HR: 1340h
AN: H13F-1647    [Abstracts]
TI: Mineral Dissolution, Enhanced CO2 Solubility Trapping and Convective Mixing
AU: * Xu, T
EM: Tianfu_Xu@lbl.gov
AF: Lawrence Berkeley National Laboratory, Mail stop 90-1116, One Cyclotron Road, Berkeley, CA 94720, United States
AU: Pruess, K
EM: K_Pruess@lbl.gov
AF: Lawrence Berkeley National Laboratory, Mail stop 90-1116, One Cyclotron Road, Berkeley, CA 94720, United States
AB: CO2 injected into an aquifer storage reservoir will tend to migrate upwards towards the cap-rock because the density of supercritical CO2 phase is lower than that of water (aqueous phase). In the upper portions of the reservoir, CO2 dissolution into groundwater will increase pH and induce mineral dissolution and complexing with dissolved ions such as Na+, Ca2+, Mg2+, and Fe2+ to form NaHCO3, CaHCO3+, MgHCO3+, and FeHCO3+. Over time these dissolution and complexing processes will increase CO2 solubility, enhance solubility trapping, and will increase the density of the aqueous phase. Aqueous phase will then move downward due to gravity, giving rise to "convective mixing". We have developed a multi-phase reactive geochemical transport model that accounts for the essential processes of flow, transport and chemistry, including changes in aqueous phase density and viscosity due to changes in dissolved species concentrations. Changes in porosity and permeability due to chemical dissolution and precipitation are also modeled. The process of enhanced solubility trapping and convective mixing was explored through application to a gulf coast sandstone saline aquifer. This work was supported by the Zero Emission Research and Technology project (ZERT) under Contract No. DE- AC02-05CH11231 with the U.S. Department of Energy.
DE: 1009 Geochemical modeling (3610, 8410)
DE: 3610 Geochemical modeling (1009, 8410)
DE: 3653 Fluid flow
DE: 8410 Geochemical modeling (1009, 3610)
SC: Hydrology [H]
MN: 2007 Fall Meeting