Pore scale modelling of Three-Phase Capillary Pressure Curves Directly in Uniformly-Wet Rock Images

n this work we developed a semi-analytical model to compute threephase capillary pressure curves and associated fluid-configurations for gas invasion in uniformly-wet rock images. The fluid-configurations and favorable capillary entry pressures are determined based on free energy minimization by combining all physically allowed three-phase arc menisci. The model was first validated against analytical solutions developed in a starshape pore space, and subsequently employed on an SEM image of Bentheim sandstone. The simulated fluid-configurations shows similar oil-layer behavior as previously imaged three-phase fluid-configurations. The simulate saturation path indicate that the oil-water capillary pressure can be described as a function of the water saturation only. The gas-oil capillary pressure can be represented as a function of gas saturation in the majority part of the three-phase region. While the three-phase displacements slightly reduce the accuracy of such representation. At small oil saturations, the gas-oil capillary pressure depends strongly on two phase saturations.