The study of pore space is of great importance in the evaluation hydrocarbons reservoir, especially in deep reservoir rocks since they control storage and migration mechanisms and can modify reservoir fluid properties. The sandstones studied in this work correspond to the Middle Neuquén Group and are classified as lithic feldarenites. The methodologies used include stratigraphic profile surveys, facies analysis, thin section petrography, petrographic image analysis and computed tomography analysis. The average porosity observed in thin sections is 17,5% and varies between 13,0% and 29,0%. Petrographic image analysis allowed determining the average porosity which corresponds to 27,4% and three basic types of pores: mainly primary intergranular, dissolution of cements (carbonates) and dissolution (congruent and incongruent) of grains (rock fragments) and unstable minerals. The computed tomography scans are 3D images, in which different algorithms were applied for the segmentation and quantification of each of the rock components. In addition, it allowed investigating the morphology of the pores, the origin and, most importantly, the degree of connection that these pore spaces preserve. The integrated study of field, laboratory (petrography) and office (analysis with software) allowed to advance in the understanding of the fluid behavior in fluvial deposits taking into account the spatial distribution of facies, diagenesis (petrographic composition of the pore space) and permeability (3D images).