PUBLIC INFORMATION SERIES
REPRESENTATIONAL PLANNING, ENGINEERING, ENVIRONMENTAL & TECHNOLOGY EXHIBITS
PRESENTATION 2013
VERY LARGE FLOATING STRUCTURES
[VLFS]
EXHIBITS
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Very large floating structure(s) [VLFS] or, as some literature refers to them, very large floating platform(s) [VLFP]) can be constructed to create floating airports, bridges, breakwaters, piers and docks, storage facilities [for oil & natural gas], wind and solar power plants, for military purposes, to create industrial space, emergency bases, entertainment facilities [such as casinos], recreation parks, mobile offshore structures and even for habitation. |
VLFS for habitation could become reality sooner than one may expect. Currently, different concepts have been proposed for building floating cities or huge living complexes
Pontoon-type VLFS' are also known in the literature as mat-like VLFSs because of their small draft in relation to the length dimensions. Very large pontoon-type floating structure is often called Mega-Floats. As a rule, the Mega-Float is a floating structure having at least one length dimension greater than 60 meters. Horizontally large floating structures can be from 500 to 5000 meters in length and 100 to 1000 meters in width, while their thickness can be of the order of about 2-10 meters.
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BUILT STRUCTURE
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Thunder Horse is the largest moored semisubmersible oil platform in the world, located in 1,920 metres [6,300 feet] of water in the Mississippi Canyon Block 778/822, Thunder Horse Oilfield, approximately one hundred fifty [150] miles [241 km] southeast of New Orleans, Louisiana in the Gulf of Mexico.
Construction cost was approximately one billion [ $ 1,000,000,000.] dollars US.
The facility is expected to operate for twenty-five [25] years producing approximately one billion [1,000,000,000] barrels of oil. At its peak, it is expected to process two hundred million [200mcf] cubic feet [5,700,000 m3] of natural gas and two hundred fifty thousand [250,000] barrels [40,000 m3] of oil equivalent per day.
The Thunder Horse Platform is owned by BP® [75%} and ExxonMobil® [25%], and operated by BP®.
The Hull Section was constructed by DSME in South Korea and was delivered in 2004 to Corpus Christi, Texas [birthplaces of Tom Edgemon] aboard MV Blue Marlin for site completion. Thunder Horse was completed at Kiewit Offshore services in nearby Ingleside, Texas, USA.
Daewoo's Shipbuilding and Marine Engineering Division Manufactured the Semisubmersible Hull and Drilling Rig for a floating production, drilling and Quarters [housing] {PDQ] Platform. Construction was completed at Okpo in Sou the Korea after Daewoo won a three hundred eighty million [$ 380,000,000.] dollar US contract for the work in November 2001.
The one hundred twenty thousand [120,000] deadweight ton hull was designed by GVA Consultants of Sweden, which Haliburton purchased from British Marine Technology.
The Thunder Horse hull is based on the four-leg semisubmersible design previously produced by GVA for the Visund Field in Norway.
In Morgan City, Louisiana J. Ray McDermott dedicated its complete facility site to build process topside modules for the Thunder Horse PDQ and for the three [3] spars for Altantis, Holstein and Mad Dog in a six hundred million [$ 600,000,000.] dollar US deal.
Some of the other major project contracts were awarded to Sulzer for pumps and to GE® [General Electric] for platform turbines. Kiewit Contractors, which previously provided construction managemental on the Hibernia gravity base structure, was responsible for heavy lift deck and hull integration on Thunder Horse while Heerema Marine Contractors installed the platform in 2005.
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It also represents a major step forward in a highly touted frontier region of the Gulf, which has been hailed as the biggest domestic discovery since Alaska’s Prudhoe Bay a generation ago.
But as Chevron’s project illustrates, there is nothing easy about operating in the remote area. Not only are the fields beneath 7,000 feet of water and as much as four additional miles below the sea floor, they are in ancient rock layers that are still not well understood by industry.
“This one, by and large, is going to be our biggest and most complex undertaking in our history in the U.S. Gulf of Mexico,” said Gary Luquette, the company’s chief of North American exploration and production, in an interview with the Houston Chronicle in advance of today’s official announcement.
To make the project feasible, Chevron and its partners are building a giant facility that will function as a single hub for the fields – located 25 miles apart – with the capacity to produce 170,000 barrels of crude oil per day and 42.5 million cubic feet of natural gas per day.
It will tie in production from three clusters of pumps and other equipment on the seafloor that will help suck oil and gas from the deep formations and send it to the platform above.
As such, it will closely resemble Shell’s Perdido hub, which in March became the first offshore facility to begin production in the ancient rock layers – deposited from 35 million to 65 million years ago – referred to by scientists as the Lower Tertiary trend.
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The massive platform, nearly half a kilometre long, will be the biggest floating offshore drilling structure in the world, weighing in at about 600,000 tonnes – equivalent to six aircraft carriers – and staffed by 110 people at a time. Five times more steel will be used in its construction than went into the Sydney Harbour Bridge. Shell would not say how much it is expected to cost, but the total cost of exploiting the company’s Australian off-shore oil fields, where it will be used, is likely to exceed $ 30bn.It will take about five years to build, and is not expected to be fully operational before 2017.Floating offshore gas platforms could be used to explore areas of the globe previously too remote for drilling. Companies are racing to discover offshore resources in deep water, as the world’s readily available stores of onshore and close-to-shore oil and gas have already been snapped up. Advances in technology and melting sea ice are also helping to allow oil and gas exploration in sensitive parts of the globe, such as the Arctic, where a scramble to claim the undersea resources is now under way.Shell has no such plans yet, and will moor its new platform 200km out to sea off the coast of Australia at the Prelude gas field. The size of the Shell platform means it can only be used on large gas fields, as it would not be economically viable on smaller fields. |
“Our innovative FLNG technology will allow us to develop offshore gasfields that otherwise would be too costly to develop,” said Malcolm Brinded, executive director, of Shell’s upstream international business. “Our decision to go ahead with this project is a true breakthrough for the LNG industry, giving it a significant boost to help meet the world’s growing demand for the cleanest-burning fossil fuel [and] help accelerate the development of gas resources.”
He said the company was seeking to develop more floating platform projects.
Ann Pickard, country chair of Shell in Australia, said the technology would be “a game-changer for the energy industry”.
Liquefied natural gas is a growing market as it is easier to transport. It is shrunk by about 600 times in the cooling process and can be transported before being turned back into a gas and used for power generation or heating, though it can also be used as a road fuel in specially adapted vehicles.
The floating platform, which Shell has now started to design in detail, will be built in South Korea. It will take gas from the Prelude field and liquefy it to -162C (-260F) on board, from where it will be removed by tankers and shipped to the rapidly growing LNG markets in Asia. Previously, gas had to be piped to onshore facilities to be liquefied.
The facility would be designed to withstand even the most severe cyclones, Shell said.
PROTOTYPICAL BALLAST COLUMN - SEMISUBMERSIBLE PLATFORM
REPRESENTATIONAL INTERIOR VIEW
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