Forward modeling of sedimentary systems is a method that simulates sedimentation processes over geological time to generate a set of facies distributed in a depositional space. The objective of using forward modeling in this work was to build a three-dimensional facieś model, from which a synthetic seismic simulation was generated, and then to analyze the relation of seismic-stratigraphic interpretations with the knowledge of the a priori generated sedimentological model. This modeling methodology was applied in a pre-salt field of the Santos Basin, Brazilian offshore, focused on the Barra Velha Formation. The modeling parameters used were (i) the initial surface of bathymetric depth; (ii) the lake level variation; (iii) the subsidence map; and (iv) the deposition rates by facies. Average-constant of acoustic impedance values were assigned to each facies and a synthetic seismic was obtained. With the facies and synthetic models available, it was possible to analyze: (i) the distribution of thicknesses and proportion of facies by region; (ii) the vertical stacking pattern and lateral facies variation; (iii) the Wheeler's distance x time diagram; and (iv) the seismic reflector patterns through the seismic facies classification. Through these analyses, it was possible to better understand the possibilities and limitations of seismic stratigraphy as an interpretation auxiliary tool in pre-salt carbonate environments.