Matthew B Johnson, Zunshen Jiao, Ying Yu, Fred McLaughlin, Scott Quillinan, Center for Economic Geology Research of the School of Energy Resources, University of Wyoming
CO₂ sequestration in geological media is the one the best available options for the long-term removal of anthropogenic CO₂. The Wyoming CarbonSAFE projects Phases I, II and III led by the University of Wyoming (UW) have documented that the Dry Fork carbon storage complex is a promising CO₂ storage location, characterized by its favorable geologic conditions (i.e., thick stacked saline aquafers and simple structure) and in close proximity to CO₂ sources. The 3D seismic attribute analysis, geophysical well logs interpretations and core observations and measurements to characterize the geological heterogeneity and simulate reservoir pressure fluctuations in three dimensions.
The Dry Fork CCS site is located within the northern Powder River Basin about six miles north of Gillette, Wyoming. The reservoir intervals with the greatest potential for CO₂ storage are the Permian-Pennsylvanian Minnelusa Formation, the Middle Jurassic Hulett Sandstone member of the Sundance Formation, and the Lower Cretaceous Lakota Sandstone of the Inyan Kara Group.
The project to date has used legacy well data, a 9875-foot-deep stratigraphic test well (more than 625 feet of core and complete log suite retrieved) and a 3 mile x 3 mile 3D seismic survey have been used to construct and reduce uncertainty in geologic models. Geologic modeling at the site includes structural and property models that delineate reservoir geometries, porosity and permeability distributions, lithofacies and fracture feature. Within the property models/volumes, we can now isolate individual reservoir horizons and construct maps of the distribution of petrophysical properties. Results of these modeling efforts are used to evaluate the injections feasibility, injected CO₂ migration and plume development, storage capacity, maximum injection pressure, reservoir pressure propagation, and determining the Area of Review fore Class VI well application in a 100 mi2 area around the Dry Fork Station. The simulation results show the heterogeneity of reservoir petrophysical property has prominent effects on the reservoir injectivity and storage capacity. This project results have significant utility in reducing risk for promoting commercial scale CO₂ storage in stacked deep saline aquifers in the Laramide Basins, Wyoming.