Petrophysical Reservoir Characterizations of the Zubair Formation and Equivalents of the Hauterivian-Aptian Basin

This study presents a comprehensive petrophysical and stratigraphic synthesis of the Zubair Formation and its Hauterivian–Barremian equivalents across five adjacent petroleum provinces: Iraq, Kuwait, Saudi Arabia, the United Arab Emirates, and Iran. Published core plug measurements (effective porosity, absolute permeability, shale fraction) were depth matched to high‐resolution wireline logs (gamma‐ray, density, neutron, sonic, resistivity) via core‐tie workflows. Porosity was obtained from density-neutron overlays; clay volume was obtained from the gamma‐ray log. Facies discrimination combined gamma‐ray vs. density and neutron to classify intervals into fluvial‐deltaic, shoreface, or lagoonal belts, while sequence‐stratigraphic panels were constructed by correlating key flooding surfaces and sand–shale boundaries. Results demonstrate that Iraqi and Kuwaiti delta‐front sands commonly exhibit the highest porosities (18-23 %) and permeabilities (200-600 mD), whereas deeper foreland equivalents in Iran display broader variability (8-22 % porosity, 5-500 mD permeability) due to enhanced compaction and cementation. Diagenetic influences, such as carbonate cementation in the Biyadh Formation (Saudi Arabia) and the Lekhwair Formation (UAE), as well as illite overgrowths in the Lower Zubair (Kuwait), further control reservoir quality. This integrated petrophysical and stratigraphic framework not only elucidates heterogeneity across national boundaries but also provides targeted insights for optimized field development and enhanced recovery planning within this prolific Lower Cretaceous petroleum system.