Anisotropic Migration Velocity Analysis by Joint Tomographic Inversion

With the advance of sophisticated and sensitive imaging tools like TTI RTM, accurate estimation of anisotropic parameters is becoming more and more important. To overcome the limitations of the time domain approaches, we propose a depth-domain technique, which is based on the migration velocity analysis principles; one of the key aspects is the use of an automatic non-hyperbolic moveout picking algorithm, which is applied on the depth migrated CIGs. The method is based on the joint inversion of two anisotropic velocity volumes, to properly describe the non-hyperbolic residual moveout curve both at short and long offsets. The method is applied to both synthetic and field data, showing how this approach can obtain a good anisotropic focusing velocity if the data contains sufficiently large offsets, but still one or more wells are needed to constrain the vertical velocity.