Study On The Lift Performance Of Gas Anchor Combination In High Gas Liquid Ratio Well

China's low-permeability oil fields are rich in oil reserves,while in the development of low-permeability oil reservoirs,CO₂ Oil displacement can improve oil recovery,but this kind of CO₂ oil displacement mode will lead to high oil-gas ratio,and the effect of high oil-gas ratio on oil field production is increasingly significant.Moreover,in high oil-bearing gas wells,the pump is prone to gas lock,and the effect of gas on pump efficiency is particularly significant.The common method to reduce the influence of gas on the efficiency of the pump is to connect the gas anchor at the suction port of the pump.The gas anchor can separate the gas-liquid mixture in the well before it is sucked into the pump,thus reducing the gas occupation rate of the medium in the well.At present,some wells with large gas content are equipped with gas anchors to prevent gas,but in some wells with high gas-liquid ratio,conventional gas anchors are not suitable for gas separation.Therefore,in high gas-liquid ratio oil wells,it is very important to improve gas separation capacity of gas anchor and reduce the influence of gas on pump efficiency.In this paper,the gas separation mechanism and separation performance of downhole gravity gas anchor are studied by using the analysis method of gas-liquid two-phase flow theory.The gas anchor and oil pump are combined as the research object to find a numerical simulation method to analyze the movement characteristics of gas-liquid mixture in the pump cavity and gas anchor cavity,and the movement of gas-liquid mixture in gravity gas anchor is studied by using this method law.According to the field application of gas anchor structure,a three-dimensional internal fluid model of gravity type gas anchor is established.Using FLUENT software and VOF model,the combined structure of oil pump and gas anchor is simulated to analyze the separation performance of gas anchor.The results show that under the condition of high gas-liquid ratio,the inlet velocity has a great influence on the separation performance of the gas anchor.The larger the inlet velocity is,the worse the separation performance of the gas anchor is.Moreover,the size parameters of the gas anchor applied in the field also have an influence on the separation performance.The smaller the outer pipe size is,the better the separation performance of the gas anchor is,while the size of the central pipe does not have a very clear influence on the separation performance Obviously.After that,the field application of gas anchor was improved,and a new type of gas anchor was designed.The gap of flow passage,the height of settling chamber and the height of gas anchor were optimized.The optimal gap of gas anchor flow passage was 25.5mm,the height of settling chamber was1.1m,and the height of gas anchor was 2.1m.When the underground gas content was 95%,the filling coefficient of oil well pump could reach more than 0.95,and the impact separation performance was studied When other working conditions are fixed,the larger the number of strokes,the worse the separation performance of the gas anchor,and the smaller the filling coefficient of the oil pump.