Chevron Australia Pty Ltd (CAPL) proposes to conduct a 4-dimensional (4D) marine seismic survey (MSS) over production licences WA-46-L, WA-47-L and WA-48-L in the Wheatstone and Iago gas fields in Commonwealth waters north of Barrow Island, Western Australia. The 4D MSS aims to repeat the acquisition of the 3-dimensional (3D) MSS conducted over the same area in 2011–2012, as part of a monitoring program. The 4D MSS is scheduled to occur between mid-December 2022 and mid-April 2023, subject to vessel availability, and is expected to take ~75 days to acquire. Seismic acquisition will be conducted 24 hours a day.

The Full Power Zone for the 4D MSS defines the area where the seismic source will be discharged at full power. The Full Power Zone extends over ~1,644 km2 and is within water depths that range from ~60 m to 1,130 m. The Operational Area for the 4D MSS defines the area where all planned activities within the scope of this EP will occur. The Operational Area extends over ~3,730 km2 and is within water depths that range from ~50 m to 1,250 m. The Operational Area is situated ~30 km from the Montebello Islands and ~119 km from the mainland.

This Environment Plan (EP) documents the assessment and management of potential environmental impacts and risks associated with the 4D MSS. This EP has been prepared in accordance with the requirements of the Commonwealth Offshore Petroleum and Greenhouse Gas Storage Act 2006 and Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 as administered and for regulatory acceptance by the National Offshore Petroleum Safety and Environment Management Authority.

The OPEP and OSMP for this plan are the documents submitted as part of the Wheatstone Project - Start-Up and Operations EP