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 drill six new subsea production wells clustered around a single drilling centre within the G&E fields. The proposed production wells are located within retention lease WA-22-R in water depths of ~1,221 metres. 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:
• drilling and completions
• 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 G&E drilling and completions are indicatively scheduled to commence from early-2027 and are estimated to take ~12–18 months to complete, with activities occurring either over a single or multiple campaigns. These schedules and durations are indicative and subject to potential delays caused by MODU/vessel, infrastructure, and/or equipment availability, regulatory approvals, weather events, or other unforeseen factors. Therefore, the drilling and completion activities may occur at any time during the 5-year in-force period of this EP.