AUS
NZ
UK
CA
USA
IND
Bass Oil Limited (ASX:BAS) has recommenced drilling at the Bunian 6 well in Indonesia following the installation and successful performance testing of a replacement mud pump. The company aims to start production by late August 2026. This development well is projected to triple production from the Indonesian field from 250 barrels of oil per day to 750 barrels per day on a 100% joint venture basis, with Bass holding a 55% operated interest. The drilling program’s costs are fully recoverable against existing production under the Tangai-Sukananti KSO terms, making this a low-risk, value-accretive growth opportunity for the debt-free oil producer.
Key Points
- Bass Oil Limited (ASX:BAS) is an Australian-listed oil producer operating in the Cooper Basin and holding a 55% operated interest in Indonesia's South Sumatra Basin.
- Drilling at the Bunian 6 well resumed after installing and testing a replacement mud pump; the well reached 1,012 metres depth as of 24 July 2026.
- The well is planned to reach approximately 1,820 metres total depth and commence production in late August 2026, targeting an initial output of 500 barrels per day from the primary TRM3 sandstone reservoir.
- Field production is expected to rise from 250 barrels per day to 750 barrels per day (100% joint venture basis), a 200% increase; Bass's 55% share equates to 140 to 410 barrels per day.
- Drilling expenses are fully cost-recoverable against existing production, with Bass Oil acting as the permit operator.
Update on Bunian 6 Well Drilling and Operations
Bass Oil released a weekly update on the Bunian 6 development well located in the Tangai-Sukananti KSO within Indonesia's South Sumatra Basin. As of 24 July 2026 at 0600 hours, the well depth reached 1,012 metres. Following the successful performance testing of a replacement mud pump, drilling operations resumed over the weekend. This replacement resolved a technical issue that had temporarily paused drilling progress.
The next drilling phase includes completing the intermediate hole section to around 1,440 metres, then running and setting the 9-5/8" intermediate casing. After casing installation, drilling will continue to the estimated total depth of approximately 1,820 metres. Upon reaching total depth, logging and completion activities will be conducted before bringing the well online. The company expects production to commence by late August 2026, in line with previously announced schedules.
Significant Production Growth Anticipated from Bunian 6 Development
The Bunian 6 well is a strategic development expected to substantially boost production at the Tangai-Sukananti KSO. Current field production from the Bunian and Tangai oil fields is approximately 250 barrels per day on a 100% joint venture basis. Upon successful completion and startup in late August 2026, production is forecast to increase to 750 barrels per day, a 200% uplift. Bass Oil’s 55% share corresponds to an increase from roughly 140 barrels per day to 410 barrels per day.
Designed as a low-risk development targeting the TRM3 sandstone reservoir, the well is modelled to initially produce 500 barrels per day. Estimated ultimate recovery is 151,000 barrels of oil on a P50 basis (100% JV share). The well’s location near the field crest aims to accelerate oil drainage and optimize reserve recovery. Bass estimates an 80% technical success probability based on internal modelling and nearby well performance, though actual results may vary depending on drilling, completion, and reservoir conditions.
Financial Advantages and Cost Recovery of Bunian 6 Project
A key financial benefit of the Bunian 6 project is its full cost-recovery structure under the Tangai-Sukananti KSO agreement. Bass Oil’s drilling and development costs are fully recoverable against existing production revenue, reducing the capital expenditure impact on earnings. This arrangement supports disciplined capital deployment aligned with production economics.
The joint venture consists of Bass Oil Sukananti Ltd as operator with a 55% interest and Mega Adhyaksa Pratama Sukananti Ltd (MAPS) holding 45%. Bass Oil’s operator role provides control over well planning, execution, and production. The cost-recovery mechanism funds development capital from production revenue, enabling the company to maintain a debt-free status while expanding Indonesian operations. This approach underscores Bass Oil’s focus on capital discipline and cash flow-driven growth.
Geological Overview and Multi-Reservoir Potential of Bunian Field
Discovered in 1998, the Bunian Field is situated in the prolific South Sumatra Basin and features a faulted anticline structure with significant oil potential. The entire Tangai-Sukananti KSO is covered by 3D seismic data, enabling comprehensive subsurface imaging. Recent integrated field studies, including reprocessing of the Sukananti 3D seismic survey and advanced seismic attribute analysis, confirmed Bunian 6 as an optimal development location. Additional drill targets such as Bunian West and Bunian North West have been identified, indicating further exploration upside.
The field contains three productive reservoir levels. Bunian 6 primarily targets the TRM3 sandstone reservoir (TRM3SS) but also plans to intersect secondary targets including the GRM and K reservoirs, both previously producing or tested in the field. The K reservoir offers additional production and reserve data, enhancing the well’s overall value. This multi-zone drilling strategy maximizes both technical and commercial returns.
Bass Oil’s Portfolio and Growth Strategy in Indonesia
Bass Oil Limited is a diversified oil and gas producer with assets across multiple regions. The company holds majority interests in fourteen permits within Australia’s Cooper Basin, including 100% ownership of the Worrior and Padulla oil fields. It also operates the Tangai-Sukananti KSO in Indonesia’s South Sumatra Basin with a 55% interest, where the Bunian 6 well is being developed. The Indonesian operations are a key growth driver, targeting significant production increases from existing fields.
Beyond current assets, Bass Oil plans to enter the Australian East Coast Gas Market in late 2026, developing three gas projects targeting this sector. This diversification supports growth in both oil production and emerging gas markets. The company maintains a debt-free balance sheet, providing financial flexibility to fund capital projects. Management and the board collectively hold over 10% of issued capital, aligning interests with shareholders. Bass Oil leverages its expertise, operational capabilities, and strong relationships in both Australia and Indonesia to drive growth.
Seismic and Geological Modelling Underpinning Bunian 6 Location
Bunian 6’s well location was selected based on an integrated field study combining advanced seismic interpretation and geological analysis. The 3D seismic data covering the Tangai-Sukananti KSO was reprocessed with modern techniques and enhanced by seismic attribute analysis, improving reservoir geometry understanding. This comprehensive approach provided high confidence in the well’s optimal placement.
Geological cross-sections show Bunian 6 near the anticline crest, chosen to accelerate oil drainage. Depth maps confirm its strategic position relative to other wells within the field development plan. The 3D geological model incorporates structural geometry, fault systems, and multi-reservoir stratigraphy, enabling accurate predictions of well performance and recovery potential. This detailed subsurface characterization supports the company’s 80% estimated technical success probability.
Production Forecast and Reserve Estimates for Bunian 6 Well
Bass Oil’s internal modelling forecasts an initial production rate of 500 barrels per day from Bunian 6, contributing the majority of the anticipated 750 barrels per day total field increase. The estimated ultimate recovery is 151,000 barrels of oil on a P50 basis (100% JV share). These estimates derive from probabilistic reserve modelling and comparative analysis of nearby wells producing from the same reservoirs.
The 80% technical success probability reflects risk-adjusted assessments of drilling, completion, and reservoir uncertainties. The company cautions that actual outcomes may differ based on operational and reservoir performance. No new information affecting these estimates has emerged as of the announcement date, indicating stable technical foundations for the well plan.
Tangai-Sukananti KSO Location and Regional Geology
The Tangai-Sukananti KSO is located within the prolific South Sumatra Basin, one of Indonesia’s most productive oil and gas regions. The permit contains the Bunian and Tangai oil fields along a trend of large oil fields extending northwest and southeast. This favorable structural and petroleum system setting supports commercial production with mature infrastructure and established operations.
Production from the KSO has remained stable at approximately 250 barrels per day in recent months, providing a reliable baseline for measuring Bunian 6’s impact. Location and depth data confirm Bunian 6’s position within the fault-bounded anticline hosting the Bunian Field. The permit’s 3D seismic coverage and developed infrastructure enable cost-effective reserve development. Additional drill targets such as Bunian West and Bunian North West indicate further growth potential beyond Bunian 6.
Development Timeline and Late August 2026 Production Target
Bass Oil targets late August 2026 for Bunian 6 production startup. As of 24 July 2026, the well had reached 1,012 metres depth, about 55% of the estimated 1,820 metres total depth. The next steps involve completing the intermediate hole to 1,440 metres and setting the 9-5/8" casing during the week following 24 July. After casing, drilling will continue to total depth, followed by logging, completion, and production commencement.
This timeline reflects a compressed development schedule. Investors should monitor weekly progress updates for any changes. The replacement mud pump installation resolved a prior technical delay, allowing operations to proceed on plan. Successful well completion and timely production startup would significantly increase production from 250 barrels per day to 750 barrels per day, enhancing cash flow from Indonesian operations.
