Bituminous sandstone deposits Asphalt Ridge

Asphalt Ridge probably is the second largest bituminous sandstone deposit in northeastern Utah's Uinta Basin. Discontinuous concentrations of bitumen occur in the Rim Rock Sandstone of the Mesaverde Group of Cretaceous age, in the overlying Uinta Formation of Eocene age and the Duchesne River Formation of Oligocene age. Future economic utilization of the Asphalt Ridge deposits depends on how efficiently the sand's petroleum products can be extracted and marketed. In the past, the cost of producing oil from bituminous sands has been prohibitive. However, with development of "in situ" (thermal) recovery methods such as those discussed in this report, the projected production costs may be reduced to a level at which oil from bituminous sands can compete with oil from conventional sources. Because the bituminous layers dip southwestward under prohibitively deep cover, only a small part of the sandstone can be mined by open pit methods. However, the Asphalt Ridge deposits are well suited to thermal recovery techniques. The thick, uniform sands of the Mesaverde Group are the best targets for such methods. It is estimated the bituminous sands in the Mesaverde contain reserves of oil totalling nearly 700 million barrels. The recovery factor probably would be between 50 and 70 per cent; so total recoverable reserves in the Mesaverde should beat least 350 million barrels of oil. Many factors have a direct effect on the degree of saturation and probability of successful extractions of the bitumen. A few seeming to favor the possibility of successful production of Asphalt Ridge are: physical properties of the reservoir rock, size of the reservoir, proximity to an existing pipeline, abundant water supply, and favorable depth of occurrence.