Hydrodynamic Control on an Oil Entrapment in Channel Sandstones of the Dakota Sandstone, South Cole Creek Field, Converse County, Wyoming

South Cole Creek field, located in the southwest Powder River Basin of Wyoming has produced 11 million barrels of oil from the Dakota Sandstone. Detailed mapping of rock and reservoir properties including sandstone isopachs, initial potentials, cumulative production, and porosity-permeability data, reveals the existence of channel sandstones with excellent reservoir properties which are surrounded by marine rocks of poorer reservoir properties. The areal extent of the accumulation is controlled by factors other than structure and stratigraphy, as water-bearing channel sandstones exist lateral to and up-dip of producing channel sandstones. By comparing the known accumulation to the theoretical model for fluid flow, it can be shown that hydrodynamics has played an important role in modifying the accumulation at South Cole Creek field.