Modeling the effects of natural fractures closure in the hydromechanical behavior of 3D reservoirs using high aspect ratio interface elements

Natural fractures significantly influence fluid flow and mechanical behavior in geological reservoirs, acting as preferential flow paths and different deformation planes. To realistically capture such effects, numerical models must incorporate these discontinuities explicitly. In addition, changes in effective stresses and reservoir depletion can lead to significant variations in hydromechanical properties, increasing the complexity of coupled analyses and hindering the assessment of reservoir production performance. This paper presents a three-dimensional discrete fracture model approach for modeling hydromechanical processes in naturally fractured media. The method employs high aspect ratio interface elements to explicitly represent fractures within a continuum mechanics framework, eliminating the need for special shape functions or integration schemes. Fracture deformation is governed by a progressive contact model based on the Barton-Bandis empirical formulation, widely used in rock mechanics. The performance and applicability of the proposed approach are demonstrated through a series of 3D numerical examples representative of realistic reservoir conditions.