short t r measurement log 1410 does not correspond to the slowness from the long t r measurement log 1420 this is one indication of inhomogeneity from the crossed dipole data it can be observed that the dispersion curves 1451 1452 do not lie on top of each other there is a characteristic difference in slowness at low frequency that indicates that the formation is anisotropic in addition the measured dispersion curves do not fit the modeled dispersion curve 1453 another indication of inhomogeneity thus it is determined that the formation at the depth of these measurements is inhomogeneous and anisotropic in a form of the present invention an integrated inversion of monopole dipole and stoneley data is performed to select a suitable rock model after classifying the formation using one of the available rock models the processing chain subsequently computes answer products appropriate to the selected model in an embodiment hereof the first stage in the processing chain is to test all of the recorded sonic data for consistency with four different models of the physics as first set forth above in the table the assumed models vary in complexity the homogeneous isotropic model is the simplest model whose physics is well understood i e there is a complete theoretical understanding of sound propagation in a homogeneous isotropic formation the inhomogeneous isotropic and the homogeneous anisotropic models are more complex requiring more physical parameters for their description for each of these models there is not as complete an understanding of sound propagation as there is for the homogeneous isotropic case the inhomogeneous anisotropic model is the most.