Patent attributes
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. The connector includes a shifting mandrel that may be activated to open the connector by a ball pumped through the return flow line, where the ball is retained in the return flow line after releasing the connector. A blanking device is then provided to blank the bore within the pig that is left after the return flow line is disconnected.
