Subsea 7 is currently experiencing the busiest period of bundle design/install
ation activity ever, Subsea 7’s bundle design manager, Martin Goodlad, told the session Advances in Subsea Construction and Technology yesterday.
A record eight bundles were installed during 2011/2012 and a further eight confirmed installations will be completed by the second quarter of 2015. He added that a number of the installed or currently in-design bundles are first for Subsea 7.
His Subsea 7 colleagues Renaud Gueret and Subhajit Lahiri presented a paper in the same session on the laying of the 127km-long umbilical laid last summer (2012) between the landfall at the Shetland Islands and the Laggan manifold. It consisted of a bundle arrangement, including two-way fibre optic communication, high voltage electricity supply, chemical supply and hydraulic power.
The installation was particularly challenging as it consisted of laying a low density product (127mm diameter, 10.6 kg/m submerged weight) along a route with particularly high currents and a large range of water depths (20-600m).
Special attention was paid to securing the umbilical should the vessel weather a storm. A lazy S-wave configuration obtained with floats connected to the umbilical was devised for this purpose.
The feasibility and concept selection study for the low temperature start-up of Shell’s Corrib project offshore Ireland was described in a joint Shell/Technip paper. The selected concept involved qualifying flexible flowlines to lower temperatures than previously were available. The Corrib project is at present in the execution phase with first gas estimated in late 2014-early 2015.
A new subsea seawater treatment and injection system was outlined in a joint Aker/Seabox paper. The system is seen as filling the “missing link” to be able to develop subsea fields without expensive tie-backs to a remote host with the use of high pressure pipelines.
Image: Subsea 7’s bundle facility at Wick.
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