Predicting Permeability of the Mishrif Reservoir for Non-Cored Wells by Integrating Conventional Well Logs, Routine Core Analysis, and Drilling Data: A Case Study of Southeastern Iraq

This study evaluates the effective permeability of the Mishrif reservoir using porosity-permeability relationships within the hydraulic flow unit framework. It uses different methods, including hydraulic flow unit (HFU) analysis, the classical method, and empirical correlations, by integrating the conventional well logs, routine core analysis, and drilling data by using Techlog software to predict permeability for non-cored wells in three wells (X-7, X-13, and X-15) for the Mishrif Formation, which is located in the Buzurgan oilfield in a southeastern Iraqi oilfield. Environmental corrections are applied to ensure accurate interpretations of log data, showing that the results of the corrections removed the borehole effects for density and gamma-ray logs. Clay volume calculations, porosity estimations, and permeability calculations are performed for the reservoir units (mA, mB, and mC) within the Mishrif Formation. The Mishrif Formation is characterized by limestone with some dolomite, indicating secondary porosity and gas effects; these results were confirmed by core and drilling descriptions. The hydraulic flow unit uses techniques that are significantly different from other flow units, such as vertically and laterally dividing the reservoir into zones to control and manage fluid flow. By using the relationships of the flow zone indicator method, each flow unit can be distinguished. In addition, the calculated porosity is confirmed by core porosity, where high matching exists between them. The FZI method provides accurate permeability estimation of the reservoir quality. It identifies the flow unit utilized for non-cored intervals in the Mishrif carbonate reservoirs, where the result is confirmed by core permeability, outperforming the classical method and empirical correlations.