Study On Oil-Water-Gas-Sand Separator For Injection And Production In The Same Well Of Ultra-High Water Cut Old Oil Wells

In view of the four phases of oil,water,gas and sand in the produced liquid of ultra-high water cut old oil wells,the four-phase cyclone separator of oil,water,gas and sand is designed and studied,and the flow field characteristics and separation in the process of realizing the four-phase separation of produced liquid,oil,water,gas and sand under the condition of ultrahigh water cut are studied by using the method of theoretical analysis and numerical simulation.Firstly,through the theoretical analysis of multiphase flow separation technology,the initial model of multiphase flow separator is established;Then,the structure parameters of each part of the initial model of the separator are optimized by using the method of fluid simulation;Finally,by comparing the simulation results obtained by fluid simulation,the optimal structural parameters of oil-water gas sand four-phase separator are selected.This provides a possibility and research idea for realizing multiphase separation of ultra-high water cut old oil wells.Firstly,based on the common multiphase flow separator and combined with the production situation of old oil wells under ultra-high water cut,an oil-water gas sand fourphase separation device suitable for old oil wells with ultra-high-water cut is designed.The device is composed of two cyclone separators in series.The gas-liquid-solid three-phase separator mainly realizes the separation of gas phase and solid phase of the produced liquid of old oil wells,and the oil-water two-phase separator mainly realizes the oil-water separation of the incoming liquid after the upper stage separation;Secondly,the three-dimensional geometric modeling and grid setting of the initial model are carried out by using gambit modeling software,and the initial model of multiphase flow separator is numerically simulated by using fluid simulation software FLUENT 19.2.According to the simulation results,the distribution law of the internal flow field of the initial model is analyzed,such as the concentration distribution law,velocity distribution law and separation efficiency of gas phase and oil phase;Then,according to the shortcomings in the simulation results of the initial model,the optimization scheme is formulated,and the optimization simulation analysis is carried out on the swirl cavity structure,large cone section,small cone section and overflow pipe structure of the initial model,and the optimal structural parameters of the model are determined.This design completes the separator design and model structure parameter optimization suitable for the four-phase separation of oil,gas and sand in ultra-high water cut old oil wells,analyzes the feasibility of the model for the four-phase separation of oil,gas and sand in ultrahigh water cut old oil wells,provides a new design idea for the separation of multi-component produced liquid in ultra-high water cut old oil wells,and provides a useful reference for the design of multi-phase separation device in ultra-high water cut old oil wells.