STUDI POTENSI BATUAN INDUK HIDROKARBON SATUAN BATULEMPUNG FORMASI RAMBATAN DAERAH WANGON SUB-CEKUNGAN BANYUMAS

Abstract

ABSTRACT – Identification of rock intervals that may have as a source rock potential is the important first step in
hydrocarbon exploration, therefore it is necessary to conduct research on the sedimentary rock containing organic
matter which with a certain level of heat and time can produce hydrocarbons in the form of oil or gas. The objective of
this study is to identify lithofacies and hydrocarbon source rock potential of Claystone Unit of the Rambatan Formation
in the Wangon Area, Banyumas Sub-Basin. Based on outcrop data showed that Rambatan Formation in the study area
predominantly composed of shale with thin intercalation of sandstones. This formation was deposited in the deep
marine environment by turbidity current. Geochemical analysis in order to determine the potential and quality of source
rock was performed on four samples (BMS-28, KLP-27, KLP-31 and BMS-120) of Rambatan shale. The analysis of
potential and source rock quality showed TOC content varied from 1.21% - 23.45% indicating “very good” quality.
Rock-Eval analisys show that the shale from sample BMS-28 and BMS-120 are poor as hydrocarbon source rock
(S2<2.5 kg / ton), while shale from samples KLP-27 and KLP-31 have good potential as hydrocarbon source rock
(S2>5 kg / ton). All samples taken from Rambatan shale showed Ro <0.6 indicate hydrocarbon maturation level has not
been reached. The low values HI of BMS-28 and BMS-120 (HI<100 mg HC / g TOC), reflects that this rock can be
classified as non-source rock, while samples KLP-27 and KLP-31 have HI values of 152 mg HC/g TOC and 294 mg
HC/g TOC will tend to produce gas and oil if it reaches maturation level. The values of HI between 100-300 mgHC/g
are generally derived from type III and II kerogen which predominantly contain terrestrial and marine organism.

Keywords : source rock, potential, quality, and maturity