Hydrocarbon Potential of Ghazij Formation, Waziristan, Khyber Pakhtunkhwa, Pakistan

Abstract

Petroleum geology is making a substantial role to eliminate the energy crises of Pakistan and brighten the country's conscious future by discovering new petroleum systems. The current research is concerned with the source rock characterization of the Eocene Ghazij Formation exposed at along the Mir Ali Miran Shah Road, North Waziristan. Organic geochemical analysis has been done through Rock Eval Pyrolysis, Biomarker and Petrographic analysis of surface samples collected from the outcrop of Ghazij Formation in the study area. Ghazi Formation in the study area contains insignificant amount of organic matter highlighting its poor source rock potential. The low TOC values are attributed to outcrop sampling where they are disturbed by weathering. Rock-Eval Pyrolysis results highlight the presence of Type II and Type III Kerogen in the lithostratigraphic unit. Pyrolysis Ts and plot of Tas vs. HI has shown that the Kerogen is mature enough to produce gas when in significant amount but Rock-Eval S, and S₂ values have shown its poor source rock potential. Due to the presence of Type II and Type III Kerogen, it has been assumed that the depositional environment of Ghazij Formation is deltaic as it is influenced by the input of both marine and terrestrial biota. Biomarker analysis of Ghazij Formation indicates that the depositional environment is both oxic and anoxic, that shows that the source is mixed (terrestrial and marine) organic matter. Whereas m/z 218 shows that terrestrial is higher than marine organic matter. The sample is thermally mature and indicating carbonate lithology. In the study area, Ghazij Formation contains mature organic matter, but in insufficient amounts to produce hydrocarbons of economical amount. Therefore, from the study, it has been concluded that Ghazij Formation, along the Mir Ali Miran Shah road in North Waziristan has poor source rock for hydrocarbon generation.