Features concerning capillary pressure and the effect on two-phase and three-phase flow

Abstract

The effect of capillary pressure related to immiscible WAG (Water Alternate Gas) is studied by use of a numerical simulator. The capillary pressure is found to have a significant effect on the pressure gradient and the total oil production both in two-phase and three-phase flow situations. When the capillary pressure is included in the simulation the total oil production is considerably lower than when the capillary pressure is neglected. Experimentally measured two-phase capillary pressure was used as input to the numerical simulator. The two-phase capillary pressure was further used to estimate three-phase flow, related to WAG processes. A network model was applied to generate a consistent set of two-phase and three-phase capillary pressure. The network model was anchored to measured two-phase data, and threephase capillary pressure was constructed. The gas-oil and mercury capillary pressure anchored the pore structure parameters, while water-oil capillary pressure anchors the wettability parameters in the network model. The network model quantifies the difference between three-phase and two-phase capillary pressure, and in the cases studied the difference between two-phase and three-phase capillary pressure was significant.