Highlights

  • Bass Oil identified oil pay in the TRM3 and K1 reservoirs at the Bunian 6 well, in line with pre-drill expectations.
  • Wireline and mud-log analysis also identified oil pay in the M sand, a third reservoir horizon not previously intersected at Bunian.
  • Bunian 6 is being completed as a tandem producer across the TRM3, K1 and M reservoirs.
  • The well is expected to lift Tangai-Sukananti production from around 250 bopd to 750 bopd on a 100% basis.
  • Bass holds a 55% operated interest in the Indonesian permit, implying an expected production increase from about 140 bopd to 410 bopd net to Bass.

Bass Oil Limited (ASX:BAS) has reported further progress from its Bunian 6 development well in Indonesia, identifying oil pay across three reservoir intervals and preparing the well for production. The result adds the M sand to the previously targeted TRM3 and K1 reservoirs, expanding the number of productive horizons encountered during the drilling program.

Bass Oil shares were trading at AUD 0.063, down 1.56%, during the morning Trading session on 3 September 2026. Despite the intraday decline, the stock remained up 110.00% over the past year, based on the supplied market information.

Bass operates the Tangai-Sukananti KSO in South Sumatra with a 55% interest. The company also holds interests in Australian assets, including majority interests across Cooper Basin permits and full ownership of the producing Worrior and Padulla oil fields.

Third Pay Zone

The Bunian 6 well intersected oil pay in the primary TRM3 and K1 sandstone reservoirs broadly in line with Bass Oil's expectations before drilling.

The more notable addition emerged from subsequent interpretation of wireline and mud-log data, which identified oil pay within the M sand at the base of the well.

Bass said oil pay had not previously been intersected in the M sand within the Bunian field. However, the same reservoir represents the primary producing interval in the adjacent Tangai oil field.

The company plans to test the M sand once Bunian 6 is brought online. Further evaluation and well-testing data will also be used to assess what the newly identified reservoir may mean for the field's reserves.

Managing Director Tino Guglielmo described the M sand result as an additional positive outcome from the well and said it could contribute to field oil recoveries.

He also said the result provided additional support for the company's interpretation that the Bunian field may extend further west.

Production Lift Expected

The drilling rig is currently completing Bunian 6 as a tandem oil producer from the TRM3, K1 and M reservoirs.

Bass expects the well to be placed into production shortly after the rig moves away from the location.

On a 100% project basis, production at the Tangai-Sukananti KSO is expected to increase from approximately 250 barrels of oil per day to 750 bopd once Bunian 6 is online.

Based on Bass Oil's 55% interest, the company's share of production is expected to increase from around 140 bopd to 410 bopd.

The company's internal modelling previously forecast initial production of approximately 500 bopd from Bunian 6 and an estimated ultimate recovery of 151,000 barrels of oil on a P50 and 100% joint-venture basis.

Bass has previously assigned an estimated 80% chance of success to the well, based on internal modelling and nearby well performance. The company noted that actual outcomes remain dependent on drilling, completion and reservoir performance.

Bunian Field Strategy

The Tangai-Sukananti KSO is located within Indonesia's South Sumatra Basin and contains the Bunian and Tangai oil fields.

The Bunian field was discovered in 1998 and is interpreted as a faulted anticline. The wider KSO area is covered by 3D seismic data, providing Bass with geological information used in identifying development and exploration targets.

Production from the field had been steady at approximately 250 bopd in recent months before the Bunian 6 development program.

Bass selected Bunian 6 following an integrated field study that included reprocessing of the Sukananti 3D seismic survey and advanced seismic attribute analysis.

The program also highlighted potential future drilling locations, including Bunian West and Bunian North West.

Bunian 6 is located near the CREST of the field structure and was designed to accelerate drainage of the existing oil accumulation.

The development well initially targeted the TRM3 and K1 sandstone reservoirs, while secondary targets included the GRM and TRM0 intervals, which have previously produced oil or recorded oil shows elsewhere in the field.

The identification of the additional M sand interval now gives Bass another reservoir to evaluate within the Bunian structure.

Investment Structure

Bass Oil Sukananti Ltd operates the Tangai-Sukananti KSO and holds a 55% interest, while Mega Adhyaksa Pratama Sukananti Ltd holds the remaining 45%.

Bass said its drilling expenditure associated with the well will be fully cost recoverable against existing production under the terms of the KSO.

This arrangement means the company's expenditure on Bunian 6 can be recovered through production generated under the operating framework.

Beyond Indonesia, Bass holds a majority interest in 14 permits in the Cooper Basin, including 100% ownership of the Worrior and Padulla oil fields.

The company also stated that it is Debt free and plans to enter the Australian East Coast gas market in late 2026, while progressing three gas projects.

Management Perspective

Guglielmo said Bunian 6 represented the first of several growth projects currently underway across Bass Oil's Australian and Indonesian operations.

He pointed to the identification of the M sand as an additional element of the well result and said the company would continue assessing its impact on recoverable oil.

Bass expects further information from the evaluation program and production testing to help quantify how the additional reservoir influences the Bunian field's reserve profile.

The immediate operational focus is now on completing the tandem production configuration and bringing the well into production after the rig departs.

What Investors May Be Watching

For Bass Oil (ASX:BAS), the next operational milestone is the commencement of production from Bunian 6 and the extent to which actual output compares with the company's expectations.

Investors may also monitor production performance across the three reservoir intervals, particularly the newly identified M sand, as testing provides additional information about its contribution to the field.

Further analysis could also clarify whether the result changes Bunian's reserve estimates and how the geological interpretation of a possible western field extension develops.

For now, Bass is preparing Bunian 6 to produce from all three identified reservoirs, with the company expecting total Tangai-Sukananti production to rise from approximately 250 bopd to 750 bopd once the well is operating.