Project Profile
Location: 186km off the northeast coast of the Shetland Islands, Scotland, UK
Water Depth: 140 metres
Start-up Year: November 1976
The Brent oil and gas field lies within UK licence block 211/29, at a depth of 140m. The Brent field was discovered by Shell-Esso in 1971 and is one of the largest oilfields in the UK North Sea. A discovery well was drilled around 1km down-dip to the west of the tip of the buried high. It is located 150km north-east of Shetland. The field includes four large platforms: Alpha, Bravo, Charlie and Delta. The field is jointly owned by Royal Dutch Shell (50%) and ExxonMobil (50%), and is Shell\'s flagship asset on the UK Continental Shelf.
The four platforms were shut down after an oil leak in January 2011. The platforms were brought under immediate maintenance. Brent Alpha and Bravo platforms restarted in August 2011, while Charlie will restart in early 2012. Shell has not yet set timelines to restart the Delta platform.
The field underwent a £1.3bn upgrade in the mid-1990s. It was the largest and most comprehensive field redevelopment ever undertaken in the North Sea. A computational fluid dynamics and finite element analysis will be conducted by DECOM North Sea under a contract awarded by Shell in August 2011. The term of the contract is 18 months, with an option to mutually extend the term.
Decommissioning Programme
The decommissioning activities cover aspects and areas such as plugging wells, topsides, removal of debris and attic oil, Brent Field Alpha jacket, drill cuttings, decommissioning the Gravity Base Structures (GBS), pipelines, and cell contents.
Decommissioning timeline
1994 – The Spar decommissioning programme is submitted
1996 – Stakeholder consultations begin in London for decommissioning of Brent Spar
1998 – The decommissioning programme for Brent Spar is resubmitted to the UK Government
1998 – The proposal is for Brent Spar to be re-used as a quay in Norway
1999 – Stakeholder consultation draws to a close for Brent Spar.
2006 – Brent decommissioning project established
2007 - Stakeholder engagement for the field’s decommissioning begins with meetings in London and Aberdeen
2007 – Shell set up an independent review group to objectively review all the scientific and engineering methods used to decommission the Brent Field.
2010 – The Wood Group PSN are awarded contract to provide support for Brent decommissioning activity on the Delta platform
2011 – The Environmental Impact Assessment (EIA) Scoping Report is made available defining the scope of the decommissioning project
2011 – Production at Brent Delta is stopped and the platform begins preparation work for decommissioning.
2013 – Allseas are awarded contract for “single lift” vessel. This technology includes the Alpha, Bravo and Delta topsides as well as the Alpha Jacket structure
2014 – Brent Delta is declared hydrocarbon-free. This means that there is no longer any oil and gas being produces on the platform – a key stage in the decommissioning process
2014 – Able UK in Hartlepool are awarded the recycling contract for the Brent Delta topsides with a target of 97% recycling of topsides
Brent Delta topside decommissioning programme
The decommissioning programme submitted by Shell for the Brent Delta recommending that the 24,200 tonne ’topside’ of the platform is removed in one piece by a heavy-lift dedicated vessel was approved by the UK Government in July 2015. The topside will be taken to Able UK, a specialised decommissioning company in Teesside, where more than 97% of the material will be reused or recycled.
Anglo-Dutch oil major Royal Dutch Shell will start dismantling its nearly 40-year-old Brent Delta platform in the North Sea in 2017, delaying the process by around one year. (July, 2016)
**Brent Delta: Topside removal Q2 2017, attic oil removal Q3 2017. Brent Alpha: Topside and oil attic removal in Q2/Q3 2017 respectively. Decommissioning programme currently under consideration by BEIS. Proposed timelines: Phase 1: Wells plug and abandonment (P&A) by end-Q1, 2019, topside preparation start of Q2, 2019 until end-Q1, 2021. Phase 2: Topsides removal in Q2 2021, conductor removal in Q3 2021, upper jacket preparation in Q1 and Q2, 2022 and upper jacket removal in Q3 2022. Brent Bravo: Wells plug and abandonment (P&A) by end-2016, topsides preparation by end-2017. Phase 2: topsides removal in Q2, 2020, attic oil removal, Q3 2020. Brent Charlie: Phase 1: Wells plug and abandonment (P&A) by end-Q3 2020, topside preparations Q2 2020 until end-Q1, 2022, topside removal Q2 2022 and conductor removal Q3 2022. All Fields Phase 3/close out: Subsea removals Q3 2022 until Q2 2024; pipeline flushing Q1 2022, pipeline campaigns Q3 2022 until end-Q3 2024. Debris removal and sweep, Q4 2024 until end-Q2, 2025; \"As left\" structural survey Q4 2025 until end-Q1 2026. Post-decomm environmental survey Q4 2025 until end-Q1 2026. Close-out report by mid-2026 if target dates met. Projected costs disclosed to UK Department of Business and Energy (BEIS) but not yet publicly released.** DF 02/01/2018
Operators:
Royal Dutch Shell: Operator with 50% interest
ExxonMobil: 50% interest
Contractors:
Wood Group: Decommissioning of the Brent Bravo platform
Able UK: Awarded the recycling contract for the Brent Delta topsides with a target of 97% recycling of topsides. (2014)
Allseas Group: Contract for “single lift” vessel. This technology includes the Alpha, Bravo and Delta topsides as well as the Alpha Jacket structure. (2013)
DECOM: Conducted computational fluid dynamics and finite element analysis
Global Energy Group: constructed SKID packages for Shell’s Brent Charlie Platform
Offshore Design Engineering: Decommissioning studies
Wood Group PSN: Contract to provide support for Brent decommissioning activity on the Delta platform. (2010)
Wood Group GTS: Rotating equipment managed maintenance services
Prosafe: Contract with Shell U.K. Limited (Shell) for the provision of the Regalia semi-submersible accommodation vessel at the Brent C platform in the UK sector of the North Sea. The short duration contract commencing Q2 2016 will provide Dynamically Positioned (DP) gangway connection for the duration of the project. This contract award follows the Regalia recently completing a successful assignment for Shell at the Shearwater platform. Total value of the contract is approximately US$24 million.
Fjords Processing: A contract to provide environmental assessments. The environmental impact studies will focus on water discharges, ecotoxicology tests and computer modelling. (September, 2016)