Oil-Source Rock Correlation Of Oil Seepage And Rock Samples Collected From The Cibulakan Formation At Palimanan Area, West Java

Abstract

This paper presents the results and discussion of a petroleum geochemistry study performed on two oil seepage and seven outcrop samples collected from the Cibulakan Formation at Palimanan area, West Java. The presence of two oil seepages in Palimanan area indicates that there is an effective source rock which has produces hydrocarbon. The objectives of the study were to determine the hydrocarbon source potential of outcrops, and to characterise selected rock extracts and oil seepage samples, and determine the progenitor source facies at time generation/expulsion. The method used in this research is field study and laboratory analysis. Field studies were conducted on oil and rock sampling, while the geochemical laboratory analysis includes Total Organic Carbon, Rock-Eval Pyrolysis, Vitrinite Reflectance, Kerogen Typing, Bitumen Extraction, Liquid Chromatography, Gas Chromatography fingerprint and GC-MS biomarker. The oil-source rock correlation to its oil based on GC fingerprint (n-alkane distributions) and GC-MS biomarker (triterpanes and sterane distributions) has been done. The oil seepage is correlated with possible source rocks from the Cibulakan Formation. Based on the n-alkane distribution the oil seepage showed biodegradation, but based on the biomarker distributions, it is interpreted that the oil seepage have been generated from a source rock facies containing mainly non-marine algal debris (Type II Kerogen) mixed with some input from terrestrial higher plant organic matter (Type III Kerogen). The oil seepage shows a moderately good correlation with the rock extracts based on GC-MS biomarker data. These biomarker parameters has been successfully used to determine the origin of oil with its precursor source rock by correlating the rock extracts to possible source rocks in the oil and gas exploration.