Measurement of Industrial Oil-Gas-Water Flow Using Multi-Mode Conductance Sensing System

To accurately decouple the individual phase fractions and velocities in three-phase flows, a novel multimode conductance sensing system is proposed. First, the sensitive field of the distributed coaxial double-ring conductance sensor (DRCS) along the pipe wall prevents it from being interfered by the gas in the center of the cross section. Thus, the DRCS provides the critical water–oil mixture conductance for the rotating electric field conductance sensors (REFCS) and the interdigital conductance sensor (ICS). In addition, the DRCS measures the oil holdup in the liquid phase. Second, the REFCS and ICS have excellent sensitive fields for quasi-uniform liquid slugs and nonuniform gas plugs, respectively. Therefore, the REFCS is utilized to determine the gas holdup of liquid slugs and bubble flows. The ICS determines the liquid film thickness and thus provides the gas holdup of the gas slugs. The average absolute percentage deviations (AAPDs) of the predicted gas and oil holdups are 3.33% and 4.22%, respectively. Moreover, the conductance sensor with multiheight electrodes (CSMHE) relies on surface charge matching to obtain global cross-correlation velocities. Finally, the proposed drift-flux model decouples the individual phase velocities. The AAPDs for predicting the superficial velocities of the oil and gas are 4.95% and 3.50%, respectively.