Science Center Objects

The USGS Energy Resources Program has studied oil shale resources of the United States, with a significant effort on the Eocene Green River Formation of Colorado, Utah, and Wyoming.  This formation contains the largest oil shale deposits in the world. Oil shale, despite the name, does not actually contain oil, but is a precursor of oil that is converted to crude oil when heated.   This website contains assessments and geologic reports, as well as spatial and tabular datasets, fischer assays and well logs from USGS oil shale research studies.

The Eocene Green River Formation of Colorado, Utah, and Wyoming contains the largest oil shale deposits in the world. Oil shale, despite the name, does not actually contain oil, but rather a type of organic matter called kerogen, a precursor of oil that is converted to a type of crude oil when heated to about 450 – 500° C.   The oil shale deposits are in three structural and sedimentary basins that have been recently assessed:

Estimated total in-place resources are about 1.5 trillion barrels of oil for the Piceance Basin, about 1.3 trillion barrels of oil for the Uinta Basin and 1.4 trillion barrels of oil in the Greater Green River Basin. The Piceance Basin is the smallest of the three principal basins of the Green River Formation in terms of area covered and contains the highest concentration of high-grade oil shale (capable of generating at least 25 gallons of oil per ton of rock), with approximately 352 billion barrels of in-place oil resource.

Photo of abandoned oil shale mine at Anvil Points, Green River Formation

Photo of abandoned oil shale mine at Anvil Points, Green River Formation, near Rifle Colorado

(Credit: Ronald C. Johnson, USGS - Central Energy Resources Science Center. Public domain.)

 

RESEARCH

Piceance Basin, Colorado 2010 Assessment

An in-place assessment of the oil shale and nahcolite resources of the Green River Formation in the Piceance Basin of western Colorado was competed in 2010. The Piceance Basin is one of three large structural and sedimentary basins that contain vast amounts of oil shale resources in the Green River Formation of Eocene age.

The oil shale interval in the Piceance Basin is subdivided into seventeen “rich” and “lean” zones and each interval was assessed for variations in gallons per ton, barrels per acre, and total barrels in each 36-square mile township. These zones are roughly time-stratigraphic units consisting of distinctive, laterally continuous sequences of rich and lean oil shale beds that can be traced throughout much of the Piceance Basin. The Radial Basis Function extrapolation method was used to generate isopach and isoresource maps, and to calculate resources.

Estimated in-place oil is about 1.5 trillion barrels, based on Fischer assay results from boreholes drilled to evaluate oil shale, making it the largest oil shale deposit in the world. The estimated in-place nahcolite resource is about 43.3 billion short tons.

Results of this assessment are available in the following publications (see 'Data and Tools' for data supporting this assessment):

Johnson, R.C., Brownfield, M.E., and Mercier, T.J., (U.S. Geological Survey Oil Shale Assessment Team), 2010a, Oil Shale and Nahcolite Resources of the Piceance Basin, Colorado: U.S. Geological Survey Digital Data Series DDS-69-Y [CD-ROM]. http://pubs.usgs.gov/dds/dds-069/dds-069-y/

Mercier, T.J., Johnson, R.C., Brownfield, M.E., and Self, J.G., 2010, In-Place Oil Shale Resources Underlying Federal Lands in the Piceance Basin, Western Colorado: U.S. Geological Survey Fact Sheet FS-2010-3041, 4 p. http://pubs.usgs.gov/fs/2010/3041/

Johnson, R.C., Mercier, T.J., Brownfield, M.E., Pantea, M.P., and Self, J.G., 2009, Assessment of in-place oil shale resources of the Green River Formation, Piceance Basin, western Colorado: U.S. Geological Survey Fact Sheet 2009–3012, 6 p. http://pubs.usgs.gov/fs/2009/3012/

 

Uinta Basin, Colorado and Utah 2010 Assessment

A comprehensive geology-based assessment of in-place oil, regardless of richness, in oil shales of the Eocene Green River Formation of the Uinta Basin of eastern Utah and western Colorado was conducted in 2010.

The oil shale interval was subdivided into eighteen roughly time-stratigraphic intervals, and each interval was assessed for variations in gallons per ton, barrels per acre, and total barrels in each 36-square mile township. The Radial Basis Function extrapolation method was used to generate isopach and isoresource maps, and to calculate resources. The total in-place resource for the Uinta Basin is estimated at 1.32 trillion barrels. This is only slightly lower than the estimated 1.53 trillion barrels for the adjacent Piceance Basin, Colorado, to the east, which is thought to be the richest oil shale deposit in the world. However, the area underlain by oil shale in the Uinta Basin is much larger than that of the Piceance Basin—3,834 mi2  vs. 1,335 mi2—and the average gallons per ton and barrels per acre values for each of the assessed oil shale zones are significantly lower in the depocenter in the Uinta Basin when compared to the Piceance. These relations indicate that the oil shale resources in the Uinta Basin are of lower grade and are more dispersed than the oil shale resources of the Piceance Basin.

Results of this assessment are available in the following publications (see 'Data and Tools' for data supporting this assessment):

Johnson, R.C., (and U.S. Geological Survey Oil Shale Assessment Team), 2010, Oil Shale Resources of the Uinta Basin, Utah and Colorado: U.S. Geological Survey Digital Data Series DDS-69-BB, [CD-ROM]. http://pubs.usgs.gov/dds/dds-069/dds-069-bb/

Johnson, R.C., Mercier, T.J., Brownfield, M.E., and Self, J.G., 2010, Assessment of in-place oil shale resources of the Green River Formation, Uinta Basin, Utah and Colorado: U.S. Geological Survey Fact Sheet 2010-3010, 4 p. http://pubs.usgs.gov/fs/2010/3010/

Green River Basin, Southwestern Wyoming and Colorado 2011 Assessment

The U.S. Geological Survey (USGS) completed in 2011 a comprehensive assessment of in-place oil in oil shales in the Eocene Green River in the Greater Green River Basin, Wyoming, Colorado, and Utah. Results of this study are provided in two publications, below (see 'Data and Tools' for data supporting this assessment):

Johnson, R.C., (and U.S. Geological Survey Oil Shale Assessment Team), 2010, Oil Shale Resources of the Eocene Green River Formation, Greater Green River Basin, Wyoming, Colorado, and Utah: U.S. Geological Survey Digital Data Series DDS-69-DD, [CD-ROM]. http://pubs.usgs.gov/dds/dds-069/dds-069-ddb/

Johnson, R.C., Mercier, T.J., and Brownfield, M.E., 2011, Assessment of In-Place Oil Shale Resources of the Green River Formation, Greater Green River Basin in Wyoming, Colorado, and Utah: U.S. Geological Survey Fact Sheet 2011-3063, 4 p. http://pubs.usgs.gov/fs/2011/3063/

 

Photo of the Green River Formation

Green River Formation along Evacuation Creek in the eastern part of the Uinta Basin, easternmost Utah

(Credit: Ronald C. Johnson, USGS - Central Energy Resources Science Center. Public domain.)