Semi-Analytical Three-Phase Relative Permeability Model for Gas-Condensate

Abstract Modeling three-phase flow in gas-condensate systems requires the relative permeability of each fluid as a function of the fluid saturation. The Coreflood laboratory and experimental measurement of three-phase relative permeability (3-PRP) data is much complicated, more time consuming and relatively expensive when compared to forecasting two-phase relative permeability data. Owing to this, many three-phase relative permeability correlations have been proposed in the petroleum industry for estimating three-phase relative permeability using geometric or arithmetic summation and interpolation of two-phase relative permeability data. After comparing results of most of the existing three-phase models to Oaks experiment, we realized that most of the existing three-phase models fail to incorporate the physical mechanisms underlying multiphase flow in gas-condensate systems. This paper aims to fill this knowledge gap by proposing a novel 3-PRP model to forecast three-phase relative permeability in gas-condensate systems. Three-phase interactions between fluids and fluid saturations are fully incorporated in this model by introducing three-phase characteristic coefficients. Using these coefficients, the total two-phase oil saturation relative to water is not only a function of the three-phase oil saturation relative to water but it is expressed as a function of the three-phase oil saturation with respect to both water and gas. The proposed 3-PRP model is successfully validated against experimentally measured three-phase relative permeability data.