The Charlemont-1 exploration well operated by ConocoPhillips Australia offshore Victoria has encountered additional gas in deeper sections of the Waarre sequence, and the joint venture believes the broader trend could, if successfully appraised, rank among the larger gas accumulations in the Otway Basin.
Drilling of Charlemont-1 began on 10 December last year with the semisubmersible Transocean Equinox. After the well penetrated the Waarre C interval at 2,552 m MD, the partners ran a 7-in. liner, following reports from 3D Energi of stronger-than-forecast formation pressures and substantial gas indications in this section.
Work in the Waarre C zone resumed on 2 January this year. Elevated gas readings were observed across the reservoir sandstones, with further gas responses then recorded in the underlying Waarre B unit and through the main Waarre A objective to a depth of 2,753 m MD.
At this point, the well entered a high-pressure zone where formation pressures exceeded prior expectations and approached the limits of safe operating conditions. As a result, the partners decided to suspend drilling before reaching the planned total depth of 2,862 m.
According to 3D Energi, the joint venture is now considering additional wireline logging to better characterise fluids in the Waarre B and Waarre A intervals and to assess whether these zones may be in communication with Waarre C.
3D Energi Executive Chairman Noel Newell said the outcome in Waarre C is particularly important because this part of the section had not been expected to contain hydrocarbons before drilling started. He added that gas shows identified across multiple Waarre sandstone layers reduce geological risk for shallower prospects along the Charlemont Trend, where direct hydrocarbon indicators have been mapped and tied back to the La Bella discovery. Newell noted that, subject to successful appraisal, the Charlemont cluster could ultimately be considered one of the more substantial gas accumulations in the Otway Basin.
The permit is operated by ConocoPhillips Australia with a 51% interest, in partnership with Korea National Oil Co. on 29% and 3D Energi on 20%.
