Geosequestration of CO2 has been identified as a promising technique to mitigate global warming. Deep un-minable coal seams are recognised as potential reservoir for CO2 sequestration, where great amount of CO2 can be stored and large volume of CH4 can be extracted during the process. However, injection of CO2 in coal seams will lead to its physical and chemical structure to be significantly changed, resulting in a modification of coal mass hydro-mechanical properties. Ultimately, these alterations will affect the safety and efficiency of the sequestration project.

This project aims to characterize coal microstructural and mineralogical changes upon CO2 injection and investigate the resultant hydro-mechanical properties alteration under in-situ conditions. In-situ CT imaging will be conducted using X-ray triaxial cell to study the fracture network change of coal due to coal-CO2 interaction at reservoir conditions and lattice Boltzmann method will be applied on the micro-CT images to determine the flow behaviour variation. Chemical and mineralogical reactions will be studied by conducting SEM-EDS, XRD and ICP-MS analysis. Mechanical property change of coal will be determined by conducting UCS, P S wave and nano-indentation tests.