The Orbost gas processing plant, previously known as the Patricia-Baleen gas plant, on the coast of the Bass Strait in south-east Australia, is undergoing upgrade and modification to handle raw gas from the Sole offshore field in the Gippsland Basin.
Owned and operated by APA Group, the Orbost gas plant started receiving gas from the sole field in March 2020 and was in the final phase of commissioning as of May 2020.
The plant operated at a capacity of 28 terajoules (TJ) of gas a day in May 2020. At full capacity, the onshore gas plant will be capable of delivering up to 68TJ of gas a day into the Eastern Gas Pipeline that runs for approximately 797km along the east coast between Victoria and New South Wales.
APA Group acquired the plant from Cooper Energy, the owner and operator of the Sole gas field, in November 2017, and invested approximately £145m ($192m) on the plant upgrade.
Construction works for the Orbost gas plant were started in April 2018, while the commissioning and start-up programme was initiated in August 2019.
The Orbost gas processing plant occupies approximately 5.2ha on the east Gippsland coast near Corringle in Victoria, approximately 375km east of Melbourne, Australia.
The plant site is located near Newmerella, approximately 10km south of Orbost.
The Orbost gas plant upgrade
The upgraded Orbost gas plant is intended to remove mercury and hydrogen sulphide from the raw gas output of the Sole gas field.
The plant upgrade involves the installation of four containerised gas engines of 1.498MW capacity each, a new hydrogen sulphide treatment facility, a thermal oxidiser and bioreactor tanks. The flare facilities of the plant were also relocated as part of the project.
The project also included upgrades and modifications to the subsea control interfaces, inlet metering and quality monitoring, inlet separation, and dew point control units.
The processed gas from the plant is transported through a 12km-long export pipeline connecting the Eastern Gas Pipeline.
Sole offshore gas field
The Sole gas field located offshore in the eastern Bass Strait approximately 65km away from the Orbost plant was originally discovered by Shell in 1972.
Currently owned and operated by Cooper Energy, the gas field produced its first gas in March 2020.
The offshore field is estimated to hold 245 petajoules (PJ) of proved and probable gas reserves. The Sole gas field development comprises two subsea production wells and is expected to produce 25PJ of gas annually over an estimated initial operational life of eight years.
The raw gas from the Sole gas field is transported to the Orbost gas processing plant through a 65km-long, 12in-diameter sub-sea pipeline.
The plant can also process gas from Cooper Energy’s undeveloped Manta gas field as well as from other gas fields in the Gippsland Basin in future.
Orbost gas plant history
The Orbost gas processing plant, earlier known as Patricia-Baleen gas plant, was originally built by Austrian company OMV. It was commissioned in 2003 to process gas from the now-depleted Patricia-Baleen gas field. The plant was upgraded in 2009 to process gas from Nexus Energy’s Longtom field.
The plant was placed in care and maintenance following the suspension of production in Longtom field in May 2015.
Santos had acquired OMV’s Gippsland assets in 2005, and subsequently sold its 50% stake in both the Sole gas field and the Orbost gas plant to Cooper Energy in October 2016. Cooper Energy sold the gas plant to APA Group
Contracts awarded for Orbost plant upgrade
Clarke Energy was awarded a contract for the engineering, design and supply of four gas engines of 1.498MW capacity each. INNIO’s Jenbacher 420 containerised gas engines were selected for the Orbost gas plant upgrade project. Private equity firm Advent International acquired General Electric’s distributed power business and rebranded as INNIO in November 2018.
Downer bagged a £36m ($51m) contract to provide construction services for the project in April 2018.
The local companies GEM Industrial, BMC Group, Whelans Group Investments, and GBG Concrete and Construction were awarded contracts in the early construction stage of the project.