Emergent chemo-hydro-mechanical phenomena in carbon geological storage

Abstract

The combustion of fossil fuels produces carbon dioxide (CO2). Carbon capture and geological storage (CCS) has been proposed to reduce the emission of greenhouse gases to the atmosphere. The properties of CO2 depend on pressure and temperature: it can be found as a gas, liquid, or supercritical, and it reacts with water to produce carbonic acid lowering the water pH and can form a solid hydrate mass. These characteristics give rise to complex chemo-hydro-thermo-mechanical coupled processes and emergent phenomena that can condition the long-term geological storage of CO2. Processes include wettability, leakage, mineral dissolution, and CH4 -CO2 replacement in hydrate-bearing sediments.