Wamsutter Development Area, Wyoming: A Case Study in Developing a Giant Tight Gas Field
Tony McClain1, James A. Hornbeck2, G. Earl Norris1, Virginia L. Riggert2,
Reinel Solano2, Frederick E. Bakun2, Eugene J. Piekenbrock2, Meredith Rhodes Carson2,
David S. Muller2, Brian W. Horn2, Debra H. Phillips2, and Evy Glorstad-Clark3
1 BP America Production Co, Houston, TX
2 BP America Inc, Houston, TX
3 EPTG, Houston, TX
The Wamsutter Development Area (WDA) is a large, tight gas accumulation in the Washakie and Red Desert Basins of the Greater Green River Basin in southwest Wyoming. The fields have produced 2 TCF from about two thousand wells since the 1970's. Primary reservoirs are in paralic and shallow marine sandstones of the Late Cretaceous Almond Formation, representing the western margin of the Cretaceous Seaway. The interplay of sea-level changes and accommodation space resulted in the deposition of a diverse suite of sandstones, siltstones, shales, and coals in a complex, but predictable sequence of tidally-dominated depositional environments. These environments of deposition ultimately control reservoir quality in sands that are prospective in a range of depths from 8,000 to 13,500 feet.
Two modes of development have been used in the WDA, each method accounting for about half of the new wells drilled. Where there are multiple wells in adjoining sections (1 mi2 each), the ‘township (36 mi2) method' integrates openhole logs, seismic attribute analysis, and production history for evaluating and prioritizing hundreds of locations. The other half of the field is developed with a more geologically-focused depositional model approach to understand and guide reservoir relationships in areas with only one or two wells per section. Both methods have established track records of success in recent drilling programs.