Final laser-beam Q-migration

Xiao, Xifeng; Feng, Hao; Egger, Christopher; Wang, Bin; Jiao, Fangxiang; Wang, Xinling

doi:10.1190/segam2014-1432.1

Cited by 13 publications

(4 citation statements)

References 5 publications

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“…We solve the ray‐centered wave equation in a tube with a weighted plane‐wave source, which produces local wavefields with similar curvatures and beam widths to traditional Gaussian beams. Other optimized beam shapes, such as the Fresnel beam (Červený & Soares, 1992) and laser beam (Xiao et al., 2014), can be introduced into the two‐way beam wave scheme, which only needs to recompute local velocity models according to the new beam width and to design a corresponding source signature. To avoid the mapping between the ray‐centered and global Cartesian coordinates, the Eulerian Gaussian beam scheme (Leung et al., 2007) can be used to numerically calculate beam wavefields but with a higher computational cost.…”

Section: Discussionmentioning

confidence: 99%

“…For instances, it has been adjusted for common‐shot gathers (Gray, 2005; Nowack et al., 2003) and extended to (an)elastic and anisotropic media (Alkhalifah, 1995; Protasov, 2015; Zhu et al., 2007). Many optimized beam shapes have been proposed to improve imaging quality for different geological structures (Nowack, 2011; Xiao et al., 2014; Yang et al., 2015). Currently, it has been incorporated into least squares inversion to produce high‐resolution reflectivity models (Hu et al., 2016; Yang et al., 2018; Yue et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

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Introduction to a Two‐Way Beam Wave Method and Its Applications in Seismic Imaging

et al. 2022

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Seismic simulation methods can be broadly categorized into two groups: (a) direct solving the wave equation using numerical algorithms, such as finite-differences (Hestholm & Ruud, 1998;Pitarka, 1999), finite-elements (Basabe & Sen, 2009), pseudo-spectral (Huang, 1992 and spectral-element approaches (Komatitsch & Tromp, 1999), and (b) the high-frequency asymptotic solution of the wave equation (Bullen, 1961;Červený, 2005). All these methods have their own advantages and drawbacks, and all are useful for specific seismic problems.Ray theory is representative of the high-frequency asymptotic methods for modeling seismic wavefields by approximating the harmonic solution of the wave equation using an infinite asymptotic series (Červený, 2005;Popov, 2002). Thus, it is also known as asymptotic ray theory. The high-frequency approximation simplifies the wave equation into an eikonal equation and a transport equation, which determine the traveltimes and amplitudes of seismic wavefields, respectively. The characteristics of the eikonal equation define seismic rays; the traveltime Abstract Ray theory gives a high-frequency asymptotic solution of the wave equation, which has been widely used in the seismic study because of its high computational efficiency and good physical insights for elementary waves. However, the fundamental high-frequency assumption makes it difficult to accurately simulate the finite-frequency effect of wave propagations. On the other hand, the Gaussian beam, as one of the advanced ray-based methods, overcomes the amplitude singularity problem near the caustics by introducing a complex-valued paraxial approximation. But Gaussian beams only use the velocity and up to second-order velocity derivative of central rays and thus does not accurately simulate the response of heterogeneity away from the rays. To bridge the gap between the ray theory and wave-equation methods, we present a two-way beam wave method and apply it to seismic imaging. A fan of central rays are first shot to extract local ray-centered model parameters in the global Cartesian coordinates. Then, a finite-difference method is used to solve the acoustic wave equation in the ray-centered coordinates to simulate wave propagations near the central rays. The beam wave method can accurately simulate the response of the velocity heterogeneities in the ray tubes and therefore produces more accurate wavefields. In addition, we discretize the ray-centered wave equation onto a non-orthogonal grid, which considerably reduces the computational cost. We apply the two-way beam wave method in seismic imaging and develop a beam wave reverse-time migration. It inherits the advantages of both ray-based and wave equation migrations, and produces clear images for complicated structures with fewer artifacts than traditional imaging methods.Plain Language Summary Seismic ray theory has evolved from classical asymptotic ray theory, through paraxial ray theory and Maslov's method, and then to the Gaussian beam method. Although the computational accuracy of the ...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Introduction to a Two‐Way Beam Wave Method and Its Applications in Seismic Imaging

et al. 2022

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“…2023, 15, 3761 2 of 15 ideal compensation methods should be based on the propagation paths of seismic waves, and the corresponding compensation must be performed during the migration process. At present, migration methods for viscous media are primarily divided into two categories based on their difference in imaging operators, i.e., Q-compensated migration methods utilizing the ray theory [3][4][5][6] and based on the wave equation theory [7][8][9][10][11][12]. Attenuation compensation via wave equation migration has high imaging accuracy for complex structures but low computational efficiency.…”

Section: Introductionmentioning

confidence: 99%

Q-Compensated Gaussian Beam Migration under the Condition of Irregular Surface

Han

Lü

et al. 2023

Remote Sensing

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The viscosity of actual underground media can cause amplitude attenuation and phase distortion of seismic waves. When seismic images are processed assuming elastic media, the imaging accuracy for the deep reflective layer is often reduced. If this attenuation effect is compensated, the imaging quality of the seismic data can be significantly improved. Q-compensated Gaussian beam migration (Q-GBM) is an effective seismic imaging method for viscous media, and it has the advantages of both wave equation and ray-based Q-compensated imaging methods. This study develops a Q-GBM method in visco-acoustic media with an irregular surface. Initially, the basic principles of Gaussian beam in visco-acoustic media are introduced. Then, by correcting the complex-value time of the Gaussian beam in visco-acoustic media, energy compensation and phase correction are carried out for the forward continuation wavefield at the seismic source of the irregular surface and the reverse continuation wavefield at the beam center, which effectively compensates the absorption and attenuation effects of visco-acoustic media on the seismic wavefield. Further, a Q-GBM method under the irregular surface is proposed using cross-correlation imaging conditions. Through migration tests for three numerical models of visco-acoustic media with irregular surfaces, it is verified that our method is an effective depth domain imaging technique for seismic data in visco-acoustic media under the condition of irregular surfaces.

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“…Ever since the basic framework of GBM was presented by Hill (1990Hill ( , 2001, it has been extended to irregular topographic conditions (Gray 2005;Yue et al 2012;Yang et al 2014) and trueamplitude migration (Gray and Bleistein 2009). In addition, many new seismic beam imaging methods have been developed, such as fast beam migration (Gao et al 2006(Gao et al , 2007, focused beam migration (Nowack 2008), and laser beam migration (Xiao et al 2014), which expand the members of the beam migration family. Most of them, however, are based on the GBM framework and use a constant initial beam parameter, which makes a seismic beam focused either at the initial position or at a certain depth.…”

Section: Introductionmentioning

confidence: 99%

An amplitude-preserved adaptive focused beam seismic migration method

et al. 2015

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Gaussian beam migration (GBM) is an effective and robust depth seismic imaging method, which overcomes the disadvantage of Kirchhoff migration in imaging multiple arrivals and has no steep-dip limitation of one-way wave equation migration. However, its imaging quality depends on the initial beam parameters, which can make the beam width increase and wave-front spread with the propagation of the central ray, resulting in poor migration accuracy at depth, especially for exploration areas with complex geological structures. To address this problem, we present an adaptive focused beam method for shot-domain prestack depth migration. Using the information of the input smooth velocity field, we first derive an adaptive focused parameter, which makes a seismic beam focused along the whole central ray to enhance the wavefield construction accuracy in both the shallow and deep regions. Then we introduce this parameter into the GBM, which not only improves imaging quality of deep reflectors but also makes the shallow small-scale geological structures well-defined. As well, using the amplitude-preserved extrapolation operator and deconvolution imaging condition, the concept of amplitude-preserved imaging has been included in our method. Typical numerical examples and the field data processing results demonstrate the validity and adaptability of our method.

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Final laser-beam Q-migration

Cited by 13 publications

References 5 publications

Introduction to a Two‐Way Beam Wave Method and Its Applications in Seismic Imaging

Introduction to a Two‐Way Beam Wave Method and Its Applications in Seismic Imaging

Q-Compensated Gaussian Beam Migration under the Condition of Irregular Surface

An amplitude-preserved adaptive focused beam seismic migration method

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