Increased oil production and reserves from improved completion techniques in the Bluebell Field, Uinta Basin, Utah. Annual report, September 30, 1993--September 30, 1994

The Bluebell field produces from the Tertiary lower Green River and Wasatch Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in a fluvial-dominated deltaic lacustrine environment, sandstones deposited in fluvial-dominated deltas; and carbonates and some interbedded sandstones of the lower Wasatch transition deposited in mud flats. Bluebell project personnel are studying ways to improve completion techniques used in the field to increase primary production in both new wells and recompletions. The study includes detailed petrographic examination of the different lithologic reservoir types in both the outcrop and core. Outcrop, core, and geophysical logs are being used to identify and map important depositional cycles. Petrographic detail will be used to improve log calculation methods which are currently highly questionable due to varying water chemistry and clay content in the Green River and Wasatch Formations. Field mapping of fractures and their relationship to basin tectonics helps predict the orientation of open fractures in the subsurface. The project includes acquiring bore-hole imaging logs from new wells in the Bluebell field thereby obtaining detailed subsurface fracture data previously not available. Reservoir simulation models are being constructed to improve the understanding of pressure and fluid flow within the reservoir. A detailed database of well completion histories has been compiled and will be studied to determine which were the most and the least effective methods used in the past