Simulation of the Immiscible WAG Process Using Cycle-Dependent Three-Phase Relative Permeabilities

Abstract

Abstract Oil recovery by immiscible WAG is dependent on the saturation cycles that occur in a core-flood or in the reservoir. For the reservoir case, segregation of gas and water can generate other saturation cycles than in a core-flood. In order to predict WAG behavior in the reservoir from experimental results, numerical models with an effective hysteresis description of the three-phase oil, water and gas relative permeabilities should be considered. There has earlier been developed a methodology that accounts for both three-phase flow effects and hysteresis effects in numerical simulations of the immiscible WAG process. Simulation studies have shown how three-phase flow description may influence the choice of drive mechanisms and also the design of a WAG process. Furthermore, a principal component analysis (PCA) is conducted on the simulation model that is consistent with the experimental data. The results from the PCA showed how the hysteresis parameters in the simulation model may be correlated to the physical system. The PCA analysis describe how the three-phase effects in water and gas relative permeabilities are connected to oil recovery. The results show that the cycle-dependent relative permeabilities increase the potential for WAG. Furthermore, the oil production trends with respect to slug length and water-oil ratio is different for models with cycle-dependent hysteresis and without hysteresis.