Brent oilfield
Encyclopedia
The Brent field is an oil field located in the East Shetland Basin
186 kilometres (115.6 mi) north-east of Lerwick
, Shetland Islands
, Scotland
at the water depth of 140 metres (459.3 ft). The field operated by Shell UK Limited
was once one of the most productive parts of the UK's offshore assets but is now nearing the end of its useful life.
initially named all of their UK oil fields after waterbirds in alphabetical order by discovery - Auk, Brent, Cormorant, Dunlin, Eider, Fulmar and so on. Brent refers to the Brent Goose
, although it is also an acronym for the members of the Jurassic Brent formation that make up the field: Broom, Rannoch, Etive, Ness and Tarbert (in turn named after features in the Scottish Highlands
).
, the Brent is the archetype for many of the fields in the area, consisting of a tilted fault block exposing the eponymous Brent formation next to bounding faults which allowed migration from deeper adjacent "kitchen" areas where the Kimmeridge Clay
Formation becomes fully mature and releases hydrocarbon
s. Unusually on a worldwide scale (but common in this basin), the seal or cap rock for the reservoir (which stops the hydrocarbons from migrating further towards the surface) is also the Kimmeridge Clay.
The reservoir depth is 2651 metres (8,697.5 ft).
s in an irregular SSW-NNE line. The first in place was the concrete legged "Condeep" Brent Bravo in 1975, followed by the concrete legged Brent Delta, Brent Charlie, and steel-jacket Brent Alpha. As of 2004, the platform still produces 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. This unit was decommissioned and removed using a heavy lifting barge in 2005.
The field supplies oil via the Brent System
pipeline to the terminal at Sullom Voe
, while gas is piped through the FLAGS
pipeline ashore at St Fergus on the north east coast of Scotland
.
The field underwent a massive £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 to convert them to low pressure operation which unlocked significant quantities of natural gas from the reservoir and extended the field life out to 2010+.
East Shetland Basin
The East Shetland Basin is a major oil-producing area of the North Sea between Scotland and Norway.Oil produced there is landed at Sullom Voe Terminal in the Shetland Islands.-See also:*Energy policy of the United Kingdom...
186 kilometres (115.6 mi) north-east of Lerwick
Lerwick
Lerwick is the capital and main port of the Shetland Islands, Scotland, located more than 100 miles off the north coast of mainland Scotland on the east coast of the Shetland Mainland...
, Shetland Islands
Shetland Islands
Shetland is a subarctic archipelago of Scotland that lies north and east of mainland Great Britain. The islands lie some to the northeast of Orkney and southeast of the Faroe Islands and form part of the division between the Atlantic Ocean to the west and the North Sea to the east. The total...
, Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
at the water depth of 140 metres (459.3 ft). The field operated by Shell UK Limited
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
was once one of the most productive parts of the UK's offshore assets but is now nearing the end of its useful life.
Name
ShellRoyal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
initially named all of their UK oil fields after waterbirds in alphabetical order by discovery - Auk, Brent, Cormorant, Dunlin, Eider, Fulmar and so on. Brent refers to the Brent Goose
Brent Goose
The Brant or Brent Goose, Branta bernicla, is a species of goose of the genus Branta. The Black Brant is an American subspecies. The specific descriptor bernicla is from the same source as "barnacle" in Barnacle Goose, which looks similar but is not a close relation.-Appearance:The Brant Goose is...
, although it is also an acronym for the members of the Jurassic Brent formation that make up the field: Broom, Rannoch, Etive, Ness and Tarbert (in turn named after features in the Scottish Highlands
Scottish Highlands
The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...
).
Geology
Situated in the East Shetland BasinEast Shetland Basin
The East Shetland Basin is a major oil-producing area of the North Sea between Scotland and Norway.Oil produced there is landed at Sullom Voe Terminal in the Shetland Islands.-See also:*Energy policy of the United Kingdom...
, the Brent is the archetype for many of the fields in the area, consisting of a tilted fault block exposing the eponymous Brent formation next to bounding faults which allowed migration from deeper adjacent "kitchen" areas where the Kimmeridge Clay
Kimmeridge Clay
The Kimmeridge Clay Formation is a sedimentary deposit of fossiliferous marine clay which is of Jurassic age. It occurs in Europe.Kimmeridge Clay is arguably the most economically important unit of rocks in the whole of Europe, being the major source rock for oil fields in the North Sea hydrocarbon...
Formation becomes fully mature and releases hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s. Unusually on a worldwide scale (but common in this basin), the seal or cap rock for the reservoir (which stops the hydrocarbons from migrating further towards the surface) is also the Kimmeridge Clay.
The reservoir depth is 2651 metres (8,697.5 ft).
Production
Production started-up on 11 November 1976 and on 13 December 1976 first tanker was loaded. The Brent field is exploited by four platformOil platform
An oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily store product until it can be brought to shore for refining and marketing...
s in an irregular SSW-NNE line. The first in place was the concrete legged "Condeep" Brent Bravo in 1975, followed by the concrete legged Brent Delta, Brent Charlie, and steel-jacket Brent Alpha. As of 2004, the platform still produces oil through a manifold (all Brent Alpha fluids are produced across to Brent Bravo). A fifth installation, the floating Brent Spar
Brent Spar
Brent Spar or Brent E, was a North Sea oil storage and tanker loading buoy in the Brent oilfield, operated by Shell UK. With the completion of a pipeline connection to the oil terminal at Sullom Voe in Shetland, the storage facility had continued in use but was considered to be of no further value...
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. This unit was decommissioned and removed using a heavy lifting barge in 2005.
The field supplies oil via the Brent System
Brent System
The Brent System pipeline transports oil from the North Sea oilfields via Cormorant Alpha to the Sullom Voe Terminal in Shetland, Scotland. Oil is transported from 20 oilfields, including:* Thistle* Murchison* Hutton* North West Hutton* Dunlin...
pipeline to the terminal at Sullom Voe
Sullom Voe
Sullom Voe is an inlet between North Mainland and Northmavine on Shetland in Scotland. It is a location of the Sullom Voe oil terminal. The word Voe is from the Old Norse vagr and denotes a small bay or narrow creek...
, while gas is piped through the FLAGS
FLAGS
The FLAGS pipeline is a natural gas pipeline in the North Sea which is used to transport liquids and associated gas from the following fields:* Cormorant A* North Cormorant* North West Hutton...
pipeline ashore at St Fergus on the north east coast of Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
.
The field underwent a massive £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 to convert them to low pressure operation which unlocked significant quantities of natural gas from the reservoir and extended the field life out to 2010+.
See also
- Brent crudeBrent CrudeBrent Crude is the biggest of the many major classifications of crude oil consisting of Brent Crude, Brent Sweet Light Crude, Oseberg, Ekofisk, and Forties . Brent Crude is sourced from the North Sea. The Brent Crude oil marker is also known as Brent Blend, London Brent and Brent petroleum...
- Energy policy of the United KingdomEnergy policy of the United KingdomThe current energy policy of the United Kingdom is set out in the Energy White Paper of May 2007 and Low Carbon Transition Plan of July 2009, building on previous work including the 2003 Energy White Paper and the Energy Review Report in 2006...
- Energy use and conservation in the United KingdomEnergy use and conservation in the United KingdomEnergy use in the United Kingdom stood at 3,894.6 kilogrammes of oil equivalent per capita in 2005 compared to a world average of 1,778.0. In 2008, total energy consumed was 9.85 exajoules - around 2% of the estimated 474 EJ worldwide total...