Measurement of High Water Holdup in Oil-in-Water Flows Using Reticular Microwave Resonant Sensor

Long-term waterflooding exploitation leads to the low flow rate and high water cut of the oil-water flows in oil wells, which has put forward a new challenge for water holdup measurement. Therefore, a reticular microwave resonant sensor (RMRS) is proposed in this paper, which can realize high-sensitive water holdup measurement of oil-in-water flows with high water cut and low velocity at 1.85 GHz-2.3 GHz. Due to the optimum design in quasi-TEM mode of the sensor based on finite element method, the resonant frequency shift measured by the RMRS are sufficiently sensitive to water holdup. After the viability of the sensor confirmed through simulation experiment, a sensor prototype is prepared. And the measurement characteristics of the sensor to water holdup is firstly investigated by static experiment. Subsequently, the dynamic experiment of vertical upward oil-in-water flows is carried out. The response characteristics of the RMRS with the change of water salinity, flow rate and water cut are analyzed. Finally, a satisfactory relationship between resonant frequency and water holdup with the consideration of water salinity is obtained. It shows that the RMRS has a good resolution to water holdup. Moreover, it can effectively restrain the influence of water salinity.