Measurement of Gas Holdup in Oil-Gas-Water Flows Using Combined Conductance Sensors

In this study, a new method for gas holdup measurement in water continuous oil-gas-water multiphase flow based on conductance sensors is proposed. This method includes the use of the combined conductance sensors and the establishment of gas holdup model. A cross-sectional type conductance sensor is applied to acquire the conductivity of oil-gas-water mixture. For the purpose to derive gas holdup from the mixture conductivity, a novel liquid conductivity sensor which has shallow detection depth is proposed and it is flush-mounted on the inner wall of pipe to detect the liquid conductivity. The performances of the cross-sectional type conductance sensor combined with the liquid conductivity sensor are evaluated by experiments. And the results indicate that the liquid conductivity sensor can online detect the liquid conductivity in the multiphase mixture effectively. Based on the measured conductivity of multiphase mixture and the conductivity of liquid, the normalized conductivity which is related to the gas holdup is defined. The gas holdup model based on flow structures is investigated and established, and finally the measurement of gas holdup independently of salinity in oil-gas-water multiphase flow based on the conductance method is achieved for the first time.