垂直下降管流流态界限转变研究

多相流广泛存在于空气钻井、氮气钻井、高压喷射钻井、泡沫钻井、完井修井作业及管道输送等领域中。多相流的研究在确保工程顺利实施方面起着极为重要的作用，在很大程度上关系到钻井、固井等质量的优劣与成败。为此，对垂直下降管流的流型转变及其流型间的转变界线进行了研究，得出了垂直下降管内油气水三相流动可分为W/O型泡状流、弹状流及环状流和O/W型泡状流、弹状流及块状流的结论。通过动力学分析，分别建立了泡状流与弹状流的转变、弹状流与环状流的转变的理论模型，实际计算表明，理论转变曲线与实验曲线基本吻合。

STUDY ON MULTIPHASE FLOW REGIMES IN VERTICAL DOWNWARD-FLOWING PIPE FLOW, REGIME BOUNDARIES, AND REGIME TRANSFORMATION

Multiphase flow widely exists in air drilling, nitrogen drilling, high-pressure jet drilling, foam drilling, completions, and workovers, and also in industries of power, chemicals, petroleum, metallurgy, pipeline transport, medical and refrigeration. Study on the hydrodynamics, flow mechanism of multiphase flow and precise detection of parameters in two-phase flow are very important for the development of modern industrial equipment. Crude oil mixture can be oil/gas two-phase flow, oil/water two-phase flow or oil/gas/water three-phase flow in transport system. Research on multiphase flow will play an important role in ensuring the successful operation, it will, to a large extent, decide the quality of the drilling and completion operations. This paper studies on the flow regime transformations of vertical downward-flowing pipe flow and the transformation boundaries. Some preliminary conclusions are made in this paper. By analyzing dynamics, theoretic models are set up for transformations between bubble flow and elastic flow, between elastic flow and annular flow. After actual calculation, it is proved that the theoretic transformation curves match the experimental curves very well.