Simulation of important processes in CO2 storage in aquifers

Abstract

This chapter shows the application of a geochemical equation of state (EOS) compositional simulator to the modeling of important processes for CO2 storage in aquifers. The simulator (GEM-GHG) models the following phenomena: (1) convective and diffusive transport of components in the gas and aqueous phases, (2) gas solubility in the aqueous phase, the increase in aqueous density with increased gas solubility, (3) intra-aqueous chemical equilibrium reactions, mineral dissolution and precipitation, and (4) leakage through the cap rock and through sealing faults. GEM can model the flow of three-phase, multicomponent fluids and can provide a robust model for any type of reservoir where the importance of the fluids' chemical composition is key to the proper prediction of essential physics. An option for Greenhouse Gas (GHG) has been added to GEM to model CO2 storage in saline aquifers. A simulation of CO2 storage in a homogeneous aquifer illustrates the downward migration of a dominant CO2-saturated plume, which is followed later by secondary plumes. Conversion of CO2 into carbonate mineral is observed around these plumes.