Anisotropic elastic reverse time migration with Gaussian beams for multicomponent data

Author(s):  
Jianen Xiao ◽  
Zhenchun Li ◽  
Kai Zhang ◽  
Qiang Liu
2015 ◽  
Vol 18 (2) ◽  
pp. 74-84
Author(s):  
Hyungwook Choi ◽  
Soon Jee Seol ◽  
Joongmoo Byun

Geophysics ◽  
2021 ◽  
pp. 1-81
Author(s):  
Benxin Chi ◽  
Kai Gao ◽  
Lianjie Huang

Elastic-wave imaging using multi-component data can provide more useful subsurface information than acoustic-wave imaging, but is usually algorithmically challenging. We develop a vector elastic deconvolution migration method for high-resolution imaging of subsurface structures in isotropic and anisotropic elastic media. Our new method employs a vector deconvolution imaging condition based on dual wavefield decomposition, including an explicit directional wavefield separation using the Hilbert transform, and a P/S vector wavefield decomposition using the low-rank decomposition method. Using three elastic models, we numerically demonstrate that our new method produces notably higher-resolution and more amplitude-balanced elastic images compared with a cross-correlation-based vector elastic reverse-time migration method.


Geophysics ◽  
2021 ◽  
pp. 1-79
Author(s):  
Johan O. A. Robertsson ◽  
Fredrik Andersson ◽  
René-Édouard Plessix

Computing images in reverse time migration and model parameter gradients from adjoint wavefields in full waveform inversion requires the correlation of a forward propagated wavefield with another reverse propagated wavefield. Although in theory only two wavefield propagations are required, one forward propagation and one reverse propagation, it requires storing the forward propagated wavefield as a function of time to carry out the correlations which is associated with significant I/O cost. Alternatively, three wavefield propagations can be carried out to reverse propagate the forward propagated wavefield in tandem with the reverse propagated wavefield. We show how highly accurate reverse time migrated images and full waveform inversion model parameter gradients for anisotropic elastic full waveform inversion can be efficiently computed without significant disk I/O using two wavefield propagations by means of the principle of superposition.


Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. T287-T300 ◽  
Author(s):  
Lasse Amundsen ◽  
Johan O. A. Robertsson

Methods for wavefield injection are used in, for instance, reverse time extrapolation of shot gathers in reverse time migration. For correct injection of recorded data without any ambiguity of the propagation direction, the wavefield-injection methodology requires pressure and particle velocity data such as multicomponent towed marine or seabed seismic recordings. We discovered that by carefully considering the models (medium parameters and boundary conditions) for injection, wavefield injection of multicomponent data can also be used to solve several long-standing challenges in marine seismic data processing by means of conventional time-space-domain finite-difference propagators. We outlined and demonstrated several of these important applications including up-down separation of wavefields (deghosting), direct-wave removal, source-signature estimation, multiple removal, and imaging using primaries and multiples. Only acoustic models are considered, but the concepts are straightforward to generalize to elastodynamic and electromagnetic models.


Geophysics ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. S225-S234 ◽  
Author(s):  
Daniel Rocha ◽  
Nicolay Tanushev ◽  
Paul Sava

Based on the energy conservation principle, we derive a scalar imaging condition for anisotropic elastic wavefield migration. Compared with conventional imaging conditions that correlate displacement components or potentials from source and receiver wavefields, the proposed imaging condition does not suffer from polarity reversal, which degrades the image quality after stacking over shots. Our imaging condition also accounts for the directionality of the wavefields in space and time, leading to the attenuation of backscattering artifacts, which commonly appear in elastic reverse time migration images in the presence of strong model contrasts. In addition, our new imaging condition does not require wave-mode decomposition, which demands significant additional cost for elastic wavefields in anisotropic media. To properly image structures, we rely on the anisotropy parameters used in migration, as one would do for any other imaging condition. Our imaging condition is suitable for arbitrary anisotropy. We show the successful application of the anisotropic energy imaging condition by performing numerical experiments on simple and complex geologic models. We compare its quality with conventional counterparts by simulating complex geologic settings with vertical or tilted transverse isotropy.


2016 ◽  
Vol 28 (4) ◽  
pp. 695-702 ◽  
Author(s):  
Jianping Huang ◽  
Maolin Yuan ◽  
Qing Zhang ◽  
Lingxiao Jia ◽  
Zhenchun Li ◽  
...  

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