ConocoPhillips Australia discovers additional gas in Otway basin Charlemont Trend

Drilling details

The wireline logging program has been completed in the Charlemont-1 exploration well across the Waarre C, B, and A sandstones to fully evaluate the nature and extent of any hydrocarbons in these units. The well is the second gas discovery under the Otway Exploration Drilling Program following the Essington discovery.

Modular dynamic testing (MDT) operations recovered a representative gas sample from a Waarre C sandstone at 2571.2 m MD confirming the presence of hydrocarbons, consistent with wireline log and drilling observations.

Preliminary rig-based compositional analysis of the sample reveals a CO₂ concentration of 16 Mol%. This is within the range of pre-drill predictions based on results from the Waarre C at La Bella gas field (12-13 Mol%), about 7 km to the east. The intersection of gas in the Waarre C was not anticipated prior to drilling and may have positive implications for the unit across the Charlemont Trend, supported by Charlemont C and E seismic amplitude.

The primary Waarre A target was intersected over a 70 m gross interval at 2,683 m MD, and data indicates probable hydrocarbon presence in Waarre A sandstones. A valid gas gradient cannot be determined within the Waarre A, and MDT pressure data indicate that the Waarre C, B, and A units do not comprise a single, continuous gas column.

Charlemont-1 has appraised the penultimate prospect at the down-dip extent of the Charlemont Trend, a prospect chain that extends up-dip to the La Bella gas discovery.  Together, these results demonstrate gas charge at both ends of the Charlemont Trend, with intervening prospects exhibiting consistent geophysical characteristics, including comparable amplitude anomalies. This continuity of geophysical response supports the interpretation of a gas-charged system along the Charlemont Trend.

Further analysis and evaluation are required to determine the commercial viability of the Phase 1 gas discoveries, and no decisions have been made regarding progression to development.

Charlemont-1 will now be plugged and the Transocean Equinox rig will be transferred to another operator in the region.

Additional wells could be drilled as part of Phase 2 of the Otway Exploration Drilling Program, but further evaluation would be required prior to confirming any next steps, the company said. 

ConocoPhillips Australia is operator of (51%) with partners 3D Energi (20%) and Korea National Oil Co. (29%).