Minerva

Project Overview

• The Minerva field is an offshore oil and gas project located south-southwest of the township of Port Campbell, Victoria, Australia.

History and Operations

• The offshore wells at the Minerva field were drilled in late 2002, and the offshore and onshore pipeline was laid in 2003. The onshore Minerva Gas Plant was completed in December 2004, and production commenced in January 2005.
• The Minerva field reached the end of its economic production life in September 2019. Following this, the wells were suspended, and the subsea system was preserved for final decommissioning. The onshore gas plant was sold for reuse to another operator.

Infrastructure

• The project includes a 10-inch common flowline (pipeline) that connects the wells to the land-based gas plant near Port Campbell. The flowline is approximately 11 km long in the offshore section and extends from the low water mark out to the 3 nautical mile limit of State waters. It crosses the shoreline via two 1.6 km horizontal directional drill (HDD) underground boreholes from Two Mile Bay.
• The pipeline bundle includes a single 250 mm gas production flowline, a single electro-hydro umbilical for wellhead control, and two chemical injection lines.

Decommissioning Plans

• The decommissioning activities are expected to commence in Q2 2025, with a possible earlier start in Q1 2025. These activities are required to be completed by 30 June 2025, as per the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) General Direction 831.
• The decommissioning involves the permanent plug and abandonment (P&A) of four wells (two former production wells and two exploration wells), removal of wellhead and subsea trees, and the recovery of subsea infrastructure using a construction support vessel (CSV).
• Woodside Energy (Victoria) Pty Ltd, on behalf of the Joint Venture Partners (including Cooper Energy (MF) Pty Ltd), is responsible for the decommissioning activities. The plan includes ongoing field management activities such as monitoring and inspection prior to removal.

Environmental Considerations

• An Environment Plan (EP) for the P&A activities and subsea removal has been prepared and submitted to NOPSEMA for assessment under the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2023. The plan assesses potential impacts and risks to the marine environment and outlines mitigation and management measures.
• The plan includes measures to reduce waste through the reuse or recycling of recovered infrastructure, with the disposal of infrastructure to be done onshore in accordance with applicable requirements.

Regulatory Compliance

• The decommissioning activities are governed by various regulations, including the Victorian Offshore Petroleum Greenhouse Gas Storage Regulations 2021 (Vic) and NOPSEMA guidelines. The titleholder, Woodside Energy (Victoria) Pty Ltd, must comply with these regulations.

Location and Geography

• The Minerva gas pipeline is located in Victorian State waters, extending from the low water mark out to the 3 nautical mile limit. The area includes the Twelve Apostles Marine National Park, and the pipeline crosses the shoreline via HDD boreholes.