Source Rock Characteristics of Loa Janan Area, Kutai Kartanegara, East Kalimantan, Indonesia

Abstract

The source rock analysis was involved examining the geochemical content of hydrocarbons in fine-grained sedimentary rocks. This study was conducted on claystone in the Loa Duri area to determine the source rock characterization, which includes the level of richness, the organic matter type, and the level of maturity. The methods used are field data collection and laboratory analysis. A field study is used to collect rock sampling, while laboratory analysis consists of the analysis of Total Organic Carbon content, Rock-Eval pyrolysis, and vitrinite reflectance (Ro). The results of the analysis of Total Organic Carbon on six claystone samples showed values ranging from 0.50-8.97%. Generally, they had the potential to form hydrocarbons in the moderate to special category. Rock-Eval pyrolysis shows Hydrogen Index values from 52–149 mg HC/g Total Organic Carbon has the potential to generate gas, with Tmax values ranging from 414–432, indicating an immature to early mature level of thermal maturity. Ro analysis on three claystone samples with values ranging from 0.40–0.48 %. The hydrocarbon potential of the research area indicates the category of organic material richness is quite excellent, with kerogen including type III. The quality of the source rock based on the value of the Hydrogen Index is included in the category of gas-prone. The low maturity value (both Tmax and Ro) is thought to be caused by the suppression phenomenon in coal-dominated areas, so the values displayed by the two parameters do not correspond to actual values.