Research On Water-cut Rate Measurement Of Oil-water Two-phase Flow Based On Multi-column Capacitance Sensor

Multiphase flow system widely exists in nature and industrial production, and thedetection parameters of oil-water two-phase flow has been one of the hot issues of modernoil industry. Oil-water phase holdup is one of the important parameters in measurement ofoil-water two-phase flow. However, the flow state of the over-flow of fluid in theground-well system is very complex, so that it is quite difficult to measure the moisture.The method for measuring the moisture of oil-water two-phase flow based onmulti-column capacitance sensor was deeply researched in this thesis.Firstly, aiming at the capacitive sensor can not satisfy the flow of fluid in oil wells inthe ground, puts forward a new capacitive sensor structure which is an external electrodecomposed of a plurality of column. The theoretical model and the simulation model ofelectric field and electric potential distribution in the sensor in which the inner space is asingle medium. The response capacitor of multi-column capacitance sensor inhomogeneous medium was deduced. The electric field sensitivity distribution sensorinterior space was investigated. And these properties provide the theoretical basis foroptimization of the structure parameters of the sensor.Secondly, considering the sensor sensitivity failures caused by electrical conductivityof high-water condition, proposed the model of multi-column capacitance sensor formeasurement in high-water condition. And to get high water cut measurement by using thefinite element software Ansys simulation results to verify the correctness of the theoreticalmodel. The theoretical model and simulation model of multi-column capacitance sensorsensitive with single-phase flow or single-phase flow as the medium in its internal spacewere established. And the response characteristics were investigated. Further, the responsecharacteristic of the sensor in low-water heterogeneous medium was investigated.Finally, considering the interference of the external environment and parasiticcapacitance on measurement, design a driving circuit with multi-column capacitancesensor. Design each circuit module according to the modularization idea, including thecapacitor-voltage conversion module, voltage-current conversion module, SCM control module and power supply module. It was verified that the sensor has good linearity andaccuracy by static height method experiments and oil-water two-phase flow dynamicexperiment using triple helix mixer.