Despite the economics and environmental benefits of PWRI (Produced Water Re-Injection) projects, the permeability reduction due to deposited particles is a persistent problem. Various models for permeability damage calculation are available. Most of them are based on one-dimensional laboratory parameters and have not considered the anisotropy of the media. In previous attempts at anisotropy modelling, the initial anisotropy of the media has been considered. However, when it comes to the damage intensity calculation, isotropic parameters have been used for the entire media, As a result, the relative damage in these models is isotropic. In this paper, a robust approach for anisotropic permeability impairment is developed based on micromechanical considerations. The damage mechanics is coupled with numerical flow code. The model formulation has been successfully tested in I D flow against the core flood tests from the Masila Block onshore Yemen. Then, the damage model has been extended to 3D using pseudo directional parameters to capture the anisotropy. A dynamic anisotropic mathematical formulation for damage intensity has been derived, implemented in a 3D numerical code and successfully tested on a field case study. The new model exhibits the expected anisotropy of damage.