Abstract: Oil and Gas Potential of Naval Oil Shale Reserve No. 2 (NOSR-2), Utah

SILVERMAN, MATTHEW R. and KENNETH W. GROVE

NOSR-2 is an 89,000-acre tract located in Uintah and Carbon Counties, Utah, that was set aside for the Navy in 1916. It is managed by the U.S. Department of Energy (DOE). Approximately 40% of the surface is owned by the Ute Indian Tribe.

NOSR-2 is located on the south flank of the Uinta Basin, 4 miles south of commercial gas production in Natural Buttes Field. No wells have been drilled on NOSR-2 with the exception of some shallow oil-shale core holes. Several seismic surveys illustrate the structural form underlying NOSR-2 and point to structural leads for petroleum exploration.

Natural Buttes is a "continuous-type" gas-saturated accumulation in the Wasatch and Mesaverde Formations. Geologic risk includes the availability of sufficient permeability to establish commercial gas flows from the typically impermeable sands. Other nearby fields have water production and/or downdip water, elements characteristic of "transitional" accumulations. Higher geological risk is associated with these types of accumulations due to the limited extent of the traps. Thermal maturity studies indicate that only the northern third of NOSR-2 may be favorable for shallow, lower-risk, continuous gas-saturated accumulations. The southern two-thirds might contain only higher-risk conventional plays.

A prominent seismically-defined fold trend extends across the southernmost portion of NOSR-2 in the area of conventional trapping conditions. Two possible structural closures and a high-risk, deep play are indicated. A 15,000-foot Precambrian test could evaluate Dakota, Morrison, Weber and Mississippian horizons on the trend.

AAPG Search and Discovery Article #90946©1997 AAPG Rocky Mountain Section Meeting, Denver, Colorado