Numerical investigations on performance of sc-CO2 sequestration associated with the evolution of porosity and permeability in low permeable saline aquifers

Abstract

Storing of supercritical carbon dioxide (sc-CO2) in the saline aquifer is studied extensively in the present work using numerical investigations. A mathematical model is developed and applied successfully to determine the movement of sc-CO2 from the injection well along the low permeable saline aquifer. The injected fluid and petrophysical properties are considered as a function of pore pressure in the formation. The impact of permeability modulus in both low and high permeable saline aquifers are studied. The impact of porosity, permeability, injection velocity, permeability anisotropy, residual water saturation, and residual gas saturation is studied. All these parameters influence the migration of sc-CO2 in the reservoir and storage capacity. It is observed that the pore pressure is highly impacted by the change in permeability and injection velocity. Porosity is inversely proportional to pore pressure buildup and directly proportional to the storing of sc-CO2 in the porous media. Due to the increase in pore pressure, the change in porosity is 14.5%, while the change in permeability is 7mD (millidarcy) for 1000 days. At a lower permeability ratio (kV/kH), due to an increase in pore pressure also, the migration of injected sc-CO2 in a vertical direction is decreased when compared with a higher permeability ratio. Thus, this work provides a better understanding of the influencing parameters for storing and migration of sc-CO2 in the low permeable saline aquifer.