Work on excavating a trench up to the landfall for the Langeled gas trunkline is well under way across the seabed off Easington in eastern England.
Initiated on 12 May, this operation is being conducted by the world’s largest cutter suction dredger, JFJ de Nul. It began about a kilometre from the shore and will extend some 20 miles out.
“The final section of the trench to the cofferdam established 240 metres into the shoreline zone has already been excavated,” reports Langeled project director Leif Solberg.
Lined with sheet piles, the cofferdam is intended to prevent the sea washing sand down into the trench in the splash zone.
The trench will be 10 metres wide and two deep, and is due to be re-filled as the pipeline is laid.
A 400-metre tunnel has already been constructed from the shoreline zone to the gas terminal at Easington, and all traces of this work will be eliminated as soon as laying has been completed.
The Tor Mor laybarge is due to lay the pipeline over its first 15 kilometres from land, but will not come closer than 500 metres to the shore.
A big winch on land will pull the pipeline through the cofferdam and in to the shoreline before the barge starts laying out into the North Sea during late June.
The LB200 laybarge has already begun installing the Langeled line south from Statoil’s Sleipner Riser gas transport hub in the Norwegian North Sea.
Once Tor Mor has completed its work, LB200 will pick up this part of the line and continue laying north until the two sections can be welded together.
Langeled will ultimately carry gas from the Ormen Lange field in the Norwegian Sea via Sleipner Riser to Easington. Statoil is responsible for this project on behalf of operator Hydro.
The Easington terminal is due to come on stream in October 2006 to deliver gas via the Sleipner area. Ormen Lange is due to come on stream 12 months later.