Study On The Measurement Method Of Flow Parameters For Vertical Upward Oil-Water And Oil-Gas-Water Multiphase Flow

In order to study on the flow patterns and flow parameter measurement of oil-water two-phase flow in the non-visually concentrating passage of packer type well logging instrument for oil-water two-phase flow, the measurement system composed of quick closing valve, mini-conductance probe, vertical multi-electrode array (VMEA) conductance sensor, helical-surface capacitance sensor and ultrasonic sensor is designed to carry out vertical upward oil-water two-phase flow dynamic experiment in a 20 mm ID pipe. The flow pattern map is constructed and the measuring responses for the two kinds of electrical sensors are calibrated. And also, the author analyzes the oil-water interfacial slippage and researches the measurement models of the partial phase flowrate and total flowrate. Additionally, Symbolic dynamic filtering is applied to extract the information of oil holdup from ultrasonic sensor fluctuating signal. To study vertical upward oil-gas-liquid three-phase flow characteristics in large diameter oil well and provide the flow pattern research basis for oil-gas-water three-phase flow well logging data interpretation method, the vertical upward oil-gas-water three-phase flow dynamic experiment was conducted in a 125 mm ID flow loop using the combination sensors of VMEA sensor and mini-conductance probe and flow pattern maps for four total mixture liquid flowrates are constructed. Also the nonlinear dynamical feature of flow pattern transition are characterized by processing and analyzing the conductance fluctuating signals for the five flow patterns with water as the continuous liquid using traditional time-frequency domain and nonlinear (chaotic attractor morphological description and complexity measures including Lempel-Ziv complexity, approximate entropy and multi-scale entropy) analysis methods and they obtain a good result of flow pattern identification. The creative points of this study are as follows:1. Based on the measurement method of mini-conductance probe, the experiment of vertical upward oil-water two-phase flow pattern in a small diameter pipe and the research of flow pattern physical model are firstly conducted. The experiment indicates that the transition boundary of to water in oil flow flow for small diameter oil-water flow basically occurs at Yw = 0.25, and the transition boundary of to oil in water flow is basically at Yw = 0.35. What is more, the flow pattern experiment result is close agreement with the flow pattern transition boundary model. Based on the experiment of quick closing valve for phase volume fraction, the response properties of the two kinds of designed sensors which are the conductance sensor and capacitance sensor are practically calibrated in oil-water two-phase flow dynamic measurement, showing that there are high sensitive and linear relationship between the measurement responses of the two sensors and the calibrated phase volume fraction. And then the measurement models of total flowrate and partial phase flowrate for vertical upward oil-water two-phase flow are established by kinematic wave theoretical model and drift model and they obtain the high precision of measurement for total and partial phase flowrate.2. The phase volume fraction measurement method by ultrasonic sensor is studied to explore the water holdup of oil-water two-phase flow with high water cut. In order to resolve the fuzzy relation between the phase volume fraction and measured ultrasonic signal, which is caused by the multi-reflection of the ultrasound for the reason of the dispersed phase oil droplets, the symbolic dynamic filtering method is introduced to process and anlyze the ultrasonic signal in the paper and the characteristic quantity named flow measure which is closely related to holdup is extracted. The author finds out that there is a good high resolution and linear relationship between the flow measure calculated by ultrasonic signal and oil holdup. Thus, it provides a new strategy for the phase volume fraction measurement for oil-water two-phase flow with high water cut.3. Through the vertical upward oil-gas-water three-phase flow pattern experiment and the analysis of conductance sensor measured signal, the author finds out that the increase of the ratio of oil flowrate to total liquid flowrate makes oil in water type slug flow occur at lower superficial gas velocity; for large diameter pipe and low flow velocity, the continuous liquid inversion occurs at about the ratio of oil flowrate to total liquid flowrate equal to 0.9 and the agitation of gas makes the phase inversion of liquids move to the low ratio of oil flowrate to total florate. The phase space state of attractor reconstructed by flow pattern fluctuating signal could reflect the dynamical evolution characteristics of three-phase flow pattern in details. The combination of Lempel-Ziv complexity measure and approximate entropy could better identify oil-gas-water three-phase flow patterns. Multi-scale entropy could reveals the nonlinear dynamical characteristics of five oil-gas-water three-phase flow patterns from different time sacles and Rate of MSE which sensitively indicates the variation of flow patterns could act as the effective criterion of three-phase flow patterns identification. The multi-scale nonlinear time series analysis of oil-gas-water three-phase flow conductance fluctuating signal provides a new approach to reveal the dynamical evolution mechanism of oil-gas-water three-phase flow pattern.