Publications

Telisa and Brown Shale Formation, commonly known as seal and source rock formation in Central Sumatra Basin, have been proven to hold a considerable amount of hydrocarbon reserves although in very low quality reservoirs. The Telisa A (TEA) in Bangko Field and the Brown Shale B (BSB) in Balam SE Field, for instance, have a huge estimation of the Original Oil in Place. However, the recovery factor of these reservoirs is currently still below 4%. This suggests that both reservoirs are ideal candidates to apply new development schemes, using advanced techniques that can maximize their production potential. This study illustrates how lithofacies, cores, fluorescence, and production data can be integrated to determine reservoir zones with a reliable and effective approach. TEA is a lower shoreface – transition post rift sediment that is characterized by fine to silt-grained, wavy lamination, and high concentration of shallow marine bioturbation, namely skolithos and cruziana ichnofacies. On the other hand, BSB, a distal deltaic of the syn-rift lacustrine system, displays very fine to silt-grained with a high amount of lake-bioturbation. However these two different sedimentation settings share a common theme, they both hold extremely very fine-grained sediment that is commonly rich with bioturbation. After analyzing several conventional cores from both formations, this study found several lithofacies types at both TEA and BSB which indicate high levels of heterogeneity. The pay determination using lithofacies as well as fluorescence data on the cores has been performed on TEA and BSB. Furthermore, the production data from the reservoir intervals is used to validate the accuracy of the determined pay zone. It was clearly observed that the data sets indicating quality production in both reservoirs are concentrated within the pay zone. In addition, this study could be useful for future potential developments of horizontal wells and fracturing intervals determination, with the ultimate goal to accelerate the production of untapped resources. Lastly, by using a proper development strategy, this study is expected to unlock others very low quality reservoirs in Central Sumatra Basin.