In the southern Uinta Basin of eastern Utah, fluvial channel sandstones of the Albian-Cenomanian Dakota Formation are economic gas reservoirs. Recovery of gas from the Dakota Formation has proven challenging due to local variability in reservoir sandstone thickness, distribution, and quality. To evaluate the physical characteristics of potential reservoir sandstones, I have constructed two photomosaics of Dakota Formation fluvial channel complexes, measured 13 vertical sections with accompanying outcrop gamma-ray logs, and recorded 1,100 paleocurrent orientations along approximately 40 kilometers of outcrop exposure. Outcrop data were compared with subsurface geophysical/petrophysical and production data to evaluate possible ties between channel sandstone attributes and hydrocarbon occurrence.
The primary controls of economic gas accumulation within the Dakota Formation are structure and channel sandstone distribution. Secondary controls include diagenesis and lithology. Amalgamated channels in the lower portions of the Dakota Formation have the greatest potential for economic gas production.