GIS AS A DATA MANAGEMENT TOOL FOR EVALUATING BASALT SEQUESTRATION POTENTIAL IN THE COLUMBIA BASIN

Though the Northwestern United States may have limited options for conventional CO₂ storage reservoirs, the region is home to thick and widespread continental flood basalts that may represent a regionally significant resource for the long-term storage of CO₂ captured from fossil-fueled power plants and other large, stationary CO₂ sources. The flows of the Columbia River Basalt Group (CRBG) have a combined thickness of approximately 5,000 m and cover an area of 168,000 sq km. Brecciated interflow zones within the CRBG may have potential for geologic storage of anthropogenic CO₂. Laboratory experiments indicate a rapid chemical reaction of basalts with both water-bearing supercritical CO₂ and the slightly acidic formation fluids containing dissolved CO₂ to precipitate stable carbonate minerals, providing encouraging evidence for the potential of basalt-based CO₂ sequestration to permanently trap injected CO₂ via mineralization as well as more universal hydrodynamic and dissolution trapping mechanisms.

DOE’s Big Sky Regional Carbon Partnership is currently investigating the suitability of basalt reservoirs underlying the Boise White Paper mill near Wallula, Washington for safe, secure CO₂ storage. The newly drilled pilot well is providing invaluable subsurface data in this part of the Columbia Basin. Combining new wellbore, seismic, and outcrop data with public data from existing water wells, gas exploration wells, airborne magnetic surveys, geothermal, structural, and basemap data via GIS, the authors present a preliminary evaluation of the local interflow zones with potential as storage intervals, an approximation of their potential CO₂ storage capacity, and a discussion of the implications these new data bring to light regarding the stratigraphy and heterogeneity of the basalts at the Wallula site. This work provides the basis for a two- and three-dimensional visualization environment as well as a GIS-based decision support tool for project researchers and managers.