Troll is a

natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ...

and

oil field A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the prese ...

in the Norwegian sector of the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

, 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 the field. The field as a whole consists of the main Troll East and Troll West structures in blocks 31/2, 31/3, 31/5 and 31/6,Bolle, L., Troll Field, 1992, in ''Giant Oil and Gas Fields of the Decade, 1978-1988'', AAPG Memoir 54, Halbouty, M.T., editor, Tulsa: American Association of Petroleum Geologists, , pp. 447-458 about west of Kollsnes, near

Bergen Bergen (, ) is a city and municipalities of Norway, municipality in Vestland county on the Western Norway, west coast of Norway. Bergen is the list of towns and cities in Norway, second-largest city in Norway after the capital Oslo. By May 20 ...

. Most of the gas lies in Troll East.

Operators

The field is operated by Equinor, which has a 30.58% interest. The other partners are Petoro (56%), Shell plc (8.1%), ConocoPhillips (1.62%) and TotalEnergies (3.69%).

Platforms

Gas and oil from the field are extracted via three platforms – Troll A, B and C. The Troll A platform, based on the Condeep technology, is the tallest structure ever to be moved. Total weight is 656,000 tons and the total height . The legs extend below sea level. This platform came into production in 1996 after being towed out from

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, Telemark to the east and Agder to the east and southeast. As of 1 January 2024, it had a population of 49 ...

in May 1995 The Troll B Platform is a semi-submersible designed by Doris and fabricated from concrete; thought to be the only concrete semisubmersible. This platform came into production in 1995. The Troll C Platform is a conventional steel hull semi-submersible designed by GVA Consultants. This platform came into production in 1999.

Area

Extending across four North Sea blocks, the whole field covers just over 700 square kilometres, corresponding to about 100,000 football pitches.

Geology

The reservoir is located in three eastward-tilted

fault block Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by Tectonics, tectonic and localized stresses in Crust (geology), Earth's crust. Large areas of bedrock are broken up into blocks by Fault (geology) ...

s 1,500 m subsea and consists of cyclic shallow-marine

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s from the Fensfjord, middle Heather, Sognefjord and upper Heather formations in the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

Viking Group, and is overlain by Upper Jurassic to

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s. Located in the eastern margin of the Viking

Graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

, water depths range from 300–355 m.

References

External links

Troll in the Interactive Energy Map of AftenbladetArticles on Troll at Equinor 50 years history page
{{Resources in Norway Oil fields in Norway Natural gas fields in Norway North Sea energy Equinor oil and gas fields Shell plc oil and gas fields ConocoPhillips oil and gas fields TotalEnergies