A reconnaissance evaluation of heavy hydrocarbons in the Tar Sand Triangle

The Tar Sand Triangle encompasses about 200 square miles in southeastern Utah. The area consists of rough, mountainous terrain, with a climate that varies from semiarid to arid. Sedimentary rocks exposed in the area range from Permian Cedar Mesa Sandstone to the Triassic(?)-Jurassic Navajo Sandstone. The main oil bearing formation is the Permian White Rim Sandstone with a saturated zone which varies from zero to 230 feet thick. Minor occurrences of oil are found in the Moenkopi Formation, Cedar Mesa Sandstone and Chinle Formation. The Triangle has an average net pay zone of 112 feet and a grade that varies from zero to 36 gallons per ton. The inferred oil resource, in-place, is estimated at approximately 5 billion barrels. There is also a potential resource of approximately A million barrels of oil in the Cedar Mesa Sandstone and Moenkopi Formation. The Tar Sand Triangle is the largest known oil-impregnated sandstone deposit in Utah, and is a combination of six separate previously named deposits. There are currently no oil development projects in the area, but a number of lease holders have applied to transfer their oil and gas leases to combined hydrocarbon leases, which would allow for their development. Development of the area will most likely be done by an in-situ recovery method because of favorable sandstone characteristics, rough terrain and the high overburden ratio.