Study On Integrated Optical Fiber Conductivity Probe Sensing Technology For Oil Well Phase Holdup Measurement

The fluid flow parameters of oil-gas-water three-phase flow,especially the dynamic monitoring of phase separation holdup,are the key to determine the production profile of oil-gas wells,injection profile of water-injection wells and water-flooded zones.They are also important data sources to guide the adjustment and optimization of oil-field development schemes to achieve stable production.With the emergence and development of optical fiber sensing technology and conductivity sensing technology,the technology of measuring the phase separation holdup of multiphase flow by combining optical fiber sensor and conductivity sensor has emerged.In this thesis,a fiber-optic sensor and a conductivity sensor are combined to study a fiber-optic conductivity integrated probe sensor that can simultaneously measure the phase-to-phase ratio of oil-gas-water three-phase flow.Firstly,in the actual production logging,aiming at the disadvantage of traditional bundled fiber-optic conductivity sensor which has low accuracy and large volume in parameter measurement,a structure model of integrated fiber-optic conductivity probe sensor is proposed,and its structural parameters are optimized.On the one hand,the simulation model of the optical fiber probe is established by ZEMAX optical analysis software,and the angle of the sensing head of the optical fiber sensor is optimized by synthesizing the optical power difference and the ability of puncturing bubbles.On the other hand,the simulation model of the conductivity sensor is established by COMSOL multi-physical field simulation software to simulate and analyze the integrated optical fiber conductivity probe.The electric field distribution and flow field distribution in the fluid are optimized according to the reliability and durability of the measurement.According to the above two aspects,the theoretical structure model of the integrated optical fiber conductivity probe is determined.Secondly,in terms of output response characteristics of optical fiber signal and conductive signal,the response characteristics of optical fiber signal and conductive signal are simulated and analyzed based on the theoretical structure model of integrated optical fiber conductive probe.The signal processing methods based on signal disassembly and conductive signal processing methods based on fuzzy clustering are studied respectively to realize the measurement of oil and gas by integrating optical fiber conductive probe,which lays a theoretical foundation for phase separation holdup of water three-phase flow.Finally,based on the optimization of the fiber-optic conductivity integrated probe structure,the integrated probe physical object is designed and developed,and the experimental platform of the oil-gas-water three-phase flow phase separation rate measurement is set up to carry out the oil-gas-water three-phase flow phase separation under different working conditions.In the rate measurement experiment,the fiber signal and the conductance signal are collected and processed,and the phase fraction of the three-phase flow of the oil and gas is obtained and compared with the standard phase separation ratio.