Troll Phase 1, pipeline/cable J-tube pull-in and trenching
- A/S Norske Shell, Bergen (Norway)
During 1995 a 4-in. steel pipeline and a 124 mm power and communication cable were pulled into pre-installed J-tubes on the Troll Phase 1 platform offshore Norway, at a waterdepth of 303 m. These diverless operations were carried out with high precision and pull-in loads remained well below calculated values. Some corrective actions were necessary to achieve tight annulus sealing at the bottom of the J-tubes, including a special gel injection operation. Following pull-ins, the appr. 65 km installations to shore were record-breaking single unreeling operations. This work was carried during June/July 1995 and completed well before pull-in and installation of other pipelines in the same route. Trenching of pipeline and cable in waterdepths up to 350 m--in a seabed generally comprised of soft clay with increasing boulder frequencies closer to shore--was successfully carried out by two different trenching machines. Only minor retrenching and corrective rockdumping were required. The article highlights J-tube pull-in/sealing and trenching experiences in the unique deepwater environment offshore western Norway.
- OSTI ID:
- 400904
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1494-7
- Country of Publication:
- United States
- Language:
- English
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