Evaluation of the Early Cambrian Khewra Sandstone by using Well Log Data, Potwar Plateau, Upper Indus Basin, Pakistan

Abstract

This study presents a petrophysical analysis aimed at evaluating the reservoir characteristics of the Khewra Sandstone in the Saba-1 well, located in the Potwar Plateau, Upper Indus Basin, Pakistan. The study area lies in the southeastern part of the Potwar Plateau. The Early Cambrian Khewra Sandstone is extensively developed and widely distributed across the Upper Indus Basin of Pakistan. The thickness of the Khewra Sandstone in the Saba-1 well ranges from 2526 to 2654 m. Based on variations in petrophysical properties, the reservoir section of the Khewra Sandstone is subdivided into three distinct zones: Sb1, Sb2, and Sb3. Among these, Sb1 is primarily composed of sandstone and exhibits favorable reservoir potential for hydrocarbons, as indicated by relatively high effective porosity (13%) and hydrocarbon saturation (59.8%). Sb2 includes sandstone with minor shale and has moderate reservoir potential for hydrocarbons, as reflected by low effective porosity (10%) and hydrocarbon saturation (58%). Sb3 is composed of shale with minor sandstone and has poor reservoir potential due to its poor effective porosity (2.50%) and hydrocarbon saturation (40%), respectively. The prospective reservoir intervals are found in the upper and middle reservoir zones, and are recommended for future exploration and development. Overall, this study highlights the significance of integrating petrophysical analysis for reservoir characterization and provides valuable insight for future hydrocarbon exploration in the Potwar Plateau and adjoining areas of the Upper Indus Basin.

Keywords: Early Cambrian, Khewra Sandstone, Potwar Plateau, petrophysical analysis, hydrocarbon potential.