Research On Thermal Chemical Complex Flooding Enhanced Oil Recovery Theory After Polymer Flooding

Enhanced oil recovery is the eternal theme of petroleum industry in the world, reservoirhas already entered the stage of high water-cut stageafter after water flooding and polymerflooding. The increasing of recovery by polymer flooding is only10%,there is nearly half ofoil after polymer flooding in underground，so it is urgently need to probe means ofincreasing the recovery after Polymer flooding. The mechanism of thermal/chemical polymerflooding after polymer flooding is complex, but the theoretical basis of enhancing oilrecovery by thermal/chemical flooding after polymer flooding is deficit at the moment.In this paper, through the study of macro mechanism and microscopic mechanism ofpolymer solution，find out the existing problems after polymer flooding, and starting fromthese issues, in-depth study on the mechanism of thermal chemical recognition technology.The thermal/chemical compound flooding mathematical model is established by basing onthermodynamic production mathematical model and combining with the actual situation andthermal/chemical recognition mechanism. we consider the three-phase fluid balance and heatbalance in the model. The model mainly includes the following equation.(1) Components ofthe mass conservation equation.(2) Energy conservation equation.(3) The surfactant transportequation. In this paper, the mathematical model is solved by both simultaneous solution andsuccessive solution. That is to say, in a time period use the fully implicit simultaneoussolution method to solve thermal oil recovery mathematical model, then use the implicitmethod to solve the surfactant transport equations.The algorithm has good stability, simpleprocess. Then use the model further research the oil displacement effect under differentinjection parameters in the thermal/chemical compound flooding after polymer floodingsystem. The research results will make the microscopic oil displacement theory developeffectively and rich micro percolation mechanics theory. The new method and theoreticalbasis is provided for the oil field to improve oil recovery after polymer flooding at the highwater-cut stage.