| Resumo: |
Installation and tie-in using tig automatic hyperbaric welding of 3 expansion loops to the Gullfaks "C" gravity base platform at 220 meters in the Norwegian sector of the North Sea. Operation performed from a dynamically positioned diving support vessel using divers and construction ROV during the summer 1989. Facing the technological challenge created by the deep diving aspects, the technical difficulties of doing welding operation at this depth, and the tight commercial constraints, a review of the tasks was conducted to optimize and reduce the offshore time, leading to innovations in the procedures selected to perform the work: Use of a working ROV, assisted by an observation vehicle, to carry out subsea tasks traditionally reserved for construction divers. Use of an hybrid team consisting of a diver assisted by a working ROV. Use of mechanized hyperbaric tig welding for all 6 tie-ins. This project was a typical example of the joint work ROV/ROBOTIC/DIVER, which proved very efficient at this depth and which opens new perspective for deeper welded tie-ins.
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