ESSO AUSTRALIA is about to begin work on the plug and abandonment of 26 wells offshore Gippsland using the jack-up rig Valaris 107.

The company has already completed the decommissioning of 88 Gippsland basin offshore wells, as well as the removal of three subsea facilities, Seahorse, Blackback and Tarwhine in the last five years at a cost of $1 billion.

Valaris 107, a KeppelFels MOD V Class B rig, capable of working in waters up to 351 feet deep, will arrive in Port Phillip this evening [25 October] from Cilegon, Indonesia on board the 2018-built, 63,581 DWT submersible heavylift vessel GPO Amethyst, owned by Norway’s GPO Heavylift.

The rig is no stranger to Australian and NZ waters, having previously worked in Bass Strait in 2023 drilling a carbon capture and storage appraisal well for the Golden Energy Storage project, and in NZ’s Maui and Pokohura gas fields for a year in 2022. The latest assignment is also expected to last a year.

When announcing the contracting of Valaris 107 ExxonMobil Australia chair, Dylan Pugh said: “The Valaris is critical to Esso Australia’s overall decommissioning strategy in the Bass Strait, and we’re very pleased to add the jack-up rig to our fleet of offshore assets.”

After the float-off in Port Phillip Valaris 107 will be towed by AHTSs MMA Coral and ENA Samurai to complete the plug and abandonment of the 26 wells across the Bream B, Perch and Dolphin wells and five subsea platforms, Mulloway, Whiptail, Marlin-1, East Pilchard-1, Halibut-1

Ports Victoria has issued a Notice to Mariners advising of a temporary exclusion zone around the heavylift and towing vessels: Vessels must not enter within 500 metres of the activity.

“Mariners are advised to navigate with caution in the vicinity of GPO Amethyst, Valaris 107 and accompanying towing vessels, having due regard to the manoeuvrability of the vessels and exclusion zone requirements,” deputy harbour master David Tilsley said.

Esso Australia is the operator of the assets in Bass Strait that are part of the Gippsland Basin Joint Venture between Esso and Woodside Energy.