首站：输气管起点，建于气田附近。First station: the starting point of the gas pipeline, built near the gas field. 主要功能：调压、计量、除尘、发送清管器、分析气体组分、检测气体水露点和烃露点等。Main functions: pressure regulation, metering, dust removal, sending pig, analysis of gas components, detection of gas water dew point and hydrocarbon dew point.