Application of Excitation Amplitude Imaging Condition to PS Wave Imaging in Elastic Reverse-time Migration

Common-image gathers (CIGs) are extensively used in migration velocity analysis. Any defocused events in the subsurface offset domain or equivalently nonflat events in angle-domain CIGs are accounted for revising the migration velocities. However, CIGs from wave-equation methods such as reverse time migration are often expensive to compute, especially in 3D. Using the excitation amplitude imaging condition that simplifies the forward-propagated source wavefield, we have managed to extract extended images for space and time lags in conjunction with prestack reverse time migration. The extended images tend to be cleaner, and the memory cost/disk storage is extensively reduced because we do not need to store the source wavefield. In addition, by avoiding the crosscorrelation calculation, we reduce the computational cost. These features are demonstrated on a linear [Formula: see text] model, a two-layer velocity model, and the Marmousi model.

Download Full-text

A Stable Q Compensated Reverse Time Migration Method Based on Excitation Amplitude Imaging Condition

Communications in Computational Physics ◽

10.4208/cicp.oa-2018-0075 ◽

2020 ◽

Vol 28 (1) ◽

pp. 141-166

Author(s):

global sci

Keyword(s):

Excitation Amplitude ◽

Reverse Time ◽

Reverse Time Migration ◽

Imaging Condition ◽

Time Migration ◽

Migration Method

Download Full-text

Polarity-consistent excitation amplitude imaging condition for elastic reverse time migration

Journal of Geophysics and Engineering ◽

10.1088/1742-2132/12/1/33 ◽

2014 ◽

Vol 12 (1) ◽

pp. 33-44 ◽

Cited By ~ 3

Author(s):

Qizhen Du ◽

Mingqiang Zhang ◽

Xufei Gong ◽

Xiaoran Chen

Keyword(s):

Excitation Amplitude ◽

Reverse Time ◽

Reverse Time Migration ◽

Imaging Condition ◽

Time Migration

Download Full-text

A modified excitation amplitude imaging condition for prestack reverse time migration

Exploration Geophysics ◽

10.1071/eg14039 ◽

2015 ◽

Vol 46 (4) ◽

pp. 359-370 ◽

Cited By ~ 2

Author(s):

Bingluo Gu ◽

Youshan Liu ◽

Xiaona Ma ◽

Zhiyuan Li ◽

Guanghe Liang

Keyword(s):

Excitation Amplitude ◽

Reverse Time ◽

Reverse Time Migration ◽

Imaging Condition ◽

Time Migration

Download Full-text

Excitation amplitude imaging condition for prestack reverse-time migration

Geophysics ◽

10.1190/geo2012-0079.1 ◽

2013 ◽

Vol 78 (1) ◽

pp. S37-S46 ◽

Cited By ~ 53

Author(s):

Bao D. Nguyen ◽

George A. McMechan

Keyword(s):

Signal To Noise Ratio ◽

Grid Point ◽

Synthetic Data ◽

Cost Effective ◽

Excitation Amplitude ◽

Reverse Time ◽

Reverse Time Migration ◽

Time Step ◽

Imaging Condition ◽

Time Migration

An implicitly stable ratio imaging condition for prestack reverse-time migration (RTM) was defined using excitation criteria. Amplitude maxima and their corresponding occurrence times were saved at each grid point during forward source wavefield extrapolation. Application of the imaging condition involves dividing the amplitudes of the back-propagated receiver wavefield by the precomputed maximum source wavefield amplitude only at the grid points that satisfy the image time at each time step. The division normalizes by the source amplitude, so only the highest signal-to-noise ratio portion of the data is used. Provided that the source and receiver wavefield amplitudes are accurate at the reflection points, the peak wavelet amplitudes in the migrated image are the angle-dependent reflection coefficients and low wavenumber artifacts are significantly reduced compared to those in images calculated by crosscorrelation. Using excitation information and time-binning for the imaging condition improves computational and storage efficiency by three or more orders of magnitude when compared to crosscorrelation with the full source wavefield. Numerical tests with synthetic data for the Marmousi2 model have shown this method to be a cost-effective and practical imaging condition for use in prestack RTM.

Download Full-text