Research On The Technology Of Thermal/chemical Combination Flooding After Polymer Flooding For Further Enhancing Oil Recovery

At present, most of the reservoir has entered high water-cut stage, through water flooding and polymer flooding in subsequent water flooding. It is necessary to explore a feasible approach to mine the remaining and sporadic oil . Therefore, this paper studied the polymer flooding mechanism (micro and macro), and proposed to resolve some problems appeared after the polymer flooding to enhance oil recovery by the thermal and chemical compound technology. A deep research on the thermal/chemical composite technology, mechanism of flooding provide the theoretical basis that is the thermal /chemical combination flooding technology can further improve recovery after polymer flooding.This paper mainly analyzed the thermal /chemical compound flooding mechanism and method of physical chemistry phenomenon, the according to the heat/chemical compound flooding technology mechanism, using mathematical methods with some experimental data from the aspects of theory and reservoir numerical simulation, established the mathematical model of 3D, three-phase multicomponent. Model considered phase equilibrium, the effects of temperature and interfaeial tension on the oil ,gas and water three-phase flow, and considered surfactants in reservoir with diffusion and the adsorption, under high temperature hot degradation and surfactant with formation water ion of chemical reaction, the loss of factors fully refect a hot/chemical compound recovery mechanism.By using the finite difference method for the discrete mathematic model. Reference by conventional thermal model method, the model was solved by using implicit finite difference and iterative method for combining solution, then substituting the obtained thermal parameters for the new chemical parameter, and at the same time implicit algorithm is used to solve the active transport equation.Using the program to simulate a block after polymer flooding by the heat/chemical complex flooding recovery technique discussed, analyzing the injection temperature and surfactant nature parameters on the effect of thermal/chemical compound flooding, and optimizing the parameters was studied for the implement. It provided the technology for field application, and theoretical basis for designing scheme. The results showed thermal and chemical compound technology can largely reduce residual oil saturation after polymer flooding, and adjust the contradiction between layers of the reservoir.