The Effect of Strong Near Surface Scattering on Seismic Imaging: Investigation Based on Resolution Analysis
Year: 2020
Author: Xiao-Bi Xie, Baoqing He, Hongxiao Ning, Yongqing He, Bo Chen
Communications in Computational Physics, Vol. 28 (2020), Iss. 1 : pp. 167–186
Abstract
In land seismic exploration, strong near-surface heterogeneities can cause serious problems in seismic data acquisition and the quality of depth imaging. By introducing random velocity models to simulate velocity fluctuations in the near-surface layer and using the point spread function to characterize image quality, we examine how the scattering generated in near-surface heterogeneities can affect the subsurface image. In addition to the commonly known scattering noises which lower the signal to noise ratio in seismic data, our results also reveal that intermediate scale heterogeneities generate forward scattering which forms phase or travel time fluctuations. Due to intermediate-scale uncertainty in the shallow part of the migration velocity model, these phase changes are carried to the target by the extrapolated wavefields, breaking the zero phase image condition at the image point. This is a primary reason for deteriorated image quality in regions with strong near-surface scattering. If this intermediate-scale information can be obtained and built into the migration velocity, the subsurface image quality can be largely improved. These results can be the basis for further numerical investigations and field experiments. The proposed analysis method can also be used to evaluate other potential methods for dealing with near-surface scattering.
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Journal Article Details
Publisher Name: Global Science Press
Language: English
DOI: https://doi.org/10.4208/cicp.OA-2018-0076
Communications in Computational Physics, Vol. 28 (2020), Iss. 1 : pp. 167–186
Published online: 2020-01
AMS Subject Headings: Global Science Press
Copyright: COPYRIGHT: © Global Science Press
Pages: 20
Keywords: Reverse time migration shallow scattering velocity model prestack depth imaging seismic resolution.