Unrevealing the Depositional Facies, and Diagenesis of Drug Formation in Zindapir Anticline, Sulaiman Province, Dera Ghazi Khan, Pakistan: Reservoir and Source Rock Characterization

Abstract

In this research work Eocene’s Drug Formation of 583m, measured in the Zindapir Anticline section is systematically sampled from each bed. Detailed petrographic analysis and microfacies study is conducted on the collected samples, furthermore, porosity, permeability, and plug analysis were also performed. The objectives were to specify the microfacies and their depositional environments and diagenetic changes as well as reservoir and source rock characterization. On the base of microfacies analysis Drug Formation is classified into twelve different facies which disclosed that the formation is deposited in the inner-shelf environment embracing tidal (MF1), lagoonal (MF2-MF5), back-reef (MF6-MF9) and fore-reef (MF10-MF12). Diagenetic alteration is studied from early to late stages. In eodiagenesis, micritization and bioturbation took place in significantly shallow marine environments and dissolution in meteoric environments. During mesodiagenesis cementation of blocky calcite, compaction, and dolomitization along the fluid path occur. Fracturing is caused during telodiagenesis. TOC of studied samples shows Drug Formation is fair to poor source rock and has an immature production index. The plug analysis of selected facies shows that the depositional texture of Drug Formation is impervious and of poor reservoir quality