Woodside gearing up for decom activities at Australian offshore gas field

Australian energy giant Woodside has submitted an environment plan (EP) to the country’s offshore regulator for subsea decommissioning activities at a gas field in the offshore Otway Basin, close to the coast of Victoria, Australia.

The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has confirmed that Woodside submitted an environment plan to undertake subsea decommissioning activities at the Minerva field, previously operated by BHP Petroleum (Victoria). This field is located in Commonwealth waters within petroleum license VIC/L22 and pipeline license VIC/PL33.

Situated approximately 11 km south-southwest of Port Campbell, Victoria, the Minerva wells lie in water depths of around 50 – 60 meters. Woodside plans to remove all subsea infrastructure and equipment from the seabed associated with this field.

The scope of the Minerva decommissioning and field management environment plan includes ongoing field management activities such as inspection and monitoring of the subsea and well infrastructure until final decommissioning.

The EP also entails the removal of the Minerva gas pipeline bundle in Commonwealth waters, which comprises approximately 4.9 km of 10-inch concrete-coated rigid-steel flowline, bunded with an electro-hydraulic umbilical and two 2-inch steel chemical injection lines and stabilization materials.

In addition, the environment plan covers the removal of Minerva subsea infrastructure within VIC-L22 consisting of five inline pipeline structures, five tie-in spools, and associated equipment and stabilization material.

According to Woodside, the equipment removal activities are planned to start as early as 3Q 2024 and require about three to five months, subject to vessel availability and weather constraints. The Minerva gas field was discovered by BHP’s Minerva-1 in 1993 and the first gas was achieved in January 2005. The field’s production ceased in September 2019.

Recently, Woodside decided to keep its participating interests in oil and gas assets off the coast of Western Australia. Before this, the Australian heavyweight sold a 10% non-operating interest in the Scarborough Joint Venture, comprising the Scarborough gas field and associated offshore and subsea infrastructure, to LJ Scarborough, a subsidiary of LNG Japan.