NMO Inversion for Multilayer Subsurface with Horizontal Transverse Isotropic Layers

摘要

The NMO inversion problem for HTI medium was solved by Contrera et al (1999) using a technique, originally developed by Grechka and Tsvankin (1999). They derived a formula for azimuth-dependent NMO velocity using 2×2 matrices responsible for the 'interval' NMO ellipses in each layer. Here I suggest an alternative approach to NMO velocity derivation for the multilayered transverse isotropic model with depth-varying orientation of the symmetry axis. This approach leads to a simplier explicit formula for NMO velocity. Explicit analytical formula for azimuth-dependent NMO velocity helps to develop insight on the anisotropy influence on reflection trveltime and to develop Dix-type inversion algorithm