Rock Physics Modeling is the process of finding a rock physics model that is consistent with the well and core date available, and can help us understand the behavior of the reservoir and non-reservoir zones. The process can also correct for some of the problems encountered in well log data. For example, we may find that some zones in the well are closely fitted with an unconsolidated sand model while other zones follow critical porosity or elliptical crack models. These models may have adjustable parameters such as pore aspect ratio or critical porosity that can be determined empirically from the local data. Similarly, some Va prediction methods are best calibrated to local conditions if core Vp & Vs data or dipole shear wave logs are available. Rock physics calibrations can also aid in selecting a fluid mixture model. Well log data can also be compared to available lab deta and to theoretical limits.