Murphy increases Cuu Long basin reserves

Murphy Oil Corp. confirmed its 2025 Hai Su Vang discovery as 'significant' and has updated the range of recoverable resources for the field following completion of the Hai Su Vang-2X (HSV-2X) appraisal well. The discovery and appraisal lie in Block 15-2/17 in Cuu Long basin, about 40 miles offshore Vietnam.  

The well spud in early October 2025 in Hai Su Vang (Golden Sea Lion) field. It was drilled to appraise the initial HSV-1X well discovery, which well encountered about 370 ft of net oil pay across two reservoirs.

HSV-2X encountered 429 ft of net oil pay across the same two reservoirs, including 332 ft of net oil pay in the deeper primary reservoir and 97 ft of net oil pay in the shallow reservoir. Within the primary reservoir, the well deepened proven oil reserves 413 ft without encountering water and extended the total hydrocarbon column to about 1,600 ft.

Formation evaluation supports reservoir continuity to the HSV-1X discovery. The primary reservoir achieved a production rate of 6,000 bo/d during flow testing of the appraisal well. The well produced high-quality, 37° API oil, which is consistent with the results from the discovery well. Further testing is ongoing.

Previous resource potential was estimated at 170–430 MMboe, but this new shallow reservoir appraisal will add to this range. Additional appraisal wells are necessary to further refine the range of recoverable resources for both reservoirs.

Following completion of HSV-2X operations, Murphy will continue its appraisal campaign to further delineate the field and evaluate additional reservoir intervals with the HSV-3X appraisal well in Block 15-1/05 and the HSV-4X well in Block 15-2/17.

Murphy’s subsidiaries Murphy Cuu Long Tay Oil Co. Ltd. and Murphy Cuu Long Bac Oil Co. Ltd. are operators of Block 15-2/17 and Block 15-1/05, respectively, (40% in each block). Partners include PetroVietnam Exploration Production Corp. (35%) and SK Earthon Co. Ltd. (25%).