Spar (platform)
A spar, named for logs used as buoys in shipping and moored in place vertically, is a type of floating oil platform typically used in very deep waters. Spar production platforms have been developed as an alternative to conventional platforms. [1]
A spar platform consists of a large-diameter, single vertical cylinder supporting a deck. The cylinder is weighted at the bottom by a chamber filled with a material that is denser than water to lower the center of gravity of the platform and provide stability.[2] Spars are anchored to the seabed by way of a spread mooring system with either a chain-wire-chain or chain-polyester-chain composition.[3]
There are three primary types of spars; the classic spar, truss spar, and cell spar. The classic spar consists of the cylindrical hull noted above, with the heavy ballast at the bottom of the cylinder.
A truss spar has a shorter cylindrical "hard tank" than a classic spar and has a truss structure connected to the bottom of hard tank. At the bottom of the truss structure, there is a relatively small, square shaped "soft tank" that houses the heavy ballasting material. The majority of spars are of this type.[4]
A cell spar has a large central cylinder surrounded by smaller cylinders of alternating lengths. At the bottom of the longer cylinders is the soft tank housing the heavy ballasting material, similar to a truss spar. There is currently only one cell spar in operation.[5]
The first spar platform was the Neptune spar, located in the Gulf of Mexico and was installed in September 1996 by Kerr McGee (now Anadarko).[6]
The world's deepest platform is Perdido, a truss spar in the Gulf of Mexico, with a mean water depth of 2,438 meters. It is operated by Royal Dutch Shell and was built at a cost of $3 billion.[7]
References
- ↑ www.fmctechnologies.com "Glossary of Terms"
- ↑ Rigzone "How Do Spars Work?"
- ↑ Offshore Magazine "State-of-the-art of spread moored systems for deepwater floating production platforms"
- ↑ Offshore Magazine "2012 DEEPWATER SOLUTIONS & RECORDS FOR CONCEPT SELECTION"
- ↑ Exploration and Production "Red Hawk showcases first cell spar"
- ↑ www.naturalgas.org "Spar Platforms"
- ↑ Shell starts production at Perdido
External links
- GlobalSecurity.org page on spar platforms - containing detailed diagramsit:Spar (piattaforma)
