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Bass Oil Limited (ASX:BAS) has provided its latest weekly update on the Bunian 6 development well located in Indonesia's South Sumatra Basin, confirming the well has reached a depth of 895 metres as of 0600 hours on 3 July 2026. The company describes Bunian 6 as a low-risk development well that, upon completion, is projected to increase production at the Tangai-Sukananti KSO from 250 barrels of oil per day (bopd) to 750 bopd on a 100% joint venture basis. With Bass Oil holding a 55% operated interest, its net production share is expected to grow from around 140 bopd to 410 bopd. Market participants are closely monitoring progress as the company targets first production from the well in early July 2026, with all drilling costs fully recoverable against current production under the KSO agreement terms.<\/p> <\/div>
Key Points<\/h3>
- Company: Bass Oil Limited (ASX:BAS)<\/li>
- Bunian 6 well depth advanced from 403 metres to 895 metres during the week ending 3 July 2026<\/li>
- Current 12-1\/4" hole section drilling toward intermediate casing point at approximately 1,400 metres; total depth planned at about 1,820 metres<\/li>
- Well completion expected to raise Tangai-Sukananti KSO production from 250 bopd to 750 bopd (100% JV basis); Bass Oil’s net share to increase from ~140 bopd to ~410 bopd<\/li>
- Initial production forecast of 500 bopd from primary TRM3SS sandstone reservoir; estimated ultimate recovery of 151,000 barrels of oil (P50, 100% JV basis)<\/li>
- Geological chance of success (Pg) estimated at 80% based on internal models and nearby well data<\/li>
- Drilling costs are fully recoverable against existing production under the KSO terms<\/li>
- Upcoming milestones include intermediate casing at ~1,400 metres, drilling to total depth of ~1,820 metres, and confirmation of first production<\/li>
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Drilling Progress: Bunian 6 Advances from 403 Metres to 895 Metres in One Week<\/h2>
In its 3 July 2026 update, Bass Oil reported significant drilling progress on the Bunian 6 well. Starting the week at 403 metres, the rig reached 895 metres by 0600 hours on 3 July, achieving a 492-metre advance within seven days. At that point, the rig was performing a wiper trip, a routine operation to clean and condition the wellbore before resuming drilling.<\/p>
A wiper trip involves withdrawing the drill string and then running it back down to detect any obstructions or tight spots that might hinder drilling or casing. The absence of reported issues aligns with the company’s classification of Bunian 6 as a low-risk development well. Drilling is currently focused on the 12-1\/4" hole section targeting an intermediate casing point near 1,400 metres. After reaching this depth, the 9-5\/8" intermediate casing will be installed and cemented before drilling continues to the estimated total depth.<\/p>
Drilling Plan: Setting Intermediate Casing at 1,400 Metres Prior to Reaching 1,820 Metres Total Depth<\/h2>
Bass Oil’s update outlines a stepwise drilling approach for Bunian 6. The immediate goal is to drill the 12-1\/4" hole section to approximately 1,400 metres, where the 9-5\/8" intermediate casing will be run and cemented to stabilize the upper wellbore. Following this, drilling will proceed to an estimated total depth of 1,820 metres.<\/p>
Upon reaching total depth, wireline logging will be conducted to assess reservoir characteristics and fluid content before well completion. The company aims to bring the well into production promptly after completion, targeting early July 2026 for first oil. This methodical drilling program reflects standard industry practice for development wells in the South Sumatra Basin.<\/p>
Bunian 6 Expected to Triple Production at Tangai-Sukananti KSO to 750 BOPD<\/h2>
The primary investment thesis for Bunian 6 centers on a substantial increase in field output. Bass Oil reports that Tangai-Sukananti KSO has maintained steady production around 250 bopd in recent months. Completion of Bunian 6 is projected to raise total field production to 750 bopd on a 100% joint venture basis, tripling current levels.<\/p>
For Bass Oil’s 55% interest, this equates to a net production increase from roughly 140 bopd to approximately 410 bopd. The forecasted uplift is largely driven by the initial production rate expected from the primary TRM3SS sandstone reservoir, estimated at 500 bopd. Internal modelling also predicts an ultimate recovery of 151,000 barrels of oil (P50, 100% JV basis). These forward-looking estimates are based on internal analysis and nearby well performance, with actual outcomes subject to drilling results and reservoir behavior.<\/p>
Primary TRM3SS Target and Secondary GRM and K Reservoirs to be Intersected by Bunian 6<\/h2>
Bunian 6 is designed to tap multiple reservoir levels within the Bunian Field. The primary target is the TRM3SS sandstone, anticipated to be the main source of initial production. The well is positioned near the crest of the Bunian anticline, a faulted structure discovered in 1998, to optimize oil recovery based on an integrated field study.<\/p>
Additionally, the well will intersect two secondary reservoirs: the GRM and K formations. Both have demonstrated oil production or testing success in other wells within the field, supporting their prospectivity. Bunian 6 will provide valuable data on the K reservoir’s production and reserve potential, identified by Bass Oil as a secondary target with upside. The entire KSO area benefits from 3D seismic coverage and advanced seismic attribute analysis, which informed the selection of Bunian 6’s location.<\/p>
80% Geological Chance of Success Supports Bass Oil’s Confidence in Bunian 6<\/h2>
Bass Oil estimates an 80% geological chance of success (Pg) for Bunian 6, based on internal modelling and nearby well results. This high probability reflects the well’s development focus, prior production history, and comprehensive 3D seismic data coverage. The company classifies the well as low-risk, consistent with its location on a proven structure.<\/p>
The company cautions that these estimates are forward-looking and may vary depending on drilling and reservoir outcomes. No new information affecting these estimates was reported at the time of the update. The 80% Pg, combined with the low-risk classification and cost recovery provisions under the KSO, frames the risk-return profile Bass Oil has communicated to investors.<\/p>
Significance of Cost Recovery Arrangement Under Tangai-Sukananti KSO for Bass Oil<\/h2>
A key financial aspect of the Bunian 6 development is that all drilling expenditures are fully cost recoverable against existing production under the Tangai-Sukananti KSO terms. This arrangement ensures that capital invested in drilling is recouped from production revenues before profit sharing among joint venture partners.<\/p>
This cost recovery mechanism provides financial protection for Bass Oil by reducing the equity risk associated with drilling investments. The company’s update confirms this structure is in place for Bunian 6, enhancing capital efficiency and cash flow management. Bass Oil also notes it is debt free, which strengthens the financial context of this program.<\/p>
Bass Oil’s 55% Operated Interest and Partner MAPS Hold Remaining 45% at Tangai-Sukananti KSO<\/h2>
Bass Oil holds a 55% operated interest in the Tangai-Sukananti KSO through its subsidiary Bass Oil Sukananti Ltd. The remaining 45% is owned by Mega Adhyaksa Pratama Sukananti Ltd (MAPS). As operator, Bass Oil manages drilling activities, with the progress of Bunian 6 directly reflecting its operational capabilities in Indonesia.<\/p>
The KSO is situated in the prolific South Sumatra Basin, hosting the Bunian and Tangai oil fields along a major hydrocarbon trend. The Bunian Field was discovered in 1998 and has been producing for several years. Bunian 6 represents the latest phase in the field’s development, supported by an integrated field study that has also identified additional drilling prospects at Bunian West and Bunian North West.<\/p>
Additional Prospective Drilling Targets at Bunian West and Bunian North West<\/h2>
Beyond Bunian 6, the integrated field study—which included reprocessing of the Sukananti 3D seismic survey and advanced seismic attribute analysis—has highlighted Bunian West and Bunian North West as future drilling targets within the KSO. These locations are mapped relative to existing wells and the Bunian structure crest in the company’s update.<\/p>
While no specific timelines, resource estimates, or capital plans for these targets were disclosed, their identification suggests Bass Oil’s development strategy at Tangai-Sukananti KSO extends beyond the current well. Investors monitoring Bass Oil’s longer-term Indonesian growth outlook may view these prospects as indicators of potential production expansion contingent on Bunian 6’s success.<\/p>
Bass Oil’s Broader Asset Base: Cooper Basin Operations and Entry into East Coast Gas Market in Late 2026<\/h2>
Although the Bunian 6 well is the focus of this update, Bass Oil’s portfolio also includes 14 permits in Australia’s Cooper Basin, with 100% ownership of the Worrior and Padulla oil fields. These Australian assets complement the company’s Indonesian operations, forming a dual-hemisphere production base.<\/p>
The company also announced plans to enter the Australian East Coast Gas Market in late 2026, supported by three gas projects currently under development. This marks a strategic diversification into domestic gas markets. Bass Oil reports it is debt free and emphasizes its commitment to shareholder value through operational expertise and management alignment, with board and management holding over 10% of issued capital.<\/p>
Upcoming Milestones as Bunian 6 Nears First Production in Early July<\/h2>
Investors should watch for the continuation of drilling through the 12-1\/4" hole section toward the intermediate casing point at approximately 1,400 metres, followed by the running and cementing of the 9-5\/8" intermediate casing. These steps precede drilling to the estimated total depth of 1,820 metres. Completion and logging will follow, with production expected to commence immediately afterward.<\/p>
Bass Oil targets early July 2026 for first production from Bunian 6, meaning production results should be available soon. Future weekly updates are likely to report on casing installation, progress to total depth, and production startup. Market watchers will also be attentive to initial flow rates from the TRM3SS reservoir relative to the forecast 500 bopd, as well as data from the secondary K and GRM reservoirs. The immediate impact of this weekly update on Bass Oil’s share price was not evident from publicly available information.<\/p>
Drilling Progress: Bunian 6 Advances from 403 Metres to 895 Metres in One Week<\/h2>
In its 3 July 2026 update, Bass Oil reported significant drilling progress on the Bunian 6 well. Starting the week at 403 metres, the rig reached 895 metres by 0600 hours on 3 July, achieving a 492-metre advance within seven days. At that point, the rig was performing a wiper trip, a routine operation to clean and condition the wellbore before resuming drilling.<\/p>
A wiper trip involves withdrawing the drill string and then running it back down to detect any obstructions or tight spots that might hinder drilling or casing. The absence of reported issues aligns with the company’s classification of Bunian 6 as a low-risk development well. Drilling is currently focused on the 12-1\/4" hole section targeting an intermediate casing point near 1,400 metres. After reaching this depth, the 9-5\/8" intermediate casing will be installed and cemented before drilling continues to the estimated total depth.<\/p>
Drilling Plan: Setting Intermediate Casing at 1,400 Metres Prior to Reaching 1,820 Metres Total Depth<\/h2>
Bass Oil’s update outlines a stepwise drilling approach for Bunian 6. The immediate goal is to drill the 12-1\/4" hole section to approximately 1,400 metres, where the 9-5\/8" intermediate casing will be run and cemented to stabilize the upper wellbore. Following this, drilling will proceed to an estimated total depth of 1,820 metres.<\/p>
Upon reaching total depth, wireline logging will be conducted to assess reservoir characteristics and fluid content before well completion. The company aims to bring the well into production promptly after completion, targeting early July 2026 for first oil. This methodical drilling program reflects standard industry practice for development wells in the South Sumatra Basin.<\/p>
Bunian 6 Expected to Triple Production at Tangai-Sukananti KSO to 750 BOPD<\/h2>
The primary investment thesis for Bunian 6 centers on a substantial increase in field output. Bass Oil reports that Tangai-Sukananti KSO has maintained steady production around 250 bopd in recent months. Completion of Bunian 6 is projected to raise total field production to 750 bopd on a 100% joint venture basis, tripling current levels.<\/p>
For Bass Oil’s 55% interest, this equates to a net production increase from roughly 140 bopd to approximately 410 bopd. The forecasted uplift is largely driven by the initial production rate expected from the primary TRM3SS sandstone reservoir, estimated at 500 bopd. Internal modelling also predicts an ultimate recovery of 151,000 barrels of oil (P50, 100% JV basis). These forward-looking estimates are based on internal analysis and nearby well performance, with actual outcomes subject to drilling results and reservoir behavior.<\/p>
Primary TRM3SS Target and Secondary GRM and K Reservoirs to be Intersected by Bunian 6<\/h2>
Bunian 6 is designed to tap multiple reservoir levels within the Bunian Field. The primary target is the TRM3SS sandstone, anticipated to be the main source of initial production. The well is positioned near the crest of the Bunian anticline, a faulted structure discovered in 1998, to optimize oil recovery based on an integrated field study.<\/p>
Additionally, the well will intersect two secondary reservoirs: the GRM and K formations. Both have demonstrated oil production or testing success in other wells within the field, supporting their prospectivity. Bunian 6 will provide valuable data on the K reservoir’s production and reserve potential, identified by Bass Oil as a secondary target with upside. The entire KSO area benefits from 3D seismic coverage and advanced seismic attribute analysis, which informed the selection of Bunian 6’s location.<\/p>
80% Geological Chance of Success Supports Bass Oil’s Confidence in Bunian 6<\/h2>
Bass Oil estimates an 80% geological chance of success (Pg) for Bunian 6, based on internal modelling and nearby well results. This high probability reflects the well’s development focus, prior production history, and comprehensive 3D seismic data coverage. The company classifies the well as low-risk, consistent with its location on a proven structure.<\/p>
The company cautions that these estimates are forward-looking and may vary depending on drilling and reservoir outcomes. No new information affecting these estimates was reported at the time of the update. The 80% Pg, combined with the low-risk classification and cost recovery provisions under the KSO, frames the risk-return profile Bass Oil has communicated to investors.<\/p>
Significance of Cost Recovery Arrangement Under Tangai-Sukananti KSO for Bass Oil<\/h2>
A key financial aspect of the Bunian 6 development is that all drilling expenditures are fully cost recoverable against existing production under the Tangai-Sukananti KSO terms. This arrangement ensures that capital invested in drilling is recouped from production revenues before profit sharing among joint venture partners.<\/p>
This cost recovery mechanism provides financial protection for Bass Oil by reducing the equity risk associated with drilling investments. The company’s update confirms this structure is in place for Bunian 6, enhancing capital efficiency and cash flow management. Bass Oil also notes it is debt free, which strengthens the financial context of this program.<\/p>
Bass Oil’s 55% Operated Interest and Partner MAPS Hold Remaining 45% at Tangai-Sukananti KSO<\/h2>
Bass Oil holds a 55% operated interest in the Tangai-Sukananti KSO through its subsidiary Bass Oil Sukananti Ltd. The remaining 45% is owned by Mega Adhyaksa Pratama Sukananti Ltd (MAPS). As operator, Bass Oil manages drilling activities, with the progress of Bunian 6 directly reflecting its operational capabilities in Indonesia.<\/p>
The KSO is situated in the prolific South Sumatra Basin, hosting the Bunian and Tangai oil fields along a major hydrocarbon trend. The Bunian Field was discovered in 1998 and has been producing for several years. Bunian 6 represents the latest phase in the field’s development, supported by an integrated field study that has also identified additional drilling prospects at Bunian West and Bunian North West.<\/p>
Additional Prospective Drilling Targets at Bunian West and Bunian North West<\/h2>
Beyond Bunian 6, the integrated field study—which included reprocessing of the Sukananti 3D seismic survey and advanced seismic attribute analysis—has highlighted Bunian West and Bunian North West as future drilling targets within the KSO. These locations are mapped relative to existing wells and the Bunian structure crest in the company’s update.<\/p>
While no specific timelines, resource estimates, or capital plans for these targets were disclosed, their identification suggests Bass Oil’s development strategy at Tangai-Sukananti KSO extends beyond the current well. Investors monitoring Bass Oil’s longer-term Indonesian growth outlook may view these prospects as indicators of potential production expansion contingent on Bunian 6’s success.<\/p>
Bass Oil’s Broader Asset Base: Cooper Basin Operations and Entry into East Coast Gas Market in Late 2026<\/h2>
Although the Bunian 6 well is the focus of this update, Bass Oil’s portfolio also includes 14 permits in Australia’s Cooper Basin, with 100% ownership of the Worrior and Padulla oil fields. These Australian assets complement the company’s Indonesian operations, forming a dual-hemisphere production base.<\/p>
The company also announced plans to enter the Australian East Coast Gas Market in late 2026, supported by three gas projects currently under development. This marks a strategic diversification into domestic gas markets. Bass Oil reports it is debt free and emphasizes its commitment to shareholder value through operational expertise and management alignment, with board and management holding over 10% of issued capital.<\/p>
Upcoming Milestones as Bunian 6 Nears First Production in Early July<\/h2>
Investors should watch for the continuation of drilling through the 12-1\/4" hole section toward the intermediate casing point at approximately 1,400 metres, followed by the running and cementing of the 9-5\/8" intermediate casing. These steps precede drilling to the estimated total depth of 1,820 metres. Completion and logging will follow, with production expected to commence immediately afterward.<\/p>
Bass Oil targets early July 2026 for first production from Bunian 6, meaning production results should be available soon. Future weekly updates are likely to report on casing installation, progress to total depth, and production startup. Market watchers will also be attentive to initial flow rates from the TRM3SS reservoir relative to the forecast 500 bopd, as well as data from the secondary K and GRM reservoirs. The immediate impact of this weekly update on Bass Oil’s share price was not evident from publicly available information.<\/p>
