|Using a geology-based assessment methodology, the
U.S. Geological Survey estimated a mean 84.6 trillion cubic feet of undiscovered
natural gas, mean of 131 million barrels of undiscovered oil, a mean of
2.6 billion barrels of undiscovered natural gas liquids in the Southwestern
|The U.S. Geological Survey (USGS) recently completed an assessment of
the undiscovered oil and gas potential of the Southwestern Wyoming
Province (fig.1). The USGS Southwestern Wyoming Province for this
assessment included the Green River Basin, Moxa arch, Hoback Basin,
Sandy Bend arch, Rock Springs uplift, Great Divide Basin, Wamsutter
arch, Washakie Basin, Cherokee Ridge, and the Sand Wash Basin. The
assessment of the Southwestern Wyoming Province is based on the geologic
elements of each Total Petroleum System TPS) defi ned in the province,
including hydrocarbon source rocks (source-rock maturation, hydrocarbon
generation and migration), reservoir rocks (sequence stratigraphy
and petrophysical properties), and hydrocarbon traps (trap formation
and timing). Using this geologic framework, the USGS defi ned nine
Total Petroleum Systems (TPS) and 23 Assessment Units (AU) within
these TPSs and quantitatively estimated the undiscovered oil and gas
resources within 21 of the 23 AUs (table
|The USGS assessed undiscovered conventional oil and gas and undiscovered
continuous (unconventional) oil and gas. The USGS estimated a mean
of 84.6 trillion cubic feet of gas (TCFG), a mean of 131 million barrels
of oil (MMBO), and a mean of 2.6 billion barrels of total natural
gas liquids (BBNGL) in nine TPSs. Nearly all (97 percent, or 82.1
TCFG) of the undiscovered gas resource is continuous and distributed
in six Total Petroleum Systems: Mowry Composite TPS (8.5 TCFG); Hilliard-Baxter-
Mancos TPS (11.7 TCFG); Mesaverde TPS (25.8 TCFG); Mesaverde-Lance-Ft.
Union Composite TPS (13.7 TCFG); Lewis TPS (13.5 TCFG); and Lance-Ft.
Union Composite TPS (8.7 TCFG) (table
1). The remainder of the undiscovered gas is associated/dissolved
gas in oil accumulations 0.13 TCFG) or is in conventional nonassociated
gas accumulations (2.3 TCFG). The Niobrara TPS is estimated to contain
a mean of about 103 MMB of continuous oil, or about 79 percent of
all undiscovered oil. The Phosphoria TPS contains a mean of 16.6 MMBO,
or about 12.5 percent of the undiscovered oil. The remainder of the
undiscovered oil is in the Mowry TPS, the Mesaverde TPS, and the Mesaverde-Lance-Ft.
Union Composite TPS (table
1). The Niobrara Continuous Gas AU and the Wasatch-Green River
Continuous Gas AU were not quantitatively assessed in this study.
|For Further Information
|Supporting geologic studies of Total Petroleum Systems and Assessment
Units, and reports on the methodology used in the Southwestern Wyoming
Province assessment are in progress.
Assessment results are available at the USGS Central Energy Team website:
Figure 1. Southwestern Wyoming Province of southwestern
Wyoming and northwestern Colorado.
|Southwestern Wyoming Province Assessment Team:
|Mark Kirschbaum (Task Leader; email@example.com), Thomas M. Finn, Robert D.
Hettinger, Edward A. Johnson, Ronald C. Johnson, Joyce Kibler, Paul G. Lillis, Philip H.
Nelson, Laura N.R. Roberts, Stephen B. Roberts, Ronald R. Charpentier, Troy A. Cook,
Robert A. Crovelli, Timothy R. Klett, Richard M. Pollastro, and Christopher J. Schenk.