The Recluse field discovery well, Apache-Woods No. 1 U.S. Fagerness, NW 1/4 NW 1/4 of Sec. 15, T56N, R74W, Campbell County, Wyoming, was drilled in July 1967. Located on an anticline mapped by the U.S. Geological Survey during an investigation for coal beds, the well was drilled to 9,268 ft (2,825 m) and bottomed in the Minnelusa. The Muddy Sandstone of Early Cretaceous age was penetrated from 7,586 to 7,640 ft (2,312-2,329 m), and a drill-stem test of the zone recovered 20 bbl of oil per hour. More than 85 oil wells have been drilled on 80-acre spacing in a field that is 8 mi (13 km) long and 1.5 mi (2.4 km) wide. Accumulation of oil in the Muddy is stratigraphic. The Muddy is a lenticular sandstone body; oil is trapped in its updip termination. Only about 20 percent of he downdip part of the sandstone lens contains water.

The Recluse field is located on the northeast flank of the Powder River basin. Production in this basin has been obtained from 14 "pay" sections--13 are Cretaceous and one, the Minnelusa Formation, is Permian-Pennsylvanian. Practically all the oil found in Cretaceous sandstones is stratigraphically trapped; half the oil obtained from the Minnelusa is also from stratigraphic traps. The Muddy Sandstone on the east flank of the Powder River basin is interpreted to be gradational from nonmarine through transitional deltaic to marine. The Muddy Sandstone at Recluse is interpreted to represent a marine barrier island; there is a marked similarity to the Galveston barrier island.