Troll A was built by Norwegian Contractors for Norske Shell, with base construction beginning in July 1991[REF] at a cost of 4150 million NOK,[REF][REF] or approximately US$650 million at the time [REF].
The Troll platform was towed over from Vats, in the northern part of Rogaland, to the Troll field, north-west of Bergen.