A HIGHER RESOLUTION STRUCTURAL INTERPRETATION OF PART OF ELK BASIN ANTICLINE, BIGHORN BASIN, WYOMING

Identifying and correlating lithostratigraphic units in outcrop and in the subsurface enables the recognition of geologic structures that may influence the distribution and recovery of hydrocarbons. Detailed lithologic descriptions from this study distinguish with higher resolution two stratigraphic units on the southwest limb of the Elk Basin Anticline. The Upper Cretaceous Bearpaw Shale Member of the Meeteetse Formation and the Teapot Sandstone Member of the Mesaverde Formation are more clearly constrained stratigraphically in Elk Basin Anticline in Wyoming as a result of this study.

Elk Basin Anticline is located 19.2 km (12 miles) north of Powell, Wyoming in the Bighorn Basin. It is a doubly plunging anticline breached exposing to the late Cretaceous Cody Formation. Elk Basin has been an active oil field since 1915 when production was established in the Frontier Formation. Production has been extended through the years to include additional Mesozoic and Paleozoic units in the subsurface. In general, the anticlinal trap controls the occurrence of oil and gas. Smaller scale features such as normal faults may control the success or failure of individual wells. Understanding the occurrence of normal faults within the field is essential to enhanced recovery operations.

Reconnaissance associated with this study identifies normal faults at the surface that had been previously only been known from a 1948 structure map drawn on the second Frontier sandstone. A higher resolution interpretation of the structure is obtained when this new data is combined with existing subsurface data.