Study on formation and migration of emulsions in porous media during chemical flooding of heavy oil

Emulsification is one of the main mechanisms of chemical flooding to enhance oil recovery in heavy oil reservoirs. The emulsification of heavy oil in porous media is closely related to reservoir temperature and oil-displacing agent concentration. The relationship between the critical concentration and temperature of the oil-displacing agent required to form oil in water （O/W） emulsions in heavy oil was studied by emulsification experiment. The emulsification and migration rules of crude oil during chemical flooding of heavy oil were studied by using high-temperature and high-pressure microscopic visual oil displacement devices. The results show that a higher temperature in the emulsification experiment indicates that the crude oil is easier to emulsify， and the critical emulsification concentration of the required oil-displacing agent is lower. The critical emulsification concentration decreases by 90% when the temperature increases from 30 °C to 90 °C during the experiment. There are three modes of emulsific