Woodside Energy Ltd (Woodside) proposes to undertake permanent plug and abandonment (P&A) and well intervention activities for five subsea wells associated with the North West Shelf Development, as part of the Petroleum Activity under this Environment Plan (EP):
• P&A of three Angel field wells (AP2, AP3, and AP4) in production licence WA-3-L;
• P&A of two Perseus over Goodwyn (PoG) wells (PER-02, PER-04) in production licence WA-1-L;
• Well intervention activity on the TPA-03 well located in WA-5-L;
• inspection, maintenance, and repair (IMR) activities in preparation for plugging and abandonment of the wells listed above.

All wells are located in Commonwealth waters in the Northern Carnarvon Basin around Woodside’s existing production facilities. The closest well to shore is approximately 125 km north of Dampier. The wells are in water depths ranging from approximately 80 m to 128 m.

The plugging and abandonment and well intervention will be undertaken using a moored or hybrid (mooring and dynamic positioning capability) semi-submersible mobile offshore drilling unit (MODU), supported by vessels. The MODU will enter the operational area to undertake plug and abandonment activities, and be removed from the operational area once activities are complete. Vessels may undertake preparatory activities, such as pre-laying of moorings and preparation of subsea infrastructure, in addition to supporting the MODU.
The plug and abandonment activities (including preparation activities) are expected to require between 28 to 50 days to complete, subject to weather, vessel and MODU availability, or other unforeseen events. Petroleum Activities Program is scheduled to occur between Q2 2025 and Q4 2026, with activities occurring 24 hours per day.

In the same MODU campaign, Woodside proposes to conduct well intervention activities at the TPA03 well to remediate a down-hole valve and continue production from the lower reservoir. Once the well intervention has been completed, the well will be shut-in until production is required. The shut-in and subsequent return to production of the well will be managed under the accepted Goodwyn Alpha (GWA) Facility Operations Environment Plan (March 2022) as part of ongoing operations. Well intervention activities at TPA03 are expected to require between 5 to 14 days to complete, subject to weather, vessel and MODU availability, or other unforeseen events.

This EP is not intended to be the final decommissioning EP for Woodside’s property in WA-1-L and WA-3-L, as such Section 270 of the OPGGS Act and title surrender requirements are not included in this EP.