plains Energy II, LLC

Ultra Petroleum Corporation is an independent exploration and production company that focuses on developing its long-life natural gas reserves in the Green River Basin of Wyoming and oil reserves in Bohai Bay, China. The company is listed on the American Stock Exchange under the symbol UPL. It had more than 155 million shares outstanding on December 31, 2005. Ultra Petroleum Corporation is located in Houston.

As an operator of oil and gas properties through various industry arrangements, Cimarex Energy provides services to non-operators and other industry partners. Cimarex services include exploration and drilling for oil and natural gas, production of oil and natural gas and the evaluation of geological and geophysical information. The company is an active explorer in the Mid-Continent and Gulf Coast regions of the United States and has a smaller program in the Permian Basin, Calif. Cimarex Energy seeks to expand in each of its existing core areas and operations throughout the U.S. The company reported reserves totaling 1.4 trillion cubic feet equivalent. Cimarex Energy has offices in Denver, New Orleans and Tulsa, Okla.