Simulation Of Downhole Gas Prevention Tools For Sucker Rod Pumping System With The High Gas-liquid Ratio Well

At present,the majority of China's oilfields have entered the middle and late stages of development,and the pressure on the ground lhas dropped significantly,resulting in an increase in natural gas.At the same time,as production progresses,some gas flooding reservoirs gradually break through the production wells,resulting in an increase in gas-liquid ratio in the production wells.When a rod pump is used to pump oil,the gas inletting pump will occupy a certain amount of space,so the pumping liquid will be reduced to reduce the coefficient of fullness,and even cause "gas locking".Gas anchor and anti-gas pump are effective tools to solve the effect of gas on pumping efficiency.They can be used alone or in combination.However,their applicable scope of gas-liquid ratio is not given quantitative evaluation and cannot effectively guide the field to reasonably select downhole gas prevention tools.For this reason,this paper adopts the research ideas of the combination of numerical simulation and object simulation to conduct in-depth research on gas anchors and anti-gas pumping pumps.The main works are as follows:(1)Considering the complex flow field of the fluid inside the gas anchor,the gas-liquid two-phase flow inside the gas anchor was simulated using a numerical simulation method.In the case of opening and closing of the pump valve,pump-specific numerical simulation software(PumpLinx)was used to simulate the gas-liquid two-phase flow inside the anti-air pump.(2)The combination of gas anchors with the best field gas distribution effect is preferred.Physical model is established,using dynamic grids,taking into account stroke and stroke times,using the Euler-PBM coupling model,the inlet adopts constant pressure boundary and pump active inlet,and the gas anchor is simulated by Fluent software,and the internal flow field and velocity field of the gas anchor are analyzed.The gas separation efficiency of gas anchors under different gas-liquid ratios was calculated.(3)The forced opening and closing anti-air pump with the best field gas distribution effect was selected.A three-dimensional model of anti-air pump was established and imported into PumpLinx software to solve the internal fluid of the anti-gas pump.The flow field and velocity field inside the anti-air pump were analyzed,and the pump efficiency of the anti-air pump was calculated under different gas-liquid ratios.(4)Based on the numerical simulation of air anchors and anti-air pumps,air-water simulation experiments were carried out for the combined gas anchors.the forced opening and closing anti-gas pump,and combined gas anchors and the forced opening and closing anti-gas pump.The experimental data were collated and analyzed.The pump efficiency of the anti-gas tools under different gas-liquid ratios was obtained.(5)Taking a gas injection well as example,analyzed the factors of pump efficiency and carried out the design of gas prevention plan and the design of pumping unit with the X2 practical well.The research result provides an important production technology for the implementation of gas injection in low permeability oilfield and an important reference for the similar wells with high gas-liquid ratio.In this paper,the combined gas anchor and the forced opening and closing anti-air pump are taken as the research objects,and the scope of application of downhole anti-gas tools is determined,which provides an important theoretical basis and method for the optimization and optimization of gas-prevention tools on site.