Abstract: Technology of foam flooding is studied for the purpose of enhancing oil recovery in oil reservoirs of high heterogeneity.Based on using the materials of foaming agents and crude oil obtained from oilfields,this paper studies the mechanism of nitrogen hot-water foam flooding enhancing oil recovery using physical simulation and reservoir simulation.A three-dimensional,three-phase,and multiple-component model is developed,and the software for three-dimension,three-phase,and multiple-component reservoir simulation is established on the basis of modularization theory.Phase equilibrium and effects of temperature and interfacial tension on multiple-phase flow in porous media are taken into account in the model,and the model can comprehensively describe the mechanisms of nitrogen hot-water foam flooding.The results of experiment and simulation show that the nitrogen hot-water foam flooding can significantly enhance displacement efficiency,lowering the remaining oil saturation.It is more effective for heterogeneous formations rather than for homogeneous ones,since the residual oil saturation is reduced 21.1%,while oil recovery is increased by 32.1%.