London inauguration marks Langeled start-up

Oct. 23, 2006
The Langeled pipeline consortium and the British and Norwegian prime ministers on Oct. 16 inaugurated the 600-km southern leg of 1,200-km Langeled pipeline, which has begun exporting gas from the Sleipner hub in the Norwegian North Sea to Easington on the UK’s east coast.

The Langeled pipeline consortium and the British and Norwegian prime ministers on Oct. 16 inaugurated the 600-km southern leg of 1,200-km Langeled pipeline, which has begun exporting gas from the Sleipner hub in the Norwegian North Sea to Easington on the UK’s east coast (OGJ, Oct. 9, 2006, Newsletter).

Statoil ASA designed and laid the 44-in. diameter southern segment on behalf of Norsk Hydro ASA, operator of the Langeled development phase, which was completed 3 billion kroner ($444.1 million) below budget. Anne Lycke, Hydro’s Langeled asset manager, told OGJ that the company secured steel supply contracts before steel prices jumped.

When complete, the Langeled pipeline will carry gas from Nyhamna on Norway’s west coast through the Sleipner riser platform and on to Easington, becoming the world’s longest subsea export pipeline. Nyhamna is the site of separation and treatment facilities for production from Ormen Lange gas-condensate field in the Norwegian Sea.

Flow from Nyhamna to Sleipner through Langeled’s 42-in. diameter northern section is to begin when Ormen Lange starts production next October. Construction is about 90% complete, according to Hydro. Remaining work includes completion of the Nyhamna gas processing plant; drilling and completion of the first production wells; testing of the subsea installations; installation of the last umbilical between Nyhamna and Ormen Lange field; and midline tie-in on Langeled.

When Ormen Lange is on stream, Langeled will deliver 70 million cu m/day of gas to the UK. The Ormen Lange reservoir, about 3,000 m below the seabottom in 800-1,100 m of water, will produce from 24 subsea wells drilled through four seabed templates.

Hydro said a challenge has been the uneven seabed, with peaks 30-60 m high, over Ormen Lange.

“The first two remotely controlled subsea production stations are located 120 km from shore at a water depth of 850 m, making Ormen Lange one of the world’s largest and most advanced subsea-to-shore developments,” Hydro said.

Eivind Reiten, president and chief executive officer of Hydro, pointed out that the Ormen Lange seabed templates will operate for 30 years without maintenance.

He said Hydro and its partners have had to solve flow-assurance problems and custom-build compressors able to maintain gas flow over the system’s great distance. They also custom-built an excavator to smooth the seabed over the field and trench along a 35º incline on the Storegga subsea landslide for the two, 30-in. multiphase pipelines that will carry well streams ashore.

“We have made what seemed impossible 5 years ago possible,” Reiten said.

Partners in the Langeled joint venture are Hydro, 17.61%; Petoro AS, 32.954%; Statoil, 14.985%; Dansk Olie & Naturgas (Dong), 10.222%; Esso Exploration & Production Norway AS, 6.947%; A/S Norske Shell, 16.503%; and ConocoPhillips, 0.779%. Gassco AS, which handles transportation of Norwegian gas to continental Europe and the UK, becomes operator as operations begin.