Microbial Carbonate Reservoirs and Analogs from Utah (SS-168)

by Thomas C. Chidsey, Jr., David E. Eby, Michael D. Vanden Berg, and Douglas A. Sprinkel

Microbial carbonates are geologically and economically important deposits, acting as hydrocarbon reservoirs in several areas including deepwater offshore Brazil and Angola, South Oman Salt Basin, Caspian Basin of Kazakhstan, and Williston Basin of North America. Utah contains unique analogs of microbial hydrocarbon reservoirs in the modern hypersaline Great Salt Lake and the lacustrine Eocene Green River Formation within the Uinta Basin of northeastern Utah. A survey of carbonate cores from active Utah oil fields also reveals a variety of microbial fabrics (of which four are previously undocumented in marine formations), associated carbonate grains, pore types, and reservoir characteristics. The reservoirs, fields, and geologic locations, respectively, are the (1) Eocene Green River Formation, West Willow Creek field, Uinta Basin, (2) Jurassic Twin Creek Limestone, Pineview field, thrust belt, (3) Triassic Moenkopi Formation, Upper Valley field, Kaiparowits Basin, (4) Pennsylvanian Paradox Formation, Greater Aneth field, Paradox Basin, and (5) Mississippian Leadville Limestone, Lisbon field, Paradox Basin.

This 112-page Utah Geological Survey Special Study provides a brief characterization (facies, geometry, distribution, and bounding surfaces) and petrographic overview (including carbonate fabrics, pore types, and diagenetic alteration) of the diverse types of microbialites and associated carbonate grains that are present within Great Salt Lake, the Green River Formation, and reservoirs (non-marine and marine) from various active oil fields in Utah’s major producing provinces. Plates include core descriptions, graphical measured sections, and geophysical well logs. The appendix consists of photographs of all cores described and evaluated as part of the study. The descriptions, data, and conclusions contained in this Special Study are anticipated to be a valuable resource for potential future carbonate hydrocarbon plays in Utah, as well as production and exploration in microbial carbonate reservoirs worldwide. Students and researchers studying these fascinating rocks will find it equally useful for years to come.

Other Information:
Published: 2021
Pages: 112
Plates: 14
Location: Utah