ABSTRACT This study investigates the characteristics of the shale facies of the Thanetian‐Ypresian Patala Formation, Kohat Plateau (North Pakistan) using integrated geochemical, mineralogical and petrographical data, along with 1‐D basin modelling analysis. The present work is designed to evaluate the unconventional oil‐bearing shale potential within the Patala Formation. The studied Patala shale facies exhibit total organic carbon (TOC) in the range of 0.51–1.54 wt.%, indicating a good source rock. The Patala shale facies represents a prospective hydrocarbon source rock, predominantly inclined toward oil generation, as it is chiefly composed of Type II and mixed Type II/III kerogen. The Patala shale facies is also characterized by a high oil saturation index (OSI) between 32.8 and 86.5 mg HC/g TOC, indicating a strong potential for oil‐bearing shale. This finding is consistent with a kerogen transformation ratio (TR) reaching approximately 65%, as demonstrated by 1‐D basin modelling of the transformation of kerogen. The substantial kerogen conversion sufficient for commercial oil generation is supported by thermal maturity stages between peak‐mature and late‐mature, reflected by vitrinite reflectance (%VRo) values between 0.86 and 1.06. However, the maximum oil generation, with TR values exceeding 50%, leads to high pressure and results in micro‐fracture pores in the Patala shale facies. Consequently, the Patala shale facies can be considered an unconventional shale‐oil reservoir, promising target for production purposes in the Kohat Plateau (North Pakistan) using hydraulic fracturing techniques.
Ishaq et al. (Thu,) studied this question.