Velocity images from stacking depth-slowness seismic wavefields

• Published in: Geophysical Journal International
• Main Authors: Jones, Geraint, Barton, Penny, Singh, Satish C.
• Other Authors: Bullard Laboratories, University of Cambridge UK (CAM), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: depth-slowness; downward continuation; intercept time; slowness; tau; velocity image; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Northeast Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-00158626; https://hal.archives-ouvertes.fr/hal-00158626/document; https://hal.archives-ouvertes.fr/hal-00158626/file/168-2-583.pdf; https://doi.org/10.1111/j.1365-246X.2006.03055.x

International audience We present synthetic and real data examples processed using a depth imaging method for long-offset multichannel seismic data via the intercept-time-slowness (τ-p) domain. The refracted and reflected information contained in the wavefield is processed simultaneously. Our scheme uses common midpoint data that is transformed to the τ-p domain and mapped to the depth-slowness (z-p) domain using a downward continuation algorithm. The velocity function for downward continuation may be obtained iteratively from the diving ray trajectory within the slowness-depth wavefield or estimated using an independent method. Horizontal events within the z-p wavefield are isolated by applying a mute function corresponding to the downward continuation velocity function in the z-p domain. Stacking the resulting wavefield gives an image trace that may be superimposed on the velocity function to form a velocity image. Following testing on synthetic data the method is applied to two long-offset marine seismic streamer data sets with offsets up to 18 km, from the northeast Atlantic margin. These examples demonstrate the potential of the method to obtain velocity images in difficult geological locations, where conventional processing has been less successful.