Source Rock Characterization for Hydrocarbon Generative Potential and Thermal Maturity of Sutunga Coals, (East Jaintia Hill) Meghalaya, India: Petrographic and Geochemical Approach

Abstract

The study presents hydrocarbon generative potential and thermal maturity of the Paleogene coals from Sutunga, Meghalaya, India using petro-geochemical method. The petrographic examination showed that the analyzed samples contain abundant vitrinite group macerals (mean 71.8%) with a significant amount of the liptinite (17.4%) group maceral, while the concentration of inertinite group is less (3.1%). Vitrinite reflectance (0.38 to 0.69 %Rom), indicates that the rank of Sutunga coals as sub-bituminous ‘B’ to high volatile bituminous ‘C’. The results obtained from rockeval pyrolysis show that the hydrogen index (HI) ranges from 245 to 348 mg HC/g TOC and temperature at S2 peak (Tmax) is 412 to 441 °C. These coals contain Type III and Type II/III kerogen and are immature in nature. The total organic carbon (TOC) and S2 yield of Sutunga coals vary from 27.5−93.3 wt%, and 86.0−300.1 mg HC/g rock respectively indicating its high potential for hydrocarbon.