Advanced seismic techniques such as EEI inversion, simultaneous inversion and so called facies based inversion are now routinely adopted for quantitative reservoir characterization of rock properties. Rock physics provides the crucial link between the quantitative geophysical measurements derived from inversion and geological parameters. However, in order to ensure that rock physics parameters, as encountered in well data, are accurately determined from spatially equivalent seismic data requires specialist processing beyond conventional image orientated workflows. Seismic data conditioning is specifically designed to provide a calibrated and conditioned AVO signal. In this regard reservoir specific processing routines are developed to mitigate multiple, random and coherent noise, over or under-corrected seismic velocities, frequency distortions and other undesirable effects. Synthetics generated at well locations are crucial for quality control at each step of the seismic data conditioning workflow. This paper demonstrates the advantages of performing seismic data conditioning, on a regional (multi-survey) North Sea seismic dataset, prior to reservoir characterization using a facies based inversion.