IMPROVED APPLICABILITY OF RAY TRACING IN SEISMIC ACQUISITION, IMAGING, AND INTERPRETATION

Abstract

Ray-based seismic modeling methods can be applied at vari-ous stages of the exploration and production process. The stan-dard ray method has several advantages, e.g., computational effi-ciency and the possibility of simulating propagation of elementa-ry waves. As a high-frequency approximation, the method also has a number of limitations, particularly with respect to a lack of amplitude reliability in the presence of rapid changes of the mod-el functions representing elastic parameters and interfaces. Giv-en the objective of improving the applicability of the standard ray method, we present a strategy that does not require specific ex-tension to finite frequencies. Instead, we define each ray-based process as an element of a system that, as a composite process, is able to obtain better results than the ray-based process applied alone. Other elements of the composite process can be finite-difference modeling or numerical solutions for surface and vol-ume integrals, which are basic constituents of Kirchhoff model-ing and imaging. We also include among the process elements re-cently developed techniques for simulating the migration ampli-tude on a target reflector and in a local volume, e.g., a reservoir zone. The model is decomposed according to its complexity into volume elements, surface elements, or a combination. The com-posite process consists of a specified interaction between process elements and model elements, which fits well with the philoso-phy of modern software design. Model elements that will be ex-posed to ray-tracing algorithms may need appropriate prepara-tion, e.g., smoothing and resampling. We demonstrate specifical-ly, in a tutorial example, that simulating the seismic response from a reflector by ray-based composite processes can yield bet-ter results than applying standard ray tracing alone.