A Single Pore Model for Displacement of Heavy Oil with Carbon Dioxide

When a gas displaces a viscous liquid in a pore, a thin liquid film is entrained as the gas finger moves forward.  The fluid mechanics of the problem (Bretherton problem), particularly those at low capillary numbers and where the entrained thin film needs disjoining pressure, are known in form of entrained film thickness as a function of capillary pressure.  To this problem, mass transfer in the form of dissolution of CO2 in oil under high pressure has been added with accompanying changes in density, viscosity and diffusivity (of CO2) in the liquid phase.  The physical property changes are taken from existing data.  The results, obtained using FLUENT and pertinent to CO2 flooding of heavy oils, will be discussed.  They include the effect on profile shapes, capillary numbers, the thickness of the oil films left behind as well as the net mass transfer rates.  They also include the deficiencies of FLUENT for this problem, where the time restrictions confine it to larger capillary numbers.  However, the capillary numbers are not too large and the method can, in principle, be extended to the low capillary numbers.  At higher (but still low) capillary numbers, the results are relevant to bubble columns.