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Source rock potential of upper cretaceous marine shales in the Wind River Basin, Wyoming: Chapter 8 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming

Data Series 69-J-8

This report is Chapter 8 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming. For more information, see: Data Series 69-J.
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Abstract

Seventy-eight samples collected from marine shales from the Cretaceous Mowry Shale, the lower part of the Frontier Formation, and the lower shaly and upper sandy members of the Cody Shale in the Wind River Basin, Wyoming, were analyzed using Rock-Eval and total organic carbon analysis to determine the source rock potential. Results indicate that the Mowry Shale has a generative potential based on organic richness that is considered to be fair to very good, and hydrogen indices and S2 /S3 ratios indicate a capability to generate both oil and gas. Maps of the Mowry indicate that it is most organic rich and oil-prone in the eastern part of the basin. Results of total organic carbon and Rock-Eval analyses for the Frontier Formation indicate that it is composed of mainly type III gas-prone kerogen, with organic richness levels that are generally poor to fair. Results of similar analyses of samples from the lower shaly member of the Cody Shale show a generative potential ranging from fair to excellent, and hydrogen indices and S2 /S3 ratios indicate that it is capable of generating both oil and gas. Maps showing the distribution of kerogen types and organic richness for the lower shaly member of the Cody Shale are similar to the Mowry and show that lower shaly member of the Cody is more organic rich and more oil-prone in the eastern part of the basin. Analyses of samples of the upper sandy member of the Cody Shale indicate that it has little or no potential as a source rock. Thermal maturity mapping based on vitrinite reflectance measurements in the coal-bearing post-Cody Upper Cretaceous and Paleocene rocks shows that Upper Cretaceous marine shales in the deeper parts of the Wind River Basin are thermally mature to overmature with respect to hydrocarbon generation.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Source rock potential of upper cretaceous marine shales in the Wind River Basin, Wyoming: Chapter 8 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming
Series title:
Data Series
Series number:
69-J-8
Year Published:
2007
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Wind River Basin Province Assessment Team
Description:
iii, 24 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Larger Work Title:
Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming (Data Series 69-J)
Number of Pages:
27
Country:
United States
State:
Wyoming
Other Geospatial:
Wind River Basin Province