Three-fold resource surge sharpens focus on Tetragon’s gas play offshore Philippines

September 4, 2026, by Melisa Cavcic

Asia-focussed oil and gas explorer Tetragon Energy has upgraded the potential of its gas portfolio off the coast of the Philippines, more than tripling the mid-case prospective resource estimate for a key exploration prospect to 8 trillion cubic feet (tcf), a boost that could strengthen the value of the acreage ahead of potential farm-out talks.

Tetragon has explained that the resource upgrade follows a more detailed evaluation of seismic data obtained from the Philippines Department of Energy, together with work by a sedimentological expert to compare the Halcon prospect with recent analogous discoveries in nearby basins.

The upgrade, based on a more detailed review of extensive seismic data and comparisons with recent discoveries in nearby basins, increases the gross 2U (P50) prospective resource at Halcon in the SC-80 permit from 2.6 tcf to 8 tcf. The resource estimates have also increased at both ends of the range.

Image shows a regional composite seismic line from the shallower water to the SW to deep water in the NE. The Halcon prospect lies in deep water, basinward of the main thrust belt, in a similar location to analogous basin floor fan discoveries. Source: Tetragon

While the low-case 1U (P90) estimate has risen from 188 billion cubic feet (bcf) to 1.7 tcf, the high-case 3U estimate has increased from 19.9 to 22.6 tcf. The geological chance of success has improved from 18% to 24%.

Conrad Todd, Tetragon’s Managing Director, commented: “This three-fold increase in our mid case (2U) prospective resource for a key prospect in our Philippines acreage highlights the true scale and opportunity we have in these exciting permits.

“We believe that with our extensive experience in this and the adjacent analogous basins. Tetragon will unlock the potential of this basin and prove it to be on the scale of those in adjacent Malaysia and Indonesia waters where numerous gas and oil discoveries of significant volume have been discovered.”

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The company sees significant geological similarities between its acreage and recent large discoveries in the deep waters of Indonesia and Malaysia around Borneo, while believing Eni’s 2023 Geng North discovery – with 5 tcf of gas initially in place (GIIP) and 400 million barrels of condensate – is highly analogous to Halcon.

The acreage is located offshore in the Philippines, north of Borneo, within an area jointly licensed by the Philippine government and the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM).

Seismic amplitude comparisons between the recent Geng North discovery made in the Kutei basin of Indonesia and the undrilled Halcon prospect in the Philippines. Tetragon emphasizes that these two maps are at the same scale.

Tetragon holds a 37.5% interest in permits SC-80 and SC-81 and acts as operator, alongside its joint venture partners: Sunda Energy, Philodrill, and PXP Energy. The latest resource upgrade comes as the operator continues to reprocess approximately 4,600 square kilometers of existing 3D seismic data.

The work is expected to further delineate Halcon, as well as the existing Dabakan and Palendag discoveries, including Palendag’s 2C resource of 470 bcf, while helping mature additional prospects across the acreage.

Early results from the seismic reprocessing are expected in the new year, with the full dataset expected to be available from mid-2027.

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Tetragon plans to engage with international companies to secure partners to fund exploration drilling, which could provide a path to proving up the estimated volumes and potentially create a significant value uplift for the company and its joint-venture partners.