Brent Field Debris and Attic Oil
There is some debris in the Brent Field – this is mainly scaffolding poles which have accumulated over time due to bad weather. UK regulations and Department for Business, Energy and Industrial Strategy (BEIS) decommissioning guidelines require removal of debris from the seabed around the platform and along pipeline corridors. Where debris is located within drill cuttings piles, removal will only take place if it can be done without undue disturbance of the drill cuttings.
Remotely Operated Vehicles (ROVs) are being used to recover scaffold poles and other debris into baskets, which are filled on the seabed, raised to the platform and shipped to shore for recycling or safe disposal.
Following completion of our decommissioning operations, further surveys will be carried out to identify and recover any additional debris located on the seabed which has arisen from the Brent decommissioning operation or from the past Brent development and production activities.
There is a small portion of oil within the top dome of the Brent Delta cells. The oil cannot be recovered with the internal process piping due to the design of the cell outlet piping and the fact that oil is buoyant on water.
Operations to recover the attic oil will be conducted offshore using Remote Operated Vehicle (ROV) technology. A hole will be drilled in each cell and oil will be extracted using a flexible piping system where it will be temporarily gathered into one storage cell for removal by ship.
Shell’s attic oil operations have been ongoing since 2014, after the cell survey project surveyed three of the cells. Safety is Shell’s top priority so operations have been designed to eliminate the use of divers, placing greater emphasis on ROV operations.
Each piece of equipment has to be expertly guided into place by a team of ROV ‘pilots’ who work on rotational shifts. Individual baseplates allow for the operations to take place and are required on each of Delta’s 16 cells.
Anchor hubs form a connection into the concrete cell tops via the base plates and provide a seal – they prevent flow of the attic oil outside the cell. This is where the other tools connect into the pump so that the oil can be extracted via the piping system.
The offshore crews supporting the attic oil project are working 24/7 with support from around 25 personnel. Activities have been gathering momentum since early in 2014 with successful deployment of the first baseplates in autumn 2015.