Reducing Dependency on Core Data for Permeability Estimation Using Well Log-Derived Electrofacies and Flow Zone Indicators (FZI) in the Mishrif Formation, Nasiriyah Oil Field, South of Iraq

Accurate estimation of permeability is essential for reliable reservoir characterization and simulation. However, core data are often limited due to their high cost and operational constraints, leading to significant uncertainty in uncored intervals. This study aims to reduce the dependence on core data for permeability estimation by integrating electrofacies derived from well logs and flow zone indicator analysis in the Mishrif Formation, Nasiriyah oil field. Electrofacies were generated using dynamic clustering based on the log data from 13 wells. This led to the identification of five electrofacies units that represent intervals with similar log responses, formed by merging 75 electrofacies, where flow zone indicators analysis identified hydraulic flow units based on the porosity and permeability data from cored wells. The resulting model was applied to uncored wells to predict the permeability along the reservoir. The predicted permeability showed high coincidence with measured core data, with a coefficient of determination (R2=0.85168), demonstrating that the integrated electrofacies-Flow Zone Indicators approach provides a reliable and cost-effective method for characterizing heterogeneous carbonate reservoirs and supporting improved reservoir modelling and field development planning.