An electrokinetic model for monitoring CO2 geosequestration

Abstract

A computational model for the monitoring CO2 flow in porous media using the electrokinetic front tracing technique is introduced. The governing field equations are derived based on the averaging theory and solved numerically based on a mixed discretization scheme [1-3]. The standard Galerkin finite element method is utilized to discretize the deformation and the diffusive dominant field equations, and the extended finite element method, together with the level-set method, is utilized to discretize the advective dominant field equations. The level-set method is employed to trace the CO2 plume front, and the extended finite element method is employed to model the high gradient in the saturation field front. This mixed discretization scheme leads to a convergent system, giving a stable and effectively mesh-independent model; furthermore, it minimizes the number of degrees of freedom, making the numerical scheme computationally efficient. Effects of the salinity content on the streaming potential are discussed.