Natural fracture reservoirs are one of the most challenging ones in terms of understanding thus modeling. The available computational tools allow representing withgood degree of certainty the presence, intensity and orientation of natural fractures in subsurface. Still, from the geological point of view, the effort should be concentrated in establishing the origin of the fracturesystem, the so called Conceptual Model. Whichever the selected method for fracture modeling (e.g. Geometric, Geostatistic, Geophysic or Geomechanic) it should be tied to a geological logic and to the available data like geological and structural models, fracture data from image logs, cores, side well cores and even outcrop analogs when available. To develop a Conceptual Model, it is fundamental to stablish the natural fractures generation mechanisms, being the tectonism and the lithostatic weight the most common factors, and fracturing by intrusion or by cooling-down of volcanic rocks and related rocks. So, it is necessary to understand the deformation history in the study area.In this study an Upper Triassic to Lower Jurassic volcaniclastic sequence, characterized by ignimbrites, ash-fall tuffs, subaqueous flows and volcanogenic sedimentary deposits, was generated during a Syn-rift phase, later reactivated at least three times. Based on well data analysis and interpretation, six different cementation stageswere recognized.Two of them, so called E2 and E3, were interpreted as cretaceous due to microthermometry after fluid inclusions analysis. Other characteristics such as fracture sizes, orientations, aperture and a potential link within volcaniclastic facies were determined.All this information resulted in the main guidelines for the subsurface 3D Natural Fractures Model