Shot-gather time migration of planar reflectors without velocity model
MetadataShow full item record
Standard migration techniques require a velocity model. A new and fast prestack time migration method is presented that does not require a velocity model as an input. The only input is a shot gather, unlike other velocity-independent migrations that also require input of data in other gathers. The output of the presented migration is a time-migrated image and the migration velocity model. The method uses the first and second derivatives of the traveltimes with respect to the location of the receiver. These attributes are estimated by computing the gradient of the amplitude in a shot gather. The assumptions of the approach are a laterally slowly changing velocity and reflectors with small curvatures; the dip of the reflector can be arbitrary. The migration velocity corresponds to the root mean square (rms) velocity for laterally homogeneous media for near offsets. The migration expressions for 2D and 3D cases are derived from a simple geometrical construction considering the image of the source. The strengths and weaknesses of the methods are demonstrated on synthetic data. At last, the applicability of the method is discussed by interpreting the migration velocity in terms of the Taylor expansion of the traveltime around the zero offset.
Published by the Society of Exploration Geophysicists. © 2011 Society of Exploration Geophysicists. Bona, Andrej. 2011. Shot-gather time migration of planar reflectors without velocity model. Geophysics. 76 (2): pp. S93-S101. A link to the Society's web site is available from the Related Links field. http://www.seg.org/
Showing items related by title, author, creator and subject.
Cooke, D.; Bona, Andrej; Hansen, B. (2009)Starting with the double-square-root equation we derive expressions for a velocity-independent prestack time migration and for the associated migration velocity. We then use that velocity to identify multiples and suppress ...
Tertyshnikov, Konstantin; Bóna, Andrej; Pevzner, Roman; Urosevic, Milovan (2012)Information about seismic velocities is an important and integral part of the seismic imaging process. The task of defining the velocity model is usually quite difficult, especially in regions with a complex geological ...
Tertyshnikov, Konstantin; Bona, Andrej; Pevzner, Roman (2013)Reflection seismic imaging faces several difficulties in hard rock environments. One of them is the estimation of the propagation velocity of seismic waves. Therefore, imaging algorithms that do not require prior construction ...