Study on the Segmental Pigging Process for the Wet Gas Gathering and Transportation Pipelines of the Puguang Gas Field

The gathering and transportation pipeline known as Line 1 of Puguang Gas Field has the characteristics of wet gathering and transportation containing high sulfur content, large drops, and liquid loading in low-lying areas. In the process of one pigging operation on the site, the surge volume provided by the no. 1 separator in the master gas gathering station was not effectively utilized and the time intervals for the neighboring pipeline sections were too long. In this paper, we designed several pigging proposals. OLGA was applied to analyze the operating parameter changes for the gathering and transportation pipeline Line 1, which finally determined a reasonable pigging sequence. We designed and selected the "optimal pigging proposal", which the time duration for the pigging operation of the seven pipeline sections was decreased to 16.91 h. Guided by the "optimal pigging proposal", the downstream pipeline sections will be challenged by the risks of ice blockage. The ground eddy device was improved in the article, for the purpose of draining liquid loadings in low-lying areas in the Puguang Gas Field and controlling the slug flow. In addition, the application effects of the device were analyzed.