DIAGENESIS AND RESERVOIR CHARACTERIZATION OF EOCENE ROCKS UNIT IN BALAKOT AREA, HAZARA DIVISION, KHYBER PAKHTUNKHWA, PAKISTAN

Abstract

A well preserved 84 meters thick section of the early Eocene carbonates is exposed along Batsangra road, in village Magrah, Balakot area. The stratigraphy of the study area ranges from the Cambrian to the Miocene age. In addition to this, the area contains the Cambrian Abbottabad Formation, the Early Paleocene Hangu Formation, the Late Paleocene Lockhart Formation, the Patala Formation, the Early Eocene Margalla Hill Limestone, the Chorgali Formation, and the Miocene Murree Formation (Ding et al., 2016). The Eocene unit of the study area includes Margalla Hill Limestone and Chorgali Formation, which consist mainly of light to darker gray nodular limestone with intercalated shales and marls. It has been studied to recognize different diagenetic environments for the observed diagenetic features and the reservoir characterization in the Eocene rock units. The Margalla Hill Limestone and Chorgali Formation are highly affected and modified by different diagenetic processes which have either reduced or enhanced the reservoir potential of the Formation. The micritization, neomorphism, dissolution, replacement, cementation, limestone nodularity, both mechanical and chemical compaction, fracturing and veins of calcite contribute to the various diagenetic processes. The porosity is observed both microscopically and macroscopically, it includes intergranular and intragranular porosities. Fracturing and dissolution are the important diagenetic processes which have enhanced the reservoir potential of Margalla Hill Limestone and Chorgali Formation. The diagenitic features and the reservoir characterization of the Eocene Carbonates exposed at Magrah Village along the Batsangra Road, in Balakot region have not been studied yet.