Abstract: A novel intelligent oil water cut measurement system based on a capacitive sensing element is proposed, taking into account the characteristics of crude oil production in China. C/U conversion, U/f conversion circuits, and temperature compensation design are implemented. Experimental results show that the system can accurately display the water cut using a full-range linear scale (0%–100%). Keywords: Crude oil water cut; Measurement system; Capacitive sensor; Conversion circuit; Temperature compensation 1. Introduction In oilfield exploration and crude oil production, the measurement of oil water cut is a fundamental and crucial issue for determining the real-time production of crude oil and natural gas from each well. Currently, the main methods for measuring the water cut of multiphase fluids in oil in China are traditional timed sampling and distillation (demulsification) analysis. Due to the long sampling cycle, timed sampling is difficult to accurately measure the actual water cut in real time when the water cut changes rapidly. Based on the characteristics of crude oil production in my country, this project designs an online crude oil water content measurement system based on the principle of capacitance measurement. It employs a clever self-equalizing capacitance sensor to convert changes in water content into changes in capacitance. After C/U and U/f conversion and temperature compensation, the data is sent to a computer for processing to achieve real-time monitoring and measurement of crude oil. The system exhibits high accuracy and high stability within the 0–100% water content measurement range. For details, please click to download: Design of an Oil Water Content Measurement System Based on a Capacitive Sensor.