Nord Stream pipeline moves another step closer to completionProjects and Operations // May 31, 2011
The Nord Stream pipeline has taken another important step towards its target of starting to deliver gas directly from Russia to the European Union by the end of 2011.
Preparations for welding together two of the three sections of the 1,224km pipeline through the Baltic Sea have now started. They will be welded together on the seabed off the coast of Finland in a complex process expected to take about two weeks.
The technical completion of the first of the twin pipelines will be achieved in June, when the final section is welded onto the pipeline off the Swedish island of Gotland.
Construction of the second of the twin pipelines is scheduled for completion in 2012.
Nord Stream was able to design its offshore pipeline to operate without an intermediate compressor station, but with three different design pressures and pipe wall thicknesses as the gas pressure drops over its long journey from Russia to landfall in Germany.
The connection of these three pipeline sections will be carried out at the two offshore locations where the design pressure changes from 220 to 200 bar and from 200 to 177.5 bar respectively.
Mid-May saw the start of the connection of the Gulf of Finland section and the Central section at a sea depth of approximately 80m. The connection of the Central and South Western sections off Gotland will take place at a depth of approximately 110m.
Each of the three sections is gauged and thoroughly pressure-tested before being joined together by hyperbaric tie-ins and subsequently linked to the landfalls in Russia and Germany.
Pre-commissioning activities are already underway: for the Gulf of Finland and Central section cleaning, gauging and pressure-testing have been successfully completed, and the pressure test for South Western section now follows.
On the site of the German landfall all piping has been completed and successfully pressure tested. For the Russian landfall site pressure testing is expected by the end of May after completion of all welding works.
Further rigorous testing will be carried out on the whole system before it becomes operational in the last quarter of 2011.