 For offshore operations, the 'footprint' for a coiled tubing operation is generally larger than a wireline spread, which can limit the number of installations where coiled tubing can be performed and make the operation more costly.A coiled tubing operation is normally performed through the drilling derrick on the oil platform, which is used to support the surface equipment, although on platforms with no drilling facilities a self-supporting tower can be used instead.For coiled tubing operations on sub-sea wells a mobile offshore drilling unit (MODU) e.g.