OREANDA-NEWS. June 21, 2011. The world’s largest pipelay vessel Allseas’ Solitaire today completed the construction of Line 2 of the Nord Stream Pipeline in Russian waters and has resumed pipe laying in Finnish waters. Over 230 kilometres of Line 2 have now been laid in the Baltic Sea, 124 kilometres of which are in Russian waters. Simultaneously, Saipem’s Castoro Sei is laying pipes in the Gulf of Finland as well. Line 1 has been completed and will be put into operation in the fourth quarter 2011.

On the Russian shore in Portovaya Bay near Vyborg, construction of landfall facilities for both pipelines and pressure tests have been completed in June. Herewith, the main scope of work on Nord Stream’s Russian section consisting of the 1.5 kilometre dry part and 124 kilometre offshore part has been finalised.  

Offshore part

Solitaire re-entered Russian waters for construction of Line 2 on schedule on May 15. 7.5 kilometres away from the shoreline the vessel picked up the pipeline, the nearshore part of which was laid by Castoro Sei in summer 2010, and continued pipe laying along the route. Due to favourable weather conditions, the pipe-laying speed averaged more than 3 kilometres per day, with the Solitaire laying 116 kilometres of Line 2 in just over a month. Between September and October 2010 the vessel laid the corresponding part of Line 1.

Dry part

Onshore facilities located 1.5 km from the shoreline include pig traps as well as isolation and emergency shutdown valves. Installation of equipment was completed in June. At the moment assembling of telemetry and automation systems is ongoing. In summer gas-in equipment required for the commissioning stage will be installed.

During the operational phase gas pressure at the start of the pipelines will be as high as 220 bar, which requires the use of steel pipes with a maximum wall thickness of 41 millimetres. To guarantee that the pipeline can withstand such operational pressure, the two pipelines of the dry part were pressure tested to confirm their integrity and safety. The pipelines were filled with water and pressurised beyond the planned maximum operating pressure by 25 percent for a minimum of 24 hours. The pressure tests have been successfully completed and both sections will now be dried and filled with nitrogen to prepare for gas-in.