Pore-level investigation of relative permeability hysteresis in water-wet systems

Network modelling studies are applied to the hysteresis phenomena in both strongly and weakly water-wet drainage/imbibition relative permeability curves. A three dimensional network model was formulated, which takes into account the underlying pore-scale physics, the initial water saturation, wettability alterations, film flow, phase trapping and realistic variations in advancing and receding contact angles. Simulations show that the nature of hysteresis changes significantly as these parameters are varied. The model also reproduces all experimentally-observed trends in relative permeability hysteresis. This is the first time that a pore-scale model has been used to provide a clear interpretation of all experimentally observed hysteresis trends.