Las Mesetas Oeste field is located on the west flank of the Golfo San Jorge basin, 70 km to Las Heras city. The area is operated by YPF S.A. In this field the main productive formation is Bajo Barreal, lower member. It is characterized by stacked fluvial channels which range from 10 to 20 meters in thickness and about 250 meters of lateral extension. The preferential orientation of these channels varies from NNW-SSE to N-S. The knowledge about the morphology and space distribution of this fluvial system is very important to define development projects. In this paper the main objective is to characterize the main fluvial geobody that occur in Bajo Barreal's base formation, which is called "Sección Tobácea". Currently, these reservoirs are poorly developed. The study area covers 180 km2. The seismic cube is Flanco Oeste 3D, which is reprocessed and regularized with 5D interpolation. By using this amplitude volume, we calculated different types of attributes, such as complex trace and spectral decomposition, to detect the main channel feature. Also, we use the electrofacies of the six wells that intercept such channel. The proposed workflow combines seismic attributes and wells information by training several neural networks to predict lithofacies within an interval of interest. In this process, a relationship is established between petrophysical facies and seismic signal changes. As a result, we obtained a volume of predicted facies and the volumes of occurrence probabilities for each facies throughout the area. Through this workflow, we could access the most probable facies and their variability along the main channel. By combining seismic attributes with well information, the interpreter can rely on extra information away from the wells. The predicted volume of facies, combined with geological analysis, provides a valuable tool to define new areas of development. Likewise, it allows optimizing the design and spacing of wells to improve the volumetric calculation and associated reserves. As result of this study, two workovers were initially proposed in areas with good prognosis according to seismic facies, plug-core and petrophysical interpretation.