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Polymer injection is a proven method for enhancing oil recovery by modifying fluid properties and improving sweep efficiency. This study focuses on the fall-off test analysis conducted on a polymer injection well in Field “X” to gain insight into its performance and reservoir characteristics. The pressure-transient signals obtained during the shut-down of the injection well are analyzed using various methods. The analytical approach involves employing the Horner method, Log-log Plot Analysis in Excel, and the Standard Model Analysis in Ecrin Software. A numerical method utilizing the Non-Linear Model in Ecrin Software is implemented, considering additional data such as relative permeability graphs, area boundaries, faults, production history, and reservoir heterogeneity. The fall-off test analysis enables the assessment of reservoir behavior and identification of the reservoir regime, including the presence of bilinear flow or a fractured well with a double porosity PSS reservoir. Furthermore, the transition zone from polymer to water mobility is delineated. Comparative analysis between the analytical and numerical methods demonstrates consistency in determining reservoir properties such as permeability, skin factor, and wellbore storage coefficient. However, the results obtained from the non-linear analysis method are selected for further interpretation due to its comprehensive consideration of additional data. The outcomes of this study provide valuable insights into the behavior and characterization of the polymer injection well in Field “X”, facilitating the optimization of polymer injection strategies and contributing to improved oil recovery in the field.