Reservoir Quality Assessment of Subsurface Sections Across Jurassic Period (Mus and Sargelu) Formations in Duhok Governorate, Kurdistan Region, Iraq

This study investigates the reservoir characteristics of Jurassic subsurface formations, specifically the Mus and Sargelu formations in Duhok Governorate within the Kurdistan Region of Iraq. Through the interpretation of detailed well log data from the X Well, essential petrophysical properties such as porosity, permeability, water saturation, and lithology are assessed to pinpoint potential hydrocarbon-bearing zones. The Sargelu Formation, encountered between depths of 1345 and 1420 meters, is characterized by heterogeneous lithologies dominated by fractured limestones interbedded with shale layers. Notably, this interval reveals effective porosity values reaching up to 18%, enhanced permeability due to fracturing, and favorable water saturation, especially between 1385 and 1400 meters. In contrast, the Mus Formation, situated between 1875 and 1925 meters, comprises primarily limestone and dolomite, displaying variable porosity and resistivity patterns. Crossplot interpretations and Pickett plots indicate potential hydrocarbon presence despite limited direct evidence from gas indicators. Overall, both formations exhibit considerable but variable reservoir quality controlled by lithologic heterogeneity, degree of fracturing, porosity distribution, and shale content. The integrated petrophysical analysis provides a deeper understanding of Jurassic reservoir behavior in this relatively underexplored region of northern Iraq.