Nugget Sandstone reserves in the southwestern Wyoming part of the Thrust Belt province are rapidly being developed in the Painter Reservoir field, Ryckman Creek field, and the Clear Creek area. This series of northeast-trending fields is situated on the hanging wall of the Absaroka thrust.

Painter Reservoir field, discovered in 1977, is located 5 mi (8 km) northeast of Evanston, and is the most southerly of the three areas. Ryckman Creek field, discovered in 1976, lies 10 mi (16 km) farther northeast. Between the two fields, the most recent discovery on the trend is the Clear Creek area where Chevron tested 25 MMCFGD from the Nugget Sandstone in September 1978.

Each area is a separate, structurally controlled Nugget Sandstone reservoir. Field limits and structural details are not yet firmly established, but seismic and drilling data outline similar structure forms, each area appearing as an asymmetric overturned fold. The hydrocarbon columns range from an estimated 500 ft (150 m) in the Clear Creek area to over 1,000 ft (300 m) in the Painter Reservoir field. The column at Ryckman Creek is approximately 575 ft (175 m). A significant gas column is present in each area.

The Nugget Sandstone reservoir rock is cross-bedded and cross-laminated. This cross-stratification creates local variation in porosity and permeability. Along the trend, average Nugget Sandstone porosity and permeability appear to decrease somewhat from north to south. At Ryckman Creek field the Nugget Sandstone is more porous and homogeneous than in Painter Reservoir field. The Clear Creek area porosity and permeability data are limited with the field in an early stage of development.

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