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ABOUT GEOSHURR | GAS IDEAS | GAS LEADS | PROSPECTS | PUBLICATIONS | LINKS |
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Southeastern Williston Basin Margin The two shallow gas projects on the southeastern margin of the Williston Basin are located near the capital city of Pierre in central South Dakota. All or portions of the following counties are included in these very large project areas: Dewey, Hughes, Potter, Stanley, and Sully. PROSPECT SE-ONE Geologic Aspects ••Gas system = in situ, late biogenic gas and some migrated, thermogenic gas. ••Reservoir = conventional sandstone and fractured sandstone and shale as local sweetspots imbedded within unconventional reservoirs spread as relatively continuous blankets; all are in the Cretaceous Dakota Formation. ••Traps =hydrodynamic in artesian ground water system along regional lineament zones; some small buoyancy traps on local structures. ••Depth = 1500 - 2000 feet. ••Area = four or five sweetspots cover a total of 250 square miles (160,000 acres) and unconventional blanket reservoirs cover about 1500 square miles (almost 1 million acres).. Economic Aspects ••Reserve estimates = 250 - 500 BCF in sweetspots and 1.5 - 3.0 TCF in unconventional blanket reservoirs. ••Distance to pipeline = sweetspots range from < 1 mile to about 15 miles. ••Historic production = almost 1 BCF for municipal use, 1890 - 1930. ••Leases = extensive areas never leased; generally inexpensive. ••Availability = exclusivity arrangement, immediate; single sweetspot prospects in the fall, 2002. PROSPECT SE-TWO Geologic Aspects ••Gas system = migrated and in situ, early generation biogenic gas. ••Reservoirs = fractured chalk in sweetspots and unconventional interbedded chalk and shale as blanket reservoirs in the Cretaceous Niobrara Formation. ••Depth < 1500 feet. ••Area = 75,000 acres in sweetspots and unconventional blanket reservoirs between sweetspots. Economic Aspects ••Reserve estimates = 1.0 TCF ••Distance to pipeline > 10 miles. ••Leases = relatively open; little activity since the late 1970’s. ••Availability = exclusivity arrangement, immediate; single sweetspot prospects in the fall, 2002. |
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