RE-EXAMINATION OF UTAH'S OIL SHALE DEPOSITS: HISTORICAL DATABASE AND NEW RESOURCE EVALUATION

With the recent increase in crude oil prices and concerns over diminishing conventional reserves, the Utah Geological Survey has begun to re-examine the state's oil shale resource. A major component of this process was to collect and preserve historical oil shale data from studies conducted in Utah and present it in a convenient electronic format for the business and scientific communities. Files in this database include Fischer assays made from drill cores or cuttings for 581 boreholes; scanned geophysical logs for 173 wells, along with an inventory of paper logs for an additional 290 wells available in the Utah Geological Survey's library; spotty to complete formation-top information for key beds in the Green River Formation for over 1000 wells; detailed lithologic descriptions for 168 wells; an overview resource map; and an extensive oil shale bibliography for research done within the state.

Most of the historical oil shale resource assessments conducted in Utah concentrated on the Green River Formation within the southeastern part of the Uinta Basin. This area holds the thickest and richest oil shale deposits in Utah, but other significant areas within the basin warrant further study. We have broadened our attention to include the entire Uinta Basin. Over 150 density and sonic logs from oil and gas wells in the basin have been digitized and tops to key oil shale zones have been picked. Correlating available Fischer assay analyses to geophysical logs has produced high-resolution shale oil yields, providing a way to map oil shale thickness and richness throughout the basin.