Pekanbaru, Riau (ANTARA) – PT Pertamina Hulu Rokan (PHR) confirmed an oil discovery at the Mustang Hitam (MTH)-001 well in Libo Jaya village, Siak Regency, Riau Province, within the Rokan Block, signaling potential for further development in Central Sumatera Basin.Suprayitno Adhi Nugroho, PHR vice president for Regional 1 Exploration, said production tests confirmed hydrocarbons, offering a positive signal for expansion despite initial low output. Untested intervals and well interventions could unlock additional potential.“MTH-001 confirmed hydrocarbons in the Menggala and Pematang URB formations. Early production is modest, but the discovery opens opportunities for further development via well intervention and evaluation of other intervals,” he said in a statement on Friday.Before confirmation, drilling operations were analyzed to ensure accuracy. MTH-001 was spudded on Sept. 4, 2025, using the 750 HP Rig PDSI 52.3, reaching a final depth of 6,464 ft measured depth and 6,351.5 ft true vertical depth subsea by Sept. 26.Geologically, the well lies in the South Aman Trough, Central Sumatera Basin, one of Indonesia’s productive hydrocarbon regions. After drilling, production testing was conducted with Rig BMS-007 from Dec. 5, 2025, to Jan. 3, 2026.Results demonstrated potential hydrocarbon resources in a new stratigraphic trap within the Pematang URB and Menggala formations of the South Aman Trough.The MTH-001 production test indicates opportunities for increased output through further development and shows mature basins still yield results with optimized data extraction and new perspectives.The Pematang URB formation is an older hydrocarbon-bearing layer, while Menggala is a sandstone reservoir, both within the Central Sumatera Basin’s Rokan Block.​​​​​​​PHR continues comprehensive assessments of reserves and development schemes, integrating subsurface data and production test results to estimate recoverable resources.“The exploration and development teams are preparing an initial production scenario to monetize this discovery optimally,” Suprayitno said.Strategically, MTH-001 is located about 3 km from Oki Field, 4 km from Kokoh Field, and 6 km from the Libo Gathering Station, allowing synergy with existing infrastructure and development efficiency.The discovery reinforces PHR’s commitment to ongoing exploration in the Central Sumatera Basin and strengthens the Rokan Block’s role as a backbone of Indonesia’s oil and gas production.PHR will continue prudent, data-driven exploration and development with a focus on safety and sustainability, supporting national production targets and Indonesia’s energy security.