Andrew oilfield
Encyclopedia
The Andrew oilfield is a relatively small hydrocarbon
field in the UK sector of the North Sea
, 230 kilometres (142.9 mi) North-East of Aberdeen
and it is operated by BP
. It is produced from a single platform
, which is also the hub of the Cyrus and Farragon subsea developments.
reservoir
was also discovered in the Cretaceous
rock below the Palaeocene.
At the time, the small size of the field made it uneconomical to develop. It was not until twenty years later when BP put together an alliance of seven contractors to share in the risk of development, including Brown & Root, Santa Fe
, Saipem
, Highlands Fabricators, Allseas, Emtunga and Trafalgar House
.
In 1994, the project was sanctioned and first oil was produced from predrilled wells in 1996.
s, mostly oil, with some natural gas condensate
. The Andrew oil is light with an API gravity
of 40°. There is also a gas cap in the Palaeocene reservoir
in addition to the lower cretaceous reservoir and the associated gas from the oil. There is estimated to be 245 Mcuft of recoverable gas, though the lower cretaceous reservoir is not fully appraised.
, with topsides
facilities supported on a four leg steel jacket. The platform is relatively small accommodating only 80 people. It contains a full process plant for separating water and gas from the production fluid
s. Platform power is provided from three 6MW gas turbines, fed principally from produced gas.
There are presently 17 operational wells, 15 producing oil from the Palaeocene, one reinjecting gas into the gas cap and another producing gas from the Cretaceous
reservoir
(known among the asset simply as "The Lower Cretaceous"). The Andrew well bay
has plenty of room for further wells as it has a total of 24 slots, only 18 of which are occupied (17 with wells and one slot with umbilical lines to Farragon). The Andrew also receives flowlines from the Cyrus subsea wells.
The Xmas trees
and wellhead
s are supplied by Vetco
. The four original pre-drilled wells (though one has since been side-tracked) on the South side of the well bay use slightly smaller wellheads than the rest because they were part of the original template before the platform was put in place.
The Xmas trees have the unusual property of having two Swab valves, rather than just one. The intention behind this was to allow the rigging up and down of pressure control equipment for well work without having to shut in the well. This would save money in lost revenue for the day the well would normally not be flowing. However, the experience over the past ten years has shown that the increased cost of maintaining an extra valve does not match the savings.
Processed oil is exported to the Forties pipeline system
then on to Cruden Bay
. Natural gas is exported to the Central Area Transmission System
to Teeside. Produced water is cleaned in the process plant to sufficient quality that it is dumped overboard.
, which is a very popular name in general among the Scots due to their more fierce sense of Scottish patriotism
. For this reason, the logo of the Andrew platform is more "Scottish" than many others. It consists of a Saltire
shaped as a drop of liquid and is more prominently displayed than the logos of other platforms.
. It was then redeveloped along with the main Andrew project for restart as a subsea tieback in 1996. It produces through three horizontal wells (though one is presently shut in) and the unprocessed production fluid
s are piped through a riser to the platform where it is produced through its own process (for metering purposes). The separated products are then exported along with the rest of the Andrew export.
Farragon is a recent development. This small Palaeocene field is still being developed by a dedicated team at BP
's North Sea headquarters in Dyce
, though it has been producing through two wells since 2006. The produced fluids are transported directly to the export line without processing, though umbilical lines tie back to the platform.
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....
field in the UK sector of the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
, 230 kilometres (142.9 mi) North-East of Aberdeen
Aberdeen
Aberdeen is Scotland's third most populous city, one of Scotland's 32 local government council areas and the United Kingdom's 25th most populous city, with an official population estimate of ....
and it is operated by BP
BP
BP p.l.c. is a global oil and gas company headquartered in London, United Kingdom. It is the third-largest energy company and fourth-largest company in the world measured by revenues and one of the six oil and gas "supermajors"...
. It is produced from a single platform
Oil 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...
, which is also the hub of the Cyrus and Farragon subsea developments.
Discovery and development
BP originally discovered oil in the Palaeocene rock in block 16/28 of the UKCS in 1974, with further appraisal work conducted by ConocoPhilips the following year. A gasNatural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
reservoir
Oil reservoir
A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...
was also discovered in the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
rock below the Palaeocene.
At the time, the small size of the field made it uneconomical to develop. It was not until twenty years later when BP put together an alliance of seven contractors to share in the risk of development, including Brown & Root, Santa Fe
GlobalSantaFe Corporation
GlobalSantaFe Corporation, which traded on the NYSE as GSF was an offshore oil and gas drilling contractor, which owned or operating a fleet of 59 marine drilling rigs...
, Saipem
Saipem
Saipem S.p.A. is an Italian oil and gas industry contractor. It is a subsidiary of Italian energy company Eni, which owns approximately 43% of Saipem's shares. Saipem has contracted for designing and constructing several pipelines, including Blue Stream, Greenstream, Nord Stream and South...
, Highlands Fabricators, Allseas, Emtunga and Trafalgar House
Trafalgar House (company)
Trafalgar House Public Limited Company was a British conglomerate with interests in property investment, property development, engineering, construction, shipping, hotels, energy and publishing...
.
In 1994, the project was sanctioned and first oil was produced from predrilled wells in 1996.
Reserves
The Andrew is estimated to have 150 Moilbbl of liquid hydrocarbonHydrocarbon
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, mostly oil, with some natural gas condensate
Natural gas condensate
Natural-gas condensate is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields....
. The Andrew oil is light with an API gravity
API gravity
The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks...
of 40°. There is also a gas cap in the Palaeocene reservoir
Oil reservoir
A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...
in addition to the lower cretaceous reservoir and the associated gas from the oil. There is estimated to be 245 Mcuft of recoverable gas, though the lower cretaceous reservoir is not fully appraised.
Hardware
The Andrew field is produced using a fixed 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...
, with topsides
Topsides
On an offshore oil platform, Topsides refers to the surface hardware installed. This includes the oil production plant, the accommodation block and the drilling rig...
facilities supported on a four leg steel jacket. The platform is relatively small accommodating only 80 people. It contains a full process plant for separating water and gas from the production fluid
Production fluid
Production fluid is the fluid mixture of oil, gas and water in formation fluid that flows to the surface of an oil well from a reservoir. Its consistency and composition varies.Fluids may be described by a multitude of characteristics including:...
s. Platform power is provided from three 6MW gas turbines, fed principally from produced gas.
There are presently 17 operational wells, 15 producing oil from the Palaeocene, one reinjecting gas into the gas cap and another producing gas from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
reservoir
Oil reservoir
A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...
(known among the asset simply as "The Lower Cretaceous"). The Andrew well bay
Well bay
A well bay is an area of an oil platform where the Christmas trees and wellheads are located. It normally consists of two levels, a lower where the wellheads are accessed and an upper where the Xmas Trees are accessed often along with the various well control panels, which will have pressure...
has plenty of room for further wells as it has a total of 24 slots, only 18 of which are occupied (17 with wells and one slot with umbilical lines to Farragon). The Andrew also receives flowlines from the Cyrus subsea wells.
The Xmas trees
Christmas tree (oil well)
In petroleum and natural gas extraction, a Christmas tree, or "tree", is an assembly of valves, spools, and fittings used for an oil well, gas well, water injection well, water disposal well, gas injection well, condensate well and other types of wells...
and wellhead
Wellhead
A wellhead is a general term used to describe the component at the surface of an oil or gas well that provides the structural and pressure-containing interface for the drilling and production equipment....
s are supplied by Vetco
Vetco
Vetco was established in July 2004 and operated through its subsidiaries and . Vetco was the result of a consortium consisting of the private equity firms Candover, 3i and taking over ABB's oil and gas division; ABB Offshore Systems. Vetco was made out of companies that have serviced the upstream...
. The four original pre-drilled wells (though one has since been side-tracked) on the South side of the well bay use slightly smaller wellheads than the rest because they were part of the original template before the platform was put in place.
The Xmas trees have the unusual property of having two Swab valves, rather than just one. The intention behind this was to allow the rigging up and down of pressure control equipment for well work without having to shut in the well. This would save money in lost revenue for the day the well would normally not be flowing. However, the experience over the past ten years has shown that the increased cost of maintaining an extra valve does not match the savings.
Processed oil is exported to the Forties pipeline system
Forties pipeline system
The Forties pipeline system is a pre-eminent pipeline network in the North Sea carrying 30% of the UK's oil, or about of oil a day, to shore. It is owned and operated by UK-based global energy company BP, who retained the asset after selling the Forties oilfield to Apache Corp. in 2003...
then on to Cruden Bay
Cruden Bay
Cruden Bay is a small village in Scotland, on the north coast of the Bay of Cruden in Aberdeenshire, 26 miles north of Aberdeen.Just south of Slains Castle, Cruden Bay was the site of a battle between Danes and Scots under King Malcolm II in 1012...
. Natural gas is exported to the Central Area Transmission System
Central Area Transmission System
The Central Area Transmission System is a natural gas transportation system from the Central North Sea to Teesside in England.-History:...
to Teeside. Produced water is cleaned in the process plant to sufficient quality that it is dumped overboard.
Logo
Andrew is named for the patron saint of ScotlandSaint Andrew
Saint Andrew , called in the Orthodox tradition Prōtoklētos, or the First-called, is a Christian Apostle and the brother of Saint Peter. The name "Andrew" , like other Greek names, appears to have been common among the Jews from the 3rd or 2nd century BC. No Hebrew or Aramaic name is recorded for him...
, which is a very popular name in general among the Scots due to their more fierce sense of Scottish patriotism
Scottish independence
Scottish independence is a political ambition of political parties, advocacy groups and individuals for Scotland to secede from the United Kingdom and become an independent sovereign state, separate from England, Wales and Northern Ireland....
. For this reason, the logo of the Andrew platform is more "Scottish" than many others. It consists of a Saltire
Flag of Scotland
The Flag of Scotland, , also known as Saint Andrew's Cross or the Saltire, is the national flag of Scotland. As the national flag it is the Saltire, rather than the Royal Standard of Scotland, which is the correct flag for all individuals and corporate bodies to fly in order to demonstrate both...
shaped as a drop of liquid and is more prominently displayed than the logos of other platforms.
Cyrus and Farragon
Cyrus and Farragon are two smaller satellite oil fields in the 16/28 Andrew block. Cyrus was originally produced in 1990 by OPV SeilleanSeillean (OPV)
The FPSO Noble Seillean is a dynamically positioned floating oil production, storage and offloading vessel. The name Seillean means "honeybee" in Gaelic.-History:...
. It was then redeveloped along with the main Andrew project for restart as a subsea tieback in 1996. It produces through three horizontal wells (though one is presently shut in) and the unprocessed production fluid
Production fluid
Production fluid is the fluid mixture of oil, gas and water in formation fluid that flows to the surface of an oil well from a reservoir. Its consistency and composition varies.Fluids may be described by a multitude of characteristics including:...
s are piped through a riser to the platform where it is produced through its own process (for metering purposes). The separated products are then exported along with the rest of the Andrew export.
Farragon is a recent development. This small Palaeocene field is still being developed by a dedicated team at BP
BP
BP p.l.c. is a global oil and gas company headquartered in London, United Kingdom. It is the third-largest energy company and fourth-largest company in the world measured by revenues and one of the six oil and gas "supermajors"...
's North Sea headquarters in Dyce
Dyce
Dyce is a civil parish and suburb of Aberdeen, Scotland, about north west of Aberdeen city centre, and best known as the location of the city's airport. It is on the River Don.- History :...
, though it has been producing through two wells since 2006. The produced fluids are transported directly to the export line without processing, though umbilical lines tie back to the platform.