LAUSR

Abstract The compressional and shear-wave velocities ( V P and V S ) have been used in studies for hydrocarbon exploration over the last decades. Nevertheless, the absence of S-wave velocity records in geophysical surveys is common. In this work, we applied the iterative method proposed by Lee (2006), which allows evaluations of P- and S-wave velocities by estimates of the consolidation parameter α. We use well-log datasets from a turbiditic reservoir at Namorado Oilfield (Campos Basin, southeastern Brazil) to test this methodology. Results were further compared to a well-established empirical model (Greenberg and Castagna, 1992). We verified a good agreement for V S results provided by both methods, and a consistent correspondence between the measured V P and those calculated by the Lee (2006) method. It was also possible to assume the reliability of the α values, although the presence of denser lithologies may produce local artifacts, which affect V P ( α ) and V S ( α ) estimates. Furthermore, the results for α, V P ( α ) and V S ( α ) pointed to: (i) an upward trending for V P V S ratio values, for profile NA-01, that indicate a possible hydrocarbon-filling zone; (ii) the presence of two distinctive α data groupings with respect to porosity, which are clearly influenced by the involved type of lithologies; and (iii) the absence of a straightforward relationship between α and porosity under pressure conditions.