An oil platform is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the continental shelf, though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be fixed to the ocean floor, consist of an artificial island, or float. In some arrangements the main facility may have storage facilities for the processed oil. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.
Offshore construction is the installation of structures and facilities in a marine environment, usually for the production and transmission of electricity, oil, gas and other resources. It is also called maritime engineering.
The Troll A platform is a Condeep gravity-based structure offshore natural gas platform in the Troll gas field off the west coast of Norway. Built from reinforced concrete, as of 2014, 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 in 1995, where it is now operated by Equinor. It is also the heaviest object moved and the object with the second highest displacement at 1.2 million tons(the object with the highest displacement is the Gullfaks C, which had a displacement approaching 1.5 million tons in comparison with Troll A's 1.2 million). Troll A was towed from the afternoon 10 May 1995 until the platform was in place 17 May 1995. It was lowered to the seabed in 303 meters of water, and had penetrated 36 meters into the soil by 19 May 1995. It was self-supporting with no further mooring required.
Petronius is a deepwater compliant tower oil platform built from 1997 to 2000 and operated by Chevron in the Gulf of Mexico, 210 km (130.5 mi) southeast of New Orleans, United States.
Ekofisk is an oil field in block 2/4 of the Norwegian sector of the North Sea about 320 km (200 mi) southwest of Stavanger. Discovered in 1969 by Phillips Petroleum Company, it remains one of the most important oil fields in the North Sea. This was the first discovery of oil after the drilling of over 200 exploration wells in the North Sea "triggered" by the Groningen gas field discovery. In 1971, Phillips started producing directly to tankers from four subsea wells. Oil production is planned to continue until at least 2050.
The Statfjord oil field is a large oil and gas field covering 580 km2 in the U.K.-Norwegian boundary of the North Sea at a water depth of 145 m, discovered in 1974 by Mobil and since 1987 operated by Equinor.
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. The initial recoverable reserve is 2.1 billion barrels, and the remaining recoverable reserve in 2004 is 234 million barrels. This oil field reached peak production in 2001 at 180,000 barrels per day (29,000 m3/d). It has satellite fields Gullfaks South, Rimfaks, Skinfaks and Gullveig.
Oseberg is an offshore oil field with a gas cap in the North Sea located 140 km (87 mi) northwest of the city of Bergen on the southwestern coast of Norway. The field, which is 25 km long by 7 km wide, was discovered in 1979 and its development is known to be one of the significant milestones in emergence of Norway's independent oil and gas industry. The Oseberg field was named after Oseberg ship, one of Norway's most significant archeological discoveries. The ancient Viking ship from the early 9th century was discovered in a 1904 historical excavation of a burial mound at the Oseberg Farm, south of Oslo.
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 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, about 65 kilometres (40 mi) west of Kollsnes, near Bergen. Most of the gas lies in Troll East.
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.
The Norwegian Petroleum Museum is located in Stavanger, Norway.
The Dunlin oilfield is situated 195 km northeast of Lerwick, Shetland, Scotland, in block number 211/23a and 211/24a. It was originally operated by Shell but was sold in 2008 and is now operated by Fairfield Energy and partners MCX.
The Cormorant oilfield is located 161 kilometres (100 mi) north east of Lerwick, Shetland, Scotland. It was discovered in September 1972 at a depth of 150 metres (490 ft). The oil reservoir is located at a depth of 2,895 metres (9,498 ft). Production started in December 1979 from the Cormorant Alpha platform and operates from two platforms and an underwater manifold centre.
Bullwinkle was a 1,736 feet (529 m) tall, pile-supported fixed steel oil platform in the Gulf of Mexico. Installed in 1988, the total weight of the platform was 77,000 tons, of which the steel jacket comprises 49,375 tons. At the time of its construction it was the third tallest freestanding structure ever built – shorter than only the CN Tower and the Ostankino Tower – and the tallest in the United States, being 6 ft (1.8 m) taller than the pinnacle of the Sears Tower. Of the total height, 1,352 feet (412 m) are below the waterline. It is located in Green Canyon Block 65, approximately 160 miles (260 km) southwest of New Orleans. Bullwinkle currently is operated by QuarterNorth Energy, LLC. The total field development construction cost was US$500,000,000 according to some sources.
A fixed platform is a type of offshore platform used for the extraction of petroleum or gas. These platforms are built on concrete and/or steel legs anchored directly onto the seabed, supporting a deck with space for drilling rigs, production facilities and crew quarters. Such platforms are, by virtue of their immobility, designed for very long-term use. Various types of structure are used, steel jacket, concrete caisson, floating steel and even floating concrete. Steel jackets are vertical sections made of tubular steel members, and are usually piled into the seabed. Concrete caisson structures, pioneered by the Condeep concept, often have in-built oil storage in tanks below the sea surface and these tanks were often used as a flotation capability, allowing them to be built close to shore and then floated to their final position where they are sunk to the seabed. Fixed platforms are economically feasible for installation in water depths up to about 500 feet ; for deeper depths a floating production system, or a subsea pipeline to land or to shallower water depths for processing, would usually be considered.
Offshore concrete structures, or concrete offshore structures, are structures built from reinforced concrete for use in the offshore marine environment. They serve the same purpose as their steel counterparts in oil and gas production and storage. The first concrete oil platform was installed in the North Sea in the Ekofisk oil field in 1973 by Phillips Petroleum, and they have become a significant part of the marine construction industry. Since then at least 47 major concrete offshore structures have been built.
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.
Slip forming, continuous poured, continuously formed, or slipform construction is a construction method in which concrete is poured into a continuously moving form. Slip forming is used for tall structures, as well as horizontal structures, such as roadways. Slipforming enables continuous, non-interrupted, cast-in-place "flawless" concrete structures that have performance characteristics superior to those of piecewise construction using discrete form elements. Slip forming relies on the quick-setting properties of concrete, and requires a balance between quick-setting capacity and workability. Concrete needs to be workable enough to be placed into the form and consolidated, yet quick-setting enough to emerge from the form with strength. This strength is needed because the freshly set concrete must not only permit the form to "slip" by the concrete without disturbing it, but also support the pressure of the new concrete and resist collapse caused by the vibration of the compaction machinery.
Sesam is a software suite for structural and hydrodynamic analysis of ships and offshore structures. It is based on the displacement formulation of the Finite Element Method.
A submarine pipeline is a pipeline that is laid on the seabed or below it inside a trench. In some cases, the pipeline is mostly on-land but in places it crosses water expanses, such as small seas, straits and rivers. Submarine pipelines are used primarily to carry oil or gas, but transportation of water is also important. A distinction is sometimes made between a flowline and a pipeline. The former is an intrafield pipeline, in the sense that it is used to connect subsea wellheads, manifolds and the platform within a particular development field. The latter, sometimes referred to as an export pipeline, is used to bring the resource to shore. Sizeable pipeline construction projects need to take into account many factors, such as the offshore ecology, geohazards and environmental loading – they are often undertaken by multidisciplinary, international teams.
