Macro-model independent migration to zero offset (CRS-MZO)
German Garabito, João Carlos Ribeiro Cruz, Walter Söllner · 2009
The Common-Reflection-Surface (CRS) stack is a well-established time imaging method that provides high quality stacks of three or two-dimensional seismic data, and important kinematic wavefield attributes, i.e. the emergence angle of the normal reflection ray, and also the radii of curvatures of the normal incidence point (NIP) and of the normal (N) waves. In the present work, we adapt the CRS stack approach for a situation of diffraction points. The obtained formalism is called Common-Diffraction-Surface (CDS) stack operator, which is successfully used to migrate multi-coverage seismic data to zero-offset sections (MZO) without knowledge of a macro-model. Like CRS method the CDS stack is defined by a second order (hyperbolic) paraxial traveltime approximation that depends on two wavefield attributes: The emergence angle of the normal ray and the radius of curvature of the NIP wave. Because the CDS stack operator depends on the kinematic wave attributes obtained from the CRS stack, only few additional computational efforts are necessaries to build the MZO sections. The so-called CRS-MZO approach presented in this paper is successfully applied to the 2-D Marmousi synthetic seismic data.