Hysteresis in Relative Permeability from Cyclic Water-Oil Corefloods

Water injection is a long-standing method for secondary oil recovery, benefiting from favorable water/oilmobility. However, ultimate recovery can be limited by gravity segregation in thick reservoirs, snap-off trapping inwater-wet rocks, and low mobility in viscous oil systems. This study investigates relative permeability hysteresisthrough six cyclic coreflooding experiments WOWO (Water-Oil-Water-Oil) on turbidite sandstones with diverseporosity and permeability. The goal is to derive drainage and imbibition Kr curves under high interfacial tensionconditions, evaluating hysteresis and saturation path effects. Water/oil tests used formation brine and dead oil atreservoir temperature and 10 bar pore pressure. 2D X-ray imaging enabled visualization of fluid fronts and capillaryend-effects. Results revealed phase-dependent hysteresis, as WOWO tests exhibited cycle-dependent hysteresis,leading to fluid trapping, mobility reduction, and deviations in Kr and Pc behavior from conventional simulatormodels.