Diagenesis and Reservoir Rock Characterization of the Samana Suk Formation at Khawri Khwar Section, Nizampur area, Khyber Pakhtunkhwa, Pakistan (T-1421) (MFN 4996)

Abstract

The middle Jurassic Samana Suk Formation is logged and sampled for facies controlled diagenisis and reservoir rock characterization. The facies analysis of the formation revealed Peloidal mudstone, spicules rich mudstone, bioclastic peloidal wackestone, peloidal packstone, peloidal intraclastic grainstone and intraclastic ooidal grainstone microfacies. The facies assemblages of the formation indicate inner ramp shoals to outer ramp depositional settings. The diagentic features of the Formation include cementation, dissolution, micritization, fracturing, stylolite, recrystallization, pyrite mineralization and dolomitization and are explained by meteoric, marine and burial diagenetic history of the rock unit. X-Ray diffraction studies revealed dolomite, calcite, and ferruginous clays cementation within Samana Suk Formation. Based on Scanning electron microscopic analysis the porosity encountered is mainly dissolution porosity, inter-granular porosity and fracture porosity. The dolomitization, dissolution and intergranular porosity is more pronounced in mudstone and wackestone microfacies while fracture porosity is captured by the packstone and grainstone microfacies of the Samana Suk Formation.