Aiming at the problems of viscous indexing,insufficient producing,and low recovery in the process of water flooding in ordinary heavy oil reservoirs,based on Ji 7 Reservoir in Xinjiang Oilfield,the foam oil cold recov-ery technology was researched induced by water-alternating-gas injection,and the foam oil sample preparation de-vice was designed by itself.The image of foam oil was characterized by Image J software,and the performance,bubble diameter,and foam number of foam oil were comprehensively analyzed;the visual plane model was designed and made to research the microscopic oil displacement mechanism of foam oil during gas injection assisted water flooding in heavy oil reservoir;the core displacement experiment was carried out to optimize the injection parameters of foam oil cold recovery induced by water-alternating-gas.The research shows that the foam oil formed by CO2 in low-viscosity crude oil has better performance;the foaming volume is 202.1 mL,the half-life is 324 s,and the viscosity reduction rate is 32.35%;the foaming volume and half-life of foam oil are usually negatively correlated with the bubble diameter and the number of foam oil;the foam oil polymerization has a stripping effect on viscous wall residual oil,and CO2 can effectively produce crude oil,oil film,and upper crude oil in small pore throat;un-der the condition of the gas-liquid ratio of 1 ∶ 1,the injection pressure of 30 MPa,and flooding rate of 0.2 mL/min,the foam oil cold recovery induced by water-alternating-gas could improve recovery by 18.90%compared with the ordinary water flooding in the heavy oil reservoir.The research results provide a theoretical basis for the foam oil cold recovery induced by water-alternating-gas injection in Ji 7 reservoir of Xinjiang Oilfield and also pro-vide a reference for the enhanced oil recovery technology of water flooding heavy oil reservoirs in other oilfields.
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