Carbon dioxide flow and interactions in a high rank coal: Permeability evolution and reversibility of reactive processes

Uncertainties exist on the efficiency of CO2 injection and storage in deep unminable coal seems due to potential reduction in the permeability of coal that is induced by CO2 adsorption into the coal matrix. In addition, there is a limited knowledge about the stability of CO2 stored in coal due to changes in gas partial pressure caused by potential leakage. This paper presents an experimental study on permeability evolution in a high rank coal from South Wales coalfield due to interaction with different types of gases. The reversibility of the processes and stability of the stored CO2 in coal are investigated via a series of core flooding experiments in a bespoke triaxial flooding setup. A comprehensive and new set of high-resolution data on the permeability evolution of anthracite coal is presented.