Hydrodynamics of Minnelusa Formation, North Powder River Basin, Wyoming

William V. Maloney

The Minnelusa Formation (Permian-Pennsylvanian) has produced over 250 million bbl of oil, from mainly stratigraphic traps in the Powder River basin. Production is dominantly from eolian sandstone reservoirs trapped by paleotopographic highs, simple closure, or porosity pinch-outs. Most of the production to date is from upper Minnelusa sandstones in the northeastern portion of the basin, where conditions are optimal for stratigraphic entrapment. The focus of this paper is on hydrodynamics as an additional control on the localization of hydrocarbons. Specifically, areas of low potential energy with respect to oil and gas can be mapped as a function of the potentiometric surface, fluid density, and aquifer configuration. This study in the Powder River basin defined an area o minimum potential energy with respect to hydrocarbons. Synhydrodynamic and posthydrodynamic hydrocarbon migration syn/post hydrodynamics will result in the majority of hydrocarbons moving toward the area of minimum potential energy. The area encompasses the majority of Minnelusa hydrocarbons discovered to date.

AAPG Search and Discovery Article #91040©1987 AAPG Rocky Mountain Section Meeting, Boise, Idaho, September 13-16, 1987.