SIMULATING THE EFFECTS OF CARBON SEQUESTRATION ON THE LAMOTTE SANDSTONE IN SW MISSOURI USING GEOCHEMIST'S WORKBENCH

City Utilities in Springfield, Missouri is considering a pilot CO₂ sequestration project within the Lamotte Sandstone, located at approximately 2,000 ft depth beneath the Southwest Power Station. Geochemical models were used to help determine the reactions that will take place within the Lamotte generated by the injection of the CO₂. Lamotte Sandstone parameters of temperature, pressure, and fugacity are assumed at 30°C, 62 bar, and 53.3 bar, respectively. Mineralogic analysis of the sandstone shows quartz, k-feldspar, albite, kaolinite, illite, smectite, and chlorite are present. Because no public water chemistry data exists for the Lamotte Sandstone in Southwest Missouri, water chemistry data reported for Bonneterre (250 miles east of Springfield) and other sandstones aquifers were included into the model. The parameters were incorporated into Geochemist’s Workbench (standard 8.0) as a proxy for the Lamotte Sandstone beneath the proposed site. Kinetic data of the minerals within the sandstone were also added to the model. Prograde and retrograde phases of CO₂ injection into the target formation were simulated. The modeling results of these phases estimate that about 70 g CO₂/kg of water will be trapped within the formation fluid. Approximately 250 to 300 g per kg of pore water of CO₂ may be trapped within carbonate minerals, mainly as dolomite, siderite, and magnesite.

This material is based upon work sponsored by the Department of Energy National Energy Technology Laboratory under Award Number DE-NT0006642 to City Utilities of Springfield, MO.