North Sea Export Pipeline

This export pipeline operated in the North Sea by Gassco had at several times been rock dumped based on previous recommendations from engineering companies. A total cost of 1.9-2.6 MUSD was demonstrated by the new Global Free Span Service to be unnecessary.

Challenge

This case was a 54 km long 32’ export gas pipeline in the North Sea, with severe scouring issues. Installation campaigns were executed both 5 years after as-laid (when 71 spans were intervened on) and 10 years after as-laid (when 192 spans were intervened on). Additionally, there had been 11 surveys in 14 years of the pipelines lifetime, which, with the new analysis, had the potential of being reduced. 

DNV solution

Estimating remaining fatigue capacity using Global Free Span service showed that the free span intervention campaigns previously carried out were unnecessary.

Outcome and benefits

In total, the new analysis from the Global Free Span service demonstrated a potential cost savings of 1.9-2.6 Million USD.