ABSTRACT

The Nord Stream offshore pipelines are two 1153-mm ID (about 48" OD) pipe strings that export gas from Portovaya Bay, near Vyborg North of St. Petersburg in Russia, to a landfall area at Greifswald in Germany, across the Gulf of Finland and the Baltic Sea.

The two routes run almost parallel, for a total length of approximately 1224 km each. In addition to Russia and Germany, the pipelines cross the Territorial Waters (TW) or Exclusive Economic Zones (EEZ) of Finland, Sweden and Denmark. Max water depth is 210 m. The total capacity of the two pipelines is 55 BstdCM/y. The transportation concept accomplishes Design Pressure Segmentation (DPS) i.e. three pipeline segments (separation at KP 300 and KP 675) with Design Pressure of 220/200/177.5 barg. The system design life is 50 years.

To confirm the assumptions made in the design and in the steel material specifications about ductile steel material behavior, burst tests were successfully performed for the four selected linepipe thicknesses resulting from DPS. In this paper the experimental program is described, and the theoretical background regarding bursting limit state is discussed. The findings are presented and compared with the outcome of numerical simulations.

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