Developing an oil reservoir has the challenge of dealing with subsurface, hence indirect data. To solve this, it is important to establish a strong conceptual model that fits with the available information. In the case of natural fractures, it is critical to understand their type and origin, which will help to decrease the uncertainty when building the natural fracture model. This paper aims to show the workflow applied to study the Huitrín Formation, located in a complex structural area in the Malargüe fold and thrust belt, in western Argentina. Initially, oil field data was analyzed, involving the characterization of the natural fractures observed both in cores and borehole images, and the structural interpretation of the available 3D seismic information. To build a more accurate conceptual model of the fracture system, a study of an analogue outcrop was performed. Fracture modes, orientation, spatial arrangement, hydraulic and kinematic apertures, cement composition and abundance, and their relationship with stratification were measured through scanlines. Thin sections of rock samples and fracture cements collected in the field were analyzed. Cement textures, composition and crosscutting relationships were observed and described. This information was useful to create a sequence of events that generated the different fracture sets through time. The integration of subsurface and outcrops data resulted essential to achieve an adequate characterization of natural fractures. These studies managed to reduce uncertainties in the geological model, providing useful data for structural interpretation, resource estimation and drilling parameters, among others.