Prestack Migration Velocity Analysis Using Time-remigration Trajectories
T.A. Coimbra, H.B. Santos, J. Schleicher and A. Novais
Event name: 76th EAGE Conference and Exhibition 2014
Session: Velocity Analysis - Theory
Publication date: 16 June 2014
Info: Extended abstract, PDF ( 1.57Mb )
Price: € 20
We present a prestack time-migration tool for local improvement of the seismic migration-velocity model. The method is based on time-remigration trajectories. It determines kinematic parameters using local-slope information of seismic reflection events. These parameters, in turn, are used to locally correct the velocity model. The main advantage of this technique is that it allows to carry out a moveout correction not just at a fixed point in a zero-offset (post-stack) time-migrated gather, but varying through all offsets of a common image gather (CIG), and taking into account the reflection-point displacement in the midpoint direction. In other words, it provides for migration velocity analysis (MVA) by time-remigration trajectories in prestack data. Tests on synthetic and SMAART-Sigsbee2B data show that the proposed tool not only increased the velocity-model resolution, but also provides a plausible time-migrated image.