Finite-difference migration by wave extrapolation in three dimensions

Three-dimensional wa ve-equation migration techniques are still quite expensive because of the huge matrices that need to be inverted. Several techniques have been proposed to reduce this cost by splitting the full 3D problem into a sequence of 2D problems. We compare the performance of splitting techniques for 3D Finite-Difference (FD) migration techniques in terms of image quality and computational cost. The FD method is complex Pad ´ e FD, and the compared splitting techniques are two and alternating four-way splitting, i.e., splitting into the coordinate directions at one depth and the diagonal directions at the next depth level. From numerical examples in inhomogeneous media, we conclude that alternate four-way splitting yields better results than the two-way splitting, with the same cost.