Brent Field Decommissioning Programme
The Brent oil and gas field, a 50:50 joint venture between Shell (operator) and Esso Exploration and Production UK (Esso) lies 186kms north-east of the Shetland Islands in the North Sea.
Why is Shell decommissioning the Brent Field?
At the time of its discovery the expected lifespan of the Brent Field was 25 years. Through continuous improvement and significant investment in the 1990s, we have extended the life of the Field well beyond original expectations. After over 40 years of service to the UK, the Brent Field is now reaching the stage where almost all the economically recoverable reserves of oil and gas have been extracted, and in line with UK legislation, the Brent Field will now be decommissioned.
The decision to decommission Brent is a natural step in the life cycle of the field.
Brent Delta stopped production in 2011 and Brent Alpha and Bravo ceased in November 2014. Production from the field currently continues through Brent Charlie.
What is the Brent Field Decommissioning Programmes document?
Decommissioning in the UK Continental Shelf follows a mature and tightly defined regulatory process that is stipulated in the UK’s Petroleum Act 1998.
As the operator of the Brent Field, Shell must submit Decommissioning Programmes to The Department for Business, Energy and Industrial Strategy (BEIS), for review, followed by public consultation, as part of the extensive approval process.
In accordance with legislation, we have submitted two Decommissioning Programmes (DP) in a single document. One DP covers the Brent installations and wells, and the other covers the Brent Field Pipelines. Our DP documents includes the recommendations for closing down and making safe the four platforms, the wells and the subsea infrastructure. T
The Decommissioning Programmes were subject to public consultation between 8 February and 10 April 2017, and a simultaneous consultation with other government departments, and statutory consultees was carried out.
The DP documents are supported by a suite of detailed Technical Documents (TDs) for each aspect of the programme; an Environmental Statement (ES); a Comparative Assessment (CA) process; and a Stakeholder Engagement Report.
What is in the Brent Field Decommissioning Programmes document?
Shell has been preparing for, and executing, the following decommissioning activities:
- Plugging and making safe the 146 wells across the Brent Field;
- Removing to shore, and recycling the platform’s topsides;
- Cutting the upper portion of the Brent Alpha steel jacket, and removing to shore for recycling.
- Removing the oil –known as ‘attic oil’ – trapped at the top of some of the subsea storage cells; and
- Recovering oil and gas debris from the seabed across the Brent Field;
After completing the comparative assessment process of feasible decommissioning options, and as a result of careful and considered evaluation, the recommendations being proposed include leaving in place the Gravity Base Structures (GBS), Brent Alpha jacket footings, the drill cuttings and GBS cell contents.
A range of options have been considered for the 30 pipelines, including: leaving in place pipelines already in stable trenches or under stable rock; complete removal (reverse reel or cutting and lifting); leaving in place with a new covering of rock; and leaving in place after trenching and burying.
Where the Decommissioning Programmes recommend leaving major installations in place in the North Sea, under the OSPAR Decision 98/3, the UK Government must consult with other countries that are signatories to the OSPAR Convention. The OSPAR convention is an agreement between 15 European countries and the EU to protect the marine environment in the North-East Atlantic.
OSPAR recognises that there are difficulties associated with removing major installations, such as concrete Gravity Base Structures and large steel jackets. In these instances, operators may make a case for exemption – or derogation – from the general rule of complete removal from the sea, but they must demonstrate that there are significant reasons why an alternative option is preferable to reuse, recycling or final disposal on land.
Shell and Esso are confident the proposals set out in the DP document are safe, technically achievable, financially and socially responsible, and environmentally sound. These recommendations are the result of 10 years of review and planning, including extensive research involving engineering studies, independent experts’ input, consultations and scientific assessments.
Under current legislation, Shell and Esso will retain ownership of and responsibility for any remaining facilities after decommissioning.
Who has Shell engaged with?
Since 2007 Shell has conducted extensive stakeholder engagement, and received input from more than 400 individuals from more than 180 organisations in the UK and Europe.
In addition, the Brent Decommissioning project established an expert panel of scientists, the Independent Review Group (IRG), to verify the technical and engineering studies that were used to develop our proposals.
Find out more about the role of the IRG and read their final report on the project.
Brent Field Decommissioning Programme and Supporting Documentation
This image shows the suite of documentation for the Brent Field Decommissioning Programmes. The Technical Documents are designed to be read after the Decommissioning Programme document, supplementing it and providing detail to the facts, assessments and conclusions presented in the Decommissioning Programme.
The Decommissioning Programmes are also available on the BEIS website:
Access the Brent Field DP on the Department for Business, Energy and Industrial Strategy (BEIS) website.
Brent Topsides Decommissioning Programmes
After detailed technical and engineering studies, it was decided that the Brent topsides would be removed using the new single lift vessel (SLV) Pioneering Spirit commissioned by Excalibur AS (part of the Allseas Group) and transported to the Able Seaton Port (ASP) facility at Teesside, operated by Able UK Limited (Able), for dismantling, recycling and disposal. This single lift technique will substantially reduce the risk, cost and environmental impact of the operation.
As part of the phased programme of offshore work, it was recognised that the Brent Delta topside would be ready for removal ahead of the formal approval of the wider Brent Field DP. It was agreed with the UK Regulator that a separate Brent Delta Topside Decommissioning Programme would be submitted
Following a thirty-day public consultation in early 2015, the Brent Delta Topside DP submitted by Shell recommending that the 24,200 tonne ’topside’ of the platform is removed in one piece by the SLV Pioneering Spirit was approved by the UK Government in July 2015.
The approval was a milestone for the project which began in 2006 and has seen engagement with stakeholders from over 180 organisations, including NGOs, academic institutions and independent scientific experts.
Following completion of the thorough topside preparations, the Brent Delta topside was removed on 28th of April 2017 and transported in May to the Able Seaton Port (ASP) facility at Teesside. Able processed the materials from the topside including asbestos, LSA/Norm and large amounts of steel.
Dismantling of the topside was completed in February 2019, and ultimately 97% of the Brent Delta topside by weight was either reused or recycled.
The Brent Delta Topside Close-out Report describes the offshore and onshore programmes of work to cut, lift, remove, dismantle, reuse, recycle and dispose of the Brent Delta topside. This report also covers the work to fit concrete caps and Aids to Navigation (AtoN) on top of the legs of the gravity based structure (GBS).
The Brent Field Decommissioning Programmes document described proposals for decommissioning the facilities in the Brent field, including proposals for decommissioning of the topsides of Brent Alpha, Brent Bravo and Brent Charlie (the Decommissioning Programme for the Brent Delta topsides having previously been approved in 2015).
The consultations provided the opportunity for consultees to raise comments on our remaining three topsides proposals. In accordance with UK decommissioning procedures BEIS had sight of our response to the comments raised by consultees in relation to the topsides, and informed us that they were satisfied that they have been addressed appropriately, and that no further consideration of proposals for the topsides was required as full removal is mandatory under OSPAR Decision 98/3.
As is to be expected when decommissioning involves large steel jackets or concrete gravity based structures, BEIS consideration of decommissioning proposals for these structures occurs over an extended timeframe to enable a robust review. Removal of topsides has no bearing on identified options for decommissioning of the Brent Alpha jacket or the Brent Gravity Based Structures, and for the management of materials in the base of the GBS legs.
In these particular circumstances, and given the timeframe involved, BEIS recognised that the execution of the remaining topsides removals can allow decommissioning to be executed cost effectively, to the benefit of the taxpayer, and without prejudice or compromise to the feasible decommissioning options for the jacket or GBS.
To this end, BEIS agreed that our topsides decommissioning proposals for Brent Alpha, Brent Bravo and Brent Charlie could be removed from the current Brent Field Decommissioning Programmes document and form a separate Brent Field Topsides Decommissioning Programme. We submitted this to BEIS in July 2018 and it was subsequently approved in August 2018.
There is no change to the OSPAR consultation process for the rest of the Brent Field Decommissioning Programme, and there is no change to any of the recommendations. We remain confident that our recommendations for the full field are safe, technically achievable, financially and socially responsible, and environmentally sound.
Following extensive topside preparation works, the Brent Bravo topside was removed on 18th of June 2019 using the SLV Pioneering Spirit. It was transported to the Able Seaton Port (ASP) facility at Teesside, where it is currently being dismantled by Able UK Limited.
The Brent Bravo Topside Decommissioning Progress Report describes the offshore programme of work carried out to cut, lift and remove the Brent Bravo topside and fit the caps and Aids to Navigation on top of the legs of the gravity base structure (GBS).
A final close out report will be submitted within twelve months of the completion of all the onshore operations to dismantle, recycle and dispose of the topside.
Brent Pipelines Decommissioning Programme
Having completed public and statutory consultations in 2017 for the Brent pipelines, as part of the Brent Field Decommissioning Programmes document, BEIS have since agreed that the proposals for the pipelines could be removed from the main document to form a separate Brent Field Pipelines Decommissioning Programme. We submitted this to BEIS in February 2020 and it was subsequently approved in March 2020.