Shell's Prelude FLNG Project, Browse Basin, Australia

The Prelude floating liquefied natural gas (FLNG) project will mark the deployment of Shell's FLNG technology for the first time. The project includes the construction of an FLNG facility, which will be used to develop Shell's Prelude and Concerto gas fields, situated in the Browse Basin, off the shore of Western Australia.

The Prelude and Concerto fields lie in the WA-371-P permit, at water depths of 250m. The first gas is expected in 2016. A $5bn investment will be made in the project.

The project was previously 100% owned by Shell. INPEX and Korea Gas Corporation respectively acquired 17.5% and 10% stakes in the project in 2012. CPC Corporation also holds a stake of 5% in the project. The remaining 67.5% stake is currently owned by Shell.

The Prelude project was approved by the Australian Government in November 2010. Shell made its final investment decision on the project in May 2011. Construction on the FLNG facility began in 2012.

Prelude discoveries

The Prelude field was discovered by the Prelude-1 exploration well in 2007. The Concerto field was discovered in March 2009 by the Concerto-1 well.

The combined reserves of the Prelude and Concerto gas fields are estimated at three trillion cubic feet.

Natural gas field development

"The Prelude project was approved by the Australian Government in November 2010."

Development drilling at the fields began in 2013. The first well was realised in December 2014. Approximately eight production wells are expected to be drilled. Installation of two Christmas trees was completed in late 2014. The FLNG facility is expected to be installed and commissioned in 2016.

Developing these fields through conventional methods was considered uneconomical due to their small size and remote location, so FLNG technology will be used.

Shell is continuing to explore the area under the WA-371-P permit. Other fields discovered in the area are also expected to be developed using the new facility.

The fields are expected to produce 5.3 million tonne a year (Mt/y) of liquids and condensate, including 3.6Mt/y of LNG, 1.3Mt/y of condensate and 400,000t/y of liquefied petroleum gas.

The field infrastructure will include six LNG storage tanks with a total capacity of 220,000m³. Upstream facilities will include seven wells, four flowlines, umbilicals and flexible risers.

FLNG facility

The Prelude FLNG facility will feature a double-hulled steel body. It will be 488m-long, 74m-wide, and weigh approximately 600,000t. It will comprise 0.26t of steel with a deck area longer than four football fields. The facility will be the biggest ever to be built in the world. It will feature gas receiving and processing facilities, control rooms, accommodation and storage facilities.

The design of the FLNG facility will enable it to withstand extreme weather conditions, including a category 5 cyclone. It will be permanently moored 200km offshore at the Prelude field at a depth of 250m. It will be moored for 25 years using four groups of mooring chains. Each mooring chain will be connected to the seabed by suction piles.

The FLNG facility will treat the gas and liquefy it to -162°C. The liquefied gas and other products will then be offloaded onto LNG carriers for distribution to markets worldwide.

"The Prelude FLNG facility is being built at the Samsung shipyard in South Korea."

The FLNG technology is considered an important milestone for the LNG industry. The technology helps in reducing costs of developing LNG projects. It assists in eliminating the need for laying pipelines for gas transport, construction of onshore LNG processing facilities, dredging and other related works.

Natural gas resources previously considered uneconomical to be developed and located far from the shore can now be developed using Shell's technology.

The technology also provides environmental benefits as it uses lesser sea bed area and eliminates the need for carrying out underwater and near shore works.

Subsea system

The project will include a subsea system comprising subsea wells, manifolds, flowlines, flexible risers and umbilicals.

Contracts for the Prelude project

The design, manufacture and commissioning of the new Prelude facility will be carried out by a consortium of Technip and Samsung Heavy Industries under a contract awarded in July 2009.

The contractual scope includes design and construction of several such FLNG facilities over a 15-year period. The Prelude FLNG facility is being constructed at the Samsung shipyard in South Korea.

Related project

Bonaparte LNG Project, Timor Sea, Australia

The Bonaparte Liquefied Natural Gas (LNG) project covers the deployment of a floating, production, storage and offloading (FPSO) LNG facility in the Bonaparte Basin in the Timor Sea, off the northern coast of Australia.

In July 2010, the consortium selected Emerson as the automation contractor for the project. The contract requires Emerson to design and deliver control and monitoring technologies for the facility.

Shell contracted FMC Technologies in June 2011 to supply subsea equipment for the project. The contract includes subsea production trees and manifolds, risers and subsea control systems.

The contract also includes an aftermarket agreement under which FMC will render installation and commissioning services. Orders associated with the aftermarket deal were awarded in late 2011.

SBM Offshore was contracted by Technip in June 2011 to engineer, procure, build and install a turret mooring system for the FLNG facility.

In June 2011, Shell contracted Air Products to supply its LNG heat exchanger for the FLNG facility.

GE Oil & Gas was contracted by Technip in September 2011 to provide two steam turbine driven compressors for the FLNG facility. The contract also involves commissioning and two years of training, operation and supply of spare components.

Technip awarded a contract to Kawasaki Heavy Industries in September 2011 to provide seven boiler units for installation on the FLNG facility. The boilers will be used to generate power and process LNG.

Mitsubishi Heavy Industries Compressor Corporation (MCO) was contracted to supply three compressor trains and a power generation system for the FLNG project, in January 2012.

In May 2012, Technip France awarded a contract to FMC Technologies to receive offshore loading arm systems for the project. FMC's Loading Systems business in Sens, France is the designer and manufacturer of the equipment.

Shell awarded the subsea installation contract for Prelude LNG project to Technip in June 2012. The scope of the contract mainly includes project management and fabrication services.

WoodGroup received a $10m contract to provide a computerised maintenance management system for the FLNG project in August 2012.

Decmil Group secured a $25m contract to design and construct Darwin Onshore Supply Base for the LNG Facility, in March 2013.

In January 2014, Emerson Network Power was contracted to supply the main uninterruptible power supply (UPS) systems for the Prelude FLNG project.

KT Maritime secured a contract from Shell in February 2014 to supply three infield support vessels (ISVs) for the Prelude project.

Civmec was contracted by Technip in August 2014 for the supply, fabrication and testing of subsea components for the Prelude development.

In April 2015, ASCO Group secured a logistics and supply base management contract for Shell's FLNG facility.

In November 2015, Monadelphous was contracted to provide maintenance, brownfield modifications and turnaround services to the Prelude FLNG project.

Atkins was contracted to develop asset integrity models for future inspection and maintenance at the Prelude FLNG offshore facility, in November 2015.

POSH Terasea was contracted to provide towage and positioning services for the FLNG platform, in January 2016.

In January 2016, Shell placed a contract with Wood Group for specialist consultancy services for the Prelude FLNG project.

ABB received a five-year contract to deliver equipment and services to the FLNG facility. The scope of contract includes supply of motors, generators, variable speed drives and low-voltage switchgear, as well as lifecycle management of the electrical equipment.

MRC Global Australia was contracted to provide maintenance, repair and operations (MRO) requirements for the FLNG project.

DOF Subsea secured a five-year contract to provide a full-time underwater services and multipurpose supply vessel (MPSV) to the FLNG facility.

Emerson was contracted to deliver automation maintenance and reliability services for the Prelude FLNG project, in September 2016.