The sequence stratigraphic analysis of Lajas Formation allowed to strengthen the knowledge of tight-gas reservoirs, in the Southeastern area of Neuquina ś basin, in the Río Neuquén field, Argentina.The seismoestratigraphic relationships, cores and logs led infersubsurface’s geometries such as clinoforms, which were related to mouth-bars. In addition, delta front lobes and transgressive deposits geometries were also identified. Based on this analysis, the evolution was interpreted. As a result, geobodie ś varieties, the setting of possible sandstones facies and the flow ś source were identified.The detail examination led to define the different hierarchies; such as parasequencesand systemstracks. Therefore, the Lajas Formation in this area constitutes a third-order sequence framework.The proposed geological-model shows better predictive characteristics and provides tools to find new stratigraphic plays, not only on the higher structural levels, also it offers advanced opportunities for development.The combination of production data and reservoir studies is consistent with the proposed sequence-stratigraphic model, enabling to understand heterogeneities, lateral continuity and reservoir connectivity features.These studies have an impact on minimizing the risk in reserves calculations and accuracy of production forecasts for future developments. Moreover, it allows to design new scenarios and development strategies for vertical as well for horizontal wells