Experimental and numerical study on the behavior of supercritical CO2 injected to low permeable rocks

In this study, we developed a new flow pump permeability test to investigate the behavior of CO2 injected into low permeable rocks. The injection of supercritical CO2 was conducted on a cored sandstone saturated with water. In addition, numerical analysis of flow pump permeability test incorporating Darcy's law for two phases flow analysis was developed in order to determine the relative permeability of saturated water and of CO2 as well as the specific storage of the core during CO2 injection. To examine the effect of CO2 state, the injection of liquid CO2 was also undertaken. It was observed that the injection of CO2 in liquid state is able to drive more CO2 flowing through the core, yet also generate a higher hydraulic pressure in comparison to supercritical CO2. The migration of supercritical CO2 in low permeable rocks within low gradient hydraulic will take very long time and indicates supercritical state becomes the appropriate state of CO2 in a long-term sequestration.