ORGANIC GEOCHEMICAL CHARACTERIZATION AND SHALE GAS POTENTIAL OF THE PERMIAN BARREN MEASURES FORMATION, WEST BOKARO SUB-BASIN, EASTERN INDIA

This study investigates the shale gas characteristics of the Permian Barren Measures Formation (Gondwana Supergroup) in the West Bokaro sub-basin of the Damodar Valley Basin, eastern India. A total of 23 core shale samples collected from a borehole located in the western part of the sub-basin were analysed using organic geochemical techniques and scanning electron microscopy. The samples are black carbonaceous shales composed chiefly of quartz, mica and clay minerals. Rock-Eval pyrolysis data show that the analysed samples contain a mixture of Type II and Type III kerogen with TOC values of 2.7 to 6.2%. Rock-Eval T-max values ranging from 443 to 452 degrees C correspond to calculated vitrinite reflectance of approximately 0.8-0.9%. A cross-plot of hydrogen index versus T-max indicates that the samples have reached peak oil to wet gas maturities. A pristane/n-C-17 versus phytane/n-C-18 cross-plot, together with biomarker parameters such as the dominance of C-29 over C-27 and C-28 steranes and high moretane/hopane ratios (0.22-0.51), demonstrate that the shale samples contain terrigenous organic matter deposited in a suboxic environment. Scanning electron microscopy images of shale samples show the presence of a complex, mostly intergranular pore network. Both micropores (>0.75m) and nanopores (