The seismic data of foothill areas is characterized by low S/N and large moveout between gathers;therefore,conventional
imaging technical workflow is not effective.First of all,we gave a review of imaging methods in foothill areas and analyzed the
characteristics of these methods.Then,it was concluded that beam-ray based method is the first choice for irregular and low S/N
data,rugged surface area and anisotropic media.Thirdly,we summarized several ray theory based methods and give two prestack
depth migration (PSDM) scheme from rugged topography,which are Kirchhoff PSDM based on 3D dynamic programming
traveltime computation approach and Gaussian beam PSDM based on Gaussian Beam dynamic ray tracing.The traveltime
computation method based on Fermat’s principle has no limitation on large velocity contrast and can adapt anisotropic
media,which has no problem for ray interpolation and shadow areas.The intrinsic character of Gaussian beam is propagate wave
in ray-centered coordinate,which get a ray path by conventional ray tracing and calculate the energy attribution around the
central ray by dynamic ray tracing.As a typical beam method,the Gaussian beam method balance the advantages of ray tracing
algorithm and wave equation propagation methods.Numerical tests on synthetic data and real data shows that this
technologies and schemes are quite effective.
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