Capacitance-based monitoring of a three-phase crude-oil flow

A simple solution is presented for identifying the phase fraction and flow rate of a petroleum carrying pipeline with three-phase stratified smooth and wavy flow. The proposed method mounts a set of semicylindrical electrodes on the internal surface of the Plexiglas pipe to monitor the total capacitance and resistance of the three-phase contents. The phase fractions are determined by relating these electrical properties with the phase angles associated with the interface between water, oil, and gas phases of the mixture. To calculate the flow rate, measured capacitances from two sets of electrodes with known separation distance are cross-correlated to determine time delay. Calculated and measured results demonstrated close agreement. The percentage error exhibited by the proposed inclined capacitive plate technique is calculated and compared with published values.