Microscopic Displacement Mechanism Of Foam In Porous Media: An Experimental Study

Foam flooding is useful for enhancing oil recovery in a high-water-cut reservoir, and improves both the macro sweeping efficiency and the micro displacement efficiency. However, the mechanism involved in foam flooding oil displacement is complex, and current studies lack an understanding of the microscopic oil displacement mechanism involved. This paper uses an experimental study to simulate foam flow in micro porous media via a micro simulation model of lithography glass. By studying the microscopic flow characteristics of air-foam, it is possible to determine that the main methods of generating air-foam are liquid membrane hysteresis (LMH), liquid membrane breaking (LMB), and reduced diameter separation (RDS). The foam exists in porous media in two states, captured foam and movable foam, and the coalescence and breaking of foam in porous media mainly occurs through gas diffusing into a liquid membrane. Based of experiments of air-foam flow, the microscopic oil displacement mechanism of foam flooding is determined. Results indicate that after air-foam displacement there is a significant decrease in the amount of remaining oil (which is in an angular, membrane, and platelet form) within the porous media. This occurs by expansion, extrusion, carrying, and the shear and drag effects of the air-foam; where the foam displaces the angular, deadend, and flake-shaped oil that remains after water flooding in porous media. This study determines that foam flooding improves ultimate oil recovery.