Generalized migration

The computation of anisotropic ADCIGs is based on the generalization of integral migration to the computation of a prestack image that includes the subsurface offset dimension ($h_{\xi}$) in addition to the usual image depth ($z_{\xi}$) and midpoint ($m_{\xi}$). Figure 1 illustrates the surface offset dimension: the image point $\left(m_{\xi},h_{\xi},z_{\xi}\right)$ belongs to the migration response of an impulse recorded at midpoint m_D, surface offset h_D and traveltime t_D - provided that the traveltime along the source and receiver paths (of length L_s and L_r, respectively) is equal to t_D.

 

imp-resp Figure 1 Illustration of generalized migration, where the prestack image is function of the subsurface offset. $\gamma$ and $\alpha_x$ are the group aperture and dip angles, respectively.