Troll A platform

The Troll A platform is a condeep offshore natural gas platform in the Troll gas field. It is the tallest construction that has ever been moved to another position, relative to the surface of the Earth, and is among the largest and most complex engineering projects in history. The platform was a televised sensation when it was towed into the North Sea in 1996, where it is now operated by StatoilHydro.

Dimensions

The "Troll A" platform has an overall height of 472 meters and weighs 656,000 tons and has the distinction of being the tallest structure ever moved by mankind. The platform stands on the sea floor m to ft|303|wiki=y|abbr=no below the surface of the sea and each of the continuous-slip-formedCite Sm
National Geographic Channel production, documentary 2007(?), rebroadcast 2009-10-02, 12-13:00 hrs EDST (Comcast Cable Television system) concrete cylindrical legs has an elevator that takes over nine minutes to travel from the platform above the waves to the sea floor. The walls of Troll A's legs are over 1 meter thick made of steel reinforced concrete formed in one continuous pour (See Slip forming) and each is mathematically a joined composite of several conical cylinders that flares out smoothly to greater diameters at both the top and bottom, so each support is somewhat wasp-waisted viewed in profile and circular in any cross-section. (See picture at right)

The four legs are joined by a "Chord shortener", a reinforced concrete box interconnecting the legs, but which has the designed function of damping out unwanted potentially destructive wave-leg resonances by retuning the leg natural frequencies.(Not present in the picture at right.) Each leg is also sub-divided along its length into compartments a third of the way from each end which act as independent water-tight compartments. The legs use groups of six (m to ft|40|wiki=yes|abbr=y tall vacuum-anchors holding it fixed in the muck of the sea floor.

Construction

Troll A was built by Norwegian Contractors for Norske Shell, with base construction beginning in July 1991. [cite web | title=Structurae - Troll A Platform | url=http://en.structurae.de/structures/data/index.cfm?id=s0003286] The base and the deck were built separately, and were joined in 1995 while the base was partially submerged. The base is a Condeep gravity base structure built from reinforced concrete.

The Troll platform was towed over 200 km from Vats, in the northern part of Rogaland, to the Troll field, 80 km north-west of Bergen. The tow took seven days.

Expansion

Troll A is scheduled for an expansion of living quarters to accommodate the increasing number of workers needed to keep up with increasing production.

Operation

Gas rises from 40 wells, and is exported through a number of pipes at better than mph to kph|2000|wiki=yes|abbr=no. Troll A is scheduled to receive two additional gas compressors to increase production volume.

World Records

In 1996 the platform set the Guinness World Record for 'largest offshore gas platform'. [cite web | author= | title= Guinness World Records - largest offshore gas platform | work=Guiness World Records | date= 1996| url=http://www.guinnessworldrecords.com/records/science_and_technology/buildings/largest_offshore_gas_platform.aspx ]

In 2006, the 10th anniversary of Statoil's operatorship of Troll gas production was celebrated with a concert by Katie Melua held at the base of the Troll A platform. As well as entertaining the workers on the rig, the concert set a new world record for the deepest underwater concert at 303 meters below sea level. [cite web | author= | title= Melua's deep sea gig sets record | work=BBC News | date= 2 October 2006| url=http://news.bbc.co.uk/1/hi/entertainment/5396970.stm ]

ee also

*HVDC Troll

References

External links

*
* [http://www.offshore-technology.com/projects/troll/troll1.html Offshore-Technology.com: Troll]
* [http://statoil.no/STATOILCOM/SVG00990.NSF?opendatabase&lang=en&artid=870B3FA8768F0BB3C1256FF50030254A Pictures of Troll]