Publications

This is an investigation of hydrocarbon source potential of rocks located at Pakintelan-Pudakpayung oil seep and its surroundings near the city of Semarang, Central Java. The coordinates of the oil seep are 7.1043412 S and 110.3992178 E. Exposed sediments of Pudakpayung area belong to Kaligetas Formation, which was deposited covering Kerek Fornation that can be found near the oil seep. For this study, geological surface mapping was conducted and combined with rock sampling in Kerek Formation for analysis of source rock potential. Based on TOC values ranging from 0.42% to 0.67%, S2 between 0.46 to 0.56 mg/g, the Kerek Formation is not a potential source rock. Pyrolysis Tmax of Kerek Formation samples range from 410°C to 430°C, the extraction is very low (<1000ppm), dominated by non-polar fraction (>80 wt%), CPI 1.43 and 1.57 so Kerek Formation is categorized as immature to early mature Source Rock. GC results obtained unimodal character (a cluster of n-alkanes), the ratio between the compound and fitana pristana shows the value (pr / ph<2), GSC shows sterana presence of C27, so Kerek Formation source rocks are from aquatic origins (mostly algae) and organic materials deposited in marine environments (Rahmat Hidayat & Fatima, 2007). Pudakpayung oil seep from the result of analysis showed that saturated hydrocarbon fraction + aromatics = 69.85 wt%, GC Chromatogram detected biodegradation, BMI ratio of 2.41, indicating that the oil seepage derived from fully mature source rocks. Results showed GSMC triterpana biomarker content (m / z = 191), indicating that the oil originated from organic materials with high levels of land plants with resin character. Based on laboratory results there is no positive correlation between the oil seep and Kerek Formation samples as source rock, specifically, differences in maturity levels, precursors of organic material and depositional environment.