Oil and gas giant Shell has set afloat the massive hull of its Prelude FLNG facility in Geoje, South Korea, which is set to be the world's first floating LNG project and the biggest ever floating production facility.

The hull of the Prelude floating LNG facility measures a staggering 488 metres in length and is set to be part of the biggest seaborne production complex in the world upon completion.

Matthias Bischel, Shell’s projects and technology director, said floating the hull alone was a task of considerable complexity and required the finest engineering capabilities from around the globe to make it happen.

Some 600 engineers have worked on design options for the facility, which will be longer than four soccer fields and displace as much water as six of the world’s largest aircraft carriers.

At nearly half a kilometre, the Prelude facility’s length from stern to bow exceeds the height of many world renowned skyscrapers, including the Empire State Building in New York and the Petronas Towers in the Malaysian capital of Kuala Lumpur.

First steel for Prelude was cut just 12 months ago, and the project’s construction is set to require approximately 26,000 tonnes of steel, 2,000 kilometres of pipework and 220,000 kilometres of cabling.

A structure of such prodigious dimensions will also require huge ancillary and support installations to permit its operation. A total of 6,700 horsepower thrusters will be employed to haul the facility to its final destination in the Browse Basin’s Prelude gas field off the Western Australian coast.

Once in operation, the facility will draw 50 million litres of cold water from the ocean every hour to cool natural gas for conversion into LNG, which it will then hold in storage tanks with the equivalent capacity of 175 Olympic-sized swimming pools.

As a permanent floating facility, the Prelude is also capable of enduring the intense rigours of the ocean’s powerful weather, and has been designed to withstand a category 5 cyclone.

The facility’s final purpose will be to process gas extracted from under the seabed into LNG and convey it to ocean carriers for delivery to export markets, thus obviating the necessity for either pipelines or onshore processing facilities.

After being moored at a location approximately 200 kilometres off the coast of Western Australia, where it is likely to remain for a period of between 20 and 25 years, Prelude is expected to produce 3.6 million tonnes of LNG per annum, as well as significant amounts of condensate and liquefied petroleum gas.

According to Shell’s own estimates, its LNG output could supply all of Hong Kong’s natural gas needs and more, equivalent to approximately 117 per cent of the city’s annual demand.

At present, there are no FLNG facilities in operation anywhere on the planet, and the Shell Prelude project will likely mark the first successful deployment of the technology, with first gas expected in 2016.

Despite its vast dimensions compared to other floating production facilities, Prelude is actually modest in size compared to onshore LNG plants, taking up around only a quarter of the area.

Following its successful deployment, the Prelude facility could kick off a new era in the use of floating LNG technology for the development of Australia’s abundant gas resources – no doubt to the immense chagrin of Western Australian Premier Colin Barnett, who has strenuously opposed adoption of the technology on the grounds that it will deprive the state of jobs and economic benefits.

 Woodside and its partners have already chosen floating technology for the Browse LNG development, while BHP and ExxonMobil have obtained Federal approval for a huge $10 billion floating LNG plant off the coast of Western Australia near Exmouth.