Balnaves is an offshore oil field located in Exploration Permit area WA-356-P, approximately 134km south-east of Mardie Station, in the Pilbara region of Western Australia.
The field is situated at a water depth of 135m, in the northern Carnarvon Basin, roughly 180km off the Western Australian coast.
The $438m Balnaves development project is operated and managed by Apache Julimar, a wholly-owned Australian subsidiary of the Apache Corporation, an oil and gas exploration and production company based in the US.
Apache Julimar’s working interest in the project was 65%. The remaining 35% stake is owned by the Kuwait Foreign Petroleum Exploration Company (KUFPEC).
Woodside Petroleum acquired Apache’s interest in the project in June 2014 in a deal that also included the acquisition of Wheatstone and Kitimat LNG projects.
The final investment decision for the offshore project was revealed by the two partners in late September 2011.
All contracts required for the development of the field were placed by June 2012. First oil from the Balnaves field was produced in August 2014. The net production from the field was 18,300 barrels (bbl) of oil equivalent a day as of October 2014.
Recoverable reserves and production
The field is estimated to hold gross recoverable reserves of up to 17 million barrels of oil and 30 billion cubic feet of gas.
The Balnaves FPSO has been producing at an average 30,000bbl a day since August 2014 and is expected to continue producing until 2018.
Discovery of the Balnaves oil field
The Balnaves field was discovered by Apache in May 2009. The Balnaves-1 discovery well was drilled by Stena Clyde, a self-propelled, semi-submersible drilling unit, when she was undertaking exploration and appraisal drilling in the Julimar-Brunello fields.
Balnaves-1 discovered light, sweet oil accumulated in a separate reservoir belonging to the Triassic Mungaroo formation, which overlies the Locker Shale. The well was drilled to a total depth of 3,261m and encountered 20m of net oil pay in the Mungaroo B20 sand.
The deliverability of the field was confirmed by Balnaves-2 and Balnaves-3 appraisal wells. The Balnaves Deep-1, drilled in March 2011, further delineated the field.
Balnaves-2 was drilled as a sidetrack to Balnaves-1. Balnaves-3, which was drilled in 2010, flowed at the rate of 9,076bbl of oil and 13 million cubic feet of gas a day during flow testing. Balnaves-4 was drilled as a sidetrack to Balnaves-3.
Balnaves Deep-2 and Balnaves Deep-3 appraisal wells were drilled by the Atwood Falcon semi-submersible drilling rig.
Balnaves offshore development and infrastructure
The development of the field comprised a subsea manifold, two production wells, one gas injection well and one water injection well tied back to an FPSO that processes liquids from the field.
The manifold is tied back to the Armada Claire floating production storage and offloading (FPSO) vessel featuring a disconnectable riser turret mooring (RTM) system.
Oil recovered from the production wells is first sent to the manifold, from where it is carried further to the FPSO via flexible pipelines and risers for separation, treatment and storage.
Produced water and gas are re-injected into the reservoir. Re-injected gas may be recovered in the future.
Armada Claire FPSO vessel processing capacity
Armada Claire is a double-hulled FPSO vessel owned by Bumi Armada. It was modified and upgraded in Singapore and, upon completion in late 2013, has been available for processing 80,000bbl of oil and 50 million cubic feet of natural gas a day.
It has a storage capacity of 750,000bbl and a reinjection capacity of 60,000bbl of water a day.
Contracts awarded for the Australian field
In September 2011, Bumi Armada was commissioned to supply and operate its Armada Claire vessel for a fixed period of four years.
The contract was worth approximately $478m (1.46bn Ringgit) and included an option for a four-year extension on an annual basis.
The FPSO was modified and upgraded by Keppel Shipyard as part of a contract given by Bumi Armada in April 2012.
Subsea installation work for the Balnaves project was undertaken by Technip under a $63m contract announced in July 2012. According to the contract, Technip provided project management, design, engineering and installation of 7km of flexible flowlines and risers, 3km of umbilicals; manifolds, spools, flying leads and jumpers, and a mooring system and riser column.
Subsea installation was carried out by Technip’s Deep Orient multipurpose installation and construction vessel.
West Coast Pilots provided marine pilotage services and marine consultancy advice for the Balnaves project.