The Petrel Field Development is an envisaged offshore gas development that seeks to bring into production an undeveloped gas discovery in northern Australian waters. The Petrel field, discovered in 1969, has remained undeveloped to date.
As proposed by Eni Australia, via its subsidiary Eni Energy Bonaparte, the development would supply gas on a long-term basis, potentially replacing supply from the ageing Blacktip field and serving domestic energy demand in the Northern Territory.
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The project is significant in regional energy planning, given the need for reliable gas supply proposals and Australia’s continued focus on utilising existing infrastructure to optimise environmental and economic efficiency.
Project Location
Petrel lies within two adjacent Commonwealth retention leases, NT / RL1 and WA-6-R, located offshore in the Joseph Bonaparte Gulf.
The field is located approximately 250km west of Darwin in water depths of around 92m to 102m, with its closest points roughly 136km from the Northern Territory shoreline near Wadeye and about 145km from the Western Australian coast.
The precise boundaries and operational area are yet to be finalised and will depend on forthcoming surveys and engineering design.
Reserves and Infrastructure Details
The Petrel field reservoir contains an estimated 970 billion cubic feet (bcf) of gas and 5.9 million barrels of condensate.
Eni forecasts a potential operating life of the Petrel development of around 20 to 30 years. Infrastructure under consideration includes an offshore platform, gas export pipeline and associated subsea equipment, as well as tie-in facilities.
The preferred concept presently under evaluation would involve routing Petrel gas into the existing Blacktip gas export pipeline, which transports gas to the Yelcherr Gas Plant (YGP).
Gas would be treated at YGP and subsequently supplied to domestic markets in the Northern Territory. Alternative development options under evaluation include constructing a direct pipeline from Petrel to YGP or to a new onshore gas processing facility near Darwin.
Development and Timeline
Eni’s planning studies for Petrel are underway; however, the project remains in the preliminary stages.
Key development milestones include the preparation and submission of an Offshore Project Proposal (OPP) to NOPSEMA, which must be accepted before any activity, including surveys, drilling or infrastructure installation, can commence.
Following OPP acceptance, detailed environment plans (EPs) for specific activities will be developed and submitted for review and approval.
The OPP covers entire phases of the project, including geotechnical and geophysical surveys, drilling of two initial production wells (with potential for up to eight more in future campaigns), installation of offshore infrastructure, operations, and eventual decommissioning at end of field life.
Additional preparatory work, such as decommissioning of the suspended Petrel-3 and Petrel-4 appraisal wells, is already under way; that EP was submitted to NOPSEMA in October 2024.
Final investment decision (FID), equipment availability, regulatory approvals and weather conditions will all influence the timeline.
Financing and Ownership
The Petrel field is held within two retention leases jointly held by Eni via its subsidiary Eni Energy Bonaparte Pty Ltd. Eni acquired its interest in these leases following its 2024 acquisition of Neptune Energy’s assets in Australia.
Eni operates the Blacktip gas field, situated about 100km south of Petrel, along with the related offshore gas infrastructure and the Yelcherr Gas Plant (YGP) that provides gas to the Northern Territory’s domestic market.
Additionally, the company possesses two offshore retention leases that encompass the undeveloped gas discoveries of Verus and Blackwood, located approximately 330km north of Darwin.
Technological Details
Though the project is at planning stage, technological approaches draw on industry-standard methods. Proposed activities include geotechnical and geophysical surveys to define the subsurface and seabed conditions, followed by drilling of production wells.
The infrastructure envisioned encompasses an offshore platform, gas export pipeline and subsea hardware. Innovative aspects under evaluation include leveraging existing infrastructure (the Blacktip export pipeline and Yelcherr Gas Plant), offering economies of scale and reduced environmental footprint.
Environmental modelling, including spill risk and hydrocarbon spill footprint modelling, has been performed to define the Environmental Management Boundary Area (EMBA) and Zone of Potential Impact (ZPI). These measures inform spill response preparedness and environmental risk management.
