First Cygnus platform in place in North Sea

Seaway Heavy Lifting’s Stanislav Yudin vessel has installed the topsides on the jacket of the Cygnus Alpha wellhead platform.

Offshore staff

LONDON – Seaway Heavy Lifting’s Stanislav Yudin vessel has installed the topsides on the jacket of the Cygnus Alpha wellhead platform.

This is the first of four platforms under construction for the GDF Suez E&P UK-operatedCygnus gas field 150 km (93 mi) from the Lincolnshire coast in the UK southern North Sea. The 1,640-metric ton (1,808-ton) topsides had sailed from the Heerema Hartlepool yard in northeast England a week earlier. 

EarlierStanislav Yudin set down Cygnus’ 548-ton subsea wye manifold and the 156-ton subsea isolation valve, both supplied by Isleburn. Later this year the vessel will return to install the two remaining Alpha complex jackets (under construction by Burntisland Fabrications in Scotland) for the process/utilities (PU) and quarters/utilities (QU) platforms, said Ian Conacher, GDF Suez’s Cygnus Asset Manager at a briefing in London.

Heerema Hartlepool is also building the 1,500-ton compression module and the 4,000-metric ton (4,409-ton) topsides for the PU and the 3,500-metric ton (3,858-ton) Bravo wellhead platform topsides, both due for delivery in April 2015. Seaway’s Oleg Strashnov vessel will install both topsides next year, with the compression module due to be added a year or more after start-up, according to analysts BritBoss.

Saipem’sCastoro Sei has laid the 51-km (31.7-mi), 24-in. Cygnus export pipeline which will connect via the wye manifold to the Eagles Transport System trunkline that runs from Perenco’s Trent platform. The Cygnus pipeline will now undergo trenching and backfilling.

Castoro Sei’s next job is the 5.9-km (3.66-mi) infield flowline connecting Cygnus A on the eastern part of the field with Cygnus B on the western side.

TheEnsco 80 jackup starts drilling the project’s 10 production wells this summer.

Cygnus is due to come onstream in 2016 and should remain in production through 2025. However, GDF Suez sees the new facilities as a potentially longer-term hub for other satellite gas structures in the area.

The company hopes to prove new gas from the Cepheus prospect to the north, where an exploratory well was at total depth last week. It also has approval from its partners to drill an appraisal well around the turn of this year on the Humphrey discovery to the south in block 44/16.

Another likely to be tested is the undrilled Bunter structure Mitre, said GDF Suez subsurface manager Andy Spencer.

Elsewhere in this region, the company is preparing to appraise the Romeo discovery close to its recently onstreamJuliet gas field, a subsea tieback to Perenco’s Pickerill platform.


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