FoundOcean news -  FoundOcean supports pipeline protection in Shetland

FoundOcean news - FoundOcean supports pipeline protection in Shetland

In January 2009, FoundOcean was contracted by Subsea 7 to provide fabric formwork supports to the 36-inch pipeline over the length of its landfall approach. The pipeline which required support, transports oil from several North Sea platforms near Shetland. The seabed is rocky, uneven and sloping and the original pipeline supports, installed years ago, had subsided.

FoundOcean provided the fabric formwork supports, grout mixing equipment, storage for 70 tonnes of cement, the grout bag deployment system and umbilicals. All the grout bags were designed to be installed by Subsea 7’s Remotely Operated Vehicles (ROVs).

Colin Barrett, Project Engineer for FoundOcean, saw no problem in installing supports at a water depth of 100 metres; his earlier experience included installing pipeline supports in West Africa at a water depth of 1,250m.

FoundOcean’s grouting equipment and an initial load of dry cement were mobilised to the Skandi Seven in Peterhead and personnel were mobilised through Lerwick. Once the initial load of cement had been used, cement was resupplied in Lerwick.

FoundOcean’s expertise and experience in varying water depths made installing pipeline supports under the 4km stretch of pipeline a routine operation. The vessel’s crane lowered the bag deployment sled to the seabed close to the pipeline. At this point the cement hose was already connected to the grout bag. An ROV pulled the formwork from the deployment sled and positioned it under the pipeline, using the formwork’s integral deployment yoke.

FoundOcean’s team then mixed and pumped the cement grout into the formwork until it was filled sufficiently to support the pipeline. The ROV then disconnected the cement line from the support for recovery to the surface.

In all, the project lasted three weeks, including the installation of eight pipeline supports in the middle of the North Sea winter season.