gorgon gas development gorgon and jansz feed gas pipeline and wells operations
(including jansz-io compression)

The revised EP will include the commissioning and start-up of the SCSt and ongoing operations of the new J-IC subsea and floating infrastructure [Table 1].

The FCS will be normally unattended, with personnel onboard during periodic inspection, maintenance and repair (IMR) campaigns. Personnel will be transferred to the FCS via helicopter or a support vessel. The SCSt will be operated and monitored remotely from a control room on Barrow Island.

The routine operation of the existing Gorgon and Jansz-Io hydrocarbon systems will continue under the revised EP. Primary activities include the flow and transportation of hydrocarbon and other produced fluids from the wells to the Gorgon Gas Facility on Barrow Island, via infield flowlines and pipelines. Periodic IMR activities will be undertaken to ensure the integrity of infrastructure is maintained.

IMR activities may include:

• visual inspections – may involve the use of remotely operated vehicles (ROVs) or similar and divers and a dive support vessel
• marine surveys
• testing and measurements
• pigging (e.g. cleaning) of pipelines
• module/component change-out, stabilisation, removal of marine growth etc.

During normal operations, vessels will typically be limited to supply/support vessels and IMR vessels. The vessel size and type will be dependent on the work scope. It is anticipated vessels will operate 24 hours per day for the duration of activities.

The revised EP will cover the ongoing operation of the hydrocarbon system (production wells, pipelines, and associated infrastructure) in Commonwealth waters for the Gorgon and Jansz-Io gas fields.

IMR activities may occur at any time, with the frequency determined using a broad risk-based approach, which will include an assessment of safety, environmental and commercial risks. The duration will depend on the scope of the activities, however works will typically be completed within 10 to 200 days.

Subject to relevant approvals, J-IC operations activities, including commissioning and start-up, are expected to commence from 2026.

As part of our environmental assessment and consultation process, we create an EMBA map to provide geographical context for stakeholders to determine if their functions, interests or activities may be affected by an offshore activity during operations or in an emergency scenario.

Figure 1 shows the EMBA, which is based on a worst-case environmental scenario, which in this case is an unplanned release (oil spill) from the hydrocarbon system and/or a vessel collision. Shoreline loading refers to areas of the coast that may be impacted by hydrocarbons.

The EMBA has been defined through combining 300 simulations for each unplanned release scenario under different weather and ocean conditions. This means that in the highly unlikely event an unplanned release does occur, a geographical area much smaller than the EMBA would be affected.

The majority of the impacts or risks directly arising from activities, or from an emergency scenario, would occur within close proximity of the OA.

Chevron Australia has systematic control measures to prevent and mitigate emergencies and to reduce the impact of planned activities on the environment, including ecological, social and cultural sensitivities.

Table 2 summarises the key impacts or risks and proposed control measures to manage these to levels that are acceptable and as low as reasonably practicable (ALARP).

Chevron Australia has undertaken extensive environmental and modelling studies and considered scientific advice and government guidance (including conservation management and recovery plans) in assessing impacts and risks to marine fauna.

The SCSt will be situated at a water depth of ~1,350 m on the seabed, where operations will result in a localised change to ambient underwater sound.

Marine fauna found at the SCSt location are predominantly pelagic and deep-sea demersal fish species. Some threatened and/or migratory fish species (e.g. whale sharks, other sharks and manta rays) may be present in the area; however, these are primarily coastal species or are associated with shallower water or features (e.g. seamounts and reefs).

Biologically Important Areas (BIAs) for several marine fauna species overlap the EMBA. Additionally, the pygmy blue whale migration BIA overlaps with the SCSt location [Figure 2].

As with most offshore areas in WA, a range of other marine mammal species are known to transit the J-IC area including Antarctic minke whales, Bryde’s whales, fin whales, humpback whales, sei whales, sperm whales, killer whales and spotted bottlenose dolphins.

The closest turtle nesting habitats to J-IC are Barrow, Montebello, and Lowendal islands, over 135 km away. Similarly, shallower internesting BIAs extend a maximum of 60 km from these nesting beaches, more than 70 km from the SCSt and FCS.

The following infrastructure is subject to a 500 m radius petroleum safety exclusion zone:

• Gorgon midline pipeline termination structure
• Gorgon M1 – production manifold and wells
• Gorgon M2 – production manifold and wells
• Gorgon M3 – production manifold and wells
• Gorgon M4 – production manifold and wells
• Jansz umbilical midline connection assembly

A new 500 m radius exclusion zone will be sought for the FCS once installed.

No other exclusion zones will be sought for the subsea infrastructure.

We acknowledge that Traditional Owner groups in the northwest region of WA have identified Sea Country as an important value and expressed a deep obligation to protect songlines, dreaming stories and the marine fauna connected to them.

Chevron Australia is committed to ongoing engagement and consultation with Traditional Owners and their representative bodies. This process will continue to inform our understanding of cultural values and features and help facilitate the co-design of appropriate controls to avoid impacts.

Petroleum activities in Commonwealth waters are regulated by NOPSEMA. Before petroleum activities can take place, Chevron Australia must develop an EP which will be assessed by NOPSEMA in accordance with the requirements of the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2023 (the Regulations).

The Regulations require us to consult with relevant persons whose functions, interests and activities may be affected by the petroleum activity.

Following consultation, we will submit to NOPSEMA a revised version of the Gorgon Gas Development Gorgon and Jansz Feed Gas Pipeline and Wells Operations EP, which will:

• describe the environment in which operations, including the operation of the J-IC infrastructure, are planned to take place;
• include an assessment of environmental impacts and risks arising from those operations;
• identify control measures to manage the potential impacts and risks to levels that are acceptable and ALARP; and
• outline how Chevron Australia has engaged with relevant persons and how their feedback has been considered and addressed.

NOPSEMA will assess whether the EP satisfies the Regulations, including whether the environmental impacts and risks of operations will be managed so that they are acceptable and ALARP before accepting the EP.

We are now seeking your feedback and input if you consider your functions, interests, or activities may be affected based on the information provided, including the summary of the key environmental impacts and risks identified to date in Table 2.

We encourage you to provide additional details about the environment, aspects, consequences of the activity or control measures or to ask for further information or consultation.

Relevant persons may request that the information they provide be treated as confidential. Chevron Australia will make this known to NOPSEMA and it will be identified as sensitive information and not published in the EP.

You can contact us with any questions, requests for information, or feedback by calling 1800 225 195 or online below.

Please contact us by Friday 30 August 2024 to be included in consultations.

The feedback we receive during consultation will be used to inform and enhance the EP before it is submitted to NOPSEMA for assessment.

We commit to keeping you informed and providing responses to any relevant person who so requests.

If you choose to provide feedback, Chevron Australia will collect your name and contact details, for the purposes of maintaining contact with you and including your feedback in our submission to NOPSEMA. Provision of this information is purely voluntary, however if you choose not to provide it, we may not be able to contact you in the future. Chevron may transfer your information to NOPSEMA if required and, if you do not identify it as sensitive, to other Chevron affiliates including our head office in the United States.

For further information regarding how we protect your personal information, and your rights, please refer to our privacy notice.