Simulação de escoamentos bifásicos água-óleo tridimensionais não-isotérmicos em reservatórios de petróleo

Abstract

This work addresses the numerical simulation of non-isothermal two-phase flows in oil reservoirs. Specifically, it deals with the problem of recovering heavy oil by heating the reservoir, aiming to reduce its viscosity and increase its mobility. Energy is transfer red to the reservoir by the injection of heated fluid or static heating well. We consider a two-phase water-oil flow, and we write the governing partial differential equations in terms of the non-wetting phase pressure (oil), the wetting phase saturation (water) and the average reservoir temperature without assuming the hypothesis of the local thermal equilibrium. We choose the Finite Volume Method to discretize the governing equations, leading to algebraic equation which are linearized via the Picard method. We also use an operator splitting, and the linearized discretized equations are solved sequentially to obtain pressure, saturation, and average temperature. We solve the algebraic equation subsystems using Preconditioned Conjugate Gradient (pressure) and Preconditioned Sta bilized Biconjugate Gradient (saturation and temperature) methods. After validating the numerical results, we performed simulations predicting the injection of heated water into a reservoir with a Slab geometry and a sensitivity analysis. In the case of production in a reservoir with an arrangement of injection and production wells of the Five-spot type, we undertook a qualitative analysis. Besides the injection of the heated fluid, we simulated the flow in the presence of a well static heater. The results demonstrated the relevance of the physical-mathematical models and the methodologies applied. Further, they also showed the positive impact that the heating of the reservoir has on the recovery of heavy oils.