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.

Contractors involved

TSC, a consortium between Technip and Samsung Heavy Industries was awarded the front-end engineering and design (FEED) contract for the Prelude FLNG facility in March 2010.

The same consortium received notice for the engineering, procurement, and construction (EPC) of the FLNG unit in May 2011.

The Prelude FLNG vessel was constructed in Samsung Heavy Industries’ Geoje shipyard in South Korea.

Emerson was subcontracted for providing process control and monitoring technologies for the Prelude FLNG in 2011. The company was also contracted for providing automation maintenance and reliability services for the FLNG facility in September 2016.

SBM Offshore was the engineering, procurement, and construction (EPC) contractor for the turret mooring system of the FLNG.

Subsea contractors for the Prelude FLNG facility

Technip was responsible for the project management as well as the fabrication and installation of the subsea system.

Technip subcontracted Civmec for the supply, fabrication and testing services for the subsea system of the FLNG in August 2014.


In June 2011, Air Products was awarded a contract by Shell Australia to provide the LNG heat exchanger for the floating facility.

Mitsubishi Heavy Industries was awarded a contract to supply three compressor trains along with power generation system for the FLNG facility, in January 2011.

General Electric provided two steam turbine-driven compressors, whereas Kawasaki Heavy Industries provided seven boiler units for the FLNG facility.

FMC Technologies (now TechnipFMC) was contracted to supply offshore loading arms of the Prelude FLNG in May 2012.

ABB was contracted for the supply of electrical equipment for the Prelude floating LNG facility in March 2016.

Other contractors

Monadelphous Group was awarded a $200m long-term maintenance and modification service contract for the Prelude FLNG project, in November 2015.

Atkins was contracted in the same month for the inspection and maintenance integrity modules of the floating LNG facility.

POSH Terasea provided towing services for the parts of Prelude FLNG from the Samsung Shipyard in Geoje, South Korea, to the project site.

Wood Group was awarded a three-year contract for providing the integration consultancy services for the LNG facility in January 2016,

MRC Global Australia was contracted a five-year- maintenance, repair and operation service contract for the project in March 2016.

Decmil Australia, a subsidiary of Decmil Group, was awarded a $25m design and construction contract in March 2013 for the Darwin Onshore Supply Base, which was built to provide logistics support for the Prelude FLNG project.