resistivity imaging Magazines & Journals
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Explicit expressions for the Fréchet derivatives in 3D anisotropic resistivity inversion
in resistivity imaging of a heterogeneous and fully anisotropic earth. The formulation involves the ...
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A numerical comparison of 2D resistivity imaging with ten electrode arrays
This paper compares the resolution and efficiency of 2D resistivity imaging survey with ...
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Rapid 2-D/3-D crosshole resistivity imaging using the analytic sensitivity function
We develop a method to obtain 2-D/3-D resistivity images for crosshole dc electric ...
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A synthetic study on crosshole resistivity imaging using different electrode arrays
By means of numerical simulations, the possibilities of crosshole resistivity ...
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Multi-channel, full waveform and flexible electrode combination resistivity imaging system
The usual practice of resistivity imaging using standard electrode arrays, such as ...
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Explicit expressions and numerical calculations for the Fréchet and second derivatives in 2.5D Helmholtz equation inversion
In order to perform resistivity imaging, seismic waveform tomography or sensitivity ...
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Crosshole resistivity imaging of aquifer properties
Crosshole resistivity tomography has been trialled at the Bolivar site north of ...
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An Adaptive Wavenumber Sampling Strategy for 2.5D Seismic-Wave Modeling in the Frequency Domain
Simulation of seismic waves from a 3D point-source in a 2D medium may be performed in the frequency-wavenumber domain (called 2.5D modelling). It involves computing the Fourier-transformed Green's function for a number of frequency (ω) and strike direction wavenumber (ky) values and doubly inverse transforming to convert to the traveltime and distance space. Such modeling produces a wavefield ...
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3-D frequency-domain seismic wave modelling in heterogeneous, anisotropic media using a Gaussian quadrature grid approach
We present an extension of the 3-D spectral element method (SEM), called the Gaussian quadrature grid (GQG) approach, to simulate in the frequency-domain seismic waves in 3-D heterogeneous anisotropic media involving a complex free-surface topography and/or sub-surface geometry. It differs from the conventional SEM in two ways. The first is the replacement of the hexahedral element mesh with 3-D ...
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A new method for crosswell reflector imaging
Imaging seismic reflectors with crosshole and VSP tomographic data is only occasionally carried ...
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A damping method for the computation of the 2.5-D Green's function for arbitrary acoustic media
In acoustic wavefield modelling, the 2.5-D approximation, in which the model parameter is considered to be invariant in the strike direction and the source is assumed to be a point excitation so that the wavefield has 3-D features, is an economical and realistic scheme for seismic full-waveform inversion. On the other hand, according to Parseval's theorem, the least-squares inversion of ...
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Surface seismic imaging by multi-frequency amplitude inversion
We have developed a new full-waveform inversion scheme for crosshole seismic imaging. In this ...
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Analytic expressions for the velocity sensitivity to the elastic moduli for the most general anisotropic media
For non-linear kinematic inversion of elastic anisotropy parameters and related investigations of the sensitivity of seismic data, the derivatives of the wavespeed (phase velocity and group velocity) with respect to the individual elastic moduli are required. This paper presents two analytic methods, called the eigenvalue and eigenvector methods, to compute the derivatives of the wavespeeds for ...
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Numerical study of seismic scattering and waveguide excitation in faulted coal seams
Finite-difference P-SV simulations of seismic scattering characteristics of faulted coal-seam models have been undertaken for near-surface P- and S-wave sources in an attempt to understand the efficiency of body-wave to channel-wave mode conversion and how it depends on the elastic parameters of the structure. The synthetic seismograms clearly show the groups of channel waves generated at the ...
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Computing the Sensitivity Kernels for 2.5-D Seismic Waveform Inversion in Heterogeneous, Anisotropic Media
2.5-D modeling and inversion techniques are much closer to reality than the simple and traditional 2-D seismic wave modeling and inversion. The sensitivity kernels required in full waveform seismic tomographic inversion are the Fréchet derivatives of the displacement vector with respect to the independent anisotropic model parameters of the subsurface. They give the sensitivity of the seismograms ...
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Wavenumber sampling strategies for 2.5-D frequency-domain seismic wave modelling in general anisotropic media
The computational efficiency of 2.5-D seismic wave modelling in the frequency domain depends largely on the wavenumber sampling strategy used. This involves determining the wavenumber range and the number of the sampling points, and overcoming the singularities in the wavenumber spectrum when taking the inverse Fourier transform to yield the frequency-domain wave solution. In this paper, we ...
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A crosswell seismic experiment for nickel sulphide exploration
A crosshole seismic tomography experiment was conducted in the Kambalda nickel district to ...
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Nonlinear traveltime inversion scheme for crosshole seismic tomography in tilted transversely isotropic media
Crosshole seismic tomography often is applied to image the velocity structure of an ...
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Composite boundary‐valued solution of the 2.5-D Green’s function for arbitrary acoustic media
Theoretically, the Green’s function can be used to calculate the wavefield response of a specified source and the Fréchet derivative with respect to the model parameters for crosshole seismic full‐waveform inversion. In this paper, we apply the finite‐element method to numerically compute the 2.5-D Green’s function for an arbitrary acoustic medium by solving a composite boundary‐valued problem ...
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Crosshole seismic inversion with normalized full‐waveform amplitude data
We investigate a simple scheme for full‐waveform amplitude spectrum inversion of crosshole seismic data with an unknown source wavelet. The method is based on our 2D/2.5D finite‐element method of acoustic‐wave modeling. The normalized amplitude data, defined as the spectral ratio of the original trace amplitude to the average amplitude for the entire common shot gather, are used for ...
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