A diverless tie-in system for large diameter pipelines
- Snamprogetti S.p.A., San Donato Milanese (Italy)
The connection of large trunk lines to subsea export facilities at water depths beyond diver capabilities has been seldom analyzed and never carried out. The difficulty lies in the fact that tie-in procedures and connection systems available on the market require flexibility of the inboard or outboard hub of the pipeline ends to be connected, which would need very long expansion loops. The solution proposed in this paper does not require any flexibility on the pipeline. This could be of primary importance in the development of future deep water subsea fields, especially in the North Sea, that would benefit from oil or gas transportation in large trunk lines connecting export to receiving facilities. The study has been carried out on a 36 inch pipeline at a maximum water depth of 380 m. Technical and economic sensitivity evaluations have been performed to verify the soundness of this concept for 16--40 inches pipeline diameters at a maximum water depth of 1000 m. The results obtained are part of a larger R and D project called PINTIES (PIpeline in the NineTIES) sponsored by Norsk Agip. A spool-piece shall be installed to recover distance and angular misalignments between the hub installed on the export riser base, or on a subsea template, and the hub welded on the pipeline end. The spool-piece is retrievable to perform surface maintenance, if required. The manufacturer of the spool piece and mechanical connectors was also involved in the design phase of these pieces. 7 refs., 16 figs.
- OSTI ID:
- 160648
- Report Number(s):
- CONF-950501-; TRN: IM9603%%230
- Resource Relation:
- Conference: 27. offshore technology conference, Houston, TX (United States), 1-4 May 1995; Other Information: PBD: 1995; Related Information: Is Part Of 27. Annual Offshore Technology Conference: 1995 Proceedings. Volume 4: Field drilling and development systems; PB: 688 p.
- Country of Publication:
- United States
- Language:
- English
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