New Play of Pre-Talang Akar Carbonate Limestone in South Sumatra Basin for Future Deep Target Exploration

South Sumatra Basin is one of the biggest and most active sedimentary basin with hydrocarbon potential in Indonesia. All large fields are mainly drilled and produced from Talang Akar sand (TAF) and Baturaja limestone (BRF) as major targets in Pertamina EP South Sumatra working area, hence it has already become mature hydrocarbon resources for decades. The idea of Eocence carbonate limestone is laterally distributed could potentially become new hydrocarbon reservoir in study area. Evaluating 252 well logs, well cuttings, regional 3D seismic data, well performance and production history, integrated subsurface interfield data analysis due to limitation of representative well data is done to objectively revisit new Pre-Talang Akar hydrocarbon prospect of undeveloped sublittoral carbonate limestone which chronostraigrpahically equivalent with terrestrial lacustrine shale that deposited in brackish water during Eocene syn-rift phase in Lahat Formation (LAF). The methods used in this study includes wellbore data analysis, petrophysical analysis, structural modelling, seismic facies study, and facies mapping. Drilling wells result among DW, GK, BL, and BN oil fields in study area shows the presence of inter-bedded hard massive limestone with clean quartz sand, volcanic tuff, and shale in Lahat zone. The indication of oil shows from cutting samples and well log petrophysical analysis leads to well GK-82 production test and confirms the provenance of oil reserves (P1) in Lahat carbonate limestone with low influx. Regional 3D seismic data also identifies onlapping seismic reflector that is interpreted as carbonate reef build up in Pre-Talang Akar of BN field and proposed to be drilled for validating 44 BSCF estimated volumetric resources. Within further study and more comprehensive subsurface data, this hydrocarbon play would have led to new insight of petroleum system and opportunity for future deep target exploration in South Sumatra Basin.