Pore-Scale Saturation, Temperature, Pressure and Velocity Characterization of SAGD Process

ABSTRACT

In this paper, pore-scale phenomena in SAGD such as steam propagation and fingering as well as entrapment of oil behind the swept zone are visualized and evaluated. Using saturation, temperature, velocity and pressure profiles at the steam chamber edge and throughout the media, the interconnectivity of each parameter is discussed. For this goal, a 2-D glass micromodel was reconstructed, binarized and meshed in COMSOL. Then the digital 2-D micromodel was fed into OpenFOAM, which is the open source CFD package of choice in this work. The mass and momentum conservation equations are used to model the fluid dynamic. For tackling the phase change, i.e. steam condensation and evaporation on the interface, within the simulation, the Lee phase change model was added to the pre-defined Volume of Fluid (VOF) based solver, compressibleMultiphaseInterFoam. The Lee model assumes that mass is transferred at a constant pressure due to temperature difference. For each phase in the multi-region model, sets of mass conservation, Navier-Stokes momentum and energy equations under nonisothermal conditions are solved simultaneously. The results show connection between temperature, pressure, velocity and flow (saturation) profile. Sharp temperature gradient between steam and oil phase was observed, pressure profile throughout the medium shows pressure buildup behind the steam-oil interface, downward flowing of condensate and heated oil as well as upward and sideways propagation of steam was observed through flow streams and velocity profile component. Heat propagation within the media and viscosity reduction was investigated. Oil entrapment behind the swept zone as well as steam chamber growth is demonstrated and finally effect of steam additives on sweep efficiency and recovery factor was reported.

A full version of this paper is available on JGMAAS Online.