f 3D kinematic inversion from a set of line profiles

2-D interval velocity analysis is inaccurate in the case of tree-dimensional structures. This is demonstrated on the isotropic two-Iayered model where two reflecting interfaces have conflicted dip azimuths (Figure 1). We consider the profile Y=5km. The stacked section (Figure 2) is obtained from CMP gathers calculated by 3-D ray tracing. Interval velocity analysis along this profile is carried out by the 2-D coherency inversion (Landa et al.,1989). This analysis provides a high coherency (normalized semblance is about 0.8) for both reflection horizons on the CMP gathers.