Unit Corporation, together with its subsidiaries, engages in the contract drilling, oil and natural gas, and mid-stream businesses in the United States. The company’s Contract Drilling segment engages in land contract drilling of onshore oil and natural gas wells for oil and natural gas companies in Oklahoma, Texas, Louisiana, Wyoming, Colorado, Utah, Montana, and North Dakota. Its Oil and Natural Gas segment is involved in the acquisition, exploration, development, and production of oil and natural gas properties located primarily in Oklahoma, Texas, Louisiana, and North Dakota, as well as in Arkansas, New Mexico, Wyoming, Montana, Alabama, Kansas, Mississippi, Michigan, Colorado, Pennsylvania, and a small portion in Canada. As of December 31, 2011, this segment had approximately 121 gross proved undeveloped wells. The company’s Mid-Stream segment buys, sells, gathers, processes, and treats natural gas. It operates 3 natural gas treatment plants, 10 operating processing plants, 35 active gathering systems, and 934 miles of pipeline in Oklahoma, Texas, Kansas, Pennsylvania, and West Virginia. The company operates a fleet of 127 drilling rigs. Unit Corporation was founded in 1963 and is based in Tulsa, Oklahoma.