Reservoir Characterization, Architecture and Seismic Sequence Stratigraphy Framework of the Santonian Section in the Central-North Area of the Santos Basin
The characterization of reservoir sandstones along wells and their integration with seismic stratigraphy has a fundamental importance in the exploration studies in the Santonian play in the Santos Basin. This work has been done in the central-north area of the Santos Basin, where the fields of Merluza, Lagosta e Mexilhão are located. The main objective is to characterize the Santonian sandstones, which form the one of the most important plays of this basin. To do this petrophysical well characterization and regional 2D seismic interpretation were used, all of this based on concepts of depositional systems and sequence stratigraphy. Petrophysical characterization, using the well log data, was performed on Interactive Petrophysics software (v. 3.4), and has worked to define rock parameters: clay volume, porosity, saturation of water, etc, providing information obout reservoir architecture, flow units and eletrofacies. All well data was exported to Petrel to the next step. The seismic interpretation, using 2D seismic data and well data, was performed on Petrel software (v. 2009.1), in which all the correlated horizons were dsigned and the surfaces created, basically providing information about the sequences, external shape, base and top, among others. The final integration permitted the observation of the behavior and distribution of the Santonian sand bodies, generally associated with slope-controlled turbidite deposits, controlled by a severe halokinetics of the Santos Basin. The sequence architecture is variable along the correlation sections, depending on the location of the well on the depositional systems model; porosity, clay volume, composition, fluid type, diagenesis and burial level are the main controller parameters. The limits of mapped sequences define different sismofacies associations and could be associated with regional unconformities. Some internal sismofacies distribution appears to have a close relationship with flow units geometry, modified by overprinted diagenesis.