ESTIMATION OF WATER AND HYDROCARBON SATURATION BASED ON WIRELINE LOGS IN CARBONATE ROCKS OF THE SARGELU FORMATION (MIDDLE JURASSIC) FROM THE KURDISTAN REGION, IRAQ

The Zagros Fold and Thrust Belt in Iraq contain host prolific hydrocarbons and recently, significant oil reservoirs have been discovered in the Jurassic carbonate rocks. The current work focuses on Water and Hydrocarbon Saturation in the carbonate rocks of the Sargelu Formation (Middle Jurassic) based on a set of conventional Wireline logs which are: Gamma-ray, Neutron porosity, Bulk Density, three sonic types, all Resistivity, photoelectric, uranium, thorium, and potassium. The Wireline log shows that the Sargelu Formation can be divided into five units based on lithology. These units were derived from different cross plots. The computation of petrophysical properties of this carbonate reservoir is complex due to several washouts and heterogeneities, caused by the exposure of shale which is strongly influencing the reservoir saturation. The Wireline log shows that the average Water saturation in the carbonates of the Sargelu Formation is 20%, with an irreducible Water saturation of 0.2% and an average Hydrocarbon saturation of 30%. Whereas, the water resistivity is 0.03 ohm.m and the Mud filtration resistivity is 0.17 ohm.m.