Study On Optimization Of Electrical Submersible Pump With Variable Frequency Drive Technique

Electrical submersible pump(ESP)is one of the most important oil production methods,which has the characteristics of large capacity,but its system efficiency is lower which leads to higher energy consumption than other oil pumping wells.The pump of ESP system is a kind of the centrifugal pump,and its capacity,head,and efficiency are closely related to motor speed.It is a simple way and effective technology to adjust the speed of the ESP by changing the power supply frequency.It is very important to establish a calculation model on the ESP performance with difference frequency,which has great value in the design process,measurement and working status diagnosis of ESP production wells.In this thesis,the ESP performance curve under different viscosities,temperatures and frequencies are studied.On the basis of viscosity of crude oil at different temperatures,the viscosity-temperature curve of crude oil is plotted,and the relationship model between frequency and capacity of ESP is established.Through Variable Frequency Drive(VFD)technique,the capacity,pressure head,pump efficiency as well as input power of centrifugal pump can be changed.The relationship between inflow of oil layer and outflow of pump can be controlled.The higher system efficiency of ESP system can be obtained with VFD technique.According to the principle of isoefficiency curve of centrifugal pump,the efficiency curve can be calculated at different frequencies based on efficiency curve at 50 Hz or 60 Hz,and the performance curve correction model under different viscosities and frequencies is established.The drawing program of the modified performance curve is compiled by using MATLAB,and the performance curve under the condition of power supply and variable frequency is analyzed.Taking 2 ESP wells as examples,this thesis studies the production of the ESP controlled by variable frequency control,calculates the performance curve and capacity of ESP after variable frequency by using the model established in this thesis,and optimizes the production parameters.In this thesis,the working conditions of ten other oil wells are analyzed,and the improvement and optimization scheme is proposed.Most of them have achieved better results through field implementation.The calculation model established in this thesis has a good application value for variable frequency ESP production system.