Troll A Platform
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The Troll A platform is a
Condeep Condeep is a make of gravity-based structure for oil platforms invented and patented by engineer Olav Mo in 1972, which were fabricated by Norwegian Contractors in Stavanger, Norway.Fagerberg; Mowery; Verspagen, p.192 ''Condeep'' is an abbrevia ...
gravity-based structure A gravity-based structure (GBS) is a support structure held in place by gravity, most notably offshore oil platforms. These structures are often constructed in fjords due to their protected area and sufficient depth. Offshore oil platforms Pri ...
offshore natural gas platform in the
Troll gas field Troll is a natural gas and oil field in the Norwegian sector of the North Sea, one of the biggest in the North Sea, holding 40% of Norway’s gas – it also possesses significant quantities of oil, in thin zones under the gas cap, to the west of ...
off the west coast of
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
. Built from
reinforced concrete Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having hig ...
, , it was the tallest structure 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 The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...
in 1996, where it is now operated by
Equinor Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, operating in 36 countries with additional investments in renewable energy. I ...
. It is often incorrectly referenced as the heaviest object ever moved as well, but it is actually the second heaviest after another
Condeep Condeep is a make of gravity-based structure for oil platforms invented and patented by engineer Olav Mo in 1972, which were fabricated by Norwegian Contractors in Stavanger, Norway.Fagerberg; Mowery; Verspagen, p.192 ''Condeep'' is an abbrevia ...
Oil platform the
Gullfaks C Gullfaks is an oil and gas field in the Norwegian sector of the North Sea operated by Equinor. It was discovered in 1978, in block 34/10, at a water depth of 130-230 meters.Petterson, O., Storli, A., Ljosland, E., Nygaard, O., Massie, I., and Ca ...
, which had a displacement approaching 1.5 million tons in comparison with Troll A's 1.2 million.


Dimensions

The Troll A platform has an overall height of , weighs 683,600 tons (1.2 million tons with ballast) and has the distinction of being the tallest and second heaviest structure ever moved by humankind. The platform stands on four legs extending down to the sea floor 303 meters (994 feet) below the surface of the sea, and the leg containing the import and export risers has an elevator that takes over nine minutes to travel from the platform above the waves to the sea floor. National Geographic Channel production, documentary 2007(?), rebroadcast 2009-10-02, 12-13:00 hrs EDST (Comcast Cable Television system) The legs must be able to withstand intense pressures, so the walls of Troll A's legs are over 1 metre thick and are made of steel-reinforced concrete that was formed in one continuous poura lengthy process that takes 20 minutes per 5 cm laid. Each leg is a mathematically joined composite of several conical cylinders that flares out smoothly to greater diameters at the top and bottom, so each support is somewhat wasp-waisted when viewed in profile and circular in any cross-section (see picture at right). The four legs are joined by a "chord shortener" (not present in the picture at right), a reinforced concrete box connecting the legs that damps out any potentially destructive wave-leg
resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillatin ...
s by retuning the legs' natural frequencies. 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 tall
vacuum-anchor In large scale oceanic civil engineering, vacuum-anchors are used to anchor gravity-based structuresA National Geographic Channel production, documentary 2007(?), rebroadcast 2009-10-02, 12-13:00 hrs EDST (Comcast Cable Television system) (such a ...
s holding them fixed in the mud of the sea floor.


Construction

Troll A was built by
Norwegian Contractors Norwegian Contractors AS was a concrete gravity base (GBS) structure supplier from 1974 to 1994. Aker Marine Contractors AS (AMC) was established in 1995 and is a continuance of the marine activities in Norwegian Contractors AS. Norwegian Contracto ...
for
Norske Shell Shell plc is a British Multinational corporation, multinational petroleum, oil and natural gas, gas company headquartered in London, England. Shell is a public limited company with a primary listing on the London Stock Exchange (LSE) and second ...
, with base construction beginning in September 1991 at a cost of 4150 million
NOK Nok is a village in Jaba Local Government Area of Kaduna State, Nigeria. The village is an archeological site. Archaeology The discovery of terracotta figurines at this location caused its name to be used for the Nok culture, of which these ...
, or approximately US$650 million at the time. The base and the deck were built separately, and were joined in 1998 while the base was partially submerged. The base is a
Condeep Condeep is a make of gravity-based structure for oil platforms invented and patented by engineer Olav Mo in 1972, which were fabricated by Norwegian Contractors in Stavanger, Norway.Fagerberg; Mowery; Verspagen, p.192 ''Condeep'' is an abbrevia ...
gravity base structure A gravity-based structure (GBS) is a support structure held in place by gravity, most notably offshore oil platforms. These structures are often constructed in fjords due to their protected area and sufficient depth. Offshore oil platforms Pri ...
built from
reinforced concrete Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having hig ...
. The Troll platform was towed over from Vats, in the northern part of
Rogaland Rogaland () is a Counties of Norway, county in Western Norway, bordering the North Sea to the west and the counties of Vestland to the north, Vestfold og Telemark to the east and Agder to the east and southeast. In 2020, it had a population of 47 ...
, to the Troll field, north-west of
Bergen Bergen (), historically Bjørgvin, is a city and municipality in Vestland county on the west coast of Norway. , its population is roughly 285,900. Bergen is the second-largest city in Norway. The municipality covers and is on the peninsula of ...
. The tow took seven days.


Expansion

In the autumn of 2010 the Troll A platform was expanded with a new module. This module contains living quarters and a new control room. The new control room and expanded facilities are needed to support the new compressors (a third and fourth are planned and being installed in 2014). These compressors are needed due to the dropping reservoir pressure in the wells. On 18 June 2013 the new support module ''M12'' for compressors 3 and 4 was lifted on board Troll A. The increased electricity consumption of these compressors required new power cables from shore, and due to grid constraints the platform is cut off from shore power if a grid emergency arises.


Operation

Gas rises from 40 wells and is exported through a number of pipes to a processing plant at
Kollsnes Kollsnes is a natural gas processing plant operated by Equinor on the southern part of the island of Oøy in Øygarden Municipality in Vestland county, Norway. It processes the natural gas from the Troll, Kvitebjørn, and Visund gas fields. K ...
. Troll A is scheduled to receive two additional gas compressors to increase production volume and compensate for dropping reservoir pressure in the wells.


World records

In 1996, the platform set the
Guinness World Record ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
for the largest offshore gas platform. In 2006, the 10th anniversary of
Statoil Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state owned enterprise, state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, petroleum company, operating in 36 countries with ad ...
's operatorship of Troll gas production was celebrated with a concert by
Katie Melua Ketevan Katie Melua (; ka, ქეთევან "ქეთი" მელუა, ; born 16 September 1984) is a Georgian and British singer and songwriter. She was born in Kutaisi and raised in Belfast and London. Under the management of comp ...
held at the base of one of the hollow legs of the platform. The concert set a new
world record A world record is usually the best global and most important performance that is ever recorded and officially verified in a specific skill, sport, or other kind of activity. The book ''Guinness World Records'' and other world records organization ...
for the deepest underwater concert, at below sea level.


See also

*
HVDC Troll The HVDC Troll is a bipolar high-voltage direct current (HVDC) electric power transmission line for the supply of the gas compressor station on the offshore construction work Troll A platform. It consists of dual set of a long bipolar submarine ...
*
Ursa tension leg platform The Ursa tension leg platform is an oil platform with a tension leg structure located at about southeast of New Orleans in the Gulf of Mexico. It is operated by Shell Oil Company. It has a total height from the seabed to its top of . Shell Oil ...
, another, taller record-breaking platform * Magnolia extended tension leg platform, the world's deepest ETLP


References


External links

*
Offshore-Technology.com: Troll
{{DEFAULTSORT:Troll A Platform Natural gas platforms Natural gas industry in Norway North Sea energy Equinor 1996 establishments in Norway