Design and application of pressure-controlled pig

Pig blockage is very likely to occur in the first pigging operation if a long-distance natural gas pipeline has notbeen pigged for a long time. In order to reduce the probability of potential pig problems and meet the high-efficient and largeflowrate needs of pipeline simultaneously, this paper brings forward a design program for pressure controlled pig. Such thepig is equipped with pressure-controlled bursting disc and pressure-controlled elastic valve drainage device at the front end, ensuring automatic bursting of the bursting disc and drainage function of pressure-controlled elastic valve automaticallyopened under the action of pressure difference in case of pig blockage happened. The pressure-controlled pig has beensuccessfully applied in the Ji'nan-Linzi Pipeline section in SINOPEC Ji'nan-Qingdao Gas Pipeline. This case indicates thatthe pig plays a key role in enhancing pipeline transmission efficiency and minimizing pipeline accidents.