Figure 3. Simplified stratigraphic chart of the Eastern Venezuela Basin (after Heppard et al., 1998). Major source rock intervals have been identified as the Upper Cretaceous San Antonio and Querecual formations in eastern Venezuela and the Naparima Hill and Gautier formations in Trinidad. Units that have been important reservoirs are also indicated. The dotted line indicates the diachronous nature of top overpressure as it climbs stratigraphically to the east.