Design And CFD Analysis Of Automatic Fracturing Flowback Fluid Separation Kettle

Fracturing technology is often used in the process of oil field exploitation,which can improve oil and gas recovery.However,horizontal well fracturing operation will produce flowback fluid containing waste gas,and the previous treatment methods have problems of high cost,high pollution and low separation efficiency.Therefore,a hydraulic fracturing fluid gas-liquid automatic separation kettle based on complex transient collision mechanism is designed,which can realize efficient gas-liquid separation.The work of this paper is as follows:(1)The structure of the new separation reactor is designed,including baffle plate,stabilizer plate,baffle trap and an interlocking coaxial buoy device that can move up and down according to buoyancy,which solves the problem of incomplete separation caused by delayed observation or operation in the previous manual operation.(2)The gas-liquid multiphase flow model inside the separation kettle was established.The numerical model was mainly described by solving the governing equation of the conservation of physical quantity,the turbulence equation of fluid flow state,and the droplet force balance equation.The flow field inside the separation kettle under different conditions was numerically simulated by FLUENT software,and the motion law and separation effect of the internal flow field were analyzed.The numerical simulation results show that the smaller the inlet velocity is,the better the gas-liquid separation effect will be.The separation efficiency is the highest when the Angle between baffle and horizontal plane is 90°;The steady flow orifice plate in the flow field can not only smooth the turbulent fluid state in the flow field,but also make the liquid stay longer in the container,thus improving the separation effect.Through discrete phase simulation analysis,it is found that the fold-line fog trap has the highest defogging efficiency,and the installation distance is shorter,and the performance is better than other shapes of fog traps.(3)The separation kettle was tested in the field,and the results showed that the automatic separation kettle could realize the separation of gas and liquid and the separation efficiency reached 96.6%;The overall sealing of the buoy device is good,and the buoy can float to the corresponding position according to the change of the liquid level height,so as to ensure the complete separation of gas and liquid and discharge,and realize the requirement of automatic separation of gas and liquid without the emergence of liquid out of the outlet and gas out of the outlet.The research work of this paper provides a certain reference for the research and development of new type separation kettle.