Activity

Petrel Exploration

Eni, through its subsidiary Eni Energy Bonaparte Pty Ltd, is the titleholder of the Petrel Gas Field (Petrel) in the Bonaparte Basin in North Western Australia. The Petrel field, discovered in 1969, is located across two retention leases, NT/RL1 and WA-6-R, ~240km west of Darwin.

Eni is proposing to undertake exploration drilling within the Petrel retention leases in the Bonaparte Basin to support potential future Petrel exploration and development activities. 

Eni proposes drilling between one to four exploration and/or appraisal wells over several campaigns, with the initial well forecast from mid-2028 in a single-well campaign.

Up to three additional wells may be drilled, either individually or in campaigns of multiple wells, within the remaining five-year validity of the EP. The timing of these subsequent activities has not been finalised.

Timeline

The Petrel Exploration Environment Plan will cover a period of five years from approval. 

The initial well campaign is proposed for Q3 2028.     

Up to three subsequent wells may be undertaken at any time during the remainder of the EP validity period, in either single or multi-well campaigns.

Consultation opened on 31 August and will conclude on 12 October 2026.

Activity Resources

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Environment

Petrel Exploration EMBA

The Environment That May Be Affected (EMBA) is derived from scientific modelling of multiple, plausible hydrocarbon spill events. This analysis combines hundreds of modelling simulations during a range of wind and current conditions and informs the risk assessment and spill response planning.

The final EMBA map is the outermost boundary of all the events considered. The actual footprint of any single possible event is expected to be much smaller.

The zone of potential impact (ZPI) or moderate exposure zone is smaller than the EMBA and represents the area where biological impacts may occur due to hydrocarbons released to the environment in the event of a vessel collision. The outermost boundary of the EMBA is based on the combined modelling outputs of two separate and highly unlikely hydrocarbon release scenarios, including the unplanned release of marine diesel oil (MDO) resulting from a vessel collision, and the unplanned release of condensate following a loss of well control.
The loss of hydrocarbons to the environment is considered highly unlikely, and Eni implements a range of preventative measures to minimise this risk.

Refer to NOPSEMA’s news bulletin for information on oil spill modelling.

What Is An Environment Plan?

The Offshore Petroleum and Greenhouse Gas Storage Act 2006 (OPGGS Act) and associated regulations provides the legal framework for the exploration and recovery of petroleum and greenhouse gas activities in Commonwealth waters which are administered by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA).

The purpose of an Environment Plan (EP) is for the titleholder of an offshore petroleum or greenhouse gas permit, to document their case for why their Petroleum Activity or Greenhouse Gas Activity meets the objects of the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 (OPGGS Environment Regulations).

An EP is a document submitted to NOPSEMA for assessment prior to the commencement of an activity, which contains information on:

The OPGGS Environment Regulations require a titleholder to have an accepted EP in place prior to undertaking any offshore Petroleum Activity or Greenhouse Gas Activity, and require that the titleholder undertakes the activity in accordance with the EP.

Should I Be Consulted?

The activity will be assessed under the Offshore Petroleum and Greenhouse Gas Storage Act 2006 (OPGGS Act) and associated Regulations for the management of potential risks and impacts of the activity.

This process includes Eni’s assessment of stakeholders and relevant persons that have an interest in the activity.

Eni treats all information provided by you as confidential, with the exception of providing information to NOPSEMA. Eni is required to provide NOPSEMA with details of all correspondence with relevant persons, including copies of written correspondence.

Personal information (other than name and contact details) is sensitive information and will not be published in the EP. You can request that any material provided to Eni, including your name and contact details, be treated as sensitive information not to be published in the Petrel-3 and Petrel-4 Monitoring and Decommissioning Environment Plan.

Please let us know if your feedback for this activity is sensitive and we will make this known to NOPSEMA in order for this information to remain confidential to NOPSEMA.

How is an OPP different to an EP?

The OPP is submitted at the beginning of a project when a company is planning a new offshore petroleum development and provides for the consideration of whole-of-project impacts and risks.

An EP is specifically focused on managing the environmental impacts of a particular offshore activity and multiple accepted EPs may be required to permit the activities that will occur during the lifecycle of the project, from exploration through to, and including, decommissioning.

EPs for petroleum activities, submitted following the OPP process, need to remain consistent with the environmental performance outcomes as they are set out in the OPP. An accepted EP must be in place for any offshore activities associated with the OPP. Activity-specific EP’s can be submitted for assessment only after the OPP has been accepted by NOPSEMA, and activities can only commence once the relevant EP has been accepted.

What is a relevant person?

NOPSEMA identifies a relevant person as follows:
“You may be a relevant person if you or your organisation have functions, interests, or activities that may be affected by an offshore petroleum activity proposed under an environment plan being prepared or already underway under an environment plan being revised.”

The information on this website is provided to assist understanding of the proposed offshore, subsea inspection and provide comments and feedback to relevant persons that may be affected by the activity and identification of additional relevant persons as defined by the OPGGS Environment Regulations.

Feedback should be directly attributable to the proposed activity and area of operation. An approved version of the final EP will be made publicly available on this website.

Further information on relevant persons, consultation and who can participate can be found in the brochure, “Consultation on offshore petroleum environment plans; Information for the community”, NOPSEMA, May 2023.