Publications

The biogenic gas discoveries in the Sibolga Basin during the 1970s exploration campaign proved the basin’s potential, however since the late 1990s, exploration activities have been non-existent and there is no significant play concept development to reinvigorate exploration appetite in the region. A recent prospectivity study of the offshore Western Aceh region has been completed by using existing well and 2D seismic datasets. The outcome reiterates the potential of this basin in providing working petroleum system for future high risk-high reward exploration strategy.

The Sibolga Basin is underlain by Jurassic shales and mudstones that represent the Woyla Group. Existing wells recorded relatively thin, marginal to shallow marine Late Eocene sediments overlying the Mesozoic section. Away from the wells, a thicker Paleogene section may exist in some graben-like, local depocentres, which are currently located under the slope setting. During the Neogene, the region was in a marine setting and a significant amount of basin fills came from the mainland Sumatra to the area northwest of Batee Fault Zone, while to the southeast of the fault zone, the sediments were from the outer-arc highs. Limited clastic supply during the Early Miocene transgressive phase encouraged carbonate growth and fine-grained clastic deposition. The Middle Miocene sedimentation was linked to major uplift and erosion of Bukit Barisan, and afterward was followed by carbonate reef growth during a transgressive phase in the Late Miocene to earliest Pliocene. During the Pliocene to Pleistocene, sediment prograded from mainland Sumatra towards the southwest, overlying the Upper Miocene section. Apart from the proven Upper Miocene carbonate play and the tested Lower Miocene carbonate and Pliocene sandstones plays, we have identified potential a new play within the Middle Miocene slope channel and fan system. Biogenic petroleum system is proven while thermogenic petroleum system can also potentially exist in the basin.