Reservoir Characterization of Eocene Carbonates and Cambrian Sands in the Eastern Potwar Region, Pakistan

Hydrocarbon prospectivity in fold-and-thrust belts remains inherently uncertain due to the combined effects of structural complexity and heterogeneous reservoir properties. The Eastern Potwar region of Pakistan, characterized by imbricate thrust systems, anticlines, and synclines, represents a typical example where conventional approaches often fail to adequately constrain reservoir quality. This study integrates seismic interpretation with rock physics modeling to evaluate the hydrocarbon potential of the Missakeswal area. Seismic analysis delineates the structural framework controlling trap development, while rock physics modeling of well log data provides quantitative constraints on lithology, porosity, and fluid effects within Eocene carbonates and Cambrian sandstones. The results demonstrate a clear inverse relationship between velocity and porosity in the carbonate units, together with significant deviations from standard empirical models in both carbonate and sandstone intervals. In particular, the Eocene carbonates exhibit deviations of up to 25% from the Raymer model for water-saturated limestone, indicating probable hydrocarbon saturation, whereas the Cambrian sands show dispersion consistent with clay-influenced elastic behavior. The integrated interpretation highlights the Missakeswal area as a promising exploration target, and demonstrates that the combined use of seismic and rock physics analysis provides a robust framework for reducing uncertainty and improving reservoir characterization in tectonically complex basins.