Production
Production started on 11 November 1976, and on 13 December 1976 the first tanker was loaded. The Brent field oil was extracted by four platforms in an irregular SSW-NNE line.[7] The first in place was the concrete-legged "Condeep" Brent Bravo, built by Norwegian Contractors in Stavanger, in August 1975. This was followed by the steel-jacket Brent Alpha built by Redpath Dorman Long in Methil and installed in May 1976; the concrete-legged Brent Delta, again built by Norwegian Contractors in Stavanger, in July 1976; and the concrete-base Brent Charlie, built by McAlpine/Sea Tank in Ardyne Point, installed in June 1978.[8] As of 2004, the field was still producing oil through a manifold (all Brent Alpha fluids are produced across to Brent Bravo). A fifth installation, the floating Brent Spar, served as a storage- and tanker-loading buoy and was installed early in the field's construction. The "spar" design of this installation led to the name by which it became the best known of the Brent installations (outside the oil industry). The field also included a remote flare, the "Brent Flare", which was used to flare off excess gas before gas handling and export facilities were installed in the field, also used as a vent in winter 1995–96. This unit was decommissioned and removed using a heavy lifting barge in 2005.[9]
The topsides for Brent Charlie were designed by Matthew Hall Engineering which was awarded the contract in January 1974.[10] Initially there were facilities for 19 oil production wells, nine water injection wells, six gas injection wells and three spare slots. The production capacity was 150000 oilbbl per day and 8.5 million standard cubic metres of gas per day. There were three production trains each with four stages of separation with the first stage separators operating at a pressure of 9.6 bar. The 14 subsea storage cells had a capacity of 400000 oilbbl. Electricity generation was powered by three 12 MW Rolls-Royce Avon gas turbines. The topside accommodation was for 120 people. There were 14 topsides modules and the topsides weight was 34,000 t.[10]
The initial design parameters of the Brent installations is summarised in the table.
The field supplied oil via the Brent System pipeline to the terminal at Sullom Voe, while gas was piped through the FLAGS pipeline ashore at St Fergus on the north-east coast of Scotland. The production of oil from the field (in 1000s barrels) was:[11] { "version": 2, "width": 400, "height": 200, "data": [ { "name": "table", "values": [ { "x": 1976, "y": 766 }, { "x": 1977, "y": 9484 }, { "x": 1978, "y": 28962 }, { "x": 1979, "y": 65323 }, { "x": 1980, "y": 51154 }, { "x": 1981, "y": 84165 }, { "x": 1982, "y": 118073 }, { "x": 1983, "y": 146079 } ] } ], "scales": [ { "name": "x", "type": "ordinal", "range": "width", "zero": false, "domain": { "data": "table", "field": "x" } }, { "name": "y", "type": "linear", "range": "height", "nice": true, "domain": { "data": "table", "field": "y" } } ], "axes": [ { "type": "x", "scale": "x" }, { "type": "y", "scale": "y" } ], "marks": [ { "type": "rect", "from": { "data": "table" }, "properties": { "enter": { "x": { "scale": "x", "field": "x" }, "y": { "scale": "y", "field": "y" }, "y2": { "scale": "y", "value": 0 }, "fill": { "value": "steelblue" }, "width": { "scale": "x", "band": "true", "offset": -1 } } } } ] } The field underwent a £1.3 billion upgrade project in the mid-1990s, which involved depressurising the entire reservoir and making extensive modifications to three of the four Brent platforms.
The field's peak production capacity reached 504,000 oilbbl of oil per day (bopd) in 1982 and it produced a total of approximately 3 e9BOE as of 2008.
The Brent field decommissioning project was initiated in 2006. Brent Delta was the first platform to cease production in December 2011, while the Brent Alpha and Bravo platforms stopped production in November 2014, Brent Charlie in March 2021.
