In the titled reservoir of average stratum temperature 65℃ and oil in place viscosity 90.34 mPa·s, a series of profiling and/or flooding operations were performed and led to a water cut of 97%. To seek for ways of further oil recovery, a laboratory experimental study on air foam flooding was made. The microscopic simulating experiment demonstrated that plugging/blocking and emulsifying mechanisms were involved in oil displacement. In static oxidation experiment, it was found that the oil could be oxidized slowly under simulated reservoir conditions with an oxidation rate of (2.261×10^-5—2.448×10^-5 molO₂·h^-1·[mL(oil)]^-1 determined, which increased with raising pressure and temperature. In the physical modeling experiment on sandpacks, air, air foam, water, and air again were injected successively after an initial water injection, which stopped at 12.35% oil recovery obtained, and an enhancement in oil recovery of 36.47%, 14.12%, 11.18%, and 0%, respectively, was observed; the changes in CO₂ and O₂ contents in the produced gas mixture indicated oxidation of experimental viscous oil and the variation in injecting pressure indicated plugging/blocking effect of the air foam. For the titled reservoir, air foam flood seems to be a practical method of EOR.