Characterization of Natural Fractures of Vaca Muerta and Mulichinco Formations in filo Morado structure, Neuquén Basin, Argentina Filo Morado is a structurally complex mature field, located in the Fold and Thrust belt of the Neuquén Province, which has been produced from fractured traditional reservoirs, Mb. Troncoso Inferior and Mb. Avilé. This study focuses on deeper units, below the currently developed ones, which are naturally fractured tight sands from Mulichinco and Vaca Muerta Formations. Filo Morado structure is characterized by a complex structure with several faults, which experienced a complex tectonic evolution through the rotation of the main horizontal stress over time. A geomechanical approach using progressive 3D models according to the different tectonic phases was carried out. This model allowed analyzing the effect of remote stresses on fault planes which create local stress fields. These interactions caused the generation of different fracture sets, orientations and main intensity fractured zones. In this mechanical model we used a homogeneous half-elastic space with a linear elastic and isotropic behavior characterized by two constants, Poisson’s ratio and Young’s Modulus. The stress tensor computed on Vaca Muerta and Mulichinco formations observation grids was combined with a Coulomb failure criterion and maximum Coulomb shear stress to create maps of both the probable secondary fault strike and location, calibrated with boreholes images data. Besides the Filo Morado field, this approach can be used as a new tool for the identification of new plays and targets in analogous structurally complex zones.