Abstract: A Multi-Disciplinary Team Approach to Reservoir Characterization of the Bluebell Field, Uinta Basin, Utah

Craig D. Morgan

With funding from the U.S. Department of Energy Class I Oil Program, a multidisciplinary team was formed to conduct a reservoir-characterization study of the Bluebell oil field. The objective is to improve completion techniques in order to increase primary production from the field.

The team consists of geologists and engineers from government, academia, and oil field service companies and operators. The study includes: detailed examination of outcrop and core; mapping of depositional cycles and surface and subsurface fracture patterns; geochemical study of reservoir fluids; a review of previous completion techniques; and construction of both single- and multi-well reservoir simulation models.

The Bluebell field produces from the Tertiary Green River and Wasatch Formations. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate rocks deposited in a fluvial-dominated deltaic-lacustrine environment.

Wells are typically completed by perforating 40 or more beds over 1,000 to 3,000 vertical feet (300-1,000 m), then applying an acid-frac to the entire interval. This technique is believed to leave many potentially productive beds damaged and/or untreated, while opening up some water and thief zones.

Improved characterization and reservoir modeling will help identify new and damaged intervals that contain significant volumes of moveable oil. Completion techniques will be designed that are best suited for those intervals. The two-year characterization study (Phase I) will be completed October 1995. The results will be demonstrated on a recompletion, a horizontal redrill of a vertical well, and a new well during the three-year Phase II portion of the project.

AAPG Search and Discovery Article #90959©1995 AAPG Rocky Mountain Section Meeting, Reno, Nevada