Transocean rig encounters gas as it spuds next well in drilling campaign offshore Australia

December 30, 2025, by Melisa Cavcic

ConocoPhillips Australia (COPA), a subsidiary of the U.S.-headquartered energy giant ConocoPhillips, has kicked off drilling activities at another well in the Otway Basin off the coast of Australia, with a semi-submersible rig owned by Transocean, an offshore drilling player.

Transocean Equinox, former Songa Equinox; Credit: ALP Maritime

After Transocean’s Transocean Equinox semi-submersible drilling rig, which was booked to search for more gas offshore Australia, made a discovery at the Essington-1 exploration well within the VIC/P79 exploration permit in November 2025, the rig spud the Charlemont-1 gas exploration well in the Otway Basin offshore Victoria on December 10, 2025.

The well intersected significant gas shows approximately 160 meters above the primary target (Waarre A) in the Waarre C on December 25, 2025, according to ConocoPhillips’ partner, 3D Energi, a Melbourne-based oil and gas exploration player whose subsidiary, TDO, has a 20% interest in both permits.

As pressures were said to be higher at 2,552 meters than anticipated, drilling was temporarily paused to assess potential adjustments to the well design, including options to continue to drill to the primary target.

The operator’s partner claims that the pre-drill evaluation of the Charlemont-1 prospect did not anticipate intersecting gas at this shallower level. As a result, activities are currently underway to assess potential adjustments to the well design to enable drilling to the primary target, the Waarre A.

ConocoPhillips Australia is the operator with a 51% stake, with partners, 3D Energi and Korea National Oil Company, holding the remaining 20% and 29% interests, respectively.