US Patent 7279052 Method for hydrate plug removal

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.