THE TARAKAN BASIN, EAST KALIMANTAN: PROVEN NEOGENE FLUVIO-DELTAIC, PROSPECTIVE DEEP-WATER AND PALEOGENE PLAYS IN A REGIONAL STRATIGRAPHIC CONTEXT

摘要

The geological history and petroleum geochemistry of the four Tarakan sub-basins (Tidung, Tarakan, Berau and Muaras) are reviewed and presented in the context of a revised stratigraphic framework, which draws on recent advances in biostratigraphy, chronostratigraphy and paleoclimatology. Neogene source rocks comprise mostly coals and organic-rich shales assigned to a 'fluvio-deltaic, paralic' depositional system. Reservoired oils in shelf settings confirm this interpretation and point to a mature Miocene 'source fades' and to likely deep-water prospectivity. Another prospective 'source play' is identified, with evidence put forward for hydrocarbons being derived from Eocene or older aquatic organic matter. This is consistent with biostratigraphic and seismic data, which suggest the development of Paleogene (and possibly older) lacustrine, brackish and marine, syn-rift sediments. An increasing body of evidence from Tarakan, and elsewhere in East Kalimantan and the Makassar Straits area, lends support to the premise that potential hydrocarbon-source sediments extend offshore into deep-water settings.