The Response of Combined Capacitance Sensor in The Horizontal Condition

摘要

For measurement of the water-cut of the fluid in a low production horizontal well, a combined capacitance sensor is designed which is composed of the cylindrical capacitance sensor and the coaxial capacitance sensor. The two sensors are of parallel connnection in the electric circuit. Because of parallel connnection of the two capacitance sensors, the surface area of the combined sensor increases. Thus in the non-stratified flow, the oil bubbles are apt to touch the sensor and its measurement resolution is improved. And in the stratified flow, the cylindrical capacitance which plays a leading role is sensitive to the hight of oil-water interface. The structure of the sensor is introduced in the paper. The electric field simulation is conducted and the sensor response in the oil/water stratified flow and bubble flow are given. Static experiment and dynamic experiment of the sensor are carried out and the response at the different flowrate and water cut is obtained. The results show that the combined capacitance sensor has a higher resolution than the traditional coaxial capacitance sensor. The novel sensor can provide a new technical method to measure the production profile water cut in a low production horizontal well.