ORGANIC PETROGRAPHY AND GEOCHEMICAL CHARACTERIZATION AND BRITTLENESS INDEX OF SELANGKAI GROUP, PEDAWAN FORMATION, AND SILAT FORMATION GAS SHALES, SANGGAU, SINTANG, AND PUTUSSIBAU REGION, WEST BORNEO

• Main Author: Ilham Nurkamil, Muhamad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/32669
• Institution: Institut Teknologi Bandung

The research location is divided into two areas, namely Sanggau and Sintang-Putussibau region, West Kalimantan Province. Geographically, research location in Sanggau region is located at coordinates 110015'00'' - 110030'00'' East Longitude and 0024'1'' - 0o45'00'' North Latitude and Sintang-Putussibau region is located at coordinates 111045'00'' - 112039'42” East Longitude and 0009'00” - 0022'19'' North Latitude. The analysis of geochemistry and organic petrography and brittleness index were carried out on ten surface samples of Selangkai Group, Eight Samples of Pedawan Formation, and Seven Samples of Silat Formation to determine its characteristics of quantity, quality, and maturity of organic matter as well as the value of gas shales brittleness index. Organic geochemical analysis consists of TOC (Total Organic Carbon) and Rock-Eval pyrolysis. Organic petrography analysis includes analysis of maseral and mineral matter, vitrinite reflectance, and TAI (Thermal Alteration Index). Brittleness index analysis through XRD (X-Ray Diffraction) quantitative. Based on the analysis results, gas shales of Pedawan Formation have quantity in poor to very well category, Selangkai Group and Silat Formation have quantity in poor to well category. Dominant of organic matter quality as type III kerogen and four samples of Silat Formation as type III-II kerogen. The maturity level lies on mature to over mature. Samples of the research area have vitrinite maseral group ranging from 6.3 to 16%. The correlation between PY and vitrinite maseral group was directly proportional or positive very strong relation in all samples, indicating the vitrinite maseral group controlled in producing hydrocarbon gas in the research area. Interpretation of gas shales depositional environment of Selangkai Group, Pedawan Formation, and Silat Formation are the lagoon environment based on the presence of lamalginite and framboidal pyrite. The value of gas shales brittleness index of Pedawan Formation ranging from 25.5 - 60,2%, Selangkai Group 26.6 - 60,3%, and Silat Formation 20,5 - 32.3%. Based on the comparison result between quantity, quality, and gas shales brittleness index with success parameters of gas shales exploration, Selangkai Group, Pedawan Formation, and Silat Formation are less suitable to be nonconventional gas bearing shale.