Prominence Energy Defines 4 Tcf Natural Hydrogen and 102 Bcf Helium Prospective Resource Portfolio in South Australia

Prominence Energy Limited (ASX: PRM) has reported maiden prospective resource estimates of approximately 4 trillion cubic feet (Tcf) of natural hydrogen and 102 billion cubic feet (Bcf) of helium across its Northern Hinge Project in South Australia, establishing a substantial new exploration portfolio ahead of a proposed drilling campaign in 2027.

Announced on October 22, 2026, the assessment covers 28 geological leads across four petroleum exploration permit application areas. The estimates were prepared by Prominence and independently audited by RISC Advisory, which found the company's resource estimation methodology and inputs reasonable, while identifying important uncertainties in geological risking.

The headline figures represent gross unrisked 2U Prospective Resources, meaning best-estimate quantities that could potentially be recovered from accumulations that have not yet been discovered. They are not proven reserves, discovered resources or measured volumes of gas in the subsurface.

The assessment identifies 4,001 Bcf of natural hydrogen, equivalent to approximately 9.29 million tonnes, alongside 101.8 Bcf of helium and 320 Bcf of petroleum gas. Prominence describes Northern Hinge as one of Australia's largest reported natural hydrogen and helium prospective resource portfolios on this basis.

The scale of the estimates is significant, but the distinction between unrisked and risked resources is central to understanding the announcement. After applying Prominence's assessed geological probabilities of discovery, the portfolio's gross risked 2U estimates fall to 543.8 Bcf of hydrogen and 13.7 Bcf of helium, together with 53.5 Bcf of petroleum gas.

These risked figures incorporate the estimated chance of geological discovery, rather than demonstrating that those quantities exist or can be produced commercially. Individual leads have assessed geological probabilities of success ranging from 6% to 18%, reflecting the early-stage nature of exploration across the region.

The Northern Hinge Project comprises exploration permit applications PELA 566, 581, 752 and 753, covering parts of the Arckaringa and Eromanga basins. These areas contain sedimentary formations overlying older geological structures that Prominence considers prospective for natural hydrogen and helium generation, migration and accumulation.

The resource assessment is based primarily on interpretations of gravity and magnetic data, geological mapping, regional well information and limited historical seismic coverage. These datasets have been used to identify potential structural traps and estimate the volumes that might be recoverable if gas accumulations are discovered.

The largest identified target is Seabrook, located within PELA 753. Prominence estimates gross unrisked 2U Prospective Resources of approximately 761 Bcf of natural hydrogen and 21.7 Bcf of helium at the lead, representing roughly one-fifth of the Northern Hinge portfolio's best-estimate hydrogen and helium potential.

Seabrook is interpreted as a fault-associated positive flower structure, with estimated vertical closure of 50–100 metres and an interpreted areal closure ranging from 50 to 290 square kilometres. Historical seismic data have also been interpreted as showing possible gas chimneys associated with faulting, although these features have not been verified through drilling.

The geological model proposes that deep faults may provide migration pathways for naturally occurring gases into shallower sedimentary reservoirs. If suitable trapping structures and effective seals are present, hydrogen and helium could potentially accumulate in recoverable quantities. Whether these geological conditions exist at Seabrook remains untested.

Prominence has identified Seabrook, Rockford, Flowstone, 581_1 and 581_2 as its five leading hydrogen and helium exploration objectives. Together, the largest leads account for approximately half of the portfolio's gross unrisked 2U prospective resources, making target selection an important consideration for the proposed drilling campaign.

Full press release can be found here.