Elastic least-squares reverse time migration

Feng, Zongcai; Schuster, Gerard T.

doi:10.1190/geo2016-0254.1

Cited by 125 publications

(30 citation statements)

References 62 publications

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“…Most elastic LSRTM implementations use images based on model perturbations (Alves and Biondi, 2016;Feng and Schuster, 2017;Xu et al, 2016;Duan et al, 2017;Ren et al, 2017).…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…This technique exploits an objective function and its residual in the data domain, and separately updates the smooth and rough (i.e., image) parts of the earth model. Least-squares migration robustly computes the rough model (Alves and Biondi, 2016;Feng and Schuster, 2017;Duan et al, 2017;Ren et al, 2017), while optimization via adjoint-state method provides the smooth updates (Tarantola, 1988;Sava, 2014). Therefore, we can classify RWI as a mixed-domain (both data-and image-domain) wavefield tomography method.…”

Section: Introductionmentioning

confidence: 99%

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Elastic-reflection waveform inversion with petrophysical model constraints

Rocha

Sava

2018

SEG Technical Program Expanded Abstracts 2018

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Elastic wavefield tomography faces challenging pitfalls due to its multiparameter and multicomponent characters, which are absent in the acoustic case. Inter-parameter crosstalk and the absence of petrophysical constraints may cause elastic inversion to fail, delivering unphysical and artifact-contaminated models. In addition, one of the goals of wavefield tomography is to deliver an earth model that generates accurate and high-quality images; however, this might not be the case for conventional data-domain tomography methods that exclude image optimization during inversion. Therefore, we propose to use the elastic reflection waveform inversion (ERWI) methodology, which inverts both for the background velocity model and for the reflectivity image, coupled with a petrophysical constraint term in the objective function. We demonstrate that constraining ERWI is successful in delivering more plausible models with fewer artifacts and that satisfy the imposed constraints. We alternate between smooth model and reflectivity updates, keeping both data fitting, image focusing and petrophysical constraints consistently satisfied in a common objective function. Compared to unconstrained inversion, our numerical examples show less-contaminated models and higher-quality images, as well as improved convergence and accuracy.

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“…Most elastic LSRTM implementations use images based on model perturbations (Alves and Biondi, 2016;Feng and Schuster, 2017;Xu et al, 2016;Duan et al, 2017;Ren et al, 2017).…”

Section: Acknowledgmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Elastic-reflection waveform inversion with petrophysical model constraints

Rocha

Sava

2018

SEG Technical Program Expanded Abstracts 2018

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“…The filter estimates the neardiagonal elements of the submatrices of the Hessian inverse for the different parameter classes. Our decoupled deblurring filter is used to improve the elastic migration image quality and speed up the convergence of elastic linearized inversion (Duan et al, 2016;Feng and Schuster, 2017;Ren et al, 2017). The results show that the filter not only balances the amplitude, increases the resolution, but also reduces the crosstalk artifacts in the elastic migration images.…”

Section: Introductionmentioning

confidence: 98%

Decoupled deblurring filter and its application to elastic migration and inversion

Feng

Schuster

Dai

2017

SEG Technical Program Expanded Abstracts 2017

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We present a decoupled deblurring filter that approximates the multiparameter Hessian inverse by using local filters to approximate its submatrices for the same and different parameter classes. Numerical tests show that the filter not only reduces the footprint noise, balances the amplitudes and increases the resolution of the elastic migration images, but also mitigates the crosstalk artifacts. When used as a preconditioner, it accelerates the convergence rate for elastic inversion.

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“…Hu et al (2016) and Yang et al (2018b) show that LSM can also be effectively implemented using Gaussian beams. For imaging elastic waves, the existing elastic LSM (ELSM) methods are mainly implemented with the two-way wave propagator (Duan et al, 2017;Feng and Schuster, 2017). However, because the computational cost of one iteration of ELSM is twice that of conventional ERTM, the expense of all ELSM iterations is often prohibitively high in large-scale applications.…”

Section: Introductionmentioning

confidence: 99%

Least-squares Gaussian beam migration in elastic media

Yue¹,

Sava

Qian³

et al. 2019

GEOPHYSICS

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Gaussian beam migration (GBM) is an effective imaging method that has the ability to image multiple arrivals while preserving the advantages of ray-based methods. We have extended this method to linearized least-squares imaging for elastic waves in isotropic media. We have dynamically transformed the multicomponent data to the principal components of different wave modes using the polarization information available in the beam migration process, and then we use Gaussian beams as wavefield propagator to construct the forward modeling and adjoint migration operators. Based on the constructed operators, we formulate a least-squares migration scheme that is iteratively solved using a preconditioned conjugate gradient method. With this method, we can obtain crosstalk-attenuated multiwave images with better subsurface illumination and higher resolution than those of the conventional elastic Gaussian beam migration. This method also allows us to achieve a good balance between computational cost and imaging accuracy, which are both important requirements for iterative least-squares migrations. Numerical tests on two synthetic data sets demonstrate the validity and effectiveness of our proposed method.

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Elastic least-squares reverse time migration

Cited by 125 publications

References 62 publications

Elastic-reflection waveform inversion with petrophysical model constraints

Elastic-reflection waveform inversion with petrophysical model constraints

Decoupled deblurring filter and its application to elastic migration and inversion

Least-squares Gaussian beam migration in elastic media

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