Shell Oil Company’s Prelude FLNG is the largest floating structure built

By : Franyi Sarmiento, Ph.D., Inspenet, May 23, 2022

The Prelude FLNG is a massive liquefied gas platform, so large it is the largest of its kind and billed as the largest floating structure ever built. It measures almost half a kilometer in length.

The Prelude even outshines the Seawise Giant, the 1,500-foot-long megatanker built in the 1970s and which reigned over the seas for decades as the largest ship on the globe.

The platform, owned by Royal Dutch Shell, is 488 meters long and 74 meters wide, weighs 600,000 tons with full tanks; It is capable of storing enough liquid to fill 175 Olympic swimming pools and could—or so its managers say, at least—withstand the onslaught of a category five cyclone. In addition to being long, the platform is tall: according to Shell itself, the turret that crosses the facility reaches 93 meters.

The platform processes natural gas, which comes from underwater fields located about 475 kilometers off the coast of Broome, in Western Australia. There it is expected to remain more or less between two and three decades. On the platform, the gas is cooled to -162ºC to convert it into LNG and facilitate its storage and transport. Then customers are transferred with boats.

The company expects to generate about 3.6 million tons of liquefied natural gas, LNG, annually. With its production alone, the company estimates, the mega-platform could generate the necessary supply to more than cover – by about 117% – Hong Kong’s demand.

The giant gas structure is the first deployment of Shell’s FLNG technology. Once finished, Prelude was positioned on its site in 2017 and at the end of 2018 it was already starting its production work.

According to the Journal of Petroleum Technology, after its premiere four years ago, Prelude has had to face several incidents. Perhaps the one with the greatest repercussions was the one registered in December 2021, when it suffered a fire that led to a power outage on board, where around 200 people live. NOPSEMA, the Australian authority on the matter, ordered him to stop production for several months.

Shell has not revealed the exact amount of construction of the Prelude, but some experts speak of a global cost of the project of 17,000 million dollars. In 2011 Samsung, in charge of the construction, pointed out that the boat would cost around 3,000 million. In their “venture”, in addition to Shell, with 67.5%, there are also Inpex from Japan (17.5%), Kogas from South Korea (10%) and CPC Corp from Taiwan (5%).

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Photos : Shell