Chevron Australia Pty Ltd (CAPL) is the operator of the Gorgon Gas Development, one of Australia’s largest natural gas projects located off the north-west coast of Western Australia (WA).

The first phase of the Gorgon Gas Development, the Gorgon Foundation Project (GFP), comprises the production of natural gas from the Gorgon and Jansz-Io fields. Hydrocarbon is transported from the offshore gas fields via two subsea pipeline networks to the Gas Treatment Plant (GTP) on Barrow Island, where it is processed for export as liquefied natural gas (LNG) or piped to the mainland for WA domestic gas users. This phase of the Gorgon Gas Development commenced operation in 2015.

The next phase of the development, the Backfill Fields Development, comprises the production of natural gas from seven backfill fields: Chandon, Chrysaor, Dionysus, Eurytion, Geryon, Semele, and West Tryal Rocks. The purpose of the Backfill Fields Development is to maintain gas supply to the existing GTP on Barrow Island to sustain production rates of LNG and domestic gas. These backfill fields are covered by the Gorgon Gas Development: Backfill Fields Offshore Project Proposal (OPP) which was accepted by NOPSEMA in October 2025.

The first of the backfill fields to be developed are the Geryon and Eurytion (G&E) gas fields, referred to as Gorgon Stage 3 (GS3). The G&E gas fields are located in the Northern Carnarvon Basin and ~80 km offshore from the closest island (Montebello Islands) and ~184 km from Onslow on the mainland coast.

CAPL is proposing to install a production flowline, Mono Ethylene Glycol (MEG) pipeline, umbilical, and associated subsea infrastructure at the G&E fields, tied back to the GFP infrastructure within the Jansz-Io field. CAPL also proposes to install an umbilical (Jansz infield umbilical) to provide power and communications to the Jansz-Io fields, which forms part of the GFP. The proposed subsea infrastructure is located within production licenses WA-39-L and WA-66-L. This EP documents the assessment and management of potential environmental impacts and risks associated with the petroleum activity in Commonwealth waters.
The scope of the petroleum activity includes:
• installation and pre-commissioning
• Field Control Station (FCS) integration
• commissioning and start-up of umbilicals
• contingency inspection, maintenance, and repair
• field support.
The petroleum activity covered within this EP can be conducted 24 hours/day and 7 days/week.

The petroleum activity is indicatively scheduled to commence from 2027 and will occur over multiple campaigns. The durations and timings are indicative and subject to change (e.g. due to potential delays caused by vessel, infrastructure and/or equipment availability, regulatory approvals, weather events, or other unforeseen factors). Therefore, the petroleum activity may occur at any time over the 5-year in-force period of this EP.