Reservoir Characteristics and Gas Flow in Tight-Gas Sands, Upper Williams Fork Formation, Northeastern Piceance Basin, Colorado

Bryan McDowell and Piret Plink-Bjorklund

This study, in conjunction with the Research Partnership for Secure Energy of America (RPSEA), is focused on reservoir characteristics of the Upper Williams Fork Formation in the northeastern Piceance Basin to better understand controls on reservoir quality in tight-gas sands. Reservoir complexity and compartmentalization are caused by: (1) the presence of multiple depositional environments ranging from fluvial to marine; (2) specific lithological and geometrical variability within each of these environments; and (3) preferential diagenetic cementation along various stratigraphic horizons. Additional complexity is added by natural fractures and inherent mechanical properties. This project shows that quantification of these relationships and relative significance of individual parameters is crucial to economic production of natural gas within the reservoir and future exploration of the basin. In order to obtain these objectives, reservoir/porosity types and high- and low-permeability zones were determined by closely spaced stratigraphic sections on centimeter-scale resolution, outcrop gamma ray profiles, and comparison with a subsurface well-log database.

AAPG Search and Discovery Article #90156©2012 AAPG Rocky Mountain Section Meeting, Grand Junction, Colorado, 9-12 September 2012