Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions

Abstract

Microstructural evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37% moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10 MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10 MPa confining pressure and after 7 h of exposure to ScCO2, and (3) coal was subjecte..