Jumbo installs FPSO mooring spread in North SeaProjects and Operations // April 16, 2014
Jumbo has completed stage one of an offshore installation contract undertaken as main contractor.
Using the J-class vessel Fairplayer Jumbo successfully installed an FPSO mooring spread for client EnQuest in the Alma and Galia field.
The second stage of the project will take place later in 2014. This will see EnQuest Producer, currently in Newcastle upon Tyne, UK, hooked up to the mooring spread.
Jumbo was awarded the contract in September 2012, due to an ability to transport large amounts of cargo aboard versatile vessels and the flexibility to adapt to project specific requirements.
The scope of work for the first campaign consisted of construction and installation of anchor piles weighing between 72 tonnes and 85 tonnes, installation of 130m bottom chain, pre-loading of the anchor piles and bottom chain and installation of 1,150m spiral strand wire.
The first shipment of anchor piles and bottom chain were transported from the Port of Rotterdam. Once on site the anchor piles were driven to the required depths with a hydraulic hammer. A sub frame was placed on the seabed to get the piles upright and into position. ROVs were utilised to verify the position of the piles.
Once the piles had been driven to the required depths, the bottom chain was deployed via a chain wheel operated from Fairplayer.
The next phase was the pre-tensioning of the piles and chain to remove potential slack in the mooring spread. To achieve this, the chain was rigged through the tensioner and pulled by the crane. A pull of around 300 tonnes from the chain led to the required pre-tensioning of 500 tonnes.
The final mobilisation saw the transport of the spiral strand wire and top chain from Rotterdam. Onsite the bottom chain was raised on-board the vessel and connected to the spiral strand wire, which was then lowered and installed via the deployment winch.
The wire was then connected to the top chain, which was deployed with the chain wheel. Detailed engineering and careful work offshore avoided any damage to the spiral strand wire.