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.