Influence of diagenetic features on petrophysical properties of fine-grained rocks of Oligocene strata in the Lower Indus Basin, Pakistan

Abstract Nari Formation is considered as one of the most important oil and gas exploration targets. These fine-grained tight sandstone reservoirs face enormous challenges due to their extremely low matrix porosity permeability. Hence, in this regard, study was carried out collect high-quality data on petrophysical properties along with mineralogy microstructural characteristics diagenesis. The experiments performed includes petrographic scanning electron microscopy, X-ray diffraction analyses. Besides, measurement assess likely influence reservoir quality. analysis shows predominantly fine- medium-grained grey samples calcite, clay, lithic fragments iron oxides. Further, thin-section observations revealed that quartz a principal mineral component all analysed ranging from 52.2 92.9%. bulk volume clay minerals range 5.3 16.1% of. permeability measured 5.08 18.56% (average 7.22%) 0.0152 377 mD 0.25 mD), respectively. main diagenetic processes affected sandstones are mechanical compaction, grain deformation, cementation dissolution have played significant role influencing quality rock. Overall, it appears primary (porosity permeability) were decreased lithification, cementation, framework dissolution. Based integrated mineralogical, analysis, laboratory-based properties, exhibited poor porosity, permeability, moderate content, which indicate reservoir.