The Survey Of Distributary Electromagnetic Flow Meter Applied To Measuring Oil/Water Two-phase Flow

Along with oil and gas exploration,most of the domestic old oil fields has been in a period of high water and high water cut,the traditional measuring methods are not good enough to meeting the needs of oilfield development,for solving the problem of measuring oil/water two-phase flow,we need to research a new measurement method.Using electromagnetic method in measuring oil/water two-phase flow may solve the problem,the structure of electromagnetic flow meter is simple,it has no moving parts or restrictor,won't occur the phenomenon of pipe blockage or wear and so on,the instrument constant is stable,so it can be used to substitute turbine flow meter.At present,to measure oil/water two-phase flow,Daqing Oilfield Limited Company has already developed the application of electromagnetic method,indoor experients and the field tests show that,in the condition of high flow and high water cut,electromagnetic method can be used to measure oil/water two-phase flow,but in the low flow,the method is restricted by the influence of water cut.So the subject adopts distributary structure,through shunting some part of oil flow,to guarantee the measurement channel can maintain a high water cut.It improves the resolution of the original instruments and broadens measurement range.The paper introduces the basic structure,flow measuring principle and technology development situation of the electromagnetic flow meter.In order to improve the adaptability for two-phase fluid at different water cut,we adopt distributed structure.To optimize the structure parameters,diversion structure of the flow meter is simulated by the simulation software Fluent.Through the simulation study of the various flow points under three different water cut(70%,80%,90%)respectively,and based on the simulation results,the reasonable diversion structure of the flow meter is obtained,when the split ratio is 20%,the width between the up inlet and the down inlet is 30mm,shunt effect of the instrument is best.The simulation result provides the reference for designing the experimental prototype.The experimental prototype of the distributary electromagnetic flow meter is fabricated and has been used for dynamic experiment in multiphase flow experimental device.The results show that compared with original electromagnetic flow meter,it can improve the limit of flow measurement,and water cut has less affection to the measurement result.