Woodside Energy Ltd (Woodside) is submitting the Greater Western Flank (GWF) 4 Drilling and Subsea Installation Environment Plan in accordance with the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2023 (Cth).

The infrastructure associated with the Petroleum activity is located in Commonwealth waters, ~140 km north-west of Karratha. The closest landfall to the Petroleum Activity is the Montebello islands ~35 km south.

The Petroleum activity consists of a subsea tie-back to existing GWF subsea infrastructure to develop incremental volumes of gas and condensate to partially fill ullage at the GWA facility. The development consists of five wells: WCA01, WCA02, ESA01, YDA01 and TPA04 tied-in via existing manifolds.

Wells will be drilled, completed and unloaded using a hybrid (DP/moored) semi-submersible mobile offshore drilling unit (MODU). Typically, two or three support vessels will support the MODU during drilling activities, with at least one vessel in the vicinity to complete standby duties, if required. Supply vessels will frequent the MODU at regular intervals throughout operations.

Installation of the subsea infrastructure, including flowlines, umbilicals, manifolds, FLETs, mattresses, flying leads and pre-commissioning are undertaken using a primary installation vessel (PIV).

The Petroleum activity is currently anticipated to commence from Q3 2026 with anchor installation activities to support drilling. Drilling and completions activities are planned to commence in Q2 2027, taking up to ~90 days per well including mobilisation, demobilisation and contingency activities. Subsea installation activities are planned to commence H2 2027 and the initial campaign for nearfield infill will take ~3 months, with a second campaigned planned for Wilcox subsea installation activities in Q4 2027 that is anticipated to take ~4 months. IMMR activities can occur at any time during the Petroleum Activity. Timing and duration of all activities is subject to change due to project schedule requirements, MODU/vessel availability, unforeseen circumstances and weather. Therefore, contingency has been included to allow both drilling and subsea installation activities to continue into 2029.

When underway, activities will be 24 hours per day, seven days per week