Onshore Oil and Gas Leasing: Who Wins the Lottery? Report by the Comptroller General of the United States [open pdf - 840KB]
"Presently, most of the 114,000 onshore oil and gas leases for over 93 million acres of Federal land are awarded under a lottery system. The Chairman, House Committee on Interior and Insular Affairs, requested that GAO review alleged irregularities in this leasing, administered by the Department of the Interior. GAO's review of drawings in New Mexico and Wyoming detected no indication of manipulation, but showed weaknesses in controls which allow the possibility for it. Basic changes, including possible alternatives to the system, are under study by the Interior."
General Accounting Office: http://www.gao.gov