Australia’s Bass Oil Limited has announced a major upgrade to the prospectivity of its producing Tangai-Sukananti KSO, located in onshore Sumatra, Indonesia.
Highlights of the upgrade, resulting from an independent review of the company’s stake in the KSO located in the prolific oil production province in southern Sumatra, include an additional 1.6 million barrels (0.893 million barrels net to Bass) of low-cost, unrisked, prospective oil resources, in two new near-field targets.
As a result of the study’s findings, Bass immediately added these new targets to its planned 2018/2019 drilling program.
Bass Oil commissioned the review during 2017, following its acquisition of a 55% stake in the licence, which includes the current producing Bunian and Tangai Oil Fields.
The Tangai-Sukananti KSO is located in the mature oil and gas producing South Sumatra Basin and includes the Bunian and Tangai Oil Fields which lie along an extensive trend of large oil fields north-west and south-east of the KSO. In 2017, Bass Oil engaged UNPAD in Indonesia, an independent petroleum geoscience and engineering consultancy associated with the Padjadjaran University, to conduct a Plan Of Field Development (POFD) being a major, multi-disciplinary, integrated study over the entire Tangai Sukananti KSO.
The POFD results are scheduled to be finalised by the end of March.
Bass said it has successfully defined two exploration prospects in addition to the existing known fields. Both prospects target oil potential at multiple reservoir levels within the prolific Talang Akar Formation, which contains the oil producing reservoirs in the existing Bunian (TRM3SS, GRM and K1 sands) and Tangai (GRM, K1 and M sands) Fields.
The Sukananti Updip prospect lies south of the Bunian Oil Field. Sukananti-1, drilled in 1996, intersected a 2 metre thick oil-filled sand at the TRM2SS reservoir level, which has significant up-dip potential on the southern flank of the Bunian Oil Field. Additionally, three other reservoir levels (TRM3SS, GRM and K1), that are oil bearing in the Bunian Field, are not within a trapping configuration at the Sukananti-1 location, but do form attractive targets at the Sukananti Updip location.
For the combined reservoirs, the Sukananti Updip prospect has 1.278 million barrels oil on an unrisked, prospective, recoverable, best estimate basis (0.703 million barrels net to Bass) with a 30% chance of geological success. Sukananti Updip has a high estimate upside of 3.156 million barrels oil on an unrisked, prospective, recoverable basis (1.736 million barrels net to Bass).
The Bunian West prospect is a faulted, anticlinal closure to the west of the Bunian Oil Field. The prospect has the potential for oil and gas at five stacked reservoir levels (TRM2SS, TRM3SS, GRM, K1 and M sands) all proven to be effective in the KSO.
For the combined reservoirs, the Bunian West prospect has 0.345 million barrels oil on an unrisked, prospective, recoverable, best estimate basis (0.190 million barrels net to Bass) with a 32% chance of geological success. Bunian West has a high estimate upside of 0.814 million barrels of oil on an unrisked, prospective, recoverable, best estimate basis (0.448 million barrels net to Bass).
The Bunian West and Sukananti Updip prospects are fully defined by the 2011 Sukananti 3D seismic survey data which was comprehensively reprocessed in 2014. Following approval by the Indonesian Government authorities (Pertamina and SKK MIGAS), the prospects will be included in Bass Oil’s 2018/2019 drilling and development program for the KSO.
Once approved by the regulator, the drilling costs of both wells will be fully cost recoverable against existing production under the terms of the KSO. Joint Venture participants in the KSO are Bass Oil Ltd (Operator 55%) and Mega Adhyaksa Pratama Sukananto Ltd (45%).