Publications

A better understanding of the potential of unconventional fossil fuels, comprising oil shale and coalbed methane (CBM) in parts of Sumatera and Kalimantan Islands, was provided by performing macroscopical, petrographical, and geochemical organic matter studies. The oil shale research was recently conducted in some selected areas of small inter-montane basins. In Sumatra, those are within Eo-Oligocene sediments in the Kuansing, Kiliranjau, Tigapuluh and Susah Mountains, and in the Ombilin, Kebuntinggi, and Asai-Rawas areas. The basins studied for oil shales are invented, approximately WNW - ESE small grabens or half-grabens, bounded by faults, and formed as a result of synrift tectonics.The coalbed methane studies were performed on coal-measures, both in Sumatera and Kalimantan. In Sumatera, the CBM study was carried out on sediments of Eo-Oligocene age in the Kuansing and Ombilin areas, and Mio-Pliocene sediments in the Sarolangun, Tanjungenim, and Bengkulu areas, whilst in Kalimantan studies were performed on sediments in the Berau, Kutai, and Barito basins.A detailed organic petrographical study, performed on mudrocks/oil shales is the subjected of potential oil source rocks in those regions. The work is focused on determining the components of the exinite maceral group, especially alginite, and also vitrinite maceral to determine reflectance level. The presence of abundant exinite macerals dominantly comprising dominantly lamalginite with significant telalginite, and minor liptodetrinite, bituminite, and resinite within the oil shale reflects that the sediments are presumed to be favorable oil source rocks, and the oil shale can be classified as lamosite. This suggestion is supported by the high TOC content and the the high PY level. Furthermore, a positive relationship occurs between alginite and TOC contents and also with pyrolysis yield. Therefore, based on these characteristics, the alginite content present in the oil shales may be used as one of the indicators for hydrocarbon generation potential in the parts of the central and south Sumatera regions. In terms of thermal maturity, the sediments are mainly included in the immature to early mature stages. In addition, the abundances of lamalginite content suggests a lacustrine depositional environment in an aerobic (anoxic) conditions.The coalbed methane research was performed on the dull to bright coals which are dominated by dull banded to bright banded coals occurring the studies area. Petrographically, the coal consists mainly of vitrinite comprising typical telocollinite and desmocollinite, with rare to sparse exinite, and minor inertinite and mineral matter. Geochemical analysis shows that the coal has low to moderate contents of volatile matter, total sulfur, ash, and moisture. The vitrinite reflectance value (Rv) tends to indicate the rank of coal ranges from subbituminous- B to high volatile bituminous-C category. Moreover, the coal thermal maturity, situated within immature to early mature levels, leads to the assumption that the expected gas present is likely to be of biogenic origin. A general low to moderate gas content level of the coal seams is gained from an in-situ coal gas calculation.Keywords: organic petrography, maceral, geochemistry, oil shale, coalbed methane (CBM), Sumatera, Kalimantan