Identification of Oil-Gas-Water Three-phase Flow Patterns in Vertical Upward Pipe Based on Multi-scale Entropy

In order to study oil-gas-liquid three-phase flow regularity in oil well, the vertical upward three-phase flow dynamic experiment with low velocity was carried out in a large diameter (125 mm i.d.) flow loop using the combination sensors of VMEA and mini-conductance probe array and six three-phase flow patterns were defined. VMEA sensor conductance fluctuating signals of five flow patterns with water as the continuous liquid were acquired. And then the multi-scale entropy processing and analysis of them are conducted to describe the dynamics characteristics of the different flow patterns. The study result indicates that the multi-scale entropy reveals the nonlinear dynamics characteristics of flow patterns in different scales and Rate of MSE as a characteristic representing approximately constant increasing rate of sample entropy at low scales sensitively indicates the variation of flow patterns and can act as the efficient criterion of three-phase flow patterns identification. And it is helpful to understand the dynamics mechanism of three-phase flow pattern evolution.