Tomographic determination of seismic velocity models with kinematic wavefield attributes

Meer over het boek

For transforming recorded seismic reflection data into a depth image, a seismic velocity model is essential. This thesis introduces a novel tomographic method for determining such models using traveltime information derived from kinematic wavefield attributes. These attributes, which are coefficients of second-order traveltime approximations, can be extracted from seismic data through coherence analyses, such as the common-reflection-surface (CRS) stack method. Unlike conventional reflection tomography that requires picking reflection events in prestack data, this approach offers significant practical advantages. The necessary attributes for tomographic inversion are obtained from CRS stack results at various pick locations in the stacked section. Each data point's attributes are interpreted as second-order traveltimes from a hypothetical subsurface point source. The inversion process aims to find a model that minimizes the discrepancy between these data and the corresponding quantities modeled by dynamic ray tracing. The thesis details the complete theory of the method and its practical applications, beginning with an overview of ray theory and the CRS stack method, followed by the development of the new tomographic inversion concept. The method is thoroughly discussed for 1D, 2D, and 3D tomographic inversion, demonstrating the entire velocity model derivation process on both synthetic and real 2D seismic datasets.