PIGGING METHOD AND APPARATUS

摘要

A method of pigging a pipeline network (4,6) connecting a host facility (1) to a remote location (2), the network including a delivery pipeline (4) for transporting a first fluid from the host facility (1) to the remote location (2) and a return pipeline (6) for transporting a second fluid from the remote location (2) to the host facility (1), the method comprising the steps of: (I) propelling a pig (24) with a first fluid along the delivery pipeline (4) to the remote location (2); (ii) capturing the pig (24) in a pig trap (42) situated in a pig transfer pipe (20) connecting the delivery and return pipelines (4,6); (iii) diverting the second fluid to propel the pig (24) out of the pig trap (42) and around the transfer pipe (20) into the return pipeline (6); and (iv) propelling the pig (24) with the second fluid along the return pipeline (6) to the host facility (1).