Source rock characterization of shale deposits (Eocene) of Kohat Basin,Pakistan

Articles in Press

Document Type : Research Paper

Authors

1 Department of Earth Sciences, University of Sargodha, Sargodha, 40100, Pakistan

2 School of Geosciences, China University of Petroleum (East China), Qingdao 266580, China

3 College of Agriculture, Department of Plant Breeding and Genetics, University of Sargodha

Abstract

Kohat Basin is a well-known petroliferous basin of Pakistan. Problem statements include limited data availability, understanding complex depositional environments, accurately measuring thermal maturity, and resolving the influence of drilling contaminants on geochemical parameters. The main objectives of the current study were to evaluate the source rock characteristics and geochemical properties of organic matter contained in Eocene shale deposits. These objectives were fulfilled by X-ray diffraction (XRD), total organic carbon content (TOC), Vitrinite Reflectance (RO), and Rock-Eval Pyrolysis analyses of shale samples collected from the Dharangi, Naripanos, and Karak sections of the Kohat Basin. XRD analysis shows that the Eocene shale of the Kohat Basin is rich in clay minerals, such as illite-smectite and kaolinite, with smaller amounts of quartz, plagioclase, and K-feldspar. Gypsum, halite, chlorite, and pyrite were present as minor constituents. The TOC values range from 1.60 wt. % to 2.90 wt. %, indicating a good to very good potential source rock. The Oxygen Index (OI), Hydrogen Index (HI), and T-max parameters from Rock-Eval pyrolysis indicate that the Eocene shale comprises type II and type II/III Kerogen, which can generate oil and gas-oil at appropriate temperatures. Vitrinite Reflectance (Ro) values ranged from 0.42 % to 1.28 %, indicating the immature to mature zone of thermal maturity. Overall, it has been evaluated that the Eocene shale of the Kohat basin has good potential for hydrocarbon generation, which can play a significant role in hydrocarbon prospectivity within the Kohat Basin.

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Article Title [Persian]

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References

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Articles in Press, Accepted Manuscript
Available Online from 29 November 2025

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  • Receive Date: 21 August 2025
  • Revise Date: 13 November 2025
  • Accept Date: 29 November 2025

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