Modeling CO2–Water–Mineral Wettability and Mineralization for Carbon Geosequestration

ConspectusCarbon dioxide (CO2) capture and storage (CCS) is an important climate change mitigation option along with improved energy efficiency, renewable energy, and nuclear energy. CO2 geosequestration, that is, to store CO2 under the subsurface of Earth, is feasible because the world’s sedimentary basins have high capacity and are often located in the same region of the world as emission sources. How CO2 interacts with the connate water and minerals is the focus of this Account. There are four trapping mechanisms that keep CO2 in the pores of subsurface rocks: (1) structural trapping, (2) residual trapping, (3) dissolution trapping, and (4) mineral trapping. The first two are dominated by capillary action, where wettability controls CO2 and water two-phase flow in porous media. We review state-of-the-art studies on CO2/water/mineral wettability, which was found to depend on pressure and temperature conditions, salt concentration in aqueous solutions, mineral surface chemistry, and geometry. We then rev...