Upstream

Key Project Components

Upstream

The Gorgon Upstream scope includes the design and construction of all wells and facilities to source gas from the Gorgon and Jansz-Io gas fields, transportation to the liquefied natural gas (LNG) plant on Barrow Island and delivery of domestic gas via a pipeline to the Western Australian mainland. It also includes the wells and facilities required for the Carbon Dioxide (CO2) Injection Project on Barrow Island. 

Work has commenced to install and tie-in the umbilicals at the Gorgon and Jansz-Io fields.

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Drilling & Completions

Eighteen high-rate, large bore development wells - eight at the Gorgon field and 10 at the Jansz-lo field - will provide the initial resource for the Gorgon Project. The project's development drilling campaign started in April 2012 with the spudding of the first Jansz-lo well by the Deepwater Frontier. 

The Gorgon wells were originally drilled by the Atwood Osprey in 2012 and perforations campaign and final well operations completed by the Ocean America drill rig in late 2014.

Drilling and completion activities also include 17 wells for the Carbon Dioxide Injection Project on Barrow Island.

Subsea Gas Gathering System

The Gorgon Project’s subsea gas gathering system is the largest ever installed in Australia. Operated from the Central Control Room on Barrow Island through subsea umbilicals, the production system is located on the ocean floor at the Gorgon and Jansz-Io gas fields.

The Jansz-Io field is located approximately 130 kilometres northwest of Barrow Island in 1,350 metres of water and will be brought onstream first. The initial subsea development is a ten well, two manifold system. The Gorgon field is located approximately 65 kilometres to the west of Barrow Island in 200 metres of water. The initial subsea development is an eight well, three manifold system. The produced gas from the wells will be gathered at several manifolds installed at each field, then transported via pipelines to Barrow Island.

All 20 main structures have been installed - some weighing in excess of 1,000 tonnes and with footprints the size of a city office building. The structures were positioned within a five metre target circle, some in water depths up to 1,350 metres using specifically developed deep water lowering system. 

The structures and pipelines are connected by 63 tie-in spool pieces. Once measurements were taken between the structures and the pipelines subsea, fabrication of the spools occured onshore. The subsea measurements were critical, with an accuracy of within a mere 50 millimetres which was a challenging task given some of the spools were in excess of 100 metres long. Due to the size and complex configuration of these spools, truss-tope spreader frames were specially built to ensure the integrity of the spool piece during lifting onshore and deployment offshore.

Subsea trees, installed at each of the fields, contain and control the production wells.

All subsea connections are completed by remote operated vehicles eliminating all diver operations.

Pipelines & Umbilicals

The Jansz-Io and Gorgon field developments are supported by a main production pipeline, monoethylene glycol (MEG) pipeline, utility pipeline and fibre optic, electro-hydraulic control umbilicals – a total of six pipelines and two umbilical casings. 

More than 800 kilometres of pipelines has been installed, including almost 200 kilometres of main production pipelines. The escarpment installation was one of the most significant challenges in the Upstream Facilities scope, creating an unsupported span of some 270 metres extending from the top of the continental shelf to the seabed in a water depth of around 750 metres.

For the crossing, the three pipelines (MEG, utility and main production line) were successfully laid into a pre-installed trench a mere eight metres wide, before continuing down the escarpment. Welding and inspection of the span section required extensive procedure development and qualification which resulted in the achievement of leading weld quality. All offshore pipelines including the corrosion resistant in-field pipelines were installed in early 2014. 

The pipelines and umbilicals come onshore on the west coast of Barrow Island. Conduits for the pipelines and umbilicals were drilled beneath the beach via horizontal directional drilling (HDD) to mimimise any environmental impacts. The HDD operation was recognised by the 2012 WA State and National Excellence Awards in the Environmental category.

All six onshore pipelines, three for each of the gas fields, have been installed across the island, from the west coast of Barrow to the east coast where they have been tied into the gas plant. Due to the limited construction footprint on Barrow Island, all 73 kilometres of onshore pipelines was installed in two trenches within a 30 metre corridor. The trenching solution also allowed the pipelines to be buried and the area restored.


 

Domestic Gas Pipeline and Meter Station

The domestic gas pipeline is now connected from the mainland through the jetty to the plant site and pre-commissioning activities are complete.

The domestic gas pipeline is now connected from the mainland through the jetty to the plant site and pre-commissioning activities are complete.

The Gorgon Project includes construction of a domestic gas plant with the capacity to supply 300 terajoules of gas per day to Western Australia. The Domestic Gas pipeline was successfully tied in to the Dampier to Bunbury Natural Gas Pipeline (DBNGP) Inlet Facility in 2013, after more than 7,400 welds were completed. 

Starting from the jetty at Barrow Island, 59.4 kilometres of pipeline was installed offshore and a further 31.8 kilometres installed within the intertidal zone and terrestrial section to the Domestic Gas Meter Station, then continuing to the tie-in at the DBNGP Inlet Facility. The Meter Station, located approximately 150 kilometres south of Karratha, reached mechanical completion in November 2013. 


Carbon Dioxide Injection Project

Carbon Dioxide ( CO2) removal and compression facilities will be located at the LNG plant site. Once the reservoir CO2 has been compressed, it will be transported by underground pipeline to one of three drill centres where it will be injected into the Dupuy Formation, approximately 2.5 kilometres beneath Barrow Island. 

The first  CO2 injection well was spudded on Barrow Island, in late 2013. Eight of the nine  CO2 injection wells and two reservoir surveillance wells have been drilled on Barrow Island.

The Gorgon Joint Venture Participants are investing around $2 billion in the design and construction of the CO2 Project. The Australian Government has committed $60 million as part of the Low Emissions Technology Demonstration Fund.