View source for Oil platform

{{Short description|Offshore ocean structure with oil drilling and related facilities}}
[[File:LUN-A.jpg|300px|thumb|The Lun-A (Lunskoye-A) platform, located off the north eastern coast of [[Sakhalin|Sakhalin Island]] and is a concrete gravity base substructure (CGBS).]] 
An '''oil platform''' (also called an '''oil rig''', '''offshore platform''', '''oil production platform''', etc.) is a large structure with facilities to extract and process [[petroleum]] and [[natural gas]] that lie in rock formations beneath the [[seabed]]. Many [[oil]] platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the [[continental shelf]], though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be [[fixed Platform|fixed]] to the ocean floor, consist of an [[artificial island]], or [[floating oil production system|float]].<ref>{{Cite journal|last=Ronalds|first=BF|year=2005|title=Applicability ranges for offshore oil and gas production facilities|journal=Marine Structures|volume=18 |issue=3|pages=251–263|doi=10.1016/j.marstruc.2005.06.001|bibcode=2005MaStr..18..251R }}</ref> In some arrangements the main facility may have storage facilities for the processed oil. Remote [[subsea]] wells may also be connected to a platform by flow lines and by [[umbilical cable|umbilical]] connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.

[[Offshore drilling]] presents environmental challenges, both from the produced hydrocarbons and the materials used during the drilling operation. Controversies include the ongoing [[US offshore drilling debate]].<ref>Compton, Glenn, "[http://thebradentontimes.com/reasons-not-to-drill-for-oil-offshore-of-florida-p19415-137.htm 10 Reasons Not to Drill for Oil Offshore of Florida] {{Webarchive|url=https://web.archive.org/web/20200805235518/http://thebradentontimes.com/reasons-not-to-drill-for-oil-offshore-of-florida-p19415-137.htm |date=2020-08-05 }}", ''The Bradenton Times'', Sunday, January 14, 2018</ref>

There are many different types of facilities from which offshore drilling operations take place. These include bottom-founded drilling rigs ([[Jackup rig|jackup barges]] and swamp barges), combined drilling and production facilities, either bottom-founded or floating platforms, and deepwater mobile offshore drilling units (MODU), including semi-submersibles and drillships. These are capable of operating in water depths up to {{convert|3000|m|ft}}. In shallower waters, the mobile units are anchored to the seabed. However, in deeper water (more than {{convert|1500|m|ft}}), the [[semi-submersible platform|semisubmersible]]s or [[drillship]]s are maintained at the required drilling location using [[dynamic positioning]].

==History==
Jan Józef Ignacy Łukasiewicz<ref>{{cite web | url=https://culture.pl/en/article/ignacy-lukasiewicz-the-generous-inventor-of-the-kerosene-lamp | title=Ignacy Łukasiewicz: Generous Inventor of the Kerosene Lamp }}</ref> ({{IPA|pl|iɡˈnatsɨ wukaˈɕɛvitʂ}}; 8 March 1822 – 7 January 1882) was a Polish pharmacist, engineer, businessman, inventor, and philanthropist. He was one of the most prominent philanthropists in the Kingdom of Galicia and Lodomeria, crown land of Austria-Hungary. He was a pioneer who in 1856 built the world's first modern oil refinery.
[[File:Oil wells just offshore at Summerland, California, c.1915.jpg|thumb|Oil wells just offshore at [[Summerland, California]], before 1906.]]
[[File:Tender and offshore oil rig platform, Louisiana.jpg|thumb|Tender and offshore oil rig platform near [[Louisiana]].]]
[[File:Schemat wydobywania ropy naftowej.svg|thumb|Diagram showing the operation of a typical oil platform: 1. Drilling rig; 2. Rock layers; 3. Oil drills; 4. Oil and natural gas.]]
Around 1891, the first submerged oil wells were drilled from platforms built on [[pilings|piles]] in the fresh waters of the [[Grand Lake St. Marys]] (a.k.a. Mercer County Reservoir) in [[Ohio]]. The wide but shallow reservoir was built from 1837 to 1845 to provide water to the [[Miami and Erie Canal]].

Around 1896, the first submerged oil wells in salt water were drilled in the portion of the [[Summerland Oil Field|Summerland field]] extending under the [[Santa Barbara Channel]] in [[California]]. The wells were drilled from [[pier]]s extending from land out into the channel.

Other notable early submerged drilling activities occurred on the Canadian side of [[Lake Erie]] since 1913 and [[Caddo Lake]] in [[Louisiana]] in the 1910s. Shortly thereafter, wells were drilled in tidal zones along the [[Gulf Coast of the United States|Gulf Coast]] of [[Texas]] and Louisiana. The [[Goose Creek Oil Field|Goose Creek field]] near [[Baytown, Texas]], is one such example. In the 1920s, drilling was done from concrete platforms in [[Lake Maracaibo]], [[Venezuela]].

The oldest offshore well recorded in Infield's offshore database is the [[Bibiheybət|Bibi Eibat]] well which came on stream in 1923 in [[Azerbaijan]].<ref>{{cite web|url=http://www.members.tripod.com/azmsa/oil.html|title=Oil in Azerbaijan|access-date=20 April 2015|archive-date=27 April 2015|archive-url=https://web.archive.org/web/20150427111525/http://www.members.tripod.com/azmsa/oil.html|url-status=live}}</ref> Landfill was used to raise shallow portions of the [[Caspian Sea]].

In the early 1930s, [[Texaco|the Texas Company]] developed the first mobile steel barges for drilling in the brackish coastal areas of the gulf.

In 1937, [[Pure Oil Company]] (now [[Chevron Corporation]]) and its partner [[Superior Oil Company]] (now part of [[ExxonMobil Corporation]]) used a fixed platform to develop a field in {{convert|14|ft|m}} of water, one mile (1.6&nbsp;km) offshore of [[Calcasieu Parish, Louisiana]].

In 1938, Humble Oil built a mile-long wooden trestle with railway tracks into the sea at McFadden Beach on the Gulf of Mexico, placing a derrick at its end – this was later destroyed by a hurricane.<ref>{{cite journal|last1=Morton|first1=Michael Quentin|date=June 2016|title=Beyond Sight of Land: A History of Oil Exploration in the Gulf of Mexico|url=https://www.academia.edu/25960555|journal=GeoExpro|volume=30|issue=3|pages=60–63|access-date=8 November 2016|archive-date=8 August 2021|archive-url=https://web.archive.org/web/20210808034610/https://www.academia.edu/25960555|url-status=live}}</ref>

In 1945, concern for American control of its offshore oil reserves caused President [[Harry Truman]] to issue an Executive Order unilaterally extending American territory to the edge of its continental shelf, an act that effectively ended the [[3-mile limit]] "[[freedom of the seas]]" regime.

In 1946, Magnolia Petroleum (now [[ExxonMobil]]) drilled at a site {{convert|18|mi|km}} off the coast, erecting a platform in {{convert|18|ft|m}} of water off [[St. Mary Parish, Louisiana]].

In early 1947, Superior Oil erected a drilling/production platform in {{convert|20|ft|m|abbr=on}} of water some 18 miles{{vague|which miles?|date=February 2010}} off [[Vermilion Parish, Louisiana]]. But it was [[Kerr-McGee]] Oil Industries (now part of [[Occidental Petroleum]]), as operator for partners [[Phillips Petroleum]] ([[ConocoPhillips]]) and [[Stanolind Oil & Gas]] ([[BP]]), that completed its historic Ship Shoal Block 32 well in October 1947, months before Superior actually drilled a discovery from their Vermilion platform farther offshore. In any case, that made Kerr-McGee's well the first oil discovery drilled out of sight of land.<ref>Ref accessed 02-12-89 by technical aspects and coast mapping. [[Kerr-McGee]]</ref><ref name="project-redsand">{{Cite web|url=http://www.project-redsand.com/|title=Project Redsand CIO &#124; Protecting The Redsand Towers|access-date=2007-06-16|archive-date=2017-07-02|archive-url=https://web.archive.org/web/20170702061430/http://project-redsand.com/|url-status=live}}</ref>

The British [[Maunsell Forts]] constructed during [[World War II]] are considered the direct predecessors of modern offshore platforms. Having been pre-constructed in a very short time, they were then floated to their location and placed on the shallow bottom of the [[Thames]] and the [[Mersey]] estuary.<ref name="project-redsand" /><ref>{{Cite magazine|magazine=Azerbaijan International|volume=11|issue=2|pages=56–63|url=http://www.azer.com/aiweb/categories/magazine/ai112_folder/112_articles/112_chronology.html|title=Azerbaijan's Oil History: Brief Oil Chronology since 1920 Part 2|author=Mir-Yusif Mir-Babayev|date=Summer 2003|access-date=2006-11-01|archive-date=2016-03-03|archive-url=https://web.archive.org/web/20160303185344/http://azer.com/aiweb/categories/magazine/ai112_folder/112_articles/112_chronology.html|url-status=live}}</ref>

In 1954, the first [[jackup rig|jackup oil rig]] was ordered by [[Zapata Oil]]. It was designed by [[R. G. LeTourneau]] and featured three electro-mechanically operated lattice-type legs. Built on the shores of the [[Mississippi River]] by the LeTourneau Company, it was launched in December 1955, and christened "Scorpion". The Scorpion was put into operation in May 1956 off [[Port Aransas]], Texas. It was lost in 1969.<ref>{{Cite web |url=http://iadc.org/dcpi/dc-septoct05/Sept05-anniversary.pdf |title=Rowan Companies marks 50th anniversary of landmark LeTourneau jackup |access-date=2017-05-01 |archive-date=2017-10-31 |archive-url=https://web.archive.org/web/20171031112929/http://iadc.org/dcpi/dc-septoct05/Sept05-anniversary.pdf |url-status=live }}</ref><ref>{{Cite web|url=http://petrowiki.org/History_of_offshore_drilling_units|title=History of offshore drilling units – PetroWiki|website=petrowiki.org|date=2 June 2015 |access-date=2017-05-01|archive-date=2017-03-22|archive-url=https://web.archive.org/web/20170322213629/http://petrowiki.org/History_of_offshore_drilling_units|url-status=live}}</ref><ref>{{Cite web |title=Building A Legend - Part 2 |url=https://www.youtube.com/watch?v=4ibvuWmF7Dc |url-status=live |archive-url=https://web.archive.org/web/20140510100159/http://www.youtube.com/watch?v=4ibvuWmF7Dc&gl=US&hl=en |archive-date=2014-05-10 |access-date=2017-05-01 |website=YouTube}}</ref>

When offshore drilling moved into deeper waters of up to {{convert|30|m|ft}}, fixed platform rigs were built, until demands for drilling equipment was needed in the {{convert|30|m|ft}} to {{convert|120|m|ft}} depth of the Gulf of Mexico, the first [[Jackup rig|jack-up rigs]] began appearing from specialized offshore drilling contractors such as forerunners of ENSCO International.

The first [[semi-submersible]] resulted from an unexpected observation in 1961. [[Blue Water Drilling Company]] owned and operated the four-column submersible Blue Water Rig No.1 in the Gulf of Mexico for [[Shell Oil Company]]. As the pontoons were not sufficiently buoyant to support the weight of the rig and its consumables, it was towed between locations at a draught midway between the top of the pontoons and the underside of the deck. It was noticed that the motions at this draught were very small, and Blue Water Drilling and Shell jointly decided to try operating the rig in its floating mode. The concept of an anchored, stable floating deep-sea platform had been designed and tested back in the 1920s by [[Edward Robert Armstrong]] for the purpose of operating aircraft with an invention known as the "seadrome". The first purpose-built drilling [[semi-submersible]] ''Ocean Driller'' was launched in 1963. Since then, many semi-submersibles have been purpose-designed for the drilling industry mobile offshore fleet.

The first offshore [[drillship]] was the ''CUSS 1'' developed for the [[Mohole]] project to drill into the Earth's crust.

As of June, 2010, there were over 620 mobile offshore drilling rigs (Jackups, semisubs, drillships, barges) available for service in the competitive rig fleet.<ref>{{cite web|url=http://www.rigzone.com/data/|title=RIGZONE – Offshore Rig Data, Onshore Fleet Analysis|access-date=20 April 2015|archive-url=https://web.archive.org/web/20150408021427/http://www.rigzone.com/data/|archive-date=8 April 2015|url-status=dead}}</ref>

One of the world's deepest hubs is currently the [[Perdido oil platform|Perdido]] in the Gulf of Mexico, floating in 2,438 meters of water. It is operated by [[Shell plc]] and was built at a cost of $3&nbsp;billion.<ref name= UPDATE1>{{cite web|date=March 31, 2010|url=https://www.reuters.com/article/idUSN3123683920100331|title=UPDATE 1-Shell starts production at Perdido|work=Reuters|access-date=20 April 2015|archive-date=21 November 2010|archive-url=https://web.archive.org/web/20101121070821/http://www.reuters.com/article/idUSN3123683920100331|url-status=live}}</ref> The deepest operational platform is the Petrobras America Cascade FPSO in the Walker Ridge 249 field in 2,600 meters of water.

== Main offshore basins ==
[[File:Gulf Offshore Platform.jpg|thumb|upright|Offshore platform, [[Gulf of Mexico]]]]
Notable offshore basins include:
* the [[North Sea]]
* the [[Offshore oil and gas in the US Gulf of Mexico|Gulf of Mexico]] (offshore [[Texas]], [[Louisiana]], [[Mississippi]], [[Alabama]] and [[Florida]])
* [[Offshore oil and gas in California|California]] (in the [[Los Angeles Basin]] and [[Santa Barbara Channel]], part of the Ventura Basin)
* the Caspian Sea (notably some major fields offshore [[Azerbaijan]])
* the [[Campos Basin|Campos]] and [[Santos Basin]]s off the coasts of [[Brazil]]
* [[Newfoundland and Labrador|Newfoundland]] and [[Nova Scotia]] ([[Atlantic Canada]])
* several fields off [[West Africa]], south of [[Nigeria]], and central Africa, west of [[Angola]]
* offshore fields in [[South East Asia]] and [[Sakhalin]], Russia
* major offshore oil fields are located in the [[Persian Gulf]] such as Safaniya, Manifa and Marjan which belong to Saudi Arabia and are developed by Saudi Aramco<ref>{{cite web|url=http://www.highbeam.com/doc/1G1-12308981.html|title=Contracts let for Marjan oil field development. (Saudi Arabian Oil Co. bids out offshore development contracts) (Saudi Arabia)|work=Middle East Economic Digest|date=March 27, 1992|archive-url=https://web.archive.org/web/20121105163103/http://www.highbeam.com/doc/1G1-12308981.html|archive-date=2012-11-05|url-status=dead|access-date=2011-02-26|via=Highbeam Research}}</ref>
* fields in [[India]] (Mumbai High, K G Basin-East Coast Of India, Tapti Field, [[Gujarat]], India)
* the [[List of oil and gas fields of the Baltic Sea|Baltic Sea]] oil and gas fields 
* the [[Taranaki Basin]] in [[New Zealand]]
* the [[East-Prinovozemelsky field|Kara Sea]] north of Siberia<ref>{{cite news|url=https://www.platts.com/latest-news/oil/moscow/russian-rosneft-announces-major-oil-gas-discovery-21300064|title=Russian Rosneft announces major oil, gas discovery in Arctic Kara Sea|access-date=2017-08-18|publisher=Platts|archive-date=2018-01-07|archive-url=https://web.archive.org/web/20180107192913/https://www.platts.com/latest-news/oil/moscow/russian-rosneft-announces-major-oil-gas-discovery-21300064|url-status=live}}</ref>
* the [[Arctic Ocean]] off the coasts of [[Alaska]] and Canada's [[Northwest Territories]]<ref>{{cite web|url=https://www.boem.gov/uploadedFiles/BOEM/Oil_and_Gas_Energy_Program/Resource_Evaluation/Resource_Assessment/2006AlaskaUndiscoveredOilandGasResources.pdf|title=Year 2006 National Assessment – Alaska Outer Continental Shelf|publisher=Dept Interior BEOM|access-date=2017-08-18|archive-date=2017-09-02|archive-url=https://web.archive.org/web/20170902171408/https://www.boem.gov/uploadedFiles/BOEM/Oil_and_Gas_Energy_Program/Resource_Evaluation/Resource_Assessment/2006AlaskaUndiscoveredOilandGasResources.pdf|url-status=live}}</ref>
* the offshore fields in the [[Adriatic Sea]]

==Types==
Larger lake- and sea-based offshore platforms and [[drilling rig]] for oil.
[[File:Types_of_offshore_oil_and_gas_structures.jpg|none|frame|Types of offshore oil and gas structures<ref>{{Cite web |title=NOAA Ocean Explorer: Expedition to the Deep Slope |url=https://oceanexplorer.noaa.gov/explorations/06mexico/background/oil/media/types_600.html |access-date=2022-06-02 |website=oceanexplorer.noaa.gov}}</ref>]]
* '''1''') & '''2''') Conventional fixed platforms
* '''3''') Compliant tower
* '''4''') & '''5''') Vertically moored tension leg and mini-tension leg platform
* '''6''') Spar
* '''7''') & '''8''') Semi-submersibles
* '''9''') Floating production, storage, and offloading facility
* '''10''') Sub-sea completion and tie-back to host facility
Jack-up drilling rigs, Drillships, and Gravity-based structure aren't pictured here.

===Fixed platforms===
{{Main|Fixed platform}}
[[File:Oil Platform Base Construction.jpg|thumb|right|A fixed platform base under construction on the [[Atchafalaya River]].]]

These platforms are built on [[concrete]] or [[steel]] legs, or both, anchored directly onto the seabed, supporting the deck with space for drilling rigs, production facilities and crew quarters. Such platforms are, by virtue of their immobility, designed for very long term use (for instance the [[Hibernia (oil field)|Hibernia platform]]). Various types of structure are used: steel jacket, concrete [[Caisson (engineering)|caisson]], floating steel, and even [[Offshore concrete structure|floating concrete]]. Steel jackets are structural sections made of tubular steel members, and are usually piled into the seabed. To see more details regarding design, construction and installation of such platforms refer to:<ref>{{Cite web|url=https://www.slideshare.net/amirkabirsadeghi/jsas-002-0401sadeghi|title=An Overview of Design, Analysis, Construction and Installation of Off…|date=October 31, 2013|access-date=July 16, 2019|archive-date=September 29, 2018|archive-url=https://web.archive.org/web/20180929133712/https://www.slideshare.net/amirkabirsadeghi/jsas-002-0401sadeghi|url-status=live}}</ref> and.<ref>{{Cite web|url=https://www.slideshare.net/amirkabirsadeghi/jsas-004-077sadeghi|title=Significant Guidance for Design and Construction of Marine and Offsho…|date=October 31, 2013|access-date=July 16, 2019|archive-date=August 5, 2020|archive-url=https://web.archive.org/web/20200805201618/https://www.slideshare.net/amirkabirsadeghi/jsas-004-077sadeghi|url-status=live}}</ref>

[[Offshore concrete structure|Concrete caisson structures]], pioneered by the [[Condeep]] concept, often have in-built oil storage in tanks below the sea surface and these tanks were often used as a flotation capability, allowing them to be built close to shore ([[Norway|Norwegian]] [[fjord]]s and [[Scotland|Scottish]] [[firth]]s are popular because they are sheltered and deep enough) and then floated to their final position where they are sunk to the seabed. Fixed platforms are economically feasible for installation in water depths up to about {{convert|520|m|abbr=on}}.

===Compliant towers===
{{Main|Compliant tower}}
These platforms consist of slender, flexible towers and a pile foundation supporting a conventional deck for drilling and production operations. Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from {{convert|370|to|910|m}}.

===Tension-leg platform===
{{Main|Tension-leg platform}}
TLPs are floating platforms tethered to the seabed in a manner that eliminates most vertical movement of the structure. TLPs are used in water depths up to about {{convert|2,000|m|ft|abbr=off|sp=us}}. The "conventional" TLP is a 4-column design that looks similar to a semisubmersible. Proprietary versions include the Seastar and MOSES mini TLPs; they are relatively low cost, used in water depths between {{convert|180|and|1300|m}}. Mini TLPs can also be used as utility, satellite or early production platforms for larger deepwater discoveries.

===Spar platforms===
{{Main|Spar (platform)}}
[[File:Devils tower 2004.JPG|thumb|upright|Devil's Tower spar platform]]
Spars are moored to the seabed like TLPs, but whereas a TLP has vertical tension tethers, a spar has more conventional mooring lines. Spars have to-date been designed in three configurations: the "conventional" one-piece cylindrical hull; the "truss spar", in which the midsection is composed of truss elements connecting the upper buoyant hull (called a hard tank) with the bottom soft tank containing permanent ballast; and the "cell spar", which is built from multiple vertical cylinders. The spar has more inherent stability than a TLP since it has a large counterweight at the bottom and does not depend on the mooring to hold it upright. It also has the ability, by adjusting the mooring line tensions (using chain-jacks attached to the mooring lines), to move horizontally and to position itself over wells at some distance from the main platform location. The first production spar{{when|date=June 2020}} was [[Kerr-McGee Corporation|Kerr-McGee's]] Neptune, anchored in {{convert|590|m|abbr=on}} in the Gulf of Mexico; however, spars (such as [[Brent Spar]]) were previously used{{when|date=June 2020}} as FSOs.

[[Eni]]'s [[Devil's Tower (oil platform)|Devil's Tower]] located in {{convert|1710|m|abbr=on}} of water in the Gulf of Mexico, was the world's deepest spar until 2010. The world's deepest platform as of 2011 was the [[Perdido oil platform|Perdido]] spar in the Gulf of Mexico, floating in 2,438 metres of water. It is operated by [[Royal Dutch Shell]] and was built at a cost of $3&nbsp;billion.<ref name= UPDATE1/><ref>{{cite news|last=Fahey|first=Jonathan|agency=[[Associated Press]]|url=https://phys.org/news/2011-12-deep-gulf-drilling-mos-bp.html|title=Deep Gulf drilling thrives 18 mos. after BP spill|date=December 30, 2011|via=Phys.org|access-date=2019-09-08|archive-date=2020-02-03|archive-url=https://web.archive.org/web/20200203184556/https://phys.org/news/2011-12-deep-gulf-drilling-mos-bp.html|url-status=live}}</ref><ref>{{cite news|url=https://apnews.com/7c57a1cc233d4a2d9ee7d047ef6d32cc|title=The offshore drilling life: cramped and dangerous|first=Jonathan|last=Fahley|date=December 30, 2011|work=AP News|access-date=2019-09-08|archive-date=2020-02-07|archive-url=https://web.archive.org/web/20200207091421/https://apnews.com/7c57a1cc233d4a2d9ee7d047ef6d32cc|url-status=live}}</ref>

The first truss spars{{when|date=June 2020}} were Kerr-McGee's Boomvang and Nansen.{{Citation needed|date=November 2010}}
The first (and, as of 2010, only) cell spar{{when|date=June 2020}} is Kerr-McGee's Red Hawk.<ref>{{cite news |url=http://www.fmctechnologies.com/en/SubseaSystems/GlobalProjects/NorthAmerica/US/KMGRedHawk.aspx?tab=%7BB01D40AB-5E2F-4710-9543-19C658AF29F5%7D |title=First Cell Spar |access-date=2010-05-24 |archive-url=https://web.archive.org/web/20110711014751/http://www.fmctechnologies.com/en/SubseaSystems/GlobalProjects/NorthAmerica/US/KMGRedHawk.aspx?tab=%7BB01D40AB-5E2F-4710-9543-19C658AF29F5%7D |archive-date=2011-07-11 |url-status=dead }}</ref>

===Semi-submersible platform===
{{Main|Semi-submersible platform}}
These platforms have hulls (columns and pontoons) of sufficient [[buoyancy]] to cause the structure to float, but of weight sufficient to keep the structure upright. Semi-submersible platforms can be moved from place to place and can be ballasted up or down by altering the amount of flooding in buoyancy tanks. They are generally anchored by combinations of chain, wire rope or polyester rope, or both, during drilling and/or production operations, though they can also be kept in place by the use of [[dynamic positioning]]. Semi-submersibles can be used in water depths from {{convert|60|to|6000|m|sigfig=1}}.

===Floating production systems===
{{Main|Floating production, storage and offloading}}
[[File:View of the Port of Las Palmas from the dock of La Esfinge (3).jpg|View of the Port of Las Palmas from the dock of La Esfinge|thumb]]
The main types of floating production systems are [[Floating Production Storage and Offloading|FPSO (floating production, storage, and offloading system)]]. FPSOs consist of large monohull structures, generally (but not always) shipshaped, equipped with processing facilities. These platforms are moored to a location for extended periods, and do not actually drill for oil or gas. Some variants of these applications, called [[Floating storage and offloading unit|FSO (floating storage and offloading system)]] or FSU (floating storage unit), are used exclusively for storage purposes, and host very little process equipment. This is one of the best sources for having floating production.

The world's first [[FLNG|floating liquefied natural gas (FLNG)]] facility is in production. See the section on [[#Particularly large examples|particularly large examples]] below.

===Jack-up drilling rigs===
{{Main|Jackup rig}}
[[File:龍口海濱.jpg|thumb|Jackup rigs in [[Longkou]], [[China]]]]
Jack-up Mobile Drilling Units (or jack-ups), as the name suggests, are rigs that can be jacked up above the sea using legs that can be lowered, much like [[Jack (device)|jacks]]. These MODUs (Mobile Offshore Drilling Units) are typically used in water depths up to {{convert|120|m|ft}}, although some designs can go to {{convert|170|m|abbr=on}} depth. They are designed to move from place to place, and then anchor themselves by deploying their legs to the ocean bottom using a [[rack and pinion]] gear system on each leg.

===Drillships===
{{Main|Drillship}}
A drillship is a maritime vessel that has been fitted with drilling apparatus. It is most often used for exploratory drilling of new oil or gas wells in deep water but can also be used for scientific drilling. Early versions were built on a modified tanker hull, but purpose-built designs are used today. Most drillships are outfitted with a [[dynamic positioning]] system to maintain position over the well. They can drill in water depths up to {{convert|3700|m|abbr=on}}.<ref>{{cite news |url=http://www.chevron.com/news/press/release/?id=2010-03-11 |title=Chevron Drillship |access-date=2010-05-24 |date=2010-03-11 |url-status=dead |archive-url=https://web.archive.org/web/20100530044448/http://www.chevron.com/news/press/release/?id=2010-03-11 |archive-date=2010-05-30 }}</ref>

===Gravity-based structure===
{{Main|Gravity-based structure}}
A GBS can either be steel or concrete and is usually anchored directly onto the seabed. Steel GBS are predominantly used when there is no or limited availability of crane barges to install a conventional fixed offshore platform, for example in the Caspian Sea. There are several steel GBS's in the world today (e.g. offshore Turkmenistan Waters (Caspian Sea) and offshore New Zealand). Steel GBS do not usually provide [[hydrocarbon]] storage capability. It is mainly installed by pulling it off the yard, by either wet-tow or/and dry-tow, and self-installing by controlled ballasting of the compartments with sea water. To position the GBS during installation, the GBS may be connected to either a transportation barge or any other barge (provided it is large enough to support the GBS) using strand jacks. The jacks shall be released gradually whilst the GBS is ballasted to ensure that the GBS does not sway too much from target location.

===Normally unmanned installations (NUI)===
{{Main|Normally unmanned installation}}
These installations, sometimes called toadstools, are small platforms, consisting of little more than a [[well bay]], [[helipad]] and emergency shelter. They are designed to be operated remotely under normal conditions, only to be visited occasionally for routine maintenance or [[well work]].

===Conductor support systems===
{{Main|Conductor support systems}}
These installations, also known as ''satellite platforms'', are small unmanned platforms consisting of little more than a [[well bay]] and a small [[process plant]]. They are designed to operate in conjunction with a static production platform which is connected to the platform by flow lines or by [[umbilical cable]], or both.

==Particularly large examples==
{{Main|List of tallest oil platforms}}
[[File:Oil platform Norway.jpg|thumb|upright|[[Troll A platform|Troll A]] [[natural gas]] platform, a [[gravity-based structure]], under construction in [[Norway]]. Almost all of the 600KT structure will end up submerged.]]

===Deepest platforms by type===
This is a list of oil wells based on the depth of the water in which they were drilled. It doesn't include how deep underground they go, which in some cases is over 10,000 metres.
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{| class="wikitable sortable sticky-header"
|+
|- style="background:#ececec;"
! Category
! Platform
! Country
! Location
! Height (meters)
! Height (feet)
! Year built
! Coordinates
|-
|[[Spar (platform)|Spar]] || [[Perdido (oil platform)|Perdido]] || {{flag|United States}} || [[Gulf of Mexico]] || 2,934 || 9,627 || 2011 || {{coord|26|7|44|N|94|53|53|W|type:landmark|name=Perdido}}
|-
|[[Floating production storage and offloading]] facility || Turritella<ref>{{Cite web |date=2016-09-06 |title=Shell starts up Stones in the ultra-deepwater Gulf of Mexico |url=https://www.offshore-mag.com/production/article/16769284/shell-starts-up-stones-in-the-ultra-deepwater-gulf-of-mexico |access-date=2024-07-10 |website=Offshore |language=en}}</ref> || {{flag|United States}} || [[Gulf of Mexico]] || 2,900 || 9,514 || 2016 || 
|-
|[[Semi-submersible platform|Semi-submersible]] || Independence Hub || {{flag|United States}} || [[Gulf of Mexico]] || 2,438 || 8,000 || 2007 || 
|-
|Extended [[Tension-leg platform]] || Big Foot || {{flag|United States}} || [[Gulf of Mexico]] || 1,580 || 5,180 || 2018 || 
|-
|[[Compliant tower]] || [[Petronius (oil platform)|Petronius]] || {{flag|United States}} || [[Gulf of Mexico]] || 640 || 2,100 || 2000 || {{coord|29|06|30|N|87|56|30|W|type:landmark|name=Petronius oil platform}}
|-
|[[Fixed platform]] || [[Bullwinkle (oil platform)|Bullwinkle]] || {{flag|United States}} || [[Gulf of Mexico]] || 529 || 1,736 || 1988 || {{Coord|27|53|01|N|90|54|04|W|type:landmark|name=Bullwinkle oil platform}}
|-
|[[Gravity-based structure]] || [[Troll A platform|Troll A]] || {{flag|Norway}} || [[North Sea]] || 472 || 1,549 || 1996 || {{coord|60|40|N|3|40|E|type:landmark|name=Troll A platform}}
|}

Other deep compliant towers and fixed platforms, by water depth:
* [[Baldpate Platform]], {{convert|502|m|abbr=on}}
* [[Pompano Platform]], {{convert|393|m|abbr=on}}
* [[Benguela-Belize Lobito-Tomboco Platform]], {{convert|390|m|abbr=on}}
* [[Gullfaks C|Gullfaks C Platform]], {{convert|380|m|abbr=on}}
* [[Tombua Landana Platform]], {{convert|366|m|abbr=on}}
* [[Harmony Platform]], {{convert|366|m|abbr=on}}

===Other metrics===
The [[Hibernia Gravity Base Structure|Hibernia]] platform in [[Canada]] is the world's  heaviest offshore platform, located on the [[Jeanne d'Arc Basin]], in the [[Atlantic Ocean]] off the coast of [[Newfoundland and Labrador|Newfoundland]]. This ''[[gravity base structure]]'' (GBS), which sits on the ocean floor, is {{convert|111|m|ft}} high and has storage capacity for {{convert|1.3|Moilbbl|m3}} of crude oil in its {{convert|85|m|ft|adj=on}} high caisson. The platform acts as a small concrete island with serrated outer edges designed to withstand the impact of an [[iceberg]]. The GBS contains production storage tanks and the remainder of the void space is filled with ballast with the entire structure weighing in at 1.2&nbsp;million [[ton]]s.

[[Royal Dutch Shell]] has developed the first [[FLNG|Floating Liquefied Natural Gas (FLNG)]] facility, which is situated approximately 200&nbsp;km off the coast of [[Western Australia]]. It is the largest floating offshore facility. It is approximately 488m long and 74m wide with [[Displacement (ship)|displacement]] of around 600,000t when fully ballasted.
<ref>{{Cite web|url=http://gastoday.com.au/news/flng_gets_serious/042981/|title=FLNG gets serious|date=August 2010|work=Gas Today|access-date=2018-12-16|archive-url=https://web.archive.org/web/20170131191710/http://gastoday.com.au/news/flng_gets_serious/042981/|archive-date=2017-01-31|url-status=dead}}</ref>

===History of deepest offshore oil wells===
This is a list of oil wells based on the depth of the water in which they were drilled.  It doesn't include how deep underground they go, which in some cases is over 10,000 metres.
{| class="sortable wikitable" style="text-align: center;" cellpadding="2"
|- style="background: #ececec;"
!Record from
!Record held (years)
!Name and location
!Height (metres)
!Height (feet)
! class="unsortable" | Refs
|-
|1980
|4
|style="text-align:left;"| MC-198 offshore oil well
|674
|2,211
|<ref name=Deepwater>{{Cite web|url=https://www.boem.gov/sites/default/files/documents/about-boem/Deepwater-Gulf-of-Mexico-Report-2019.pdf|title=Deepwater Gulf of Mexico|date=December 31, 2019|page=65}}</ref>
|-
|1984
|2
|style="text-align:left;"| MC-852 offshore oil well
|1,077
|3,534
|<ref name=Deepwater/>
|-
|1986
|1
|style="text-align:left;"| MC-731 offshore oil well
|1,646
|5,400
|<ref name=Deepwater/>
|-
|1987
|1
|style="text-align:left;"| AT-471 offshore oil well
|2,071
|6,794
|<ref name=Deepwater/>
|-
|1988
|6
|style="text-align:left;"| MC-657 offshore oil well
|2,292
|7,520
|<ref name=Deepwater/>
|-
|1996
|2
|style="text-align:left;"| AC-600 offshore oil well
|2,323
|7,620
|<ref name=Deepwater/>
|-
|1998
|2
|style="text-align:left;"| AT-118 offshore oil well
|2,352
|7,716
|<ref name=Deepwater/>
|-
|2000
|1
|style="text-align:left;"| WR-425 offshore oil well
|2,696
|8,845
|<ref name=Deepwater/>
|-
|2001
|2
|style="text-align:left;"| AC-903 oil well, offshore United States
|2,965
|9,727
|<ref name=Deepwater/>
|-
|2003
|5
|style="text-align:left;"| AC-951 oil well, offshore United States
|3,051
|10,011
|<ref name=Deepwater/>
|-
|2008
|3
|style="text-align:left;"| LL 511 #1 (G10496) oil well, offshore United States
|3,091
|10,141
|<ref name=1-D-1>{{Cite web|url=https://www.oedigital.com/news/449575-how-deep-is-your-well|title=How deep is your well?|first=Elaine|last=Maslin|date=May 1, 2016}}</ref>
|-
|2011
|2
|style="text-align:left;"| CYPR-D7-A1 oil well, offshore [[India]]
|3,107
|10,194
|<ref name=1-D-1/>
|-
|2013
|0
|style="text-align:left;"| NA7-1 oil well, offshore India
|3,165
|10,384
|<ref name=1-D-1/>
|-
|2013
|3
|style="text-align:left;"| 1-D-1 oil well, offshore India
|3,174
|10,413
|<ref name=1-D-1/><ref name=Raya-1>{{Cite web|url=https://www.offshore-energy.biz/uruguay-first-offshore-well-in-years-breaks-world-record/|title=Uruguay: First offshore well in years breaks world record|date=April 1, 2016}}</ref>
|-
|2016
|4
|style="text-align:left;"| Raya-1 oil well, offshore [[Uruguay]]
|3,400
|11,155
|<ref name=Raya-1/><ref name=Ondjaba-1>{{Cite web|url=https://www.oedigital.com/news/474583-total-to-drill-deepest-ever-offshore-well-using-maersk-rig|title=Total to Drill Deepest Ever Offshore Well Using Maersk Rig|date=January 14, 2020}}</ref>
|-
|2021
|TBD
|style="text-align:left;"| Ondjaba 1 oil well, offshore [[Angola]]
|3,628
|11,903
|<ref name=Ondjaba-1/><ref>{{Cite web|url=https://www.enverus.com/blog/offshore-drilling-keeps-getting-deeper/|title=Offshore Drilling Keeps Getting Deeper|first=Dai|last=Jones|date=August 8, 2024}}</ref>
|}

==Maintenance and supply==
[[File:Vung Tao Oil Field.jpg|thumb|A platform supply vessel for an oil platform in the [[Vũng Tàu]] oil field.]]
A typical oil production platform is self-sufficient in energy and water needs, housing electrical generation, water desalinators and all of the equipment necessary to process oil and gas such that it can be either delivered directly onshore by pipeline or to a [[Floating production storage and offloading|floating platform]] or tanker loading facility, or both. Elements in the oil/gas production process include [[wellhead]], [[production manifold]], [[production separator]], [[glycol]] process to dry gas, [[gas compressor]]s, [[Water injection (oil production)|water injection pumps]], [[oil/gas export metering]] and [[main oil line]] pumps.

Larger platforms are assisted by smaller ESVs (emergency support vessels) like the [[United Kingdom|British]] [[Iolair]] that are summoned when something has gone wrong, ''e.g.'' when a [[search and rescue]] operation is required. During normal operations, [[platform supply vessel|PSVs]] (platform supply vessels) keep the platforms provisioned and supplied, and [[anchor handling tug supply vessel|AHTS vessels]] can also supply them, as well as tow them to location and serve as standby rescue and firefighting vessels.

==Crew==

===Essential personnel===
Not all of the following personnel are present on every platform. On smaller platforms, one worker can perform a number of different jobs. The following also are not names officially recognized in the industry:
*[[OIM (offshore installation manager)]] who is the ultimate authority during his/her shift and makes the essential decisions regarding the operation of the platform;
*Operations Team Leader (OTL);
*Offshore Methods Engineer (OME) who defines the installation methodology of the platform;
*Offshore Operations Engineer (OOE) who is the senior technical authority on the platform;
*PSTL or operations coordinator for managing crew changes;
*Dynamic positioning operator, navigation, ship or vessel maneuvering (MODU), station keeping, [[Plant process and emergency shutdown systems#Fire and gas system (FGS)|fire and gas systems]] operations in the event of incident;
*Automation systems specialist, to configure, maintain and troubleshoot the process control systems (PCS), process safety systems, emergency support systems and vessel management systems;
*Second mate to meet manning requirements of flag state, operates fast rescue craft, cargo operations, fire team leader;
*Third mate to meet manning requirements of flag state, operate fast rescue craft, cargo operations, fire team leader;
*Ballast control operator to operate fire and gas systems;
*Crane operators to operate the cranes for lifting cargo around the platform and between boats;
*Scaffolders to rig up scaffolding for when it is required for workers to work at height;
*Coxswains to maintain the lifeboats and manning them if necessary;
*Control room operators, especially FPSO or production platforms;
*Catering crew, including people tasked with performing essential functions such as cooking, laundry and cleaning the accommodation;
*Production techs to run the production plant;
*[[Helicopter]] [[Aviator|pilot]](s) living on some platforms that have a helicopter based offshore and transporting workers to other platforms or to shore on crew changes;
*Maintenance technicians (instrument, electrical or mechanical).
*Fully qualified medic.
*Radio operator to operate all radio communications.
*Store Keeper, keeping the inventory well supplied
*Technician to record the fluid levels in tanks

===Incidental personnel===
Drill crew will be on board if the installation is performing drilling operations. A drill crew will normally comprise:
[[File:Viuna jackup .jpg|thumb|Welders performing repairs on a Jack-up rig.]]
* [[Toolpusher]]
* [[Driller (oil)|Driller]]
* [[Roughneck]]s
* [[Roustabout]]s
* [[Company man]]
* [[Mud engineer]]
* [[Motorman (drilling)|Motorman]] See: [[Glossary of oilfield jargon]]
* [[Derrickhand]]
* [[Geologist]]
* [[Welders]] and Welder Helpers
[[Well services]] crew will be on board for [[well work]]. The crew will normally comprise:
* Well services supervisor
*[[Wireline (cabling)|Wireline]] or [[coiled tubing]] operators
* Pump operator
* Pump hanger and ranger

==Drawbacks==
{{For|fuller discussion|United States offshore drilling debate}}

===Risks===
[[File:Edda 2-7C and rescue boats after capsizing of ALK NOMF-02734-1-012.jpg|thumb|The great distance from land can make rescue operations more difficult as in the capsizing of the [[Alexander L. Kielland (platform)|Alexander L. Kielland]] platform which claimed the lives of 123 people.]]
[[File:United States Navy SEALs train on a California oil platform 437.jpg|thumb|[[United States Navy SEALs]] train on a California oil platform.]]
The nature of their operation—extraction of volatile substances sometimes under extreme pressure in a hostile environment—means risk; accidents and tragedies occur regularly. The U.S. [[Minerals Management Service]] reported 69 offshore deaths, 1,349 injuries, and 858 fires and explosions on offshore rigs in the Gulf of Mexico from 2001 to 2010.<ref>{{cite news | title = Potential for big spill after oil rig sinks | date = 2010-04-22 | url = https://www.nbcnews.com/id/wbna36683314 | work = NBC News | access-date = 2010-06-04 | archive-date = 2015-07-21 | archive-url = https://web.archive.org/web/20150721180038/http://www.nbcnews.com/id/36683314/ | url-status = live }}</ref> On July 6, 1988, 167 people died when [[Occidental Petroleum]]'s [[Piper Alpha]] offshore production platform, on the Piper field in the UK sector of the [[North Sea]], exploded after a gas leak. The resulting investigation conducted by Lord Cullen and publicized in the first [[Cullen Report]] was highly critical of a number of areas, including, but not limited to, management within the company, the design of the structure, and the Permit to Work System. The report was commissioned in 1988, and was delivered in November 1990.<ref>http://www.oilandgas.org.uk/issues/piperalpha/v0000864.cfm{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The accident greatly accelerated the practice of providing living accommodations on separate platforms, away from those used for extraction.

The offshore can be in itself a hazardous environment. In March 1980, the '[[flotel]]' (floating hotel) platform ''[[Alexander L. Kielland (platform)|Alexander L. Kielland]]'' capsized in a storm in the [[North Sea]] with the loss of 123 lives.<ref>{{cite news | url=http://news.bbc.co.uk/onthisday/hi/dates/stories/march/27/newsid_2531000/2531091.stm | title=North Sea platform collapses | work=BBC News | access-date=2008-06-19 | date=1980-03-27 | archive-date=2008-04-08 | archive-url=https://web.archive.org/web/20080408093037/http://news.bbc.co.uk/onthisday/hi/dates/stories/march/27/newsid_2531000/2531091.stm | url-status=live }}</ref>

In 2001, ''[[Petrobras 36]]'' in [[Brazil]] exploded and sank five days later, killing 11 people.

Given the number of grievances and conspiracy theories that involve the oil business, and the importance of gas/oil platforms to the economy, platforms in the United States are believed to be potential terrorist targets.<ref>{{cite web |last1=Jenkins |first1=Brian Michael |title=Potential Threats To Offshore Platforms |url=https://apps.dtic.mil/sti/tr/pdf/ADA216866.pdf |publisher=The RAND Corporation}}</ref> Agencies and military units responsible for maritime counter-terrorism in the US ([[United States Coast Guard|Coast Guard]], [[Navy SEALs]], [[United States Marine Corps Force Reconnaissance|Marine Recon]]) often train for platform raids.<ref>{{cite news |last1=Feloni |first1=Richard |title=Gen. Stanley McChrystal explains what most people get wrong about Navy SEALs |url=https://www.businessinsider.com/stanley-mcchrystal-on-misconception-of-navy-seals-2015-8 |publisher=Business Insider}}</ref>

On April 21, 2010, the ''[[Deepwater Horizon]]'' platform, 52 [[nautical mile|miles]] off-shore of [[Venice, Louisiana]], (property of [[Transocean]] and leased to [[BP]]) [[Deepwater Horizon oil spill|exploded]], killing 11 people, and sank two days later. The resulting undersea gusher, conservatively estimated to exceed {{convert|20|e6USgal|m3}} as of early June 2010, became the worst oil spill in US history, eclipsing the [[Exxon Valdez oil spill]].

===Ecological effects===
[[File:Gulf Coast Platforms.jpg|thumb|upright=1.25|right|[[National Oceanic and Atmospheric Administration|NOAA]] map of the 3,858 oil and gas platforms extant in the Gulf of Mexico in 2006.]]
In British waters, the cost of removing all platform rig structures entirely was estimated in 2013 at £30&nbsp;billion.<ref>http://www.raeng.org.uk/publications/reports/decommissioning-in-the-north-sea {{Webarchive|url=https://web.archive.org/web/20141020145352/http://www.raeng.org.uk/publications/reports/decommissioning-in-the-north-sea |date=2014-10-20 }}.</ref>

Aquatic organisms invariably attach themselves to the undersea portions of oil platforms, turning them into artificial reefs. In the Gulf of Mexico and offshore California, the waters around oil platforms are popular destinations for sports and commercial fishermen, because of the greater numbers of fish near the platforms. The [[United States]] and [[Brunei]] have active [[Rigs-to-Reefs]] programs, in which former oil platforms are left in the sea, either in place or towed to new locations, as permanent artificial reefs. In the US [[Gulf of Mexico]], as of September 2012, 420 former oil platforms, about 10 percent of decommissioned platforms, have been converted to permanent reefs.<ref>{{cite web|url=http://sero.nmfs.noaa.gov/habitat_conservation/documents/pdfs/efh/gulf_decommissioning_and_rigs_to_reefs_faqs_final.pdf|via=sero.nmfs.noaa.gov|title=Decommissioning and Rigs-to-Reefs in the Gulf of Mexico: FAQs |url-status=usurped|archive-url=https://web.archive.org/web/20131109224846/http://sero.nmfs.noaa.gov/habitat_conservation/documents/pdfs/efh/gulf_decommissioning_and_rigs_to_reefs_faqs_final.pdf |archive-date=2013-11-09}}</ref>

On the US Pacific coast, [[marine biologist]] Milton Love has proposed that oil platforms off California be retained as [[artificial reef]]s, instead of being dismantled (at great cost), because he has found them to be havens for many of the species of fish which are otherwise declining in the region, in the course of 11 years of research.<ref>{{Cite news|last=Urbina|first=Ian|date=15 August 2015|title=Vacation in Rome? Or on That Oil Rig?|work=The New York Times|url=https://www.nytimes.com/2015/08/16/sunday-review/vacation-in-rome-or-on-that-oil-rig.html|access-date=|archive-date=5 February 2021|archive-url=https://web.archive.org/web/20210205020749/https://www.nytimes.com/2015/08/16/sunday-review/vacation-in-rome-or-on-that-oil-rig.html|url-status=live}}</ref><ref>{{cite web |vauthors=Page M, Dugan J, Love M, Lenihan H |title=Ecological Performance and Trophic Links: Comparisons Among Platforms And Natural Reefs For Selected Fish And Their Prey |url=http://www.coastalresearchcenter.ucsb.edu/cmi/ecoperformance.html |publisher=University of California, Santa Barbara |access-date=2008-06-27 |archive-date=2008-05-09 |archive-url=https://web.archive.org/web/20080509163446/http://www.coastalresearchcenter.ucsb.edu/cmi/ecoperformance.html |url-status=live }}</ref> Love is funded mainly by government agencies, but also in small part by the [[California Artificial Reef Enhancement Program]]. [[Professional diving#Scientific diving|Divers]] have been used to assess the [[fish]] populations surrounding the platforms.<ref>{{cite book |vauthors=Cox SA, Beaver CR, Dokken QR, Rooker JR |chapter=Diver-based under water survey techniques used to assess fish populations and fouling community development on offshore oil and gas platform structures |veditors=Lang MA, Baldwin CC |title=The Diving for Science, "Methods and Techniques of Underwater Research" |series=Proceedings of the American Academy of Underwater Sciences 16th Annual Scientific Diving Symposium, Smithsonian Institution, Washington, DC |publisher=American Academy of Underwater Sciences (AAUS) |year=1996 |chapter-url=http://archive.rubicon-foundation.org/4689 |access-date=2008-06-27 |via=Rubicon Foundation |archive-date=2009-08-22 |archive-url=https://web.archive.org/web/20090822015936/http://archive.rubicon-foundation.org/4689 |url-status=live }} {{cite web|url=http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/4689/AAUS_1996_14.pdf?sequence=1|title=Full text|access-date=2019-09-09|archive-date=2016-08-19|archive-url=https://web.archive.org/web/20160819164101/http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/4689/AAUS_1996_14.pdf?sequence=1|url-status=usurped}}</ref>

== Effects on the environment ==
[[File:Smoke from controlled oil fire in Gulf of Mexico, Louisiana, after Deepwater Horizon Oil Spill, May 5, 2010.jpg|thumb|Smoke from controlled oil fire in Gulf of Mexico, Louisiana, after the [[Deepwater Horizon oil spill]], May 5, 2010.]]
[[File:Marco Polo at Dusk.jpg|thumb|Long-term [[gas flare]]s could have impacts on the environment.]]
Offshore oil production involves environmental risks, most notably [[oil spill]]s from oil tankers or pipelines transporting oil from the platform to onshore facilities, and from leaks and accidents on the platform.<ref>{{cite video|title=Debate Over Offshore Drilling|medium=internet video|work=[[CBS News]]|date=2008|url=http://www.webcastr.com/videos/news/debate-over-offshore-drilling.html |access-date=2008-09-27|archive-url= https://web.archive.org/web/20080824002817/http://www.webcastr.com/videos/news/debate-over-offshore-drilling.html |archive-date=2008-08-24|url-status=dead}}</ref> [[Produced water]] is also generated, which is water brought to the surface along with the oil and gas; it is usually highly saline and may include dissolved or unseparated hydrocarbons.

Offshore rigs are shut down during hurricanes.<ref>{{cite journal |last1=Kaiser |first1=Mark J. |title=The impact of extreme weather on offshore production in the Gulf of Mexico |journal=Applied Mathematical Modelling |date=October 2008 |volume=32 |issue=10 |pages=1996–2018 |doi=10.1016/j.apm.2007.06.031 |quote=When a hurricane enters the GOM, oil production and transportation pipelines in the (expected) path of the storm shut down, crews are evacuated, and refineries and processing plants along the Gulf coast close. Drilling rigs pull pipe and move out of the projected path of the storm, if possible, or anchor down|doi-access=free }}</ref> In the Gulf of Mexico the number hurricanes is increasing because of the increasing number of oil platforms that heat surrounding air with methane. It is estimated that oil and gas facilities in the Gulf of Mexico emit approximately 500000 tons of [[methane emissions|methane]] each year, corresponding to a 2.9% loss of produced gas. The increasing number of oil rigs also increases the number and movement of oil tankers, resulting in increasing {{CO2}} levels which directly warm water in the zone. Warm waters are a key factor for hurricanes to form.<ref>{{Cite journal|last1=Yacovitch|first1=Tara I. |last2=Daube|first2=Conner |last3=Herndon|first3=Scott C. |date=2020-03-09|title=Methane Emissions from Offshore Oil and Gas Platforms in the Gulf of Mexico|journal=Environmental Science & Technology |volume=54|issue=6|pages=3530–3538 |doi=10.1021/acs.est.9b07148|pmid=32149499|bibcode=2020EnST...54.3530Y |issn=0013-936X |doi-access=free}}</ref>

To reduce the amount of carbon emissions otherwise released into the atmosphere, [[methane pyrolysis]] of natural gas pumped up by oil platforms is a possible alternative to [[flaring]] for consideration. Methane pyrolysis produces non-polluting [[hydrogen]] in high volume from this natural gas at low cost. This process operates at around 1000&nbsp;°C and removes carbon in a solid form from the methane, producing hydrogen.<ref>{{Cite web|url=https://www.newscientist.com/article/mg23230940-200-crack-methane-for-fossil-fuels-without-tears/|title=The reaction that would give us clean fossil fuels forever|first=Jon|last=Cartwright|website=New Scientist|access-date=2020-10-20|archive-date=2020-10-26|archive-url=https://web.archive.org/web/20201026044037/https://www.newscientist.com/article/mg23230940-200-crack-methane-for-fossil-fuels-without-tears/|url-status=live}}</ref><ref>{{Cite web|url=https://phys.org/news/2013-04-hydrogen-methane-co2-emissions.html|title=Hydrogen from methane without {{CO2}} emissions|first=Karlsruhe Institute of|last=Technology|website=phys.org|access-date=2020-10-20|archive-date=2020-10-21|archive-url=https://web.archive.org/web/20201021215453/https://phys.org/news/2013-04-hydrogen-methane-co2-emissions.html|url-status=live}}</ref><ref>{{cite web |last1=BASF |title=BASF researchers working on fundamentally new, low-carbon production processes, Methane Pyrolysis |url=https://www.basf.com/us/en/who-we-are/sustainability/we-produce-safely-and-efficiently/energy-and-climate-protection/carbon-management/interview-methane-pyrolysis.html |website=United States Sustainability |publisher=BASF |access-date=19 October 2020 |archive-date=19 October 2020 |archive-url=https://web.archive.org/web/20201019120013/https://www.basf.com/us/en/who-we-are/sustainability/we-produce-safely-and-efficiently/energy-and-climate-protection/carbon-management/interview-methane-pyrolysis.html |url-status=live }}</ref> The carbon can then be pumped underground and is not released into the atmosphere.
It is being evaluated in such research laboratories as Karlsruhe Liquid-metal Laboratory (KALLA).<ref>{{Cite web |url=https://www.europeanenergyinnovation.eu/Latest-Research/Spring-2019/KITT-IASS-Producing-CO2-free-hydrogen-from-natural-gas-for-energy-usage |title=KITT/IASS – Producing {{CO2}} free hydrogen from natural gas for energy usage |access-date=2020-10-20 |archive-date=2020-10-30 |archive-url=https://web.archive.org/web/20201030213425/http://www.europeanenergyinnovation.eu/Latest-Research/Spring-2019/KITT-IASS-Producing-CO2-free-hydrogen-from-natural-gas-for-energy-usage |url-status=live }}</ref> and the chemical engineering team at University of California – Santa Barbara<ref>{{cite web |last1=Fernandez |first1=Sonia |title=low-cost, low-emissions technology that can convert methane into hydrogen without forming {{CO2}} |url=https://phys.org/news/2017-11-potentially-low-cost-low-emissions-technology-methane.html |website=Phys-Org |publisher=American Institute of Physics |access-date=19 October 2020 |archive-date=19 October 2020 |archive-url=https://web.archive.org/web/20201019193709/https://phys.org/news/2017-11-potentially-low-cost-low-emissions-technology-methane.html |url-status=live }}</ref>

== Repurposing ==
If not [[Decommission (ship)|decommissioned]],<ref>{{cite web |title=The Afterlife of Old Offshore Oil Rigs – ASME |url=https://www.asme.org/topics-resources/content/the-afterlife-of-old-offshore-oil-rigs |website=www.asme.org |publisher=[[American Society of Mechanical Engineers]] |archive-url= https://web.archive.org/web/20210120122113/https://www.asme.org/topics-resources/content/the-afterlife-of-old-offshore-oil-rigs |archive-date=20 January 2021 |language=en |date=2019 |url-status=live}}</ref> old [[Semi-submersible platform#Mobile offshore drilling units (MODU)|platform]]s can be repurposed to [[Carbon capture and storage|pump {{CO2}} into rock]]s below the seabed.<ref>{{Cite news|url=https://www.bbc.com/news/uk-scotland-edinburgh-east-fife-49277556|title=Old oil rigs could become {{CO2}} storage sites|work=BBC News |date=August 8, 2019|access-date=October 8, 2021|archive-date=November 8, 2020|archive-url=https://web.archive.org/web/20201108001119/https://www.bbc.com/news/uk-scotland-edinburgh-east-fife-49277556|url-status=live}}</ref><ref>{{Cite news |url=https://www.thetimes.com/uk/science/article/ageing-oil-rigs-could-be-used-to-store-carbon-and-fight-climate-change-cd7jl9qcm |title=Ageing oil rigs could be used to store carbon and fight climate change |website=[[The Times]] |access-date=2020-10-20 |archive-date=2020-10-26 |archive-url=https://web.archive.org/web/20201026042455/https://www.thetimes.co.uk/article/ageing-oil-rigs-could-be-used-to-store-carbon-and-fight-climate-change-cd7jl9qcm |url-status=live |last1=Watson |first1=Jeremy }}</ref> [[Odyssey (launch platform)|Others]] have been [[Sea Launch#Launches|converted to launch rockets into space]], and [[SpaceX floating launch platform|more are being redesigned]] for use with heavy-lift launch vehicles.<ref name=nsf20210119>{{cite news |last=Burghardt |first=Thomas |url=https://www.nasaspaceflight.com/2021/01/spacex-rigs-starship-spaceports/ |title=SpaceX acquires former oil rigs to serve as floating Starship spaceports |work=[[NASASpaceFlight]] |date=19 January 2021 |access-date=20 January 2021 |archive-date=20 January 2021 |archive-url=https://web.archive.org/web/20210120001114/https://www.nasaspaceflight.com/2021/01/spacex-rigs-starship-spaceports/ |url-status=live }}</ref>

In [[Saudi Arabia]], there are plans to repurpose decommissioned oil rigs into a [[The Rig, Saudi Arabia|theme park]].<ref>{{cite news |author=<!--not stated--> |date=2024-01-19 |title=Saudi Arabia unveils plan to build a massive adventure tourism destination 'The Rig': Check details|url=https://www.cnbctv18.com/travel/destinations/saudi-arabia-unveils-plan-to-build-a-massive-adventure-tourism-destination-the-rig-check-details-18842361.htm |work=CNCB |location= |access-date=2024-01-25}}</ref>

== Challenges ==
Offshore oil and gas production is more challenging than land-based installations due to the remote and harsher environment. Much of the innovation in the offshore petroleum sector concerns overcoming these challenges, including the need to provide very large production facilities. Production and drilling facilities may be very large and a large investment, such as the [[Troll A platform]] standing on a depth of 300 meters.

Another type of offshore platform may float with a mooring system to maintain it on location. While a floating system may be lower cost in deeper waters than a fixed platform, the dynamic nature of the platforms introduces many challenges for the drilling and production facilities.

The ocean can add several thousand meters or more to the [[fluid column]]. The addition increases the equivalent circulating density and downhole pressures in drilling wells, as well as the energy needed to lift produced fluids for separation on the platform.

The trend today is to conduct more of the production operations [[subsea]], by separating water from oil and re-injecting it rather than [[Pumping (oil well)|pumping]] it up to a platform, or by flowing to onshore, with no installations visible above the sea. Subsea installations help to exploit resources at progressively deeper waters—locations that had been inaccessible—and overcome challenges posed by sea ice such as in the [[Barents Sea]]. One such challenge in shallower environments is [[Seabed gouging by ice|seabed gouging by drifting ice features]] (means of protecting offshore installations against ice action includes burial in the seabed).
[[File:StatfjordA(Jarvin1982).jpg|thumb|The oil platform Statfjord A in the [[Statfjord oil field]] with the [[flotel]] Polymariner which contains sleeping quarters for the crew, 1982.]]
Offshore manned facilities also present logistics and human resources challenges. An offshore oil platform is a small community in itself with cafeteria, sleeping quarters, management and other support functions. In the North Sea, staff members are transported by helicopter for a two-week shift. They usually receive higher salaries than onshore workers do. Supplies and waste are transported by ship, and the supply deliveries need to be carefully planned because storage space on the platform is limited. Today, much effort goes into relocating as many of the personnel as possible onshore, where management and technical experts are in touch with the platform by video conferencing. An onshore job is also more attractive for the aging workforce in the [[petroleum industry]], at least in the western world. These efforts among others are contained in the established term [[integrated operations]]. The increased use of subsea facilities helps achieve the objective of keeping more workers onshore. Subsea facilities are also easier to expand, with new separators or different modules for different oil types, and are not limited by the fixed floor space of an above-water installation.

==See also==
{{div col|colwidth=27em}}
* [[List of tallest oil platforms]]
* [[Accommodation platform]]
* [[Chukchi Cap]]
* [[Deep sea mining]]
* [[Deepwater drilling]]
* [[Drillship]]
* [[North Sea oil]]
* [[Offshore geotechnical engineering]]
* [[Offshore oil and gas in the United States]]
* [[Oil drilling]]
* [[Protocol for the Suppression of Unlawful Acts against the Safety of Fixed Platforms Located on the Continental Shelf]]
* [[SAR201]]
* [[Shallow water drilling]]
* [[Submarine pipeline]]
* [[TEMPSC]]
* [[Texas Towers]]
{{div col end}}

==References==
{{Reflist}}

==External links==
{{Commons|Oil platform}}
* {{usurped|1=[https://web.archive.org/web/20170626212641/http://oilrigdisasters.co.uk/ Oil Rig Disasters]}} Listing of oil rig accidents
* [https://web.archive.org/web/20190805122859/http://oilrig-photos.com/ Oil Rig Photos] Collection of pictures of drilling rigs and production platforms
* [https://web.archive.org/web/20071020233211/http://divinglore.com/Offshore_Platforms.htm An independent review of offshore platforms in the North Sea]
* [https://web.archive.org/web/20080101062156/http://www.vulcanhammer.info/off/conventional.php Overview of Conventional Platforms] Pictorial treatment on the installation of platforms which extend from the seabed to the ocean surface

{{Tallest buildings and structures}}
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[[Category:Oil platforms| ]]
[[Category:Offshore engineering]]
[[Category:Petroleum production]]
[[Category:Drilling technology]]
[[Category:Natural gas technology]]
[[Category:Structural engineering]]