Pipeline pig apparatus, and a method of operating a pig

A bi-directional pig apparatus for removing wax and hydrate deposits in subsea hydrocarbon production flowlines, the apparatus comprising:

• a pig arranged for movement inside at least a portion of a pipe, wherein the pig comprises:
• a non-magnetic tubular body having a longitudinal axis coinciding with a central axis of the portion of the pipe, and
• one or more magnets comprising a permanent magnet or a magnetisable material arranged in a circumferential wall of said body;
• at least one through-going opening between opposite ends of said tubular body, to allow fluids (F) in the pipe to flow through said body;
• and
• a propulsion means arranged and configured for imparting a motive force to the pig, whereby the pig is movable in either direction inside the portion of the pipe independently of fluid flow in the pipe.