Petroleum source rock characterization and hydrocarbon generating potential of sediments from Surghar range, Kohat plateau, Upper Indus Basin

Abstract

This study focusses on the investigation of hydrocarbon generating potential of the Surghar Range Kohat Plateau, Upper Indus. The potential source rock of Paleocene, Cretaceous and Jurassic rocks including the Patala, Hangu, Chichali, SamnaSuk, Shinawari, Datta formations were assessed through geochemical analysis of their well cuttings. These analyses include Rock-Eval Pyrolysis, TOC, Kerogen type, thermal maturity and depositional environment. The TOC, wt. % reveals that sixteen samples of M-03 well of Patala Formation (0.91−10.62 wt %) show excellent quality, while other formations belong to N-02 and C-02 exhibit have fair to good quality of OM. The hydrogen index (HI) values of M-03 oil well for the Patala formation are ranging from 200 to 318 exhibit Type II/III Kerogen. HI value of N-02 well for the Patala Formation are greater than 300 indicates Type II Kerogen whereas other samples show OM of Type III Kerogen. The thermal maturity of the Patala Formation of M-03, N-02 and C-02 oil wells falls in early stage oil window and all the other analyzed formations are thermally immature. Genetic potential is generally in good range except for small number of samples from Chichali, SamanaSuk, Shinawari and Datta formations, which indicate poor genetic potential values. This study uniquely identifies the kerogen types and thermal maturity of under study formations, providing critical insights for understanding their economic viability. By highlighting the differences in organic matter quality across formations, it fills a gap in the existing literature and supports informed decision-making for future exploration efforts.