CHARACTERIZATION OF THE EMERGING DOUGLAS CREEK HORIZONTAL PLAY, UINTA BASIN, UTAH (Invited Presentation)

Horizontal wells producing from the Uteland Butte, Wasatch, and Castle Peak intervals in the Uinta Basin have been a primary driver of production growth in the past 10 years, driving basinwide oil rates above 140,000 bbls/d in 2023. Although location inventories in those intervals remain strong, operators have begun to explore other zones and have been actively testing the Douglas Creek Member (DC) of the Eocene Lower Green River Formation as a horizontal target. In the Central Basin region of the Uinta Basin, the Douglas Creek is 200-800’ thick and can be subdivided into two main intervals. The Lower Douglas Creek is an unconventional play characterized by world-class TOC and interconnected organic porosity which is readily mapped using sonic logs. The Upper Douglas Creek is a tight conventional play with fine-grained dolomicrites serving as the primary reservoirs and drilling targets, which can be mapped by tying wireline facies to core and cuttings analysis. Oils produced from Douglas Creek wells show distinct geochemical characteristics when compared to oils produced from the Castle Peak, Uteland Butte, and Wasatch, indicating the two zones are separate tanks and do not require concurrent development to maximize drainage efficiency. Maturity trends from vitrinite reflectance show the entire Douglas Creek to be within the oil window of >0.8 Vro for Type I kerogen. Bottomhole pressure calculations show the reservoir to be overpressured at 0.65 – 0.75 psi/ft which is supported by extensive calcite “beef” fracturing in the source rocks. There is much work to be done as the play shifts from standalone exploration wells into full cube development, but it is clear the Douglas Creek represents an exciting new chapter in the potential of the Uinta Basin.