In view of the increasing water content in China's oil fields, foam has good pugging performance and flow redirection effect, and has broad application prospects. In this paper, the sealing characteristics of bubble redirection effect was studied, the fluid flow was investigated under the condition of different seal characteristics of foam, and effect of flow redirection and enhancing oil recovery was examined. The results show that the foam has good plugging performance, and can be effectively blocked under suitable conditions. The higher the back pressure, gas liquid ratio and core permeability are, the lower the injection speed is, the bigger the resistance factor and residual resistance factor of the foam are, the greater the plugging is. For non-homogeneous reservoirs with a permeability differential of 5.56, foam has effect of flow redirection and can plug the high permeability layer in core selectively. The subsequent injection of water into the low permeability layer will drive out the residual oil, and the bubble drive will increase the recovery rate by 28%.

Aiming at the bad stability performance of normal foam in the Yan Chang No.6 oil field, a high stability gel foam system was developed and then evaluated in the aspect of stability and plugging. Through comparison and selection, now the system is made up of 0.4% FP388 foam agent, 0.3% AZ polymer, 0.3% T1&T2 crosslinker, and 0.3% CK2 foam stabilizer. The stability experiment of gel foam indicate that the half life of gel foam is 12 d and the viscosity of gel foam can stay at a high level, also remains stable in 30 d under 80 ℃ and 10 000 mg/L mineralization degree environmental conditions. The foam gel system has good injection and gel forming properties and can effectively seal medium high permeability reservoir.