Integra lDMO in anisotropic media

Integral (Kirchhoff-style) dip moveout (DMO) is an efficient way of handling irregular common-midpoint (CMP) geometries that are typical of 3-D seismic surveys. An anisotropic implementation of the integral DMO requires proper and efficient construction of the DMO operator. Developing the DMO impulse response in a transversely isotropic u(z) medium requires solving a system six equations to obtain six unknowns that include, among other things, the zero-offset time and surface position of the specular reflection point. However, in 2-D homogeneous media, the system of equations need to be solved reduces to two, which can be efficiently handled using any numerical technique. Also, to aid in the efficiency of the DMO implementation, the DMO operator is developed using equations of group and phase velocities established by setting Vso=O Although not a practical setting, such a simplification yields DMO operators in TI media that are extremely close to those obtained with a more practical value of Vso (=0.6 Vpo) at a reduced cost. Additional efficiency measures are suggested in the Kirchhoff implementation. This includes setting up tables of DMO operator trajectories for each offset, which is necessary to eliminate repetitive construction of the operator.