Geological Interpretation regroups a set of "applets" to perform marker and fault interpretation, well correlation and fine scale stratigraphic modeling from isochore. Fine model stratigraphy is controlled by isochore construction, 2D correlations of stratigraphic boundaries and paleo-geologic maps. Quality control and easy interactive editing are available in 2D and 3D in order to provide the Reservoir Modeling Module with an accurate stratigraphic and fault analysis model. Fault contact QC and editing provides quality control for the Seismic Interpretation Module; fault displacement and juxtaposition diagrams can validate the horizon/fault contacts. Before constructing a reservoir model, faults contacts and displacement obtained from interpretation need to be validated and eventually edited. Fault/horizon contacts are typically difficult to interpret, so innovative visualization techniques and fast editing tools provide essential help in the construction of coherent reservoir models.