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Expanding Horizons in the Eastern Uinta Basin: Gas Plays Growing in New Ways

Davis, Gary D.
Westport Oil and Gas Company, LP, Denver, CO

The Uinta basin is a prolific Laramide-age gas and oil-producing basin located in northeastern Utah. Sediments as thick as 30,000 feet are present in the basin. The upper Cretaceous and Tertiary sequences, represented by the Mesaverde Group, Wasatch and Uinta Formations represent terrigenous clastics and minor carbonate rocks deposited in an overall regressive sequence. The sediments serve as source, reservoir and seal in a series of basin-centered gas accumulations. Sporadic exploratory drilling typically encountered significant shows of natural gas but the lack of a consistent market and pipeline access stunted widespread activity. Recent improvement in gas markets, technological advances in drilling and particularly completions rekindled interest in this prolific gas-prone basin.

A number of companies are re-visiting the Mesaverde Group and Wasatch Formation stratigraphic plays and re-defining the boundaries of economic production. Conventional wisdom classifying these rocks as “too tight and too wet” to produce is rejected. Laramide structural influence appears to play a more significant role than originally assumed in these classic stratigraphic plays. In particular, structural influence affecting and enhancing natural fracturing appears to positively influence productivity.

The eastern Uinta basin is poised to vastly increase its contribution to Rocky Mountain natural gas production. Accompanying this development are many related considerations, including: the role of modern seismic; associated water production and disposal; compression and take away capacity limitations; optimal well spacing; well completion methods; lands access; and, environmental interventionism.