The Prelude FLNG

FLNG is the acronym of Floating Liquefied Natural Gas and refers to floating production unit of liquefied natural gas (LNG).

Floating Liquefied Natural Gas is not the chemical derivative of any form of natural gas, this wording was invented to describe the manufacturing process to produce LNG.

For more than a decade, the world’s biggest liquefied natural gas producers led by Royal Dutch Shell Plc plotted how to move their $170 billion industry onto barges at sea to tap remote fields. Now they’re finally doing it.
 
Shell will forge the hull of a floating LNG plant in South Korea by year-end that will be the world’s largest vessel, weighing six times the biggest aircraft carrier, a Nimitz-class warship. Some 5,000 workers will build the factory to produce LNG off Australia’s northwest coast in a $13 billion project that also will shield Shell from escalating costs it would have to pay at the country’s onshore plants.

Facts:

The Prelude FLNG facility will be 488m long, 74m wide and will displace around 600,000 tonnes of water. It will be the largest floating offshore facility in the world.

Over 1.6 million man hours were worked for the Front End Engineering and Design (FEED) phase of development for the Prelude FLNG Project.

It will be the largest floating structure ever built and will be permanently moored about 200km from the coast during its 25 years of production.

The vessel, to be built by South Korea's Samsung Heavy Industries, will be six times heavier than the world's biggest aircraft carrier and designed to withstand severe category 5 cyclones.

Prelude is expected to produce 3.6 million tonnes per annum of LNG, and 1.3 million tons of gas condensate a year.

Once operational, the Prelude FLNG facility will produce at least 5.3 million tonnes per annum (mtpa) of liquids: 3.6 mtpa of LNG, 1.3 mtpa of condensate (equivalent to 35,000 bbl/d) and 0.4 mtpa of LPG.

Shell plans to spend between $30bn and $50bn on Australian LNG projects over the next decade.

Topsides weight is estimated in excess of 50,000 tonnes. Shell’s FLNG design is suitable for more distant offshore fields, designed to operate under harsh conditions and process a wide range of gas compositions.
 

Technology

The floating facility will chill natural gas produced at the field to –162°C, shrinking its volume by 600 times so it can be shipped to customers in other parts of the world. Ocean-going carriers will load the LNG as well as other liquid by-products (condensate and LPG) for delivery to market.

The Prelude FLNG facility will be built at Samsung Heavy Industries’ Geoje Island ship yards in South Korea. The Samsung ship yard is one of the few yards in the world big enough to construct a facility of this size.

Once constructed, the facility will be towed to its location, approximately 475 kilometres north-northeast of Broome, Western Australia. The facility will be moored and hooked up to the undersea infrastructure and the whole production system commissioned.

The Prelude FLNG facility has been designed to withstand the most powerful tropical cyclones. It will remain permanently moored at the location for around 25 years before needing to dock for inspection and overhaul.
The LNG, LPG and condensate produced will be stored in tanks in the hull of the facility. LNG and LPG carriers will moor alongside to offload the products.

  

Key facts

Location:	Browse Basin, Australia
Depth:	~250 meters
Category:	Floating liquefied natural gas
Interest:	Shell 100%
Fields:	Prelude and potentially other Shell natural gas assets in the region
FLNG facility production capacity:	At least 5.3 million tonnes per annum (mtpa) of liquids: 3.6 mtpa of LNG, 1.3 mtpa of condensate and 0.4 mtpa of LPG
Key contractors:	Technip/Samsung Heavy Industries consortium