Prelude floating liquefied natural gas (FLNG) project located in the Browse Basin offshore Western Australia represents the world’s biggest FLNG facility.
Operated by Shell Australia, the Prelude FLNG commenced production in December 2018.
The $14bn FLNG project is jointly owned and developed by Shell (67.5%), Inpex (17.5%), Korea Gas Corporation (KOGAS, 10%), and CPC (5%).
The FLNG facility has the capacity to produce 5.3 million tonnes of liquids and condensate a year (Mtpa), including 3.6Mtpa of LNG, 1.3Mtpa of condensate, and 0.4Mtpa of liquefied petroleum gas (LPG).
Prelude FLNG project development background
The Prelude FLNG project is based on the gas production from the Prelude and Concerto gas fields located in the Browse Basin, approximately 475km north-northeast of Broome. The offshore gas fields are together estimated to hold three trillion cubic feet (tcf) of hydrocarbon reserves.
The Prelude and Concerto gas fields were discovered in 2007. The Australian government approved the development of the Prelude gas field in November 2010.
Final investment decision (FID) on the project was made by the development partners in May 2011. Construction on the project was started in October 2012.
Prelude FLNG design details
Moored at a water depth of 250m, the Prelude FLNG facility is a double-hulled steel structure measuring 488m-long and 74m-wide. The vessel weighs approximately 600,000t and is capable of producing 110,000 barrels of oil equivalent (boe) a day.
The subsea system for the Prelude FLNG involves 14 subsea risers and six umbilicals.
The FLNG vessel houses three LNG processing trains to treat the gas and liquefy it to -162°C. It also features seven offshore footless marine loading arms, including four LNG loading arms and three liquefied petroleum gas (LPG) loading arms.
The LNG, LPG, and condensates produced at the FLNG facility are directly loaded into tankers for shipping.
The Prelude FLNG unit is moored with four sets of mooring chains that are connected to the seabed by suction piles.
The estimated operational life of the Prelude FLNG is 25 years.
Prelude FLNG in numbers:
- >600 engineers worked on the facility’s design options
- >200km (125 miles) is the distance from the Prelude field to the nearest land
- 4 soccer fields, laid end to end, would be shorter than the facility’s deck
- 175 Olympic-sized swimming pools could hold the same amount of liquid as the facility’s storage tanks
- 6,700 horsepower thrusters will be used to position the facility
- 50 million litres of cold water will be drawn from the ocean every hour to help cool the natural gas
- 6 of the largest aircraft carriers would displace the same amount of water as the facility
- 93 metres (305 feet) is the height of the turret that runs through the facility, secured to the seabed by mooring lines
- -162° Celsius (-260° Fahrenheit) is the temperature at which natural gas turns into LNG
- 1/600 is the factor by which a volume of natural gas shrinks when it is turned into LNG
- 117% of Hong Kong’s annual natural gas demand could be met by the facility’s annual LNG production
- 20-25 years is the time the Prelude FLNG facility will stay at the location to develop gas fields
