Experiment on liquid and supercritical CO2 distribution using micro-focus X-ray CT for estimation of geological storage

AbstractCarbon capture and storage (CCS) is a global challenge to the mitigation of global warming and climate change. Geological sequestration is an immediately available and technologically feasible method to achieve a substantial reduction in the carbon dioxide (CO2) emissions to the atmosphere. The density of CO2 is less than that of water, and therefore, injected CO2 migrates upward in the aquifer owing to the buoyancy force. Therefore, geological storage techniques require a mechanism that will prevent the upward migration of the injected CO2 and a highly impermeable layer (caprock structure) is generally employed to prevent CO2 leakage from the storage reservoirs. The evaluation of the storage site and the assessment of CO2 leakage risks and storage costs are difficult. The present study was aimed at clarifying the fundamental mechanism of CO2 migration in a reservoir. The behavior of CO2 in water-saturated sandstone was observed by microfocus X-ray computed tomography (CT)