The Gorgon expansion project aims at maintaining the 15.6 Mtpa of LNG production. Image courtesy of Chevron.
Gorgon phase two expansion project includes the infill development of seven new production wells in the Gorgon field and four new production wells in the Jansz-Io field. Image courtesy of Chevron.

Gorgon gas project expansion encompasses the expansion of Gorgon natural gas project located on the Barrow Island, approximately 60km off the northwest coast of Western Australia.

The $5.1bn expansion project is aimed at maintaining the 15.6 million tonnes  per annum (Mtpa) liquefied natural gas (LNG) production capacity and increasing the domestic gas supply from 200 tera joules per day (Tj/d) to approximately 300Tj/d.

Developed with an estimated investment of $54bn, Gorgon produced first gas in March 2016 and has an expected operational lifespan of 40 years.

The  project comprised the development of Gorgon and Jansz-Io offshore gas fields in the Greater Gorgon area in the Barrow sub-basin of the Carnarvon Basin, and three LNG trains and a domestic gas plant on the Barrow Island.

Chevron, the project operator, holds a controlling 47.3% interest in the project, while ExxonMobil and Shell hold 25% stake each. The remaining interests are held by Osaka Gas, Tokyo Gas, and JERA.

Gorgon gas project stage two development details

Chevron announced the Gorgon stage two development plan in April 2018. The second phase of development involves additional production wells in Gorgon and Jansz-Io fields, as well as new subsea structures and offshore pipelines to maintain feed gas flow to the Barrow Island facility.

Seven new production wells will be drilled in the Gorgon field and four new production wells in the Jansz-Io field, as part of the phase two. Further, additional subsea structures and offshore pipelines will be installed to provide feed gas for the onshore processing facility at Barrow Island.

Drilling of the new production wells is expected to begin in 2019, with the entire expansion expected to be completed in 2023.

Gorgon LNG plant details

The onshore facilities for the Gorgon gas project include a 15.6Mtpa three-train LNG plant, a 300Tj/d domestic gas treatment plant, a 2.1km LNG jetty with two loading berths, and a 2.1km materials offloading facility (MOF) at Barrow Island.

The LNG plant site houses three 5.2Mtpa LNG processing trains, three acid gas removal unit trains, two 180,000m³ LNG tanks, four 38,000m³ condensate tanks, five gas turbine generators, two monoethylene glycol (MEG) processing facilities, and two inlet processing units.

Further, the LNG plant has been equipped with two CO2 compression trains and nine CO2 injection wells to inject and store CO2 at the Dupuy Formation deep reservoir unit, which is located more than 2km beneath the Barrow Island.

Domestic gas from the Barrow Island is supplied to Western Australia through a 90km-long pipeline connected to the Dampier- Bunbury natural gas pipeline.

Contractors involved with the Gorgon gas project expansion

TechnipFMC was awarded the subsea installation contract for the Gorgon phase two development in July 2018.

The scope of the contract includes project management and engineering, transportation, installation and pre-commissioning of umbilicals, flying leads and manifolds, as well as the transportation, fabrication, installation and testing of rigid spools.

Baker Hughes, a subsidiary of GE, was awarded two contracts for the supply of subsea production systems and well completion equipment for the Gorgon phase two development, in June 2018.

The scope of the subsea production systems supply contract includes the supply of subsea production trees, two eight-slot manifolds, fatigue-resistant wellheads and specialty connectors, subsea control systems and associated equipment.

The scope of the five-year well completion equipment and services contract includes coring work, liner hangers, completions and wellbore cleanup technology.