DECOMMISSIONING of Basker Manta Gummy wells off Victoria’s Gippsland is now over 70% complete, according to a market update from Cooper Energy.

Specialised vessel Q7000, owned by Houston’s Helix Energy Solutions Group, began work late last year and has now completed the lower abandonments, with all seven wells successfully plugged.

“This is a significant milestone, removing any future environmental risk from the hydrocarbon reservoirs, as they are now permanently isolated,” the company said.

Helix Q7000 will now progress to the upper well abandonment work scope, with the programme on-schedule to be complete in early May.

Elsewhere in Bass Strait Woodside Energy, as operator of the Minerva field off Port Campbell on behalf of owners Woodside and Cooper Energy, is  removing all infrastructure.

Woodside notes the Minerva field reached the end of its economic production life in September 2019.

Immediately following the cessation of production, the Minerva wells were suspended and the subsea system was left in a preserved state (i.e. wells isolated and production system flushed of hydrocarbons) for final decommissioning. The onshore gas plant was sold for reuse to another operator, and a vessel-based campaign was conducted in Q1 2021 to disconnect flowlines from wells and install barrier plugs.

The latest work includes plug and abandonment (P&A) of two former production wells and two exploration wells, removal of infrastructure above the mudline, and removal of the Minerva 10-inch pipeline to shore and associated infrastructure. The P&A work is expected to take two months and the infrastructure removal 1-2 months, subject to weather conditions.