A method, system and computer readable medium is presented for use in enhancing oil recovery in a subsurface reservoir comprising. The method, system and computer readable medium defines a plurality of grid levels on a geological model of a subsurface reservoir. Connectivities and transmissibilities are calculated between neighboring cells in the same grid and between connecting cells between different grid levels. Gas and/or fluid dynamics are simulated using dynamic grid refinement where the connectivities and transmissibilities are updated at each time step based on the previously calculated connectivities and transmissibilities.