Evaluation of the impact of CO2, co-contaminant gas, aqueous fluid and reservoir rock interactions on the geologic sequestration of CO2

Lowering the costs of front-end processes (e.g., separation) in the geologic sequestration of CO2 can dramatically lower the overall costs. One possible approach is to sequester less-pure CO2 waste streams that are less expensive or require less energy to separate from flue gas or a coal gasification process, etc. The objective of this research is to evaluate the impacts of CO2 itself, as well as an impure CO2 waste stream, on geologic sequestration using reaction progress models, reactive transport simulators and analogous reactive transport experiments run in a plug flow reactor. Specifically, we are investigating the potential for co-injecting the SOx, NOx, and H2S present in coal-fired waste streams along with the CO2. We present here the results of reactive transport simulations made to investigate the long-term impact of dissolved CO2, H2S and SO2 on carbon sequestration in the Frio Fm., TX. The results suggest that addition of relatively large amounts of H2S to a CO2 injection should not adversely impact injectivity or sequestration compared to the injection of CO2 alone. The co-injection of SO2, however, could produce significantly different results, if conditions are such that SO2 can oxidize to sulfate. In the long-term the simulations suggest that carbonate mineral formation can sequester a significant fraction of the injected carbon through the formation of calcite, magnesite and dawsonite. (c) 2005 Elsevier B.V. All rights reserved.