Anisotropy parameters estimation from multi-component seismic data

2011 ◽  
Author(s):  
Xixi Li ◽  
Pu Wang ◽  
Botao Li ◽  
Tianyue Hu
Keyword(s):  
Seismic Data ◽  
Parameters Estimation ◽  
Anisotropy Parameters

Traveltime approximation for converted waves in elastic orthorhombic media

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. C229-C237 ◽  
Author(s):  
Shibo Xu ◽  
Alexey Stovas
Keyword(s):  
Seismic Data ◽  
Real Data ◽  
Processing Parameters ◽  
Model Parameters ◽  
Seismic Data Processing ◽  
Converted Wave ◽  
Rational Form ◽  
Time Migration ◽  
Taylor Series Approximation ◽  
Anisotropy Parameters

The moveout approximations are commonly used in seismic data processing such as velocity analysis, modeling, and time migration. The anisotropic effect is very obvious for a converted wave when estimating the physical and processing parameters from the real data. To approximate the traveltime in an elastic orthorhombic (ORT) medium, we defined an explicit rational-form approximation for the traveltime of the converted [Formula: see text]-, [Formula: see text]-, and [Formula: see text]-waves. To obtain the expression of the coefficients, the Taylor-series approximation is applied in the corresponding vertical slowness for three pure-wave modes. By using the effective model parameters for [Formula: see text]-, [Formula: see text]-, and [Formula: see text]-waves, the coefficients in the converted-wave traveltime approximation can be represented by the anisotropy parameters defined in the elastic ORT model. The accuracy in the converted-wave traveltime for three ORT models is illustrated in numerical examples. One can see from the results that, for converted [Formula: see text]- and [Formula: see text]-waves, our rational-form approximation is very accurate regardless of the tested ORT model. For a converted [Formula: see text]-wave, due to the existence of cusps, triplications, and shear singularities, the error is relatively larger compared with PS-waves.

scholarly journals Estimation of the anisotropy parameters from imaging moveout of diving wave in a factorized anisotropic medium

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. C139-C150 ◽  
Author(s):  
Shibo Xu ◽  
Alexey Stovas ◽  
Tariq Alkhalifah
Keyword(s):  
Anisotropic Medium ◽  
Waveform Inversion ◽  
Velocity Model ◽  
Parameters Estimation ◽  
Model Parameters ◽  
Full Waveform ◽  
Vertical Heterogeneity ◽  
Analytical Formulas ◽  
Anisotropy Parameters ◽  
The One

The importance of diving waves is being realized because they provide long-wavelength model information, which can be used to help invert for the reflection information in full-waveform inversion. The factorized model is defined here as a combination of vertical heterogeneity and constant anisotropy, and it admits closed-form description of the traveltime. We have used these resulting analytical formulas to describe the behavior of diving waves in a factorized anisotropic medium, and we used an approximate imaging moveout formulation (residual moveout after imaging) to update the velocity model when the wrong model parameters (isotropic assumption) were used for imaging. We then used these analytical representations of the image moveout to establish a semblance analysis framework to search for the optimal anisotropic parameters. We have also discussed different parameterizations of the factorized medium to find the one that gave the best accuracy in anisotropy parameters estimation.

Borehole-Driven 3D Surface Seismic Data Processing Using DAS-VSP Data

2021 ◽  
Author(s):  
Gang Yu ◽  
Junjun Wu ◽  
Yuanzhong Chen ◽  
Ximing Wang
Keyword(s):  
Data Processing ◽  
Data Acquisition ◽  
Seismic Data ◽  
Field Data ◽  
Seismic Data Processing ◽  
3D Surface ◽  
Data Volume ◽  
Vsp Data ◽  
Seismic Data Acquisition ◽  
Anisotropy Parameters

Abstract A 3D surface seismic data acquisition project was conducted simultaneously with 3D DAS-VSP data acquisition in one well in Jilin Oilfield of Northen China. The 3D surface seismic data acquisition project covered an area of 75 km2, and one borehole (DS32-3) and an armoured optical cable with high temperature single mode fiber were used to acquire the 3D DAS-VSP data simultaneously when the crew was acquiring the 3D surface seismic data. The simultaneously acquired 3D DAS-VSP data were used to extract formation velocity, deconvolution operator, absorption, attenuation (Q value), anisotropy parameters (η, δ, ε) as wel as enhanced the surface seismic data processing including velocity model calibration and modification, static correction, deconvolution, demultiple processing, high frequency restoration, anisotropic migration, and Q-compensation or Q-migration. In this project, anisotropic migration, Q-migration was conducted with the anisotropy parameters (η, δ, ε) data volume and enhanced Q-field data volume obtained from the joint inversion of both the near surface 3D Q-field data volume from uphole data and the mid-deep layer Q-field data volume from all available VSP data in the 3D surface seismic surveey area. The anosotropic migration and Q-migration results show much sharper and focussed faults and and clearer subsutface structure.

Role of the inhomogeneity angle in anisotropic attenuation analysis

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. WB177-WB191 ◽  
Author(s):  
Jyoti Behura ◽  
Ilya Tsvankin
Keyword(s):  
Attenuation Coefficient ◽  
Seismic Data ◽  
Spectral Ratio ◽  
Ratio Method ◽  
Attenuation Coefficients ◽  
Anisotropic Models ◽  
High Attenuation ◽  
Wide Range ◽  
Anisotropy Parameters ◽  
Attenuation Anisotropy

The inhomogeneity angle (the angle between the real and imaginary parts of the wave vector) is seldom taken into account in estimating attenuation coefficients from seismic data. Wave propagation through the subsurface, however, can result in relatively large inhomogeneity angles [Formula: see text], especially for models with significant attenuation contrasts across layer boundaries. Here we study the influence of the angle [Formula: see text] on phase and group attenuation in arbitrarily anisotropic media using the first-order perturbation theory verified by exact numerical modeling. Application of the spectral-ratio method to transmitted or reflected waves yields the normalized group attenuation coefficient [Formula: see text], which is responsible for amplitude decay along seismic rays. Our analytic solutions show that for a wide range of inhomogeneity angles, the coefficient [Formula: see text] is close to the normalized phase attenuation coefficient [Formula: see text] computed for [Formula: see text] [Formula: see text]. The coefficient[Formula: see text] can be inverted directly for the attenuation-anisotropy parameters, so no knowledge of the inhomogeneity angle is required for attenuation analysis of seismic data. This conclusion remains valid even for uncommonly high attenuation with the quality factor [Formula: see text] less than 10 and strong velocity and attenuation anisotropy. However, the relationship between group and phase attenuation coefficients becomes more complicated for relatively large inhomogeneity angles approaching so-called ‘‘forbidden directions.’’ We also demonstrate that the velocity function remains practically independent of attenuation for a wide range of small and moderate angles [Formula: see text]. In principle, estimation of the attenuation-anisotropy parameters from the coefficient [Formula: see text] requires computation of the phase angle, which depends on the anisotropic velocity field. For moderately anisotropic models, however, the difference between the phase and group directions should not significantly distort the results of attenuation analysis.

scholarly journals PRONY FILTERING OF SEISMIC DATA: MATHEMATICAL AND PHYSICAL MODELLING

2013 ◽  
Vol 31 (1) ◽  
pp. 151 ◽  
Author(s):  
Georgy Mikhailovich Mitrofanov ◽  
Viatcheslav Ivanovich Priimenko
Keyword(s):  
Seismic Data ◽  
Physical Modelling ◽  
Parameters Estimation ◽  
Physical Models ◽  
Seismic Signals ◽  
Optimal Method ◽  
Filtering Method ◽  
Local Areas ◽  
The Media

This article presents results of the Prony filtering method testing using mathematical and physical models. They illustrate features and capabilities of the proposed method of processing and analysing the recorded signals, which also include reflected seismic signals. Guidelines for choosing the optimal method parameters are demonstrated using examples. The use of such parameters provides the best extraction and parameters estimation of target signals. Based on them, it allows us to analyse the absorbing and scattering properties of the media for the local areas, for the analysed reflectors in particular. RESUMO: Este artigo teve por objetivo apresentar e analisar os resultados da aplicação do método de filtragem de Prony em modelos físicos e matemáticos. Tais resultados ilustram as características e o potencial do método proposto no processamento e na análise de sinais, incluindo também os eventos sísmicos de reflexão. As diretrizes para escolher os parâmetros otimizados do método são demonstradas através de exemplos. O uso de tais parâmetros proporciona a melhor estimativa, e viabiliza a separação dos sinais alvo. Com base em tais sinais, é possível analisar as propriedades de absorção e dispersão dos meios em áreas locais, em particular, nos refletores analisados.Palavras-chave: transformada de prony; decomposição de sinal e filtragem; dispersão e absorção de energia sísmica; efeitos de frequência

scholarly journals VSP polarization angles determination: Wysin-1 processing case study

2018 ◽  
Vol 66 (5) ◽  
pp. 1047-1062 ◽  
Author(s):  
Mateusz Zaręba ◽  
Tomasz Danek
Keyword(s):  
Seismic Data ◽  
Seismic Profile ◽  
Seismic Data Processing ◽  
Profile Data ◽  
Experiment Data ◽  
High Quality ◽  
Walkaway Vsp ◽  
Anisotropy Parameters ◽  
Borehole Seismic

Abstract In this paper, we present an analysis of borehole seismic data processing procedures required to obtain high-quality vertical stacks and polarization angles in the case of walkaway VSP (vertical seismic profile) data gathered in challenging conditions. As polarization angles are necessary for more advanced procedures like anisotropy parameters determination, their quality is critical for proper media description. Examined Wysin-1 VSP experiment data indicated that the best results can be obtained when rotation is performed for each shot on data after de-noising and vertical stacking of un-rotated data. Additionally, we proposed a procedure of signal matching that can substantially increase data quality.

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