Numerical Simulation of Non-Isothermal Two-Phase Flow in Oil Reservoirs: Slab Geometry and Heated Fluid Injection

We address the numerical simulation of non-isothermal two-phase water-oil flow in oil reservoirs and deal with the problem of heavy oil recovery by heating the reservoir (via injection of heated fluid), aiming at reducing its viscosity and increasing its mobility. We write the governing equations in terms of the non-wetting phase pressure (oil), the wetting phase saturation (water), the reservoir average temperature without assuming the local thermal equilibrium hypothesis, and we consider that relative permeabilities vary with temperature. The Finite Volume Method is employed, and we linearize the resulting algebraic equations using the Picard method. The linearized discretized equations are solved sequentially to obtain the pressure, saturation, and average temperature using the Preconditioned Conjugate Gradient (pressure and average temperature) and Preconditioned Stabilized Biconjugate Gradient Method (saturation) methods. After validating the numerical results, we performed a sensitivity analysis considering a reservoir with slab geometry. The results showed the positive impact that reservoir heating has on the recovery of heavy oils.