This descriptive definition refers to a floating system with infield flow lines and associated subsea infrastructure to connect the subsea production and injection wells.
SPAR platforms are among the largest offshore platforms in use.
These huge platforms consist of a large cylinder supporting a typical fixed rig platform.
The cylinder does not extend all the way to the seafloor, but instead is tethered to the bottom by a series of cables and lines.
The large cylinder serves to stabilize the platform in the water, and allows for movement to absorb the force of potential hurricanes.
For these reasons the SPAR are the preferred design in the deep waters of the Gulf of Mexico
The first SPAR platform in the Gulf of Mexico was installed in September of 1996.
Its cylinder measured 770 feet long and was 70 feet in diameter, and the platform operated in 1,930 feet of water.
SPAR has to date been designed in three configurations:
– Conventional SPAR in one-piece cylindrical hull
– Truss SPAR where the midsection is composed of truss elements connecting the upper buoyant hull (called a hard tank) with the bottom soft tank containing permanent ballast
– 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 was the Keer-McGee’s Neptune, anchored in 1,930 ft (590 m) in the Gulf of Mexico; however, SPAR (such as Brent SPAR) were previously used only as FSOs
ENI’s Devil Tower located in 5,610 ft (1,710 m) of water, in the Gulf of Mexico, was the world’s deepest SPAR until 2010.
The world’s deepest platform is currently the Shell’s Perdido SPAR in the Gulf of Mexico, floating in 2,438 meters of water. It was built at a capital expenditure of $3 billion
In 2012, Aker Solutions has been awarded a FEED (front-end engineering and design) contract from Statoil to design the world’s largest SPAR platform for the Aasta Hansteen field development in the Norwegian North Sea.