Array Conductance Sensor Optimization And Conductance Fluctuating Signal Analysis

Aiming at the measurement problems of the oil/water two-phase flow in the well logging,the structure parameters of an conductance probe well logging sensor are optimized on the base of the theory study of a conductance probe with vertical Multi-Electrode Array (VMEA). Firstly, the paper uses the Finite Element Method (FEM) to calculate the electric field inside the sensor. The conception of axial uniform degree and radial uniform degree are used to investigate the distribution of the electric field inside the pipeline and then determines the height and thickness of every electrode and the space between the exciting electrodes. By introducing the concept of sensitivity, the sensitivity distribution of the phase volume fraction and mixture velocity measuring electrodes inside the pipeline is calculated by fixing the space between the exciting electrodes and changing the space between the other two electrodes continuously. The structural parameters of the sensor are obtained preliminarily according to the measuring sensor has the even sensitivity in the measuring area. Secondly, the concepts of total information volume, effective information volume, concentration of effective information and integrative evaluating indicators are applied to investigate the space of the phase volume fraction electrode. Finally the optimized structural parameters of the conductance probe well logging sensor are obtained.The conductance fluctuating signals in the concentrating flow channels are acquisited in the oil/gas/water three-phase experiment device of Tianjin University by using Daqing conductance type logging tool. The flow type of unsteady gas/liquid two-phase in the concentrating flow channels is characterized by applying the wavelet transform and chaotic recurrence analysis method. The dynamic character of unsteady gas/ liquid two-phase in the concentrating flow channels is investigated in the view of multi-scale and nonlinear analysis and obtains the results of chaos recurrence analysis in each scale. The result indicates that the gas/liquid two-phase conductance fluctuating signals could reflect the two-phase flow characters of gas/liquid from low frequency to high frequency by using the multi-scale nonlinear analysis method. The all flow patterns take on the good recurrence feature and recurrence plots behave the development line texture structure in low frequency, while the different flow patterns represent different features in high frequency recurrence plots.