Seismic amplitude inversion for interface geometry: practical approach for application

Wang, Yanghua; White, Robert S.; Pratt, R. G.

doi:10.1046/j.1365-246x.2000.00144.x

Cited by 15 publications

(8 citation statements)

References 33 publications

(55 reference statements)

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“…These parameters are then assumed to be known a priori in the interface inversion. Application examples of the multi-stage damped subspace method are shown in WANG (1999) and WANG et al (2000).…”

Section: In6ersion Resultsmentioning

confidence: 99%

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%

Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Wang¹,

Pratt

2000

Pure appl. geophys.

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“…The model parameter can be recovered as

m = {boldm}_{prior} + {((), G^{T} boldG + μ C_{m}^{- 1})}^{- 1} {boldG}^{T} Δ d,

where

Δ d = d - g ({boldm}_{prior})

is the data residual, μ proportional to

σ_{n}

is the trade‐off parameter of the regularization term and can be estimated using varied methods to guarantee an optimal solution (Wang ; Wang et al . ; Wang and Pratt ; Downton ; Alemie and Sacchi ).…”

Section: Methodsmentioning

confidence: 99%

Seismic amplitude inversion for the transversely isotropic media with vertical axis of symmetry

Zhang

2019

Geophysical Prospecting

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Transverse isotropy with a vertical axis of symmetry is a common form of anisotropy in sedimentary basins, and it has a significant influence on the seismic amplitude variation with offset. Although exact solutions and approximations of the PP‐wave reflection coefficient for the transversely isotropic media with vertical axis of symmetry have been explicitly studied, it is difficult to apply these equations to amplitude inversion, because more than three parameters need to be estimated, and such an inverse problem is highly ill‐posed. In this paper, we propose a seismic amplitude inversion method for the transversely isotropic media with a vertical axis of symmetry based on a modified approximation of the reflection coefficient. This new approximation consists of only three model parameters: attribute A, the impedance (vertical phase velocity multiplied by bulk density); attribute B, shear modulus proportional to an anellipticity parameter (Thomsen's parameter ε−δ); and attribute C, the approximate horizontal P‐wave phase velocity, which can be well estimated by using a Bayesian‐framework‐based inversion method. Using numerical tests we show that the derived approximation has similar accuracy to the existing linear approximation and much higher accuracy than isotropic approximations, especially at large angles of incidence and for strong anisotropy. The new inversion method is validated by using both synthetic data and field seismic data. We show that the inverted attributes are robust for shale‐gas reservoir characterization: the shale formation can be discriminated from surrounding formations by using the crossplot of the attributes A and C, and then the gas‐bearing shale can be identified through the combination of the attributes A and B. We then propose a rock‐physics‐based method and a stepwise‐inversion‐based method to estimate the P‐wave anisotropy parameter (Thomsen's parameter ε). The latter is more suitable when subsurface media are strongly heterogeneous. The stepwise inversion produces a stable and accurate Thomsen's parameter ε, which is proved by using both synthetic and field data.

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“…Strong outliers might have strong and biased influence on the model update. As the frequency‐domain data samples are complex valued, it is not easy to mitigate the data noise in a way similar to our method for winnowing traveltimes and amplitudes (Wang et al 2000). Waveform inversion is a highly non‐linear problem but if, in a linearized procedure, strong outliers are transferred linearly to strong model updates, this causes the problem to be unstable and divergent.…”

Section: Waveform Inversion Of Real Datamentioning

confidence: 99%

Crosshole seismic waveform tomography - I. Strategy for real data application

Wang¹,

Rao²

2006

Geophysical Journal International

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S U M M A R YThe frequency-domain version of waveform tomography enables the use of distinct frequency components to adequately reconstruct the subsurface velocity field, and thereby dramatically reduces the input data quantity required for the inversion process. It makes waveform tomography a computationally tractable problem for production uses, but its applicability to real seismic data particularly in the petroleum exploration and development scale needs to be examined. As real data are often band limited with missing low frequencies, a good starting model is necessary for waveform tomography, to fill in the gap of low frequencies before the inversion of available frequencies. In the inversion stage, a group of frequencies should be used simultaneously at each iteration, to suppress the effect of data noise in the frequency domain. Meanwhile, a smoothness constraint on the model must be used in the inversion, to cope the effect of data noise, the effect of non-linearity of the problem, and the effect of strong sensitivities of short wavelength model variations. In this paper we use frequency-domain waveform tomography to provide quantitative velocity images of a crosshole target between boreholes 300 m apart. Due to the complexity of the local geology the velocity variations were extreme (between 3000 and 5500 m s −1 ), making the inversion problem highly non-linear. Nevertheless, the waveform tomography results correlate well with borehole logs, and provide realistic geological information that can be tracked between the boreholes with confidence.

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Seismic amplitude inversion for interface geometry: practical approach for application

Cited by 15 publications

References 33 publications

Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Seismic Amplitude Inversion for Interface Geometry of Multi-layered Structures

Seismic amplitude inversion for the transversely isotropic media with vertical axis of symmetry

Crosshole seismic waveform tomography - I. Strategy for real data application

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