The Norpipe is an offshore pipeline transporting natural gas over a total length of 443 kilometres from the Ekofisk field in the North Sea to Emden. The pipeline has been in operation since September 1977 and is intended to be operated until at least 2028. The Norwegian company Gassco AS is the operator of the Norpipe.
During the annual inspection of the Norpipe in the German sector of the North Sea, several freespans, i.e. pipeline sections not in contact with the seabed, were detected near the island of Juist. These freespans were classified as critical for the structural integrity and thus for the further safe operation of the pipeline by DNV GL as technical expert for the German Mining Authority (LBEG). Consequently, an immediate remediation of the affected pipeline sections by the operator was imperative.
The presentation focuses on the required remediation works at the freespan in the tidal channel Bantsbalje south of Juist. The finally selected remediation method will be explained and evaluated in detail highlighting the specific challenges of conducting work on a ” live” pipeline in the protected landscape Lower Saxony Wadden Sea National Park.