Effect of Temperature and Calcite on Carbon Dioxide Transport and Hydrate Stability in Geological Formations

Abstract

All of the simulated systems showed evidence of carbon dioxide transport and interface stability heavily affected by presence of calcite and temperature. CO2 molecules are able to cross both aqueous layers. At low temperatures, CO2 molecules assumed positions at the centers of the partial hydrate cavities. These CO2 molecules tended to remain trapped and behaved very similar to the bulk hydrate CO2 guest molecules. The neighboring free water molecules formed hydrate-like hydrogen bonded structures. At all simulations temperatures, many CO2 molecules were adsorbed on calcite surface. The calcite adsorption rate of CO2 molecules increased with the temperature. When the molecules come close to the calcite surface, a single CO2 molecule is adsorbed onto a calcium ion so as to maximize the electrostatic attraction. These calcium-CO2 pairs are very stable and will permanently remove CO2 from solution thus enhancing the efficiency of CO2 storage in geological formations for carbon emission mitigation and enhanced oil recovery.