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Chemical viscosity reduction flooding is a new method to improve heavy oil recovery. The existing numerical simulation methods can not accurately describe the physical and chemical changes of each component and phase in the process of viscosity reduction flooding. Combined with oil-water two phase control equation, viscosity reducer concentration mass transfer equation and related auxiliary equation, a fully coupled chemical viscosity reduction displacement model of concentration and seepage field was established. Viscosity concentration relations of viscosity reducer solution, the relationship of the moisture content emulsion viscosity and interfacial tension of crude oil and the viscosity reducer solution of auxiliary equation was got through physical model experiment. The high order upwind scheme with boundedness overcomes the deficiency of the first order upwind scheme and calculation accuracy of concentration divergence was improved. The finite volume method was preferred to improve the accuracy of solving. The results of numerical simulation and core displacement experiment were verified. On this basis, the numerical experiment of viscosity reducer flooding was carried out and injection and production parameters of viscosity reduction flooding were optimized. The results show that the established model can characterize the viscosity control effect of viscosity reducing agent. With the increase of viscosity reducing agent concentration, injection rate and injection speed, the recovery degree increases gradually while the growth rate of recovery degree decreases gradually. The increase degree of recovery is maximum with 0. 4% concentration of viscosity reducing agent. Reasonable injection amount is ranged from 0. 2 PV to 0. 6 PV. The scheme with large slug and high viscosity reducing agent concentration in slug is recommended. The reasonable injection rate should be designed according to the field's own capacity. The study provides an important technical means for optimizing and adjusting the development mode of viscosity reduction flooding in heavy oil reservoirs. [ABSTRACT FROM AUTHOR]