Patterson-UTI Energy, Inc., together with its subsidiaries, provides onshore contract drilling services to independent oil and natural gas operators in North America. It provides pressure pumping services consisting of well stimulation and cementing for completion of new wells and remedial work on existing wells to oil and natural gas operators primarily in the Appalachian Basin. The company also provides drilling fluids, completion fluids, and related services to oil and natural gas operators offshore in the Gulf of Mexico and on land in Texas, New Mexico, Oklahoma, and the Gulf Coast region of Louisiana. In addition, it engages in the development, exploration, acquisition, and production of oil and natural gas assets in Texas, New Mexico, Mississippi, and Louisiana. As of December 31, 2008, the company had a drilling fleet of 344 land-based rigs. Patterson-UTI Energy was founded in 1978 and is headquartered in Houston, Texas.