Abstract

Clay Basin, for which the field is named, is in northeastern Utah’s Daggett County on the north flank of the Uinta Mountains. Clay Basin is a topographic depression and a breached surface anticline where the soft Upper Cretaceous Mancos Shale is exposed along the crest of the anticline and forms the interior of the basin, and the resistant overlying Mesaverde Group forms hogbacks on the north, east, and west flanks of the depression and the structure. The Mancos Shale, in fault contact with the Precambrian Red Creek Quartzite, forms the southern flank.

Gas was discovered in Clay Basin in the Upper Cretaceous Frontier Formation in 1927 and in the Lower Cretaceous Dakota Sandstone in 1935. Since construction of a pipeline in 1937, the field has produced more than 176 billion cubic ft of gas (BCFG) from the two formations and continues to produce more than 1 BCFG per year from the Frontier Formation. In 1976, the Dakota Sandstone reservoir was converted to gas storage, the largest gas storage facility in the Rocky Mountain region. Typically, gas is injected into the Dakota Sandstone from May through October and withdrawn during the winter heating season from November through March.