THE ROCK SPRINGS UPLIFT, WYOMING: AN OUTSTANDING GEOLOGICAL CO2 STORAGE SITE

According to the 2010 U.S. EPA Greenhouse Gas Reporting Program, stationary sources in southwestern Wyoming annually emit 29+ Mt of CO₂, or approximately 50 percent of the state’s CO₂ emissions. These industrial CO₂ emissions come from coal-fired power plants, gas and trona processing plants, pipeline compression stations, chemical production facilities, and gas field complexes. It is essential that Wyoming proactively pursue carbon capture and storage (CCS) technology to prepare for potential regulatory, political, and economic paradigm shifts that could diminish industrial activities in the Greater Green River Basin, consequently damaging the state’s economy.

Previous work using a generalized regional database suggested that the Rock Springs Uplift in the center of the Greater Green River Basin had the attributes to become a commercial-scale CO₂ storage site. To reduce uncertainty and refine previous numerical simulations (performance assessments) of the Uplift, data from a 3-D seismic survey over the area of interest (5 miles × 5 miles), a stratigraphic test well (12,800+ feet deep), 916 feet of high-quality core, a specialized log suite, a VSP survey, fluid samples, and laboratory analyses have been used. This new database has resulted in a more accurate evaluation of the spatial heterogeneity of reservoir/seal petrophysical properties. The integration of seismic attributes with observations from log suites, core, continuous permeability scans, fluid samples, and laboratory analyses produced distribution volumes of porosity, permeability, lithofacies, and fractures in the Madison Limestone and Weber Sandstone. Input of these volumes into the numerical simulations has resulted in improved performance assessments of the CO₂ storage capacity of the reservoir interval. In previous simulations, the spatial distribution of the injected CO₂ plume is cylindrical with few marginal irregularities, whereas in the new simulations, the CO₂ plume occupies a larger volume and displays pronounced marginal irregularities. The new data and performance evaluations demonstrate that the Rock Springs Uplift in the Greater Green River Basin remains an outstanding large-scale geological CO₂ storage site, and provides the information necessary to design commercial injection/storage facilities on the Uplift.