Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Brandsberg-Dahl, S. Articles by Xiao, X. Search for Related Content GeoRef GeoRef Citation

Migration of surface seismic data with VSP Green's functions

BP America, Houston, USA

Xiang Xiao

University of Utah, Salt Lake City, USA

Corresponding author: hornbyb2{at}bp.com

Seismic migration is the process by which wavefields recorded on or near the surface are mapped back into the subsurface to form an image of the subsurface structure. Common to all current migration methods is that they rely on a model of the subsurface for computing Green's functions. These computed Green's functions are approximations of the true Green's function in the subsurface. The more accurate the method used for computing the Green's functions, and to some extent also the choice of imaging condition, the better image we will get. Most state-of-the-art migration methods will use Green's functions that include multiple arrivals and some finite-frequency effects, allowing them to image fairly complex geologic structures. However, the computational model in most cases uses only scalar velocity that is smooth on a wavelength scale, thus ignoring scattering effects from small-scale structure, anisotropy, and other intrinsic rock effects. Further, whatever the model is, it has to be derived from the data itself or some other form of remote measurement of velocity in the subsurface. At the very best, this will be a nonunique solution to an inverse problem based on the data. Commonly, much more crude approximations are used; for example, only trying to match the predicted first arrivals to the observed first arrivals.