Marathon Oil Corp., Houston, (NYSE: MRO) has acquired an approximately 8,700-net-acre leasehold in the Piceance Basin of Colorado from Petroleum Development Corp., Bridgeport, W.Va., (Nasdaq: PETD) for $354 million in cash. The property is in Garfield County in the Greater Grand Valley Field complex, and the primary reservoir is the Williams Fork formation of the Mesaverde Group. Marathon plans to participate in drilling approximately 700 wells during the next 10 years that could add 180 million cubic feet of gas. The net recoverable reserves are estimated to be more than 900 billion cubic feet of gas, and production is scheduled to begin in 2007.