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Frequency-Domain full-waveform inversion Based on Tunnel Space Seismic Data

Engineering 2022年第11期18卷 197-206页

作者： Mingyu Yu Fei Cheng Jiangping Liu Daicheng Peng Zhijian Tian Hubei Subsurface Multiscale Imaging Key Laboratory(SMIL) Institute of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China Hubei Key Laboratory of Marine Geological Resources China University of GeosciencesWuhan 430074China

Tunnel seismic detection methods are effective for obtaining the geological structure around the tunnel face,which is critical for safe construction and disaster mitigation in tunnel engineering.However,there is often a lack of accuracy in the acquired geological information and physical properties ahead of the tunnel face in the current tunnel seismic detection methods.Thus,we apply a frequency-domain acoustic full-waveform inversion(FWI)method to obtain high-resolution results for the tunnel structure.We discuss the influence of the frequency group selection strategy and the tunnel observation system settings regarding the inversion results and determine the structural imaging and physical property parameter inversion of abnormal geological bodies ahead of the tunnel face.Based on the conventional strategies of frequency-domain acoustic FWI,we propose a frequency group selection strategy that combines a low-frequency selection covering the vertical wavenumber and a high-frequency selection of antialiasing.This strategy can effectively obtain the spatial structure and physical parameters of the geology ahead of the tunnel face and improve the inversion resolution.In addition,by linearly increasing the side length of the tunnel observation system,we share the influence of the length of the two sides of the observation systems of different tunnels on the inversion results.We found out that the inversion results are the best when the side length is approximately five times the width of the tunnel face,and the influence of increasing the side observation length beyond this range on the inversion results can be ignored.Finally,based on this approach,we invert for the complex multi-stratum model,and an accurate structure and physical property parameters of the complex stratum ahead of the tunnel face are obtained,which verifies the feasibility of the proposed method.

关键词： Tunnel seismic detection full-waveform inversion Frequency select strategy Observation system

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High-resolution bone microstructure imaging based on ultrasonic frequency-domain full-waveform inversion

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Chinese Physics B 2021年第1期30卷 295-310页

作者：李义方石勤振李颖宋小军刘成成他得安王威琪 Department of Electronic Engineering Fudan UniversityShanghaiChina Human Phenome Institute Fudan UniversityShanghaiChina Academy for Engineering and Technology Fudan UniversityShanghaiChina

The main challenge in bone ultrasound imaging is the large acoustic impedance contrast and sound velocity differences between the bone and surrounding soft tissue. It is difficult for conventional pulse-echo modalities to give accurate ultrasound images for irregular bone boundaries and microstructures using uniform sound velocity assumption rather than getting a prior knowledge of sound speed. To overcome these limitations, this paper proposed a frequency-domain fullwaveform inversion(FDFWI) algorithm for bone quantitative imaging utilizing ultrasonic computed tomography(USCT).The forward model was calculated in the frequency domain by solving the full-wave equation. The inverse problem was solved iteratively from low to high discrete frequency components via minimizing a cost function between the modeled and measured data. A quasi-Newton method called the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm(L-BFGS) was utilized in the optimization process. Then, bone images were obtained based on the estimation of the velocity and density. The performance of the proposed method was verified by numerical examples, from tubular bone phantom to single distal fibula model, and finally with a distal tibia-fibula pair model. Compared with the high-resolution peripheral quantitative computed tomography(HR-p QCT), the proposed FDFWI can also clearly and accurately presented the wavelength scaled pores and trabeculae in bone images. The results proved that the FDFWI is capable of reconstructing high-resolution ultrasound bone images with sub-millimeter resolution. The parametric bone images may have the potential for the diagnosis of bone disease.

关键词： quantitative imaging full-waveform inversion bone microstructure ultrasonic computed tomography high resolution

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Source-Independent Amplitude-Semblance full-waveform inversion using a Hybrid Time-and Frequency-Domain Approach

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Communications in Computational Physics 2020年第6期28卷 328-341页

作者： Benxin Chi Lianjie Huang Geophysics Group Los Alamos National LaboratoryLos AlamosNM 87545USA

full-waveform inversion is a promising tool to produce accurate and high-resolution subsurface models.Conventional full-waveform inversion requires an accu-rate estimation of the source wavelet,and its computational cost is high.We develop a novel source-independent full-waveform inversion method using a hybrid time-and frequency-domain scheme to avoid the requirement of source wavelet estimation and to reduce the computational cost.We employ an amplitude-semblance objective function to not only effectively remove the source wavelet effect on full-waveform inver-sion,but also to eliminate the impact of the inconsistency of source wavelets among different shot gathers on full-waveform inversion.To reduce the high computational cost of full-waveform inversion in the time domain,we implement our new algorithm using a hybrid time-and frequency-domain approach.The forward and backward wave propagation operations are conducted in the time domain,while the frequency-domain wavefields are obtained during modeling using the discrete-time Fourier trans-form.The inversion process is conducted in the frequency domain for selected frequen-cies.We verify our method using synthetic seismic data for the Marmousi model.The results demonstrate that our novel source-independent full-waveform inversion pro-duces accurate velocity models even if the source signature is incorrect.In addition,our method can significantly reduce the computational time using the hybrid time-and frequency-domain approach compared to the conventional full-waveform inversion in the time domain.

关键词： Amplitude semblance full-waveform inversion hybrid time and frequency domain source independent source wavelet

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Elastic full waveform inversion Based on the Trust Region Strategy

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American Journal of Computational Mathematics 2021年第4期11卷 241-266页

作者： Wensheng Zhang Yijun Li State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China School of Mathematical Sciences University of Chinese Academy Sciences Beijing China

In this paper, we investigate the elastic wave full-waveform inversion (FWI) based on the trust region method. The FWI is an optimization problem of minimizing the misfit between the observed data and simulated data. Usually, the line search method is used to update the model parameters iteratively. The line search method generates a search direction first and then finds a suitable step length along the direction. In the trust region method, it defines a trial step length within a certain neighborhood of the current iterate point and then solves a trust region subproblem. The theoretical methods for the trust region FWI with the Newton type method are described. The algorithms for the truncated Newton method with the line search strategy and for the Gauss-Newton method with the trust region strategy are presented. Numerical computations of FWI for the Marmousi model by the L-BFGS method, the Gauss-Newton method and the truncated Newton method are completed. The comparisons between the line search strategy and the trust region strategy are given and show that the trust region method is more efficient than the line search method and both the Gauss-Newton and truncated Newton methods are more accurate than the L-BFGS method.

关键词： Elastic Wave Equations full-waveform inversion Trust Region Strate-gy Line Search Strategy Newton-Type Method Time Domain

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A review on reflection-waveform inversion

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Petroleum Science 2020年第2期17卷 334-351页

作者： Gang Yao Di Wu Shang-Xu Wang Unconventional Petroleum Research Institute State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Beijing 102249China College of Geophysics State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Beijing 102249China

full-waveform inversion(FWI)utilizes optimization methods to recover an optimal Earth model to best fit the observed seismic record in a sense of a predefined norm.Since FWI combines mathematic inversion and full-wave equations,it has been recognized as one of the key methods for seismic data imaging and Earth model building in the fields of global/regional and exploration seismology.Unfortunately,conventional FWI fixes background velocity mainly relying on refraction and turning waves that are commonly rich in large offsets.By contrast,reflections in the short offsets mainly contribute to the reconstruction of the high-resolution interfaces.Restricted by acquisition geometries,refractions and turning waves in the record usually have limited penetration depth,which may not reach oil/gas reservoirs.Thus,reflections in the record are the only source that carries the information of these reservoirs.Consequently,it is meaningful to develop reflection-waveform inversion(RWI)that utilizes reflections to recover background velocity including the deep part of the model.This review paper includes:analyzing the weaknesses of FWI when inverting reflections;overviewing the principles of RWI,including separation of the tomography and migration components,the objective functions,constraints;summarizing the current status of the technique of RWI;outlooking the future of RWI.

关键词： full-waveform inversion Reflection-waveform inversion Tomographic component Migration component Travel time-based objective function waveform-based objective function Constraint

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Seismic-Wave Scattering,Imaging,and inversion

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Communications in Computational Physics 2020年第6期28卷 1-40页

作者： Lianjie Huang Michael Fehler Yingcai Zheng Xiao-Bi Xie Los Alamos National Laboratory MS D452Los AlamosNM 87545USA Massachusetts Institute of Technology Department of EarthAtmospheric&Planetary Sciences77 Massachusetts AvenueCambridgeMA 02139USA University of Houston Department of Earth&Atmospheric SciencesHoustonTexas 77004USA University of California Santa CruzCA 95064USA

Ru-Shan Wu has made seminal contributions in many research areas in geophysics,such as seismic-wave propagation,scattering,imaging,and inversion.We highlight some of his research in holography imaging,diffraction tomography,seismic-wave scattering and its applications to studying Earth’s heterogeneity,oneway wave propagation and one-return wave modeling,beamlet and dreamlet applications,strong non-linear full-waveform inversion,and direct envelop inversion.

关键词： Beamlet diffraction tomography dreamlet full-waveform inversion holography imaging one-way one-return seismic wave propagation seismic scattering

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