Abstract This paper presents a new methodology to evaluate mechanical formation damage due to drilling and oil production. The methodology covers a wider range of stress path adding new insight to fluid flow analysis in porous media. In some reservoirs occur large deformations during oil production due to the increasing of effective stresses. This may cause permanent damage to the reservoir, as the rock structure changes, lowering the permeability and the final oil recovery. A series of rock mechanics tests were carried out, including velocity measurements of P and S waves. These tests showed that plastic behavior is always present and that a yielding region occurs and that it may be represented by the cap model. This methodology allowed a near wellbore evaluation and permeability investigation using stress path concept.