Editing Oil platform (section)

===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>