The Brae field is a Scottish oil field. The name comes from a Scots language word for hillside. The field was discovered in 1974 by well 16/7-1 drilled by a semi-submersible rig Odin Drill for operator Pan Ocean.
The Fields were operated by Marathon Oil from their inception until 2019 and are now operated by TAQA Bratani. They are located in UKCS block 16/7a. Three accumulations total about 70 million tonnes of oil liquids and a further 22 cubic kilometres of gas. The main platforms currently produce from underlying reserves, with regular infill drilling to identify and exploit undrained pockets in the Brae stratigraphy. A number of subsea tieback fields in the area produce through facilities on the platforms, extending their viability into the future. Gas is exported to St Fergus, Scotland via the SAGE pipeline system and oil is exported via the Forties system.
Field reservoirs The hydrocarbon reservoirs in the Brae field have the following properties. +Brae field reservoir propertiesFieldBrae SouthBrae CentralBrae NorthReservoirUpper Jurassic sandsUpper JurassicDepth12,000-13,500 ft12,000 ftOil column1,500 ftAPI gravity37°33°47° (NGL)Sulfur0.64 %0.64 %Gas Oil Ratio1,400 scf/bbl5,000 scf/bblCarbon dioxideUp to 35%8 %Pressure & temperature7,200 psi, 240 °F7,000 psi, 240 °FBubble point pressure3,688 psiRecoverable reserves, oil267 million bbl; 40 million tonnes65 million bbl; 9.0 million tonnes 204 million bbl; 21 million tonnesRecoverable reserves, NGL33 million bbl NGL6 million bblRecoverable reserves, gas155 billion cubic feet682 billion cubic feet; 22 billion cubic metres
Topside facilities The topsides for Brae Alpha (Brae South) were designed by Matthew Hall EngineeringMatthew Hall Engineering publicity brochure n.d. but c. 1990 which was awarded the contract in August 1979. Initially there were facilities for 19 oil production wells, 14 water injection wells, two gas injection wells and 11 spare slots. The production capacity was 100,000 barrels of oil per day, 12,000 barrels of Natural Gas Liquids (NGL) per day and 4.25 million standard cubic metres of gas per day. There are two production trains each with three stages of separation with the first stage operating at the exceptionally high initial pressure, for that time, of 248 bar. Electricity generation was powered by four 25 MW Rolls-Royce SK-30 gas turbines. The topside accommodation was for 240 people. There were 14 topside modules and the topsides weight was 31,000 tonnes.
The topsides for Brae Bravo (Brae North) were designed by Matthew Hall Engineering which was awarded the contract in October 1983. Initially there were facilities for 12 oil production wells, three gas injection wells and 19 spare slots. The production capacity was 75,000 barrels of liquid hydrocarbons per day, and 11.3 million standard cubic metres of gas per day. There is a single production train with four stages of separation with the first stage operating at a pressure of 103. Electricity generation was powered by three 24 MW Rolls-Royce/GEC ERB-124C gas turbines. The topside accommodation was for 240 people. There were 21 topside modules and the topsides weight was 33,000 tonnes.
The topsides for East Brae were designed by Matthew Hall Engineering which was awarded the contract in October 1988. Initially there were facilities for 13 oil wells, and four gas injection wells and 13 spare slots. The production capacity was 120,000 barrels of liquid hydrocarbon per day, and 17.6 million standard cubic metres of gas per day. There is a single production train with three stages of separation with the first stage operating at a pressure of 102 bar. Electric power is provided from Brae A and Brae B by subsea cable. The topside accommodation was for 160 people. The topsides weight was 18,500 tonnes and may later have been extended to 20,000 tonnesRockrose Energy BRAE AREA, East Brae Topsides and Braemar Decommissioning Programmes, 8th July 2020 I03 by RockRose Energy, fetched from; https://assets.publishing.service.gov.uk/media/5f744b158fa8f5188f48d600/East_Brae_Topsides_and_Braemar_DP.pdf
Reference/report number: 9030-RRE-99-PM-RT-00001-000, I03. Fabrication details are shown in the table. +Brae platforms – constructionInstallationFabrication contractorSiteInstallation dateBrae AlphaMcDermott ScotlandArdersierApril 1982Brae BravoMcDermott ScotlandArdersierJune 1987Brae EastTrafalgar House Offshore FabricatorsMethilMay 1993 +Brae platforms key factsPlatformBrae AlphaBrae BravoBrae EastTypeSteel jacketSteel jacketSteel jacketFunctionDrilling, production, accommodationDrilling, production, accommodationDrilling, production, accommodationCoordinates58°41’33”N 01°16’54”E58°47’32”N 01°20’51”EWater depth112 m99.5 m116 mJacket weight18,600 tonnes22,000 tonnes20,000 tonnesLegs88Piles3636Topsides weight32,000 tonnes40,000 tones18,500-20,000 tonnesAccommodation240240160Well slots463413 + 13 spareWells planned14 producers, 14 water injection, 2 gas injection12 production; 3 gas injectionInstallationJune 19821987May 1993Production startJuly 19831988December 1993Production stop (Cessation of Production, CoP)2024July 5, 2018Application submitted 2015, approved 2017, CoP friday April 18 2025.Decommission and removalStarts in 2025 or 2026Starts in april 2021Starts in 2025 planned completion by end of 2028.BRA AREA East Brae Upper Jacket and Associated Riser Sections Decommissioning Programmes, fetched from https://assets.publishing.service.gov.uk/media/66a1f7b7ce1fd0da7b592cac/East_Brae_Upper_Jacket_DP_final.pdf dated june 2025 revision 8, Reference/report number; ID: 9030-TAQ-99-PM-RP-00003-000.
Decommissioning Several of the platforms used in the Brae field have reached a CoP (Cessation of Production) point, and are actively being or are scheduled for decommission and dismantling and removal.
Decommissioning of Brae East
Report by contractor RockRose Energy concludes that the decommission expects to consist of 20,326 tonnes of installations and 2,663 tonnes of pipeline. Of the installations, 100% (20,326 tonnes) is expected to be removed, and of the pipeline roughly 38,5% (740 tonnes) will be removed, thus leaving 1,923 tonnes of pipeline in situ. 90% of all materials of installations are calculated to be recycled, 5-10% to be reused and less than 5% to be disposed. Of the pipeline, 25% will be disposed and 75% will be recycled.
See also Energy policy of the United Kingdom Energy use and conservation in the United Kingdom
References
External links DECC Fields Index DTI Brown Book 2001 Marathon Oil