Remigration-trajectory Time-migration Velocity Analysis in Regions with Strong Velocity Variations
H.B. Santos, T.A. Coimbra, J. Schleicher and A. Novais
Event name: 77th EAGE Conference and Exhibition 2015
Session: Velocity Model Building - Theory II
Publication date: 01 June 2015
Info: Extended abstract, PDF ( 1.53Mb )
Price: € 20
Remigration trajectories describe the position of an image point in the image domain for different source-receiver offsets as a function of the migration velocity. They can be used for prestack time- migration velocity analysis by means of determining kinematic migration parameters, which in turn, allow to locally correct the velocity model. The main advantage of this technique is that it takes the reflection-point displacement in the midpoint direction into account, thus allowing for a moveout correction for a single reflection point at all offsets of a common image gather (CIG). We have tested the feasibility of the method on synthetic data from three simple models and the Marmousoft data. Our tests show that the proposed tool increases the velocity-model resolution and provides a plausible time-migrated image, even in regions with strong velocity variations. The most effort was spent on the event picking, which is critical to the method.