Conductance Sensor With Self-Calibration and Venturi Tube Based Flowrate Measurement for Gas–Water Slug Flow

As the water cut in the oil field is becoming higher and higher, developing low-cost flowrate measurement methods for gas–water two-phase flow is of great importance. Among different sensing techniques, the conductance sensor has received widespread attention due to its fast response and low cost, but its practical application in oilfields is limited due to the fact that the output signal of the conductance sensor is related to the liquid conductivity. This issue can be overcome by the normalization of the full-liquid output voltage of the conductance sensor. However, the full-liquid output voltage is generally difficult and expensive to obtain in field applications. In order to improve the practicability, this article proposes a conductance sensor with online self-calibration to suppress the dependence on the full-liquid output voltage. Furthermore, a flowrate measurement method for horizontal gas–water slug flow is presented based on the proposed conductance sensor with self-calibration and a Venturi tube. The experimental results show that the mean absolute percentage errors (MAPEs) of predictions of gas flowrate and liquid flowrate are 4.62% and 4.26%, respectively, which is promising for practical applications in oilfields.