Abstract: A thruster pig for sending through a pipe from an entrance facility to a receiving location, for servicing or monitoring, by pumping a thrusting fluid into the pipe to force the pig forward is disclosed. The thruster pig includes a body having a front end and a back end, where the back end includes a reaction surface to which said the thrusting fluid applies a motive force. The body is slightly smaller in diameter than the inner diameter of the pipe. The pig also includes a seal circumferentially arranged on the pig to seal between said body and said pipe. A desired differential pressure is maintained over the pig to urge said pig forward through the pipe by pumping a fluid into the annulus between the pipe and the return flow line while returning fluid through said return flow line utilizing connected servicing or monitoring equipment. A connector releasably connects a return flow line to the pig.

Abstract: A method for removal of deposits such as hydrate plugs from a pipeline is provided including inserting a thruster pig connected to a return flow line into the pipeline The pig is then advanced forward into the pipeline by pumping a thrusting fluid into an annulus between the pipeline and the return flow line while removing deposits continuously or intermittently and returning flow as appropriate from ahead of the pig through the return flow line. The return flow line is then disconnected from the pig after sufficient deposit removal and retrieved from the return flow line. Next, the pig may then be transported through the pipeline by the pipeline fluid to a pig receiving location once the pipeline flow is resumed.

Abstract: A pig for pumping thru pipelines for the cleaning of the pipelines which provides for fishing neck type profiles for remote attachment and removal in case of pipeline blockages, provides for the fishing neck type profiles to include valving which will allow communication between the ends of the pig to prevent hydraulic locking in the high pressure ambient condition of subsea pipelines, and provides for interconnection and operation of valving on each end of the pig.