Mesaverde Gas Play - Eastern Uinta Basin, Utah

Paul B. Anderson, Consulting Geologist, 807 East South Temple #101, Salt Lake City, UT 84102, phone: 801-364-6613, fax: 801-741-8097, [email protected]

The Mesaverde Group is quickly becoming a major producer of gas in the Uinta basin, Utah. Gas from the Mesaverde in the interior of the Uinta basin appears to fit a basin-centered gas model although the transition into conventional traps is poorly understood. Current production from Mesaverde only completions is concentrated on the east to northeast, and west edges of the Greater Natural Buttes field. Early production from the Mesaverde has generally been commingled with basal Wasatch sands. These commingled wells are examined to approximate the production contribution from the Mesaverde. Few Mesaverde only wells have been completed in the heart of the Greater Natural Buttes field, but the play is rapidly expanding out and into all of the eastern Uinta basin. Good reservoir and source rocks in the Mesaverde are present throughout the Uinta basin.

Three subsurface cross sections, with formational contacts within the group, depositional facies, tested intervals with results, Ro values, are developed for this play. Cumulative production, IP, isopach of the Mesaverde Group, and structure on the Castlegate maps help evaluate this play. Because many Mesaverde completions are commingled with Wasatch zones, these wells have a percent net Mesaverde perforations indicator to help estimate the influence of the Mesaverde completion zones. Mesaverde completions by decade are mapped to visually tract where the play is headed and how it has developed historically. Funding by the Utah Geological Survey has supported this study.