煤层气低压采气管线气、液两相流演化分析

Analysis of Gas-liquid Two-Phase Flow Evolution in Low-Pressure Coalbed Methane Pipeline

在煤层气田开发的中后期,为保持抽采速率,控制递减率,管网运行压力逐年降低。结合贝克流型分界法进行流型划分并对流型演化的影响因素进行分析,在煤层气采气管线中两相流发展演化的过程中通常为雾状流、环状流、层状流、波浪流、段塞流依次出现,影响流型发展的因素包含降温、合并、捕获、叠加、重力作用及特殊管段等。同时因相对流速变化或截流效应,高持液率的相态也会向低持液率的相态转化。对气液两相流的演化过程进行研究有助于系统分析积液产生的原因并采取科学的治理对策。为提高冬季管线运行效率,降低煤层气开发的操作成本,在进一步研究中需要深入分析两相流演化的各类影响因素,探索采取干预措施,为管线优化设计提供依据。

In the mid-to-late stages of coalbed methane field development,to maintain extraction rates and control decline rates,pipeline network operating pressures are gradually reduced each year.Combining Beck's flow pattern boundary method,the flow patterns in coalbed methane production pipelines are categorized and the influencing factors of their evolution are analyzed.In the development and evolution of two-phase flow in coalbed methane pipelines,mist flow,annular flow,laminar flow,wave flow,and slug flow appear successively.Factors affecting pattern development include cooling,merging,capturing,superposition,gravity,and special pipe sections.Additionally,due to changes in relative velocity or the cutoff effect,the phase with high liquid holdup will also transform into the phase with low liquid holdup.Studying the evolution process of gas-liquid two-phase flow helps in systematically analyzing the causes of liquid accumulation and in taking scientific countermeasures.To improve pipeline operating efficiency in winter and reduce coalbed methane development operating costs,further research is necessary to deeply analyze various influencing factors of two-phase flow evolution and explore intervention measures,providing a basis for optimized pipeline design.