Downstream

The Gas Processing Facility

Downstream

The Downstream scope on Barrow Island includes the design and construction of a three-train, 15.6 million tonne per annum liquefied natural gas (LNG) facility and a domestic gas plant with the capacity to provide 300 terajoules of gas per day to Western Australia. It also includes the materials offloading facility, LNG jetty and operations and accommodation facilities.

Both LNG Tanks are now ready for LNG.

The offshore gas facilities will be connected to the gas treatment plant site via a 12.5 kilometre feed gas pipeline and other associated pipelines that will traverse from the west coast to the east coast of Barrow Island.

Components of the Downstream scope include:

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LNG Plant Site

The plant site includes three, 5.2 million tonnes per annum processing trains. A total of 51 process modules, weighing more than 200,000 tonnes make up the main components of the three trains. The first module – the knock-out flare drum (SANA) – was delivered in September 2012. The final module required for Train 1 – the liquefaction module (TADA) was delivered in June 2014. TADA is the heaviest required for the Project’s first processing train, weighing 6,300 tonnes – equal to the weight of more than 2,500 average size cars.

There are a total of 236 pre-assembled rack (PARs) modules which act as the main “artery” of the LNG plant, which will carry gas from one process unit to another during operations. The first PAR arrived in June 2012. 

There are two LNG storage tanks, each with a capacity of 180,000 cubic metres or the equivalent to 72 Olympic size swimming pools. The first tank received “Ready for LNG” status in October 2014, followed by the second tank in January 2015. There are four condensate tanks, each with a capacity of 38,000 cubic metres. Construction has been completed on three of the four tanks. 

The project has two Monoethylene glycol (MEG) processing facilities on the plant site – one for the Jansz-Io field and the other for the Gorgon field. MEG will play a critical role in the transportation of the gas from the fields to the plant, acting like antifreeze to absorb water and prevent hydrates from forming. Each facility includes four storage tanks – two rich MEG tanks and two lean MEG tanks which will enable MEG to be regenerated and re-used in a continuous cycle. Hydrotesting activities on the four monoethylene glycol (MEG) tanks required for Train 1 start-up were completed in May 2015. 

Five gas turbine generators (GTG) will be used to power the LNG plant and associated facilities. In April 2015, the Project started-up the first GTG using domestic gas introduced from the Dampier to Bunbury Natural Gas Pipeline via Gorgon’s domestic gas pipeline. Once Gorgon is operational, the five GTGs will have the capacity to provide 584 megawatts of electricity – almost as much as the Kwinana Power Station which supplies much of the greater Perth area.

In early 2015, the ground flare required for the introduction of commissioning fuel gas became operational. Connected to the plant site by PARs, the Project’s ground flare consists of four flare boxes approximately 150 metres long, 75 metres wide with 14 metre high walls. The selection of a ground flare over an elevated vertical flare stack helps minimise environmental impacts by reducing light emissions due to the lower profile and height of the walls. 

Marine Facilities

The jetty is complete – except for the loading arm installation.

An 18-month dredging program encompassed the removal of 7.6 million cubic metres of material to create an approach channel, turning basin and berth pockets to provide safe shipping access to the 2.1 kilometre Materials Offloading Facility (MOF) and LNG jetty facilities. The MOF became operational to large vessels in late 2011 and was fully completed by the end of 2012. 

The project’s 2.1 kilometre jetty consists of steel trusses 70 metres in length, supported by 56 gravity-based concrete structures, known as caissons, leading to the two loading platforms. All 56 jetty caissons were installed by late 2013.

The two LNG loading platforms have been installed. The platforms are standalone modules that include piping and equipment and will be used to load LNG on to vessels when the plant is operational. Each platform weighs about 530 tonnes - about the equivalent of an Airbus A380 aircraft.

Adjacent to the jetty head, a facilities equipment room, substation and workshop have been installed on the Marine Operations Platform. The substation will provide power to equipment on the jetty, including the LNG loading arms. Thirty five roadways provide vehicle access along the jetty. The longest and heaviest roadway is more than 91 metres long and weighs more than 680 tonnes. 

Building and Services

Completion of site preparation work allowed construction to start on the Permanent Operations Facility (POF) in 2012. The POF includes an operations centre, workshop, warehouse, laboratory and fire station. Once complete, the POF will become the nerve centre of the LNG plant.

In early 2014, all equipment and instrument control systems required to control the plant during operations was fitted in the Central Control Room (CCR) within the operations centre at the POF. The CCR will be used to oversee all aspects of plant operation, including the gas treatment and liquefaction process. In January 2015, the first team members of the Operations team commenced commissioning and monitoring systems in the CCR. 

Butler Park is the Gorgon Project’s workforce accommodation village on Barrow Island. Completed at the end of 2012, it accommodates around 4,000 people in Grade 5 cyclone rated, shelter-in-place facilities. The accommodation village currently houses the construction workforce, but will also house the operations and shutdown/turnaround workforce once the plant is operational. Facilities included within the park include -

• Single person, air conditioned accommodation units, each with an en-suite bathroom, TV and telephone. 
• Medical Centre. 
• Kitchen/dining rooms. 
• Wet mess and barbeque areas. 
• Fully equipped gymnasium and outdoor recreational facilities, including multifunction sports facilities and swimming pools. 

The accommodation village at Barrow Island was named in honour of conservationist and environmental consultant Dr Harry Butler, recognising his contribution to conservation management, particularly on Barrow Island.