Impacts of the rugged terrain on operations of the Baoji-Hanzhong Natural Gas Pipeline

Considering actual performance of the Baoji-Hanzhong Natural Gas Pipeline, this paper discusses the impacts of rugged terrain on operations of natural gas pipelines in respect of throughput, as well as the impacts of hydrostatic resistance and slug flows on pigging operations. A simplified calculation equation for hydrostatic resistance of accumulated water is used, and the function between heights and elevation differences of water slugs and the hydrostatic resistance is determined. Research results show that rugged terrains may significantly affect transportation capacities of natural gas pipelines. Throughputs without consideration to differences in elevations are generally higher than those with the differences considered. In addition, hydrostatic resistances and slug flows induced by rugged terrain may negatively affect both travelling speeds and audio monitoring over pigs. Hydrostatic resistances may even be high enough to break pigs. By using the simplified calculation equation for hydrostatic resistance, the pressure deviations before and after pigs can be determined accurately. The research results may provide theoretical guidance for pigging operations along the Baoji-Hanzhong Natural Gas Pipeline.