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Oil & gas

Behind Shell Prelude, the world’s largest floating offshore facility.

Classification, certification, verification and validation across multiple contractors

Key facts

  • 01.


    Shell Australia (operator) and contractors: Technip (France), Samsung Heavy Industries (Korea) and Single Buoy Moorings (Monaco)

  • 02.


    Floating liquefied natural gas (FLNG) unit

  • 03.


    Global construction for operation offshore northwest Australia

Project background

Compliance_-_Classification_certification_and_verification_-_Shell_Prelude_-_4746x1622Shell Prelude is the largest floating offshore facility in the world, at 488m long, 74m wide and displacing about 600,000 tonnes of water. Construction requires some 260,000 tonnes of steel, with Prelude’s turret the largest ever built. The asset will be moored at a depth of 250m for 25 years without dry docking, in the Browse Basin, offshore northwest Australia. Prelude has been designed to withstand category five cyclones and its technology has generated over 150 patents.

  • Production capacity: 5.3 million tonnes per annum (mtpa): 3.6 mtpa LNG, 1.3 mtpa condensate, 0.4 mtpa LPG (propane, ethane, butane).
  • LNG chilled to -162oC, shrinking volume 600-fold.


How we helped

Our services to Prelude include:

  • classification of the substructure (hull) and turret
  • certification of the topsides, turret and equipment against project and international codes and standards; we expect to issue at least 924 certificates covering in excess of 1,100 tagged item
  • verification and validation of the overall unit against performance standards within a safety case regime.

Our support was delivered globally across multiple contracts, including:

  • Technip France (Paris) for topsides design appraisal and construction and commissioning surveys in Korea
  • Samsung Heavy Industries (Geoje, Korea) for substructure design appraisal and survey
  • Shell Australia for validation of the overall unit and of the subsea and risers (involving Shell and FMC in Malaysia)
  • Single Buoy Moorings for turret design appraisal (Monaco) and construction surveys (Dubai)
  • multiple vendors in Europe, Asia and North America for classification and certification of equipment packages.


A workforce of more than 5,000 are helping to build the world’s largest floating offshore facility, Prelude FLNG, at South Korea’s Geoje shipyard for the energy multinational Shell.

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