Simultaneous inversion for model geometry and elastic parameters

Wang, Yanghua

doi:10.1190/1.1444514

Cited by 36 publications

(17 citation statements)

References 33 publications

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“…impedance contrast, the assumption of constant velocity layers can be adopted in the amplitude inversion which however, may also allow elastic properties to vary along interfaces (WANG, 1999). In practice, travel-time inversion with constant layer velocities should only be used produce a preliminary estimate, which in turn is used for the estimation of the source amplitude A 0 and the absorption coefficients p(z).…”

Section: In6ersion Resultsmentioning

confidence: 99%

“…Thus, it is ideally suited to the problem in which the model space includes parameters of different physical units. However, even when all parameters have the same physical dimension (such as in the interface variation problem), appropriate partitioning of different parameter components into separate subspaces may also be efficient in accelerating convergence of the amplitude inversion (WANG andHOUSEMAN 1994, 1995). The basis vectors {a (j) , j=1, .…”

Section: The Subspace In6ersion Methodsmentioning

confidence: 99%

“…The model consists of two syncline interfaces (interfaces 3 and 4), which are beneath two approximately flat interfaces (interfaces 1 and 2), and are above another flat interface (interface 5). This example model, chosen to illustrate the problems in the reconstruction of a deep and curved interface, is built actually with reference to an existing seismic profile from the North Sea (WANG, 1999).…”

Section: Preliminary In6ersion Test a Multi-layered Velocity Modelmentioning

confidence: 99%

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Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Wang¹,

Pratt

2000

Pure appl. geophys.

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Seismic amplitude data are used to invert for the geometry of reflection interfaces of multi-layered structures, in which the reflection interface is parameterised by a set of Fourier series with different wavenumbers. Two main difficulties arise in amplitude inversion: a high wavenumber oscillation artificially generated by inversion on shallow interfaces, and a failure to recover the long wavelength components of deep, curved interfaces. To overcome these difficulties, the capabilities of two inversion algorithms, a damped subspace method and a multi-scale scheme are investigated. Based on those two schemes, we develop a multi-stage damped subspace method to abate the instability of high wavenumber components and, simultaneously, to enhance the resolution of the low wavenumber components of the subsurface reflectors from seismic amplitude inversion.

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Section: In6ersion Resultsmentioning

confidence: 99%

Section: The Subspace In6ersion Methodsmentioning

confidence: 99%

Section: Preliminary In6ersion Test a Multi-layered Velocity Modelmentioning

confidence: 99%

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Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Wang¹,

Pratt

2000

Pure appl. geophys.

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“…This quantitative tuning factor is similar to a weighting matrix related to different model parameters suggested by Wang (1999), in which a weighting matrix was defined by the ratio of Frechet sub-matrices, with respect to various classes of model parameters. Since the λ value in Eq.…”

Section: Q Modelmentioning

confidence: 99%

Simultaneous inversion for velocity and attenuation by waveform tomography

Gao

Wang

2016

Journal of Applied Geophysics

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Seismic waveform tomography can invert for the velocity and attenuation ( 1 − Q ) variations simultaneously. For this simultaneous inversion, we propose two strategies for waveform tomography. First, we analyze the contributions of the real part and the imaginary part of the gradients, associated with the velocity and attenuation parameters respectively, and determine that the combination of the real part of the gradient subvector for the velocity parameter and the imaginary part of the gradient subvector for the attenuation parameter would produce an optimal inversion result. Second, we attempt to balance the sensitivities of the objective function to the velocity and the attenuation parameters. Considering the magnitude differences between these twotype parameters in the simultaneous inversion, we apply preliminarily a normalization to both the velocity model and the attenuation model. However, for balancing their sensitivities, we further adjust the corresponding model updates using a tuning factor. We determine this tuning parameter adaptively, based on the sensitivities of these two parameters, at each iteration. Numerical tests demonstrate the feasibility and reliability of these two strategies in full waveform inversion.

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“…could be used in the amplitude inversion, in principle, to estimate three parameters, provided an appropriate inverse algorithm is adopted. The practical implementation of the inversion for those three parameters and the application to real data are presented in Wang (1999), where the reflection coefficient at the reflector is calculated using equation (16) and the transmission coefficients in the overburden medium are evaluated using equation (17).…”

Section: Figmentioning

confidence: 99%

Approximations to the Zoeppritz equations and their use in AVO analysis

Wang

1999

GEOPHYSICS

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139

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To efficiently invert seismic amplitudes for elastic parameters, pseudoquartic approximations to the Zoeppritz equations are derived to calculate P-P-wave reflection and transmission coefficients as a function of the ray parameter p. These explicit expressions have a compact form in which the coefficients of the p 2 and p 4 terms are given in terms of the vertical slownesses. The amplitude coefficients are also represented as a quadratic function of the elastic contrasts at an interface and are compared to the linear approximation used in conventional amplitude variation with offset (AVO) analysis, which can invert for only two elastic parameters. Numerical analysis with the second-order approximation shows that the condition number of the Fréchet matrix for three elastic parameters is improved significantly from using a linear approximation. Therefore, those quadratic approximations can be used directly with amplitude information to estimate not only two but three parameters: P-wave velocity contrast, S-wave velocity contrast, and the ratio of S-wave and P-wave velocities at an interface.

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Simultaneous inversion for model geometry and elastic parameters

Cited by 36 publications

References 33 publications

Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Simultaneous inversion for velocity and attenuation by waveform tomography

Approximations to the Zoeppritz equations and their use in AVO analysis

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