What is Prelude?

The Prelude FLNG facility is 488m long and 74m wide. It has been designed to remain moored in the field for at least 25 years.

The technical components of Prelude’s subsea infrastructure

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The technical components of Prelude’s subsea infrastructure.
Detail 1

Anchor chains

The Prelude FLNG facility is connected to a series of anchor chains which secure the facility to the seafloor.

Detail 2

Flexible risers and flowlines

There are four, 12-inch flexible risers below the Prelude facility. LNG Products are transferred to Prelude by four 12-inch flowlines.

Detail 3

Subsea system hardware

The subsea system is made up of hardware that includes wellheads, subsea Christmas trees, production manifolds and a riser-based manifold.

Detail 4

Umbilical

The steel tube umbilical provides power and hydraulics to control the subsea system hardware. 

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What happens at Prelude?

LNG is made by taking water and other impurities out of the gas and cooling it to minus 165 Celsius. Condensate is also produced during the process, which is a light hydrocarbon, somewhat like diesel.

After processing, the gas is transferred onto carrier vessels and transported to customers throughout the world.

Prelude is supported by three infield support vessels, which provide security surveillance, emergency standby and product transfer support. Other multi-purpose supply vessels provide additional transport and logistical support, out of Darwin.

The offshore infrastructure is supported by onshore servicing. The helicopters which transfer personnel to and from Prelude are refuelled at the Djarindjin Airport, which is Aboriginal owned and employs local people.

Prelude has an onshore supply base located in Darwin, Northern Territory, which houses equipment and spare parts.

Shutdowns for maintenance are expected to be needed every four years. Underwater equipment is designed to require minimal maintenance and is inspected regularly.

Where is Prelude?

Prelude is located approximately 475km north-east of Broome, Western Australia, in the Browse Basin.

Prelude’s safety zone extends in a 1.5km radius around the facility.
  

What is an Environment Plan?

An Environment Plan, or EP, outlines all the environmental impacts and risks of an activity and how these are managed to minimise risks to the environment. It is required by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) for approval (acceptance), prior to starting an offshore oil and gas activity.

Shell is submitting a revised EP to update NOPSEMA with the latest information collected since activities started in 2017. Prelude began production in December 2018 and offloaded the first LNG cargo in June 2019.

Why is Shell updating the Prelude EP?

NOPSEMA requires all EPs extending longer than five years to be revised. Since the existing Prelude EP was accepted by NOPSEMA in late 2016, Shell has gathered new learnings through the operation of the facility and developed an improved understanding of the local environment. The revised EP will assist our ongoing management of environmental impacts.

Learn more about Prelude

Physical Presence

Find out more about Prelude’s physical infrastructure.

Local Environment

Review a description of the environment surrounding Prelude.

The Crux Project

The Crux project forms an important part of Shell Australia’s gas portfolio, identified as the primary source of backfill gas supply to the Prelude FLNG facility.