An imaging work flow using locally coherent events - A CRS based approach

Abstract

The Common Reflection Surface (CRS) stack is a multi-parameter processing approach based on locally coherent reflection events. Best coherency is obtained if the fitted reflection data are hyperbolic within the CRS apertures under consideration. The latter applies to the source receiver aperture and the CMP displacement. Based on the hyperbolic assumption the CRS attributes are determined during the optimisation procedure to best fit reflection events in the data. These attributes are the backbone of the CRS workflow. The CRS attributes are steering the stack, the velocity model building by Normal Incidence Point (NIP) tomography, the multiple suppression, and the enhancement and regularization of pre-stack data. Pre-stack data enhancement and data regularization is performed by so called partial stacks to form CRS supergathers. Partial stacks are essential to remove artefacts caused by adaptive filtering of multiples in pre-stack data. Pre-stack depth migration of CRS supergather leads to CIGs which have an improved S/N and are better suitable to residual move out analysis and quality control than conventional CIGs. Pre-stack depth migrated sections obtained from CRS supergathers display an S/N ratio almost comparable to the CRS stack section.