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Future Prospects on Rawlins Arch: Modern Look at Oil and Gas Exploration in a Historic Area

David W. Bieber, Theodore D. Sheldon

The Rawlins arch in south-central Wyoming is a major north-south feature that is approximately 60 mi long and 20-40 mi wide. It is bounded by the Granite-Ferris-Seminoe Mountain uplifts on the north, the Medicine Bow-Sierra Madre Mountain uplifts on the south, the Hanna and Kindt basins on the east, and the Great Divide and Washakie basins on the west. Major tectonic events have occurred in the area during the Pennsylvanian, Jurassic-Cretaceous, and Late Cretaceous-Tertiary. Locally, evidence exists for structural deformation that predates the Cambrian.

Significant production was established on the Rawlins arch in 1916, at Lost Soldier field, which has the highest recovery per acre of any Rocky Mountain oil field. Within the area, major exploratory efforts were made in the 1920s and 1940s. Since that time, little new exploration has taken place, although development and enhanced recovery operations are ongoing. The area is sparsely drilled and has the potential for significant hydrocarbon accumulations. Historically, fields were found by surface mapping, and involved structural closures. Recent discoveries include stratigraphic and subtle structural traps. Productive rocks range in age from Cambrian through Late Cretaceous, and include clastic and carbonate reservoirs with matrix and fracture porosity and permeability. Multiple sourc and sealing beds, fault conduits, and sealing faults allow multiple pay zones. Drilling depths are relatively shallow, and few drilling and completion problems exist. Many pipelines afford good access to markets for produced hydrocarbons. All these factors make the Rawlins arch an attractive area for exploration.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.