With the continuous development of gas field development technology, the application of long-distance gas-liquid mixed transportation pipeline in production and construction projects is increasingly common. After some gas field gathering and transportation pipelines enter the late stage of production, they are affected by the decrease of gas production and the increase of gas field water, and they are confronted with the problem of excessive effusion.Reasonable consideration of pigging and slug control treatment will greatly save the investment of slug catcher. Segmented pigging technology can reduce the size of slug catcher, and it has economic advantages in large-diameter and high-pressure gathering and transportation pipeline project. Therefore, it is necessary to explore the liquid accumulation and drainage rules of pigging in gathering and transporting pipelines in order to accurately determine the segment position and operation interval. Based on the collection and transportation pipeline effusion and pigging drainage rule, thispaperanalyzes the segmented pigging effusion and drainage rule, deduces the correlation formula of initial effusion, pigging time and drainage volume, and further discusses the main factors influencing the segmented pigging effusion and drainage rule by combining with the dynamic simulation results of commercial software. The research results show that the segmented pigging of gathering and transporting pipelines in large-diameterand high-effusion gas fields has significant influence on the catcher load, and the reversed segmented pigging can greatly reduce the catcher load, and the derived segmented ratio and the calculation formula of catcher load are relatively accurate. The research results in this paper can provide some references for pigging scheme of gas field gathering and transportation pipelines and the idea of setting slug catcher.

Keywords:Gas gathering; Multiphase pipeline; Segmentedpigging; Slug flow