Variations of internal pressure within reservoirs structurally compartmentalized by sealing faults induce changes in deformations and stresses. If these changes are significant, they can create favorable conditions for fault reactivation by shear or tensile modes. In that scenario, the conditions that develop within reactivated fault zones can trigger potential geomechanical problems such as oil exudation, seismicity and loss of casing integrity. Therefore, it is necessary to forecast the geomechanical behavior of the field and establish limits for pressure changes within the reservoir. This paper deals with a methodology for the evaluation of fault reactivation and fluid migration, using 2D and 3D Finite Element models. In these models, discrete faults are introduced through zero thickness interface elements. The reactivation mechanisms and fluid migration are controlled by the Mohr-Coulomb plastification criterion. 2D and 3D geomechanical models of a field with a set of faults were built in order to compare their predictions. According to the results, different injection pressure limits can be obtained using 2D and 3D models. Furthermore, the 3D configuration of faults that intersect each other can create preferential flow paths for migration of fluids which are not observed in simplified 2D models.

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