Modeling leakage scenarios of CO2 enriched brine through fault from storage reservoir to the surface with retardation due to matrix diffusion and adsorption in the matrix of the dissolved phase CO2 including behavior of exolved CO2 on two phase flow

After injection of carbon dioxide in reservoirs it dissolves in the formation water thus producing CO2 enriched brine. Although CO2 saturated brine gets denser than the formation water yet there is risk of brine leakage towards the surface due to either increased reservoir pressure as a result of CO2 injection or large-scale groundwater motion. The flow of brine through weaker zones, like faults, may cause the transport of dissolved CO2 and while reaching the shallower depths, aqueous phase CO2 may come out of solution as a separate gas phase. This study presents the results of brine leakage through fault including the effects of matrix diffusion and adsorption on the mobility and spreading of CO2. Breakthrough curves show retardation of CO2 transport along the fracture caused by matrix diffusion and adsorption in the rock-matrix. Two phase flow develops as a result of evolving gas phase due to exolution of CO2aq and significant saturation of gas phase CO2 is observed towards the surface.