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Petrel-3 and Petrel-4 Decommissioning

Discovered in 1969, the Petrel-3 and Petrel-4 wells were drilled in the 1980s. The wells were suspended in accordance with the regulations at the time, with barriers across and above the reservoir, including the testing of the barriers.

Eni plans to decommission these wells according to Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2023 (Cth) (Environment Regulations) and have submitted a five year Environment Plan for Monitoring and Decommissioning to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA).

The submitted EP details the required activities for the decommissioning of Petrel-3 and Petrel-4.

These activities include:

  • General Video Inspection – annual visual survey of the two suspended wells
  • Geotechnical Survey
  • Geophysical Survey
  • Pre-abandonment Vessel Campaign
  • Decommissioning (plug and abandonment) of Petrel-3 and Petrel-4
  • As-left Survey

Timeline

The Monitoring and Decommissioning Environment Plan (EP) will cover a period of five years from the date of regulator approval. 

The first activity – General Video Inspection (GVI) – is anticipated to be conducted in Q4 2025 and may be included in the geophysical and geotechnical surveys.

Planning for the GVI and subsequent activities will be subject to vessel and rig availability and weather conditions.

Consultation opened on 19 June 2024 and concludes on 28 August 2024.

Activity Resources

Activity Flyer
PDF / 766 KB
EP Under Assessment
EP Under Assessment

Environment

Petrel-3 & Petrel-4 Decommissioning 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 may be representative of an area of biological impact from hydrocarbons. The outermost boundary of the EMBA is based on an accidental release of marine diesel oil (MDO) to the environment in the unlikely event of a vessel collision damaging a fuel tank. 

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

Oil Spill Modelling Video
Oil Spill Modelling Environment Bulletin
Petrel EMBA

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:

  • description of the activity
  • description of the existing environment (natural, cultural and social)
  • environmental risk assessment
  • environmental management measures and commitments
  • details of the titleholder and other information specified the OPGGS Environment Regulations.
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.

Contact us

Contact Eni

Email
Address
  • Eni House 226 Adelaide Terrace Perth WA 6000 
  • PO Box 6862 East Perth WA 6892
Phone
Register your interest in engagement with Eni for the Petrel field development or the Petrel-3 and Petrel-4 Decommissioning and a representative will contact you accordingly.

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.