Tetragon triples recoverable gas estimate at Halcon prospect offshore Philippines

Tetragon Energy has increased its estimate of recoverable gas resources at the Halcon prospect offshore the Philippines from 2.6 Tcf to 8 Tcf following seismic analysis and benchmarking against regional discoveries.
Sept. 3, 2026
2 min read
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Why this news matters:

  • The revised estimate moves Halcon into a resource size category that could attract major international operators and LNG-focused investors.

  • The prospect highlights growing exploration interest in underexplored deepwater areas of Southeast Asia as countries seek new domestic gas supplies.

Courtesy Tetragon Energy
Seismic interpretation across the SC-80 and SC-81 permits

Seismic interpretation across the SC-80 and SC-81 permits highlights the Halcon prospect, which Tetragon Energy says supports an estimated 8 Tcf of recoverable gas resources following updated geological analysis.

Halcon prospect at a glance

  • Location: Offshore southern Philippines, north of Borneo

  • Operator: Tetragon Energy (37.5%)

  • Partners: Sunda Energy, Philodrill, PXP Energy

  • Previous recoverable estimate: 2.6 Tcf

  • Updated recoverable estimate: 8 Tcf

  • Basis for revision: Seismic review and analogue field analysis

  • Next steps: 3D seismic reprocessing and exploration well funding discussions

Tetragon Energy has upgraded prospective resources of its Halcon gas prospect offshore the Philippines from 2.6 Tcf to 8 Tcf recoverable.

This follows evaluation of available seismic data over the acreage obtained from the Philippines Department of Energy as well as analysis by a sedimentological specialist comparing Halcon to recent analogous discoveries made by Eni and Petronas in nearby deepwater basins, such as Geng North in the Kutei Basin offshore Indonesia.

Southeast Asia has seen renewed interest in frontier gas exploration in recent years, with operators pursuing large gas discoveries to support regional energy security and growing LNG demand.

If confirmed through drilling, an 8-Tcf recoverable resource would rank among the larger undeveloped gas opportunities in the region and could strengthen the Philippines' long-term domestic gas supply outlook as production from the Malampaya gas field continues to decline.

Tetragon has a 37.5% operated interest in the surrounding offshore permits SC-80 and 81, in partnership with Sunda Energy, Philodrill and PXP Energy.

Courtesy Tetragon Energy
map of Tetragon operated permits SC80 and SC81 offshore Borneo

Tetragon Energy’s SC-80 and SC-81 permits are located in the Sandakan Basin offshore the southern Philippines, north of Borneo. The acreage occupies a geological setting analogous to the hydrocarbon-rich deepwater basins of Northwest Sabah, Malaysia, and the Kutei Basin offshore Indonesia, where major oil and gas discoveries have been made. Resource volumes shown are based on the IHS regional database.

The offshore area, which is north of Borneo, is jointly licensed by the government of the Philippines and the Bangsomoro Autonomous Region in Muslim Mindanao (BARMM).

Seismic reprocessing continues of the 4,600 sq km of existing 3D seismic data, and it will be used to further delineate Halcon, the Dabakan and Palendag discoveries (estimated at 470 Bcf) and to mature other prospects. 

The full dataset should be available from mid-2027. Tetragon also plans to approach IOCs on funding drilling of exploration wells.

“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," said managing director Conrad Todd.

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About the Author

Jeremy Beckman
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Jeremy Beckman

Staff Writer / Editor, Europe

Jeremy Beckman has been Editor Europe, Offshore since 1992. Prior to joining Offshore he was a freelance journalist for eight years, working for a variety of electronics, computing and scientific journals in the UK. He regularly writes news columns on trends and events both in the NW Europe offshore region and globally. He also writes features on developments and technology in exploration and production.

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