Oil recovery from a Utah tar sand deposit by in situ combustion

The U. S. tar sand resource consists of an estimated 30 billion barrels (4.7Gm^3 ) of oil. Most of this resource is in six large deposits in Utah. Through research and development to prove tar sand oil recovery methods, the Department of Energy is attempting to stimulate commercialization of this resource. Two in situ combustion field experiments have been conducted in Utah's Northwest Asphalt Ridge deposit. The second of these experiments, described in detail, was completed in early 1978 and consisted of a reverse combustion preparatory phase followed by a forward combustion production phase. Oil recovery exceeding 20 percent of the oil-in-place from a 40 ft by 120 ft (12m by 36m) nine-well line pattern provides encouragement for larger scale technical and economic demonstrations. This report includes the following in detail: the design of the oil production process and its related air injection and production facilities; ignition of the process; conduct of the process (for 183 days); effluent monitoring; data acquisition (including use of an on-site minicomputer); data analysis; and resultant conclusions.