This paper represents the third installment in a sequence of reservoir characterization articles that follow a workflow whose ultimate goal is to understand and predict the rock properties of a reservoir away from well control. The first article (Singleton, 2008) described a method to detect anomalous seismic attenuation. This was important because seismic data at the well location have a steep falloff in amplitude caused by high attenuation in and above the reservoir interval. The second article (Singleton, 2009) dealt with the seismic gathers that were input into the inversion process. It is of the utmost importance that the quality of data input into a simultaneous prestack inversion be as high as possible. Errors in seismic gathers (low SNR, resolution loss from excessive NMO stretch, nonflat reflectors, offset amplitude problems, multiples, etc.) are broadcast straight into the inversion impedance volumes, so this is a critical step in geophysical reservoir characterization.