The San Eduardo Member corresponding to the Hauterivian, is proposed by Zavala et al (2002), within the Pilmatué Member, with a thickness of approximately 150 meters composed of tabular banks of fine to very fine sandstone, massive, partly calcareous towards the base, whose individual thicknesses range from 20 cm. up to 130 meters of power. This unit outcrops near to the locality of the same name. Since this identification on the surface, several exploratory prospects have been defined with the aim of individualizing the unit in the subsoil and evaluating its potential as a reservoir. This paper presents a petrophysical characterization works carried out by integrating geological control data and well log, from one of the wells carried out, having the aforementioned surfaceanalog as a geological model. The result of this integrated study, based on the inverse methodology of interpretation of logs (probabilistic method), showed a tight gas reservoir; with a total thickness of more than 100 meters; with porosities less than 10%; an evaluated average permeability of 0.001 mD (from the magnetic resonance recording); with gas production forecast. The estimated net thickness was around 90 meters. Likewise, a pore size characterization work was carried out using the information from the magnetic resonance recording. The choice of the probabilistic method allowed obtaining interpretation models applicable to the available well information, integrating outcrop data, conventional and special electrical log, and gas chromatography and description of geological control drilling cuttings