Editing Oil platform (section)

==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.