Harding oilfield
Encyclopedia
The Harding oilfield is a small oil field operated by BP
, in the North Sea
block 9/23b, approximately 200 miles (321.9 km) North-East of Aberdeen
and in 110 metres (360.9 ft) of water.
at a depth of 1850 metres (6,069.6 ft). The abundance of napthalmic acid in the oil however made the development unattractive at the time. The crude is heavy and naphthenic and is generally of a lower value compared to other North Sea oils. Consequently the decision was made to export it by tanker rather than co-mingle it in a pipeline. The oil from the Harding field therefore requires to be stored offshore. The selected development solution was a heavy-duty steel jack-up production unit based on a proprietary design by Technip
Geoproduction resting on a concrete gravity base which had storage for 550000 barrels (87,443 m³) of oil.
. The largest is the central field, hosting most of the wells
as well as the site of the gas re-injection. There is also smaller fields to the North, North-East, South and South-East, all named as such. This has led to a unique well naming system in addition to the traditional use of DTI well numbers and slot numbers, which identifies a well by the particular field in which it has been drilled and its purpose.
The formations
are unconsolidated, making the wells
likely to produce sand. In order to prevent this, traditional cased hole completions are not used on any of the Harding wells. Instead, all wells used sandscreens.
ed. The central reservoir is supported by two water injection
wells and a gas injector. The south and north fields have the support of one water injector each, though the injector in the north field is currently suspended.
All produced water is reinjected. In addition there are two aquifer wells to provide extra injection water, if required.
Without a pipeline, the bulk of the produced gas
has been reinjected into the cap of the central reservoir
, sequestering it for production after 2009, when the platform is converted to a gas producer after decline of oil production.
, to investigate alternative development options for the gas resources in the area.
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"...
, in 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...
block 9/23b, approximately 200 miles (321.9 km) 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 in 110 metres (360.9 ft) of water.
Discovery and development
The field was discovered in 1987, when oil was found in EoceneEocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
at a depth of 1850 metres (6,069.6 ft). The abundance of napthalmic acid in the oil however made the development unattractive at the time. The crude is heavy and naphthenic and is generally of a lower value compared to other North Sea oils. Consequently the decision was made to export it by tanker rather than co-mingle it in a pipeline. The oil from the Harding field therefore requires to be stored offshore. The selected development solution was a heavy-duty steel jack-up production unit based on a proprietary design by Technip
Technip
Technip is a provider of project management, engineering, and construction services for the oil and gas industry, headquartered in Paris, France....
Geoproduction resting on a concrete gravity base which had storage for 550000 barrels (87,443 m³) of oil.
Reservoir
The Harding field is in fact composed of five separate reservoirsOil 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...
. The largest is the central field, hosting most of the wells
Oil well
An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...
as well as the site of the gas re-injection. There is also smaller fields to the North, North-East, South and South-East, all named as such. This has led to a unique well naming system in addition to the traditional use of DTI well numbers and slot numbers, which identifies a well by the particular field in which it has been drilled and its purpose.
The formations
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...
are unconsolidated, making the wells
Oil well
An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...
likely to produce sand. In order to prevent this, traditional cased hole completions are not used on any of the Harding wells. Instead, all wells used sandscreens.
Production
Harding presently produces around 17 koilbbl/d of oil, from 15 wells, and 9 Mcuft/d of gas, most of which is re-injected. All production wells are gas liftGas lift
Gas lift is one of a number of processes used to artificially lift oil or water from wells where there is insufficient reservoir pressure to produce the well. The process involves injecting gas through the tubing-casing annulus. Injected gas aerates the fluid to reduce its density; the formation...
ed. The central reservoir is supported by two water injection
Water injection (oil production)
Water injection refers to the method in oil industry where water is injected back into the reservoir, usually to increase pressure and thereby stimulate production. Water injection wells can be found both on- and offshore, to increase oil recovery from an existing reservoir...
wells and a gas injector. The south and north fields have the support of one water injector each, though the injector in the north field is currently suspended.
All produced water is reinjected. In addition there are two aquifer wells to provide extra injection water, if required.
Without a pipeline, the bulk of the produced gas
Natural 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...
has been reinjected into the cap of the central 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...
, sequestering it for production after 2009, when the platform is converted to a gas producer after decline of oil production.
Harding Area Gas Project
The Harding reservoir also contains gas, which BP hopes to develop at some future stage. BP announced plans in 2006 to develop the gas resources via the Harding Area Gas Project. A combination of factors has made this original development concept uncompetitive; particularly low gas prices and increased development costs. The project is being recycled and BP is in discussion with its partner, Maersk OilMaersk Oil
Maersk Oil is a Danish oil and gas company owned by the A. P. Moller-Maersk Group. The company was established in 1962 when Maersk Group was awarded a concession for oil and gas exploration and production in the Danish sector of the North Sea...
, to investigate alternative development options for the gas resources in the area.