Study On Flow Measurement Technology Of Multiphase Flow Frequency Difference Method

Flow rate,as a core measurement parameter in the intelligent stratified oil production system,directly affects the deployment effect of stratified oil production,and is of great significance for adjusting oil and gas production strategies and optimizing production processes.According to the characteristics of downhole multiphase flow,combined with the advantages of Doppler measurement technology,the study of multiphase flow frequency difference method flow detection technology can provide real-time and accurate flow information for intelligent stratified oil production technology.Based on the theory of ultrasonic propagation attenuation,this paper studies the relationship between the operating frequency and propagation attenuation of ultrasonic waves;through simulation analysis,the influence of suspended particles of different sizes,concentrations,positions and materials in the fluid by ultrasonic waves on the scattered sound field and the amplitude of the echo received signal is analyzed.Provide reference for the selection of ultrasonic working frequency;derive different sensor layout methods according to Doppler principle,and analyze the advantages and disadvantages of each sensor layout method.Therefore,in order to obtain real-time,accurate and effective flow information of multiphase fluids,it is necessary to select the appropriate operating frequency and layout of the ultrasonic sensor according to different measurement environments.Because the ultrasonic wave is affected by the external environment during the propagation process,it will cause interference to the echo receiving signal,thereby affecting the flow measurement accuracy of the multiphase flow frequency difference method.In this paper,factors such as ultrasonic working frequency,sensor layout,multiphase fluid characteristics and ambient temperature are analyzed.Among them,the characteristics of multiphase flow,such as flow velocity,density and viscosity,are related to the turbulence intensity of the pipeline fluid,and the environmental temperature affects the performance of the hardware circuit and the ultrasonic propagation speed.Due to the difference in the weights of various factors in different working environments,the key influencing factors are compensated and corrected in order to improve the stability,applicability and reliability of the measurement system.An indoor simulation test platform was built to test the performance of the multiphase flow frequency difference method flow measurement system.The temperature test of the hardware circuit is done to ensure that it can work normally at 125 ?;the temperature and pressure test of 125 ? and 45 MPa are carried out on the instrument equipped with the ultrasonic measuring system to test the reliability and stability of the instrument;use the multi-phase flow chamber The simulation cycle device tests the performance of the ultrasonic flow measurement system.By analyzing the test data,it can be concluded that the measurement system has good repeatability of multiple test data,and the relative measurement error is within 15%.After compensation and correction of the multiphase flow frequency difference method flow measurement system,the relative error of the flow measurement increased by2%?%0.