The paper by Liyuan Lang et al explore air-foam's effectiveness in recovering heavy oil across various reservoir conditions, analyzing its flow behavior in porous media and the impact of key factors like gas-liquid ratio, injection rate, and crude oil saturation. They utilized foaming agent XHY-4 at 0.1 wt%, revealing air-foam's capability to enhance oil recovery by displacing fluid from high to low permeability zones, thus decreasing water cut.