Circuit Design And Experimental Study Of The Fiber Gas Holdup And Impedance Water Holdup Three-phase Flow Combination Logging Tool

At present, most of the old oil fields in China are in the middle and late stage of exploitation, and the phenomenon of low yield, high water content and three phase flow in oil wells is common. It is very necessary to identify the flow state of the three-phase flow, the total flow measurement and each phase holdup for the oil field development. Due to the extreme complex flow of the three-phase flow, and the parameter detection is very difficult, there is no mature technology of accurate measurement of three-phase flow parameters in oil wells.In this paper, the measurement of oil, gas and aqueous three-phase flow in oil well is realized by combination with many sensors, such as fiber sensor, impedance water holdup meter and turbine sensor, etc. Whereby, detecting down hole gas holdup due to the fiber probe sensor is sensitive to gas phase; measuring downhole water holdup due to the impedance water holdup meter is sensitive to aqueous phase; measuring three-phase flow total flow by turbine flow meter. The down hole oil, gas and aqueous three-phase flow measurement can be realized through comprehensive interpretation of the data.Based on the above scheme, the overall structure of the fiber gas holdup and impedance water holdup three-phase flow combination logging tool is designed. FPGA as the core component of downhole tool circuit is designed and signal conditioning, data encoding, data transmission and signal acquisition are realized. The principle experiment prototype is processed, and oil, gas and aqueous three-phase flow experiment is carried out in the vertical well of the multiphase flow experiment device. Signal sensor and optical fiber sensor impedance moisture collection, data will be transmitted to the host computer. Gas phase flow chart expresses the fiber sensor response and water holdup chart expresses impedance sensor response under the condition of three-phase flow is separately made. The results shows that fiber sensor is significant distinguished for gas phase flow, while is not sensitive to oil-water ratio when oil and water two-phase total flow is must under the condition of three-phase flow; impedance sensor is significant distinguished for liquid phase water holdup, and its response value offsets towards the direction of the liquid phase water holdup decrease. The experimental results show that the measurement of oil and gas water three phase flow is feasible.