Well Study— Sauk III-IV Interval in the American Quasar 16-21A Horse Heaven-state Well, Confusion Range, West-central Utah

Abstract

More than 15,000 ft (4572 m) of Sauk megasequence strata are exposed in mountain ranges across the eastern Great Basin of western Utah (Figure 1; see Miller et al., 2012). The upper parts, Sauk II to Sauk IV, are particularly well exposed in the western desert of Utah, in and around the Ibex area (Figure 2). Division of the Sauk megasequence into four parts follows Miller et al. (2012). This area was also the location of several wildcat wells that were drilled in the late 1970s and early 1980s (Figure 1). From 1991 to 2003, Evans et al. have collected gamma-ray profiles from measured stratigraphic sections in the Confusion, Fish Springs, and House Ranges, as well as the Wah Wah Mountains and sections in eastern Nevada. Profiles from the Ibex area can be correlated confidently with some subsurface gamma-ray logs. As a consequence, key stratigraphic markers exposed in measured sections can be identified in well logs, and conversely, well logs can be used to help delineate the distribution of facies and large-scale structures. Figure 1. Locations of wells penetrating Cambrian and Ordovician strata and locations of measured stratigraphic sections with gamma-ray profiles in west-central Utah. ARCO = Atlantic Richfield Company. 10 mi (16.1 km). Figure 2. Lithostratigraphic units associated with the Sauk III-IV interval in the mountain ranges of west-central Utah. The gamma-ray profiles from measured stratigraphic sections are indicated at the right side.