Publications

Although it is not the only way in hydrocarbon exploratiton, geochemistry is intensively and widely used for evaluating the prospectiveness of an area.Compared with early explorations whichwere only based on surface oil/gas seeps, surface geological study or structures which were found by seismic, the application of geochemistry concept can giie direction and guidance in an advance exploration stage. In some cases it can delineate the prospect area to be drilled and can reduce some ambiguities.Principles of hydrocarbon formation and migration, supported by results of laboratory analyses on exploration well cuttings and the Lopatin method, were applied in the exploration approach of the Northwest Java area.Source rock analysis shows that the Lower Cibulakan sediments (Eq. Talang Akar) are the main source in the area. However, in carbonates of Batu Raja and Parigi, only poor source rock indications were found, although both are commercial oil producers. Using a TOC cut off 0.5%, the distribution of mature source rocks of the area can be delineated by applying Lopatin method which was supported by geothermal gradient and burial history, the distribution of mature source rock area of TTI at least 15 can be defined. Based on the source rock distribution and ",mature area", maps, we can generate a ",play map",. Previous and recent discoveries in the N.W. Java area are located in the favourable areas which are defined by geochemistry parameters.