Research On Power Supply Technology For Improving Recovery Rate Of Low Permeability Reservoir

Nowadays,by external direct current electric field to enhance the ratio of oil recovery is a new technology to improve oil recovery.As the shortage of petroleum and gas resources has been a major problem for all countries in the world.Our country's major permeability oil fields in intermediate or advanced have entered the high water cut stage.But most of the discovered reservoirs are low permeability reservoirs,so the method we used before can not meet the new technical requirements.And the method of enhancing oil recovery by external electric field has a great future.This paper set up the model with the action of external electric field of the permeation and streaming law of two phase in different structures.Based on electron-osmosis theory.Receive the limited-element equations of two-phase flow.And then obtain exact solution of the problem by using analytic method of COMSOL Multi-physics.Analyzed the consistency of the water saturation and the water phase relative permeability on the relative permeability curve in theory,it is also discussed that the water saturation is lower when the applied electric field exists,than that in the absence of the electric field,finally validation the correctness of the two phase flow mathematical model in gap medium under applied electric field.In this paper,the variation trend of water saturation in the gap media module under the presence of the applied electric field is analyzed,and the gap media module with different gap width,different gap number and different gap structure under external electric field is constructed,and simulated and analyzed.Research results show that the applied electric field can make the gap medium water saturation decline in module.The research results show that with the increase of external electric field,water saturation of all the module have reduced.Especially for the narrower,fewer and the smaller connectivity.Through the deeply study,it is found that in the range of 0~240V,when the external DC electric field is 160 V,the effect of the module is the most significant,the water saturation of the two phase flow module is the smallest,and the oil saturation is the largest.According to the results of numerical simulation,set the 160 V as a standard of the output regulated DC power,combined with the Buck buffer circuit,soft switching technology and double closed-loop control circuit to design a regulated DC power.Validated and emulated the model based on MATLAB,obtain a electric field with reliable output.