Inverting geophysical data for reservoir properties of interest requires linking the underlying geology to the observed data. In order to do so, the geologic heterogeneity needs to be modeled to examine how it controls the reservoir properties and affects any geophysical measurements. This task becomes exceedingly complex because of the infinite number of possible geologic models that could be constructed even though most of them are unreasonable from a geologic standpoint. If seismic data are used to constrain that modeling process, then the ambiguity in the problem may be reduced. Two reservoir parameters of interest for both fluid-flow and geologic modeling are saturation (Sw) and net-to-gross (N/G). Rock-physics trends indicate that the elastic and seismic responses of these two properties typically overlap one another. In seismic applications, therefore, a change in one property can be easily misinterpreted as a variation in the other. Within a reservoir-modeling scenario, how can these two parameters be conditioned by seismic data, and ultimately how can they be extracted from seismic amplitude given the inherent ambiguity?