Patterson-UTI Energy, Inc., through its subsidiaries, provides onshore contract drilling services to major and independent oil and natural gas operators in the United States and Canada. The company operates through three segments: Contract Drilling, Pressure Pumping, and Oil and Natural Gas. The Contract Drilling segment markets its contract drilling services primarily in Texas, New Mexico, Louisiana, Colorado, Wyoming, North Dakota, Oklahoma, Pennsylvania, Ohio, West Virginia, and western Canada. As of December 31, 2015, this segment had a drilling fleet of 221 marketable land-based drilling rigs. The Pressure Pumping segment offers pressure pumping services that consist of well stimulation and cementing for the completion of new wells and remedial work on existing wells, as well as hydraulic and nitrogen fracturing, cementing, and acid pumping services in Texas and the Appalachian region. The Oil and Natural Gas segment owns and invests in oil and natural gas assets as a non-operating working interest owner located principally in Texas and New Mexico. Patterson-UTI Energy, Inc. was founded in 1978 and is headquartered in Houston, Texas.