Buoy manufacturer CRP Marine Ltd., Skelmersdale, U.K., has completed trials of a pipelay technique for installation of East Troll gas field pipelines in the Norwegian North Sea.
Troll's export pipelines are to be installed in 984 ft of water. Installation at such depth without buoys would pull a pipelay vessel under, CRP said.
Instead, pipelay contractor European Marine Contractors Ltd., Kingston-upon-Thames, U.K., will use 125 buoys made by CRP, each with a net buoyancy of 2,640 lb, to counter the weight of pipeline sections.
"The greatly reduced weight of the pipeline allows installation to be performed at significantly reduced lay barge tensions and permits the pipeline to locate onto preinstalled supports on the seabed, said CRP.
Because of the great water depth, the buoys are designed to be released by remotely operated vehicles.
CRP is slated to complete manufacturing of the buoys in April. They will see first use this summer in construction of a pipeline from East Troll field to the Kollsnes, Norway, terminal.
They also will be used next year during laving of Zeepipe IIB from Kollsnes to Norway's Block 16/11 offshore gas transmission hub.
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