Abstract: The influence factor on the stability of foam system formed by CO₂ and FCY is researched with foam scanner and interfacial tension meter. The relations among surface tension, modulus, foam entrainment and foam stability are systematically analyzed, The relation of the modulus and rebirth ability is explained, too. It is recognized that Entrainment ability and deformation ability influence foam stability mostly. The increase of entrainment ability and deformation ability enhances the foam stability, rebirth ability of foam system is effected by deformation ability, the increase of modulus makes the rebirth ability drop. The bound of modulus for foam system must meet the request of foam stability and rebirth ability.

Key words: foam flooding, CO₂, modulus, entrainment ability, deformation ability, rebirth ability, foam stability