Research On Electromagnetic Correlation Flow Measurement Technology For Multiphase Flow

With the development of oil field,many Wells are multiphase flow composed of oil,gas and water.The flow rate is a parameter that must be measured in the process of stratified oil production,but the flow state of the downhole fluid is very complex,which makes the measurement of the flow rate very difficult.Aiming at the shortcomings of current flow measurement of oil,gas and water multiphase flow in production logging,a flow measurement model based on electromagnetic flow and correlation flow was proposed to solve the problem of oil,gas and water multiphase flow measurement in oil production logging.The magnetic field distribution of the rectangular coil,the track coil and the saddle coil of the sensor in the electromagnetic correlation flow measurement system is simulated by using the finite element software COMSOL,and the evaluation index of the magnetic field distribution of the excitation coil is put forward,and then the optimal shape of the excitation coil of the electromagnetic correlation flow sensor is obtained.In order to ensure that the electric fields generated by the two pairs of electrodes do not interfere with each other and that the output signals of the two pairs of electrodes are correlated to a certain extent,the size of the electrode and the distance between the two pairs of electrodes are designed by the electromagnetic correlation method.At the same time,the influence factors of the flow measurement results by electromagnetic correlation method are analyzed and studied to reduce the error in flow measurement.Finally,on the basis of theoretical calculation and simulation research,the hardware circuit of flow measurement based on electromagnetic correlation method is designed,and the corresponding software program and upper computer software are designed.The overall design scheme is verified experimentally on the multi-phase flow simulation platform in the laboratory.Under different contents of gas-water and oil-gas-water multiphase flow,the experimental data of different flow rates of mixed fluids were measured,and the data processing and result analysis were carried out.The experimental results show that the relative error of measurement is less than 15%,and the measurement results meet the requirements of the project assessment index on the measurement accuracy.The system has been tested in the field pipeline for multiphase flow,and the field application shows that it is feasible to measure the electromagnetic correlation flow of multiphase flow.