Kerogen geochemistry and thermal decomposition kinetics of Early Permian shales from the Talchir Basin of Odisha, Eastern India.

Talchir Basin forms the southeastern end of the Gondwanan Son–Mahanadi Master Basin of India and hosts extensive sedimentary successions of coals and shales of Early Permian to Upper Triassic ages. Significant coal-bearing formations in the basin include the Barakar and Karharbari. This study intends to characterize the properties of kerogen in carbonaceous shales and coals of the Barakar and Karharbari Formation of Talchir coalfield in the Talchir Basin of Odisha, Eastern India, along with their kerogen degradation kinetics, to infer the hydrocarbon generation potential. The samples form part of formations exposed in the Kaniah and Nandijhar regions of Angul in the state of Odisha, Eastern India. The total organic carbon (TOC) content of carbonaceous and silty shales from Kaniah ranges between 1.9 to 9.6 wt.% and 1.1 to 7.2 wt.%, respectively, whereas that of coals ranges between 16.6 and 46.9 wt.%. The pyrolysis Tmax lies between 417° and 530°C. Organic matter is characterized by Type III, thermally immature to early mature kerogen. Kerogen decomposition kinetics indicates wide activation energy distribution, while its transformation and hydrocarbon generation occur at lower temperatures with faster rates. Compared to Karharbari, the organically rich and thermally mature shales of Barakar exhibit promising potential for natural gas generation. Research highlights: Kerogen properties and thermal decomposition kinetics of Permian Shales, Talchir Basin, Eastern India. High TOC content (1.9–46.9 wt.%); however, low thermal maturity in immature to early oil window. Kerogen transformation and hydrocarbon generation occur at lower temperatures with faster rates. Suitable for facile conversion into hydrocarbon products using artificial processes. [ABSTRACT FROM AUTHOR]