Summary: South Bakken Thickness Constraints

The South Bakken or Great Basin Pilot oil shale, located in Nevada and Utah, is age equivalent to and similarly organically rich and thermally mature as the North Dakota Bakken oil shale except that the Pilot is much thicker (up to 900 feet thick) and more regionally extensive (77,860,000 acres where the Pilot is 100 feet thick or more after structurally restoring the basin). The Pilot basin is poorly understood because the State of Nevada has never authorized a state geologic survey and much of the geologic mapping of western Utah is comprised of student field camp mapping. Additional limitations include a lack of useful regional seismic data, paucity of wells that have penetrated the oil shale (there are no deep (‘15,000’) tests in the Pilot basin), and the scant number of available proprietary and published measured sections. The authors have created a preliminary Pilot oil shale thickness map constrained by nearly 500 control points from wells, measured sections, and other sources. In contrast, more than 4000 wells constrain the Bakken shale. However, the authors have recently devised a method of creating thousands (more than 2000 locations) of additional thickness control points with surface gamma-ray logs and outcrop samples by applying modern, high-resolution GPS technology with old-fashioned geologic mapping techniques. A new thickness map constrained by the new dataset is greatly refining our knowledge of the Pilot Basin and is helping to identify the "sweet spots" in the basin for resource exploration.

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