Macallum’s EP 494 gas inventory expands after seismic sharpens Gadee targets

Seismic work takes EP 494 to 2,506 PJ

Macallum New Energy Limited (ASX:MNE) has turned a sharper seismic picture into a much larger headline resource inventory, reporting 2,506 petajoules of arithmetic mean prospective gas across its 100%-owned EP 494 permit in the North Perth Basin. The estimate combines prospects and leads, rather than reserves, and is based on undiscovered accumulations that still require drilling and development assessment.

The most visible upgrade is at Gadee, where the combined mean prospective gas resource for Gadee East and Gadee West has risen 70% to 221 PJ from 130 PJ reported before the new seismic. The company said the Barberton 3D survey, acquired over 117 square kilometres earlier this year, has defined two separate fault blocks with multiple stacked Jurassic reservoir sands and moved Gadee to drillable status.

The result builds on the company’s Barberton 3D seismic survey, which was previously reported as completed ahead of prospect maturation and potential 2027 drilling.

Gadee offers the clearest near-term drilling target

Gadee East carries a mean estimate of 182 PJ of gas and 1.36 million barrels of condensate, with a stated 40% chance of geological discovery and a 55% chance of development if successful. Gadee West adds 39 PJ of gas, 15 million barrels of oil and 0.29 million barrels of condensate, with a 29% geological chance of discovery and the same 55% development chance.

Macallum said the crest of the primary Intra-Yarragadee target sits at about 2,000 metres true vertical depth subsea, and that wells are being designed to test both structures. At Gadee East, an anomalous seismic amplitude response appears to conform to the area of maximum closure, although the company cautioned that without a nearby well it may not be possible to distinguish gas-bearing sands from high-quality wet sands without drilling.

BTD remains the portfolio’s largest gas opportunity

Barberton Terrace Deep is the largest component of the revised inventory, with a mean prospective resource of 1,513 PJ of gas and 6.81 million barrels of condensate. Advanced processing of the existing 2D seismic improved the structure’s definition, while a newly recognised Triassic target in the Lower Lesueur Sandstones helped offset a reduction in the Permian best estimate.

The revised mapping places BTD about 250 metres shallower than previously imaged, which Macallum said could reduce exploration well costs and may support better reservoir quality. Those potential benefits remain untested: the reported volumes are unrisked, and the company has not reported a discovery or a commercial development.

Farmout process opens ahead of 2027 wells

Yarra remains a lead rather than a prospect because a data gap covers the interpreted structural crest. Its mean estimate is 199 PJ of gas, 25.1 million barrels of oil and 1.50 million barrels of condensate, but its geological chance of success is 17%. Additional 2D seismic may be needed before a well can be positioned optimally.

Macallum intends to begin seeking a strategic joint venture partner for a campaign of up to two wells in the second half of 2027, while continuing preliminary planning across Aberfeldy, Gadee East, Gadee West and BTD. The company’s earlier Aberfeldy resource estimate included an oil-bearing scenario and a late-2027 drilling target, making partner terms and well selection important tests of how the enlarged portfolio is prioritised.

The permit’s work-program well commitment has been extended to November 2028, although Macallum says it remains focused on drilling in H2 2027. The next milestones are the Condor 2D seismic interpretation, a decision on the specific well location expected in early 2027, and the outcome of the farmout process. Until then, 2,506 PJ is best read as an exploration inventory with considerable geological and commercial uncertainty, not as a measure of future production.