Navegando por Autor "TYGEL, Martin"

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Acesso aberto (Open Access)
2-D ZO CRS stack by considering an acquisition line with smooth topography
(2005-03) OLIVA, Pedro Andrés Chira; CRUZ, João Carlos Ribeiro; CALLAPINO, German Garabito; HUBRAL, Peter; TYGEL, Martin
The land seismic data suffers from effects due to the near surface irregularities and the existence of topography. For obtaining a high resolution seismic image, these effects should be corrected by using seismic processing techniques, e.g. field and residual static corrections. The Common-Reflection-Surface (CRS) stack method is a new processing technique to simulate zero-offset (ZO) seismic sections from multi-coverage seismic data. It is based on a second-order hyperbolic paraxial traveltime approximation referred to a central normal ray. By considering a planar measurement surface, the CRS stacking operator is defined by means of three parameters, namely the emergence angle of the normal ray, the curvature of the normal incidence point (NIP) wave, and the curvature of the normal (N) wave. In this paper the 2-D ZO CRS stack method is modified in order to consider effects due to the smooth topography. By means of this new CRS formalism, we obtain a high resolution ZO seismic section, without applying static corrections. As by-products the 2-D ZO CRS stack method we estimate at each point of the ZO seismic section the three relevant parameters associated to the CRS stack process.
Acesso aberto (Open Access)
A quick review of 2D topographic traveltimes
(2005-03) CALLAPINO, German Garabito; OLIVA, Pedro Andrés Chira; TYGEL, Martin; SANTOS, Lúcio Tunes
The Common-Reflection-Surface (CRS) stacking method was originally introduced as a data-driven method to simulate zero-offset sections from 2-D reflection pre-stack data acquired along a straight line. This approach is based on a second-order hiperbolic traveltime approximation parameterized with three kinematic wavefield attributes. In land data, topographic effects play an important role in seismic data processing and imaging. Thus, this feature has been recently considered by the CRS method. In this work we review the CRS traveltime approximations that consider the smooth and rugged topography. In addition, we also review the Multifocusing traveltime for a rugged topography. By means of a simple synthetic example, we finally provide first comparisons between the various traveltime expressions.