Diffraction imaging and time-migration velocity analysis using oriented velocity continuation

Decker, Luke; Merzlikin, Dmitrii; Fomel, Sergey

doi:10.1190/geo2016-0141.1

Cited by 49 publications

(19 citation statements)

References 38 publications

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“…When the noise is low, the diffracted wavefield can be retrieved by subtracting the reflected wavefield from the recorded wavefield. In this study, we perform the separation using a dip‐guided PWD filter approach in the time domain on common‐offset gathers (as in, e.g., Decker et al., 2017; Fomel et al., 2007). This approach assumes that reflections are locally planar events in common‐offset domain (Harlan et al., 1984).…”

Section: Methodsmentioning

confidence: 99%

“…A classic application for diffraction imaging is to derive migration velocity fields by focusing analysis of the diffracted wavefield (e.g., Decker et al., 2017; Fomel et al., 2007; Preine et al., 2020). Under the correct migration velocity, diffractions will collapse (focus) to a point at their apex.…”

Section: Methodsmentioning

confidence: 99%

“…Several approaches for diffraction separation have been developed. Some exploit the difference in moveout of reflections and diffractions in common‐shot or common‐midpoint (CMP) domains (Khaidukov et al., 2004), or the difference in dip and lateral continuity between reflections and diffractions in common‐offset domain (Decker et al., 2017; Fomel et al., 2007; Taner et al., 2006). Others rely on wavefront attributes and the assumed coherence of seismic reflections to model and subtract the reflected wavefield (Dell & Gajewski, 2011; Schwarz & Gajewski, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Seismic Diffraction Imaging to Characterize Mass‐Transport Complexes: Examples From the Gulf of Cadiz, South West Iberian Margin

et al. 2021

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Mass‐transport complexes (MTCs) are often characterized by small‐scale discontinuous internal structure, such as slide blocks, rough interfaces, faults, and truncated strata. Seismic images may not properly resolve such structure because seismic reflections are fundamentally limited in lateral resolution by the source bandwidth. The relatively weak seismic diffractions, instead, encode information on subwavelength‐scale structure, with superior illumination. In this paper, we compare diffraction imaging to conventional, full‐wavefield seismic imaging to characterize MTCs. We apply a seismic diffraction imaging workflow based on plane‐wave destruction filters to two 2D marine multichannel seismic profiles from the Gulf of Cadiz. We observe that MTCs generate a large amount of diffracted energy relative to the unfailed confining sediments. The diffraction images show that some of this energy is localized along existing discontinuities imaged by the full‐wavefield images. We demonstrate that, in combination with full‐wavefield images, diffraction images can be utilized to better discriminate the lateral extent of MTCs, particularly for thin bodies. We suggest that diffraction images may be a more physically correct alternative to commonly used seismic discontinuity attributes derived from full‐wavefield images. Finally, we outline an approach to utilize the out‐of‐plane diffractions generated by the 3D structure of MTCs, normally considered a nuisance in 2D seismic processing. We use a controlled synthetic test and a real‐data example to show that under certain conditions these out‐of‐plane diffractions might be used to constrain the minimum width of MTCs from single 2D seismic profiles.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seismic Diffraction Imaging to Characterize Mass‐Transport Complexes: Examples From the Gulf of Cadiz, South West Iberian Margin

et al. 2021

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“…Likewise applied before migration, there are some techniques that make direct use of wave-field coherence for diffraction separation (Berkovitch et al, 2009;Dell and Gajewski, 2011;Bauer et al, 2016;Bakhtiari Rad et al, 2018). While these methods specifically target the diffracted wave field for extraction, recent developments have shown that a more surgical, amplitude-preserving separation can be achieved by assessing the coherence of reflections instead (Schwarz and Gajewski, 2017a;Schwarz, 2019b).…”

Section: Introductionmentioning

confidence: 99%

Coherent diffraction imaging for enhanced fault and fracture network characterization

Schwarz

Krawczyk

2020

Solid Earth

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Abstract. Faults and fractures represent unique features of the solid Earth and are especially pervasive in the shallow crust. Aside from directly relating to crustal dynamics and the systematic assessment of associated risk, fault and fracture networks enable the efficient migration of fluids and therefore have a direct impact on concrete topics relevant to society, including climate-change-mitigating measures like CO2 sequestration or geothermal exploration and production. Due to their small-scale complexity, fault zones and fracture networks are typically poorly resolved, and their presence can often only be inferred indirectly in seismic and ground-penetrating radar (GPR) subsurface reconstructions. We suggest a largely data-driven framework for the direct imaging of these features by making use of the faint and still often underexplored diffracted portion of the wave field. Finding inspiration in the fields of optics and visual perception, we introduce two different conceptual pathways for coherent diffraction imaging and discuss respective advantages and disadvantages in different contexts of application. At the heart of both of these strategies lies the assessment of data coherence, for which a range of quantitative measures is introduced. To illustrate the versatility and effectiveness of the approach for high-resolution geophysical imaging, several seismic and GPR field data examples are presented, in which the diffracted wave field sheds new light on crustal features like fluvial channels, erosional surfaces, and intricate fault and fracture networks on land and in the marine environment.

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“…Khoshnavaz et al (2016a) proposed to use predictive painting (Fomel 2010) of local slopes to estimate the kinematic attributes, which substitutes the need for curvatures by using the result of predictive painting. The local slopes are also applied to other steps of seismic data processing and imaging (Cooke et al 2009;Bóna 2011;Khoshnavaz et al 2016b;Khoshnavaz 2017;Decker et al 2017;Casasanta and Fomel 2011). The local slopes can be obtained by so-called plane-wave destruction (PWD) (Claerbout 1992;Fomel 2002;Fomel and Stovas 2010).…”

Section: Introductionmentioning

confidence: 99%

Automatic estimation of traveltime parameters in VTI media using similarity-weighted clustering

Liu

Zhang

et al. 2020

Pet. Sci.

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Compared with hyperbolic velocity estimation methods, nonhyperbolic methods (such as shifted hyperbola) are better choices for large offsets or vertical transverse isotropy (VTI) media. Since local seismic event slope contains subsurface information, they can be used to estimate zero-offset two-way traveltime and normal moveout velocity. The traditional velocity estimation methods require a great deal of manual work and are also prone to human error. In order to estimate the traveltime parameters for VTI media automatically, in this paper, we propose to use predictive painting and similarity-weighted clustering to obtain traveltime parameters. The predictive painting is used to estimate zero-offset two-way traveltime, and the shifted-hyperbola traveltime equation is used to obtain velocity and anisotropy attributes. We first map local slopes to zero-offset two-way traveltime and moveout-parameters domain and then use similarity-weighted k-means clustering to find the maximum likelihood anisotropy parameters of the main subsurface structures. In order to demonstrate that, we apply the similarity-weighted clustering method to synthetic and field data examples and the results are of higher accuracy when compared to the ones obtained using multiparameter semblance-based method. From estimation error section, it can be seen that the estimation error of multiparameter semblance-based method is about 3-5 times that of the proposed method.

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Diffraction imaging and time-migration velocity analysis using oriented velocity continuation

Cited by 49 publications

References 38 publications

Seismic Diffraction Imaging to Characterize Mass‐Transport Complexes: Examples From the Gulf of Cadiz, South West Iberian Margin

Seismic Diffraction Imaging to Characterize Mass‐Transport Complexes: Examples From the Gulf of Cadiz, South West Iberian Margin

Coherent diffraction imaging for enhanced fault and fracture network characterization

Automatic estimation of traveltime parameters in VTI media using similarity-weighted clustering

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