Abstract The Cerro Piedra field, west of Las Heras (Province of Santa Cruz), is one of the fields located on the western flank of the San Jorge basin. The occurrence of both amplitude anomalies, as seen on the seismic section, and gas layers (penetrated by several wells) which partially account for such anomalies led us to carry out this study. Its main objective is to implement a methodology aimed at identifying gas zones, which can be extrapolated into adjoining fields. Well data, detail geologic correlations, velocity laws, VSPs (YPF.SC.CP.X-4 and YPF.SC.CP.e-21 wells), and 2D seismic sections are available to achieve the above objective. The study has focused on a gas layer of Tertiary age which occurs at a depth of about 500m below ground level and is approximately 30 m thick. The main interest of this layer concerns its fluid content and the fact that it is within the seismic resolvable limit.