Journal of Canadian Petroleum Technology, Vol.43, No.5, 30-40, 2004
Issues with reservoir geomechanical simulations of the SAGD process
In the SAGD process, steam injection may result in pore pressure changes around the steam chamber in the reservoir. The magnitude of the pore pressure change depends on the steam injection pressure and the relative position of the steam chamber within the reservoir. Injected steam also increases the temperature within and adjacent to the steam chamber and thus introduces thermal expansion effects. The complex interaction of pore pressure and temperature throughout the reservoir result in varying degrees of reservoir geomechanical interactions that must be considered when contemplating reservoir geomechanical simulations of the SAGD process. The primary geomechanical influence on SAGD recovery is associated with the volume change of the sand matrix in, response to effective stress changes induced by steam injection pressures and temperatures. Reservoir parameters and processes, such as compressibilty, porosity (pore volume), absolute permeability, relative permeability, saturations, capillary pressure, enthalpy transmissibility, gas evolution, and thermal expansion effects, are all affected by bulk volume changes. In this paper, variations of these parameters due to geomechanical effect are analyzed and discussed based on related test results, calculation, and simulation. Their impacts on reservoir geomechanical simulations of the SAGD process are discussed.