| In the oil field extraction process,accurate crude oil water content measurement will have a significant impact on field production,extraction efficiency,extraction cost,and extraction strategy.Exploring new methods for water content detection in oil-water two-phase flow to improve detection accuracy is a current research hotspot.In this paper,the detection method of oil-water two-phase flow based on magneto-acoustic coupling is proposed for the electrical characteristic parameters of oil-water two-phase flow,and its working mechanism and implementation method are studied.Firstly,the working mechanism of magneto-acoustic coupling is analyzed to reveal the principle of magneto-acoustic coupling to excite magneto-acoustics,and the response relationship between magneto-acoustic signal and conductivity of oil-water two-phase flow is analyzed.A water content measurement model based on magneto-acoustic coupling for oil-water two-phase flow was constructed using COMSOL software,and the excitation method and signal characteristics for generating magneto-acoustic signals were analyzed.A method for detecting weak magnetoacoustic signals based on phase-locked amplification is studied according to the characteristics of the weak signals excited.The structure and operating principle of the phaselocked amplifier circuit are analyzed,and the phase-locked amplifier implementation circuit as well as the dipole amplifier and filter circuit are designed;Developed FPGA+DDS-based excitation signal generation circuit and data acquisition circuit to realize high-speed acquisition of multi-channel weak magnetoacoustic signals;A data acquisition system based on LabView software was developed to acquire multiple signals in real time.Design of indoor experimental protocols,build an experimental platform of magneto-acoustic coupled oil-water two-phase flow multi-channel weak magneto-acoustic signal acquisition system,test the magneto-acoustic signal phase-locked amplifier circuit and acquisition circuit,and the test results of each module meet the design requirements.In the experiments,the weak magnetoacoustic signals were collected by ultrasonic transducers installed in four directions of 0°,90°,180° and 270° of the pipeline,and the data were read by the software of the host computer and analyzed,which proved that there is a strong "skin effect" at the interface of oil-water twophase flow,and verified that the magnetoacoustic coupling technology is feasible for the detection of water content in oil-water two-phase flow. |
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