The Basker–Manta–Gummy (BMG) subsea facilities are located entirely within Retention Lease VIC/RL13, in Commonwealth waters off south‑eastern Victoria. The facilities are situated in water depths of approximately 135 to 270 metres, about 50 kilometres offshore and south of Cape Conran.
Oil production from the BMG field ceased in 2010. The floating production, storage and offloading facility (FPSO) and associated buoyant infrastructure were removed in 2011. A Petroleum Safety Zone is currently in place around the remaining subsea infrastructure, with the exception of sections of the Basker‑6 flowline and umbilical that are trenched and buried beneath the seabed (gazettal reference A443819). The project is subject to General Direction 824. The development was not assessed as a controlled action under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) (EPBC referral 2005/2026).
Decommissioning of the remaining BMG subsea infrastructure is being undertaken in phases:
- Phase 1, which involved permanently plugging and abandoning the seven subsea wells and recovering associated well equipment, was completed in May 2024.
- Phase 2, which is covered by this Environment Plan, involves the decommissioning and removal of the remaining subsea infrastructure and is proposed to be completed no later than 31 December 2030.
Phase 2 activities (this Environment Plan) include:
- Ongoing field management of the remaining infrastructure from completion of the well plug and abandonment campaign until final removal and post‑activity monitoring is complete.
- Removal of wellheads to at or below seabed.
- Removal of subsea flowlines, umbilicals and any other infrastructure located above seabed.
- Contingency de‑burial of the Basker‑6 umbilical and flowline where required to facilitate removal. Removal methods for flowlines and umbilicals may include reverse reeling, lift‑and‑cut techniques, or a combination of these.
- Leaving selected steel components (steel pile) that are buried below the seabed in place.
Offshore Phase 2 decommissioning activities are expected to occur over approximately 75 days in total. Activities may involve up to three construction and support vessels operating concurrently. The Environment Plan is designed to provide for these activities to be undertaken at any time of year.
