由于煤层气地层压力低，整个地面集输系统需采取低压集气方案，因此地面集输管线中压降尤为重要。管道积液是管线压降不可忽视的因素，结合煤层气集输管线中低压力、低液量、高流速的流动特点，选择倾斜管段中BeggsBrill气液两相流关系式，对地面起伏管线中的持液率进行分析。通过计算不同管径、不同产水量工况下管线中的流型变化及持液率变化，预判管线积液情况，指导煤层气管线排液设计，这对煤层气地面集输设计及生产运行管理具有实质性参考意义。

The coal-bed methane gathering system is taking low pressure system for its low formation pressure, so the gathering pipeline system pressure drop is particularly important. The effusion part cannot be ignored in the pipeline. This paper has combined with the coalbed gas pipeline characteristics (low pressure, low fluid volume, high velocity, selecting the section of inclined tube gas-liquid two-phase flow equation ( Beggs-brill equation to analyze the flow characteristic in methane gas pipeline. This paper calculates the liquid hold-up in by different pipe diameters and different water conditions in the gathering pipeline and estimates the liquid condition in gathering pipeline. The results are helpful in the design and management in ground engineering of coal seam gas.