Abstract
This study aims to investigate the permeability and storativity characteristics of sedimentary rocks injected with supercritical CO2. Recent development of CO2 storage in sedimentary rocks requires knowledge of CO2 behavior in deep undergroundcharacterized as geological layers with low hydraulic gradient, high pressure and high temperature. Therefore, we developed a new flow pump permeability test, so that the test will be able to reproduce similar physical condition of deep underground whereCO2 behaves in supercritical state. The injection of supercritical CO2 was conducted on a cored Ainoura sandstone saturated withwater. A numerical simulation based on the theoretical analysis of flow pump permeability test incorporating Darcy's law for two phases flow was also undertaken in order to interpret the experimental results especially to examine the relative permeability and saturation of the saturated water and supercritical CO2 including the specific storage of the sandstone during supercritical CO2 injection. It is observed that, supercritical CO2 apparent to spend a very long time in flowing through the sandstone pores. The specific storage of the sandstone increases due to the displacement of the saturated water by incoming supercritical CO2. Very slow process of supercritical CO2 migration in the sandstone pores might be caused by the low hydraulic gradient employed in the experiment and the effect of capillary pressure functioning as such capillary trapper. These results indicate low permeable rocks could become an effective storage of supercritical CO2. This study also shows that a new developed flow pump permeability test has been able to work with supercritical CO2 injection to low permeable rocks.
