In order to solve the problems such as the breakthrough of flue gas

frontal advance of combustion drive and conventional plugging technology do not meet the requirement of fire drive in the fire drive test area of Hongshanzui oilfield in Xinjiang. We used the device for testing the foam flow in core and the visual microscopic displacement model to study the flow experiment and the microscopic mechanism of flue gas foam. The experimental investigation showed: the gas-liquid ratio was an important factor that affects the capacity of foam blocking; the foam blockage ability was the strongest when the foam system was mixed with gas and the gas-liquid with ratio 1∶1; the oil recovery factor increased by 12.6 % after the flue gas foam injection. The microscopic mechanism research showed: the main reason why foam had the ability of blockage was the new foam blocked the big pore and increased the flow resistance of the fluid. The migration of foam in porous media was a kind of separate migration of gas phase and liquid phase; the trap and flow state of the foam were constantly transformed with the change of external conditions. The study can provide reference for the control of gas channeling in the fire flooding test area of Hongshanzui oilfield in Xinjiang and is helpful to improve the theory of bubble control.