Woodside proposes to undertake permanent plug and abandonment (P&A) of three subsea exploration wells associated within the Julimar-Brunello Field (WA-49-L) using a Mobile Offshore Drilling Unit (MODU) with combined Dynamic Positioning (DP) and mooring capability. In addition, Woodside proposes to remediate/remove and/or isolate Non-Water-Based-Mud (NWBM) in the annulus of one additional well using a MODU or inspection, maintenance, and repair (IMR) vessel. Support vessels will undertake preparatory activities, such as IMR activities, pre-laying and recovery of moorings and/ or tether clump weights, anchor hold testing. All four wells in this scope were drilled as exploration or appraisal wells between 2007 – 2011.

The three wells scheduled for P&A were suspended following exploration activities in accordance with the regulation of the time period (temporarily abandoned in today’s terminology). The temporary abandonment methodology conducted does not align with the current legislative requirements, regulatory expectations, and best practice for permanent abandonment, driving the need for further P&A activities

All wells are located in Commonwealth waters of the Barrow Sub-Basin around Woodside’s existing production facilities. The Petroleum Activity is located in Commonwealth waters in the Barrow Sub-Basin. The wells are located in title area WA-49-L, approximately 185 kilometres (km) WNW of Karratha in ~135 m to 171 m water depth.

The MODU and support vessels are expected to operate within the Operational Area for approximately three to seven months, including mobilisation, demobilisation and contingency activities. When underway, activities will be 24 hours per day, seven days per week. Timing and duration of the P&A activities is subject to change due to project schedule requirements, metocean conditions, vessel availability, unforeseen circumstances and weather. For this reason, the Environment Plan will be prepared as a 3-year EP.