Numerical Simulation of the Storage of CO2 and COi-H2S Gas Mixture in Deep Saline Aquifers

Numerical simulations were performed to understand the flow and storage potential of pure CO2 and CO2-H2S gas mixtures in deep saline aquifers. Flow and distribution of the injected CO2 and CO2-H2S gas mixtures in different forms in typical aquifers were studied. During injection of the supercritical gas/gas mixture into the aquifer, the gases follow the first drainage curve. Subsequently, however, the flow of brine and gas is counter-current and driven mostly by gravity, so hysteresis in the relative permeability curve results in substantial volumes of gas trapping as well as more contact with brine and this in turn leads to both more dissolution in the brine and more reactions and thus storage as precipitated minerals. Strategies for maximizing these beneficial storage effects were studied. Simulations using a compositional reservoir .simulator.