Balcron Oil Co., Billings, Mont., has completed a discovery on the Black Hills uplift that may be the first production from Pennsylvanian First Leo sandstone of the Minnelusa formation in South Dakota.
Balcron's 21-5 Nautilus-Federal, in 5-10s-2e, Fall River County, pumped 125 b/d of 29.4 gravity oil from First Leo perforations at 3,008-20 ft. Neither gas nor water showed on the test.
On a Leo drillstem test at 3,000-15 ft, Balcron recovered 1,924 ft of highly gas-cut oil with 1,700 cc of oil in the sample chamber.
Fields in this part of the state produce mainly from Second and Third Leo sands, says Petroleum Information Corp., Denver. The area is about 26 miles southwest of Hot Springs, S.D.
Balcron drilled a wildcat about one half mile northwest of the discovery well in late 1989.
The company hasn't released production information on that well, 24-32 Poseidon-Federal, in 32-9s-2e, but the well is said to have been pump testing in mid-September and to have had oil on the pit.
OTHER RESULTS
Drillstem test and log results from 24-32 PoseidonFederal indicate Balcron might have another Alum Creek field on its hands.
Those results indicate gas mostly composed of nitrogen in First Leo. Second Leo had a poor show of oil, and fourth Leo contained black sulfur water with about 800 ppm hydrogen sulfide. Fifth Leo was tight.
Balcron plans to drill at least three offsets to the discovery and has asked that 40 acre spacing be established in the area.
The discovery well is 2.5 to 4 miles south and southwest of Leo oil production in Porter Ranch and Edgemont fields.
Leo sands are the primary exploration target in southwestern South Dakota, wrote Anthony K. Petres, a geologist with the state oil and gas division in Rapid City (OGJ, Mar. 27, 1989, p. 75).
Petres said nine small fields produce in Custer and Fall River counties, including Alum Creek field, which has been waterflooded successfully. Secondary recovery in that field is expected to duplicate primary recovery.
Alum Creek, the largest field in Fall River County, has seven producers and covers 4.5 sq miles on 160 acre spacing.
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