Abstract: Air foam flooding has very bright future because of its comprehensive displacement mechanism and unique air
source predominance. To apply the technique successfully in high temperature reservoir丆this paper conducted study on the
temperature resist air foam system. By examining the foam volume and liquid separating half-life period of ten temperature
resist surfactants at 110 亷 and 6  104 mg/L丆we screen out the anionic-nonionic surfactant LS which has satisfactory high
temperature foam performance. We evaluate the foam performance of LS at reservoir environment and the result shows that LS
could form more abundant foam at high pressure seal condition than atmospheric pressure丟the persistent shear of porous media
and plenty air flow is in favor of LS fully playing its foam performance. By adding foam stabilizer WP whose concentration is
beyond 0.1%丆the liquid separating half-life period of LS could be evidently enhanced. After aging under 110亷and 6104 mg/L
for 90 d丆the liquid separating half-life period of 0.2%LS+0.1%WP only shortens by 20%丆and its IFT with Guan80 crude oil
remains 10..2 mN/m. Furthermore丆the emulsification capability of air foam is satisfactory丆oil and water being separated almost
completely after standing short length of time.

Key words: air foam, temperature resist, foam volume, half-life period, high pressure, emulsification