Study On Artificial Lifting Optimization Design Of Electric Submersible Pump Well With High Gas-oil Ratio

With the development of oil field,formation pressure and saturation pressure drop,dissolved gas is separated from crude oil to form free gas.Once a large amount of free gas enters the electric submersible pump,the pump characteristics may deteriorate,surge,or even air lock.In the field practice of oil field,the head of electric submersible pump is greatly reduced due to the gas lock,and even the problem of shutdown often occurs.Considering the working environment(sea water section and air section)of the offshore electric submersible pump well,the calculation method of the well bore temperature of the electric submersible pump well is derived.The combination method of beggs Brill and Lockhart Martinelli is selected as the wellbore pressure calculation method.The verification results show that the two methods have higher accuracy than other methods.The lifting design method of electric submersible pump is put forward as the theoretical basis for compiling the lifting optimization design software of electric submersible pump well with high gas oil ratio.According to the characteristics of the electric submersible pump geometry,we use the Pro / engineer software to build the geometry model,the ICEM software to mesh,the fluent module in the ANSYS software as the solver to simulate the pressure distribution,multiphase fluid distribution and velocity distribution of the internal fluid of the electric submersible pump under the condition of high gas oil ratio.The simulation results show that a large number of gases form air bags and occupy the flow channel.This paper studies the influence of different working conditions on the characteristic curve of electric submersible pump,and analyzes the sensitivity of the characteristic curve of electric submersible pump under different gas content and suction pressure.The results show that the ESP is sensitive to the gas content.Through the numerical simulation model,the correction coefficients of different suction pressure and gas-liquid ratio are proposed,and a database is formed.Based on the above research results,the optimization design software for the lift of ESP wells is developed.The software has the function of optimization design for the lift of ESP wells with high gas oil ratio and good stability.In this paper,two oil wells in Pinghu oil and gas field are taken as an example to design the electric submersible pump lifting.The corresponding parameters such as the depth of pump running,the pressure of pump suction port,the ratio of suction gas and liquid,and the selection of electric pump,motor and cable are obtained.The practice shows that the method and the corresponding optimization software have good adaptability and can fully reflect the influence of high gas oil ratio on the optimization design of electric submersible pump.