Recent drilling in the Absaroka plate of the thrust belt has confirmed the presence of a major gas-condensate accumulation in the Whitney Canyon area of Uinta County, Wyoming. Reserves are primarily in porous and/or fractured Paleozoic carbonate formations. Triassic carbonate rocks also appear to be commercially productive.

The discovery well, which was scheduled as a 13,400-ft (4,020 m) test, was spudded in October 1976. Mechanical problems were encountered at a depth of 10,691 ft (3,027 m) in the Permian Phosphoria Formation and the well was subsequently completed in the Triassic Thaynes Formation. Paleozoic gas production was established in 1978 by the Amoco-Chevron-Gulf 2. This well drilled a nearly normal stratigraphic section of Jurassic Twin Creek Limestone through Ordovician Big Horn Dolomite before crossing the Absaroka thrust at a true vertical depth of 15,516 ft (4,655 m). Cretaceous sandstones and shale were drilled to a total depth of 16,224 ft (4,867 m) or 15,894 ft (4,768 m) true vertical depth. A development well approximately 1 mi (1.6 km) north of the Amoco-Chevron-Gulf 2 drilled a simi ar stratigraphic sequence.

The Whitney Canyon structure is a north-south-trending geophysical anomaly with little or no surface expression; its general shape can be defined quite well with reflection seismic. At the Phosphoria level, the structure is approximately 10 mi (16 km) long and 2 mi (3.2 km) wide with 2,500 ft (750 m) of structural closure.

Gas tested from the Triassic Thaynes Formation is sweet, whereas the Paleozoic gas is sour with a hydrogen sulfide content of 18% or less. Environmental considerations and construction of a gas treatment plant probably will delay Paleozoic gas production until 1982.

Although reserve estimates are quite speculative, the Whitney Canyon structure appears to be in the giant field category.

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