A multi-layer reduced model for flow in porous media with a fault and surrounding damage zones

In this work, we present a new conceptual model to describe fluid flow in a porous media system in presence of a large fault. Geological faults are often modeled simply as interfaces in the rock matrix, but they are complex structures where the high strain core is surrounded by the so called damage zones, characterized by the presence of smaller fractures which enhance the permeability of the medium. To obtain reliable simulation outcomes, the damage zone as well as the fault, have to be accurately described. The new model proposed in this work considers both these regions as lower dimensional and embedded in the rock matrix. The model is presented, analyzed, and tested in several configurations to prove its robustness and ability to capture many important features, such as high contrast and heterogeneity of permeability.