A Novel Conical Spiral Transmission Line Sensor-Array Water Holdup Detection Tool Achieving Full Scale and Low Error Measurement

To dynamically monitor the horizontal well, we studied the oil–water two-phase water holdup detection method based on transmission lines, and designed a micro-sensor and a sensor-array water holdup detection tool. We modeled the relationship of the dielectric constant of the transmission line filling medium and the amplitude and phase shift of the electromagnetic wave signal on the transmission line by using the time-domain analysis. We proposed a novel method to measure the water holdup of oil–water mixtures based on the phase shift of signals on the conical spiral transmission line. Furthermore, we simulated and optimized the structural parameters by software simulation, and developed a small conical spiral water holdup sensor suitable for arraying. The single sensor with detection circuits can achieve the full scale (water holdup from 0% to 100%) measurement with resolution better than 3%. On this basis, 12 sensors are used to develop a clock-like sensor-array water holdup detection tool, realizing the array detection of the distribution of the cross-section medium in horizontal wells.