The Solitaire laybarge has completed laying the main pipeline that carries the unprocessed wellstream from Statoil's Snoøhvit field in the Barents Sea to land.
The 143-km pipeline comes ashore at Melkøya outside Hammerfest in northern Norway. This is the world's longest multiphase-flow pipeline, which has an external diameter of 28-in.
The pipeline will bring gas ashore for processing and liquefaction before the gas is exported as LNG.
"Multiphase transfer of the wellstream to land represents a substantial technological leap," says Margareth Øvrum, executive vice president for technology and projects. "This marks the culmination of more than 20 years of research and development."
Statoil will use the pipeline as a full-scale laboratory to provide information on multiphase flow transport over long distances when the Snoøhvit line becomes operational in autumn 2006. New commercial opportunities will open for this technology, the company says.
The pipelaying operation began from Melkøya on April 18 with 12-m lengths of line pipe welded together continuously on the laybarge. The operation consisted of welding and coating the line while feeding it out over a stinger (ramp) from the stern of the vessel at 5 km/d.
Three pipe carriers shuttled between theSolitaire and Polarbase outside Hammerfest to ensure a steady supply of line pipe.
To reduce long free spans on the seabed, gravel is dumped over the pipeline. This work has started.
Gas deliveries from the Hammerfest LNG plant at Melkøya will start on Oct. 1, 2006.