MIOCENE BO JONGMANIK FORMATION AND ITS POTENTIAL AS A HYDROCARBON RESERVOIR ROCK IN THE BOGOR ZONE, BASED ON OUTCROP OBSERVATIONS

摘要

Outcrops of the Bojongmanik Formation are exposed in the Cinanggung, Cikaniki and Hambaro Rivers, in the Leuwiliang District, Bogor, West Java. The Miocene Bojongmanik Formation is a part of the Bogor Zone which is mostly covered by volcanic deposits, such as the Genteng Formation and the Young Volcanic deposit. Sandstones in the Bojongmanik Formation were investigated as reservoir rocks for hydrocarbons within a possible petroleum system. This study combines field observations, sampling and laboratory analyses. Routine methods of measuring section to several outcrop in Cinanggung, Cikaniki and Hambaro Rivers were used in the field. Intercalation of sandstones and carbonaceous shales with lignite and limestone interbedded in parts were observed in the field. Characteristics of these sandstones were analyzed in the laboratory and showed both good porosity and permeability potential as a hydrocarbon reservoir based on petrography analyses. Mineralogy, lithological association and sedimentary structures indicate that this area is a shallow marine deposit. This paper provides detailed petrographic and facies descriptions which show the Bojongmanik Formation has potential to be a reasonable hydrocarbon reservoir.