基于南海某气田变径海底管道注气排水清管工程背景，设计适用于变径率59%的海管变径清管器，对其通过性能、耐磨性能和排水性能进行研究分析。设计测试管路模拟实际的变径海底管道系统，基于测试管路采用洁净水作为驱动介质，验证了变径清管器在变径率59%的管路内的通过性能。变径清管器在20.32cm管路中密封板呈现均匀褶皱形态，其运行压力最大为4×10⁵Pa（表压），满足实际使用需求。采用压缩空气作为驱动介质，研究了变径清管器的排水性能。变径清管器由20.32cm管路运行至30.48cm管路时的运行压力较变径清管器由30.48cm管路运行至20.32cm管路时运行压力大，但前者的排水效果要优于后者。模拟测试的变径清管器将应用于南海某气田变径海底管道排水实践。

Based on the background of a reducing subsea pipeline in a gas field located in the South China Sea， a multi-diameter pig with a reducing rate of 59% is designed， and its passing performance， wear resistance and dewatering performance are analyzed. A test pipeline is designed to simulate the actual reducing subsea pipeline system. Based on the test pipeline， using fresh water as the driving medium， the passing performance of the multi-diameter pig in the pipeline with a reducing rate of 59% is verified. The multi-diameter pig has a uniform fold shape on the sealing plate in the 20.32cm pipeline， and its operating pressure is up to 4×10⁵Pa （gauge pressure）， which meets the actual use requirements. Using compressed air as the driving medium， the dewatering performance of the multi-diameter pig is studied. The operating pressure of the multi-diameter pig running from an 20.32cm pipeline to a 30.48cm pipeline is higher than that of the pig running from a 30.48cm pipeline to an 20.32cm pipeline， but the dewatering performance in the former case is better than that in the latter case. The multi-diameter pig after simulation test will be applied to the dewatering of a subsea reducing pipeline in a gas field in the South China Sea.