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Troll oil pipeline: Advanced landfall solution at Mongstad

Conference ·
OSTI ID:400910
 [1];  [2]; ;  [3]
  1. Snamprogetti S.p.A., Fano (Italy)
  2. Universale Bau, Munich (Germany)
  3. Statoil, Stavanger (Norway)

The landfall of the 16-in. Troll Oil Pipeline is achieved by means of a 30-in. cased borehole routed through hard metamorphic rock using up-to-date technology for drilling, down hole directional control and path survey. The borehole, which extends over a total length of 760 m, starts in a clear area inside the Mongstad Refinery and pierces in the lowermost part of Fensfjord`s southern steep sided cliff at 314 m water depth. The deep waters at th4e offshore end required completely diverless operations. Pipeline installation inside the borehole was carried out as part of the pipelay start-up with the aid of an onshore located pull-in winch. Main topics faced during the design and the adopted technical solutions are presented, notably: borehole route and size; borehole approach route and intervention works, corrosion protection system; and auxiliary devices such as the bellmouth at the offshore end and the anchor block at the onshore end. Experience feedback from construction activities is discussed focusing on technology performance, contingencies and remedial actions.

OSTI ID:
400910
Report Number(s):
CONF-9606279--; ISBN 0-7918-1494-7
Country of Publication:
United States
Language:
English

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