Poststack diffraction imaging using reverse-time migration

Silvestrov, Ilya; Baina, R.; Landa, Evgeny

doi:10.1111/1365-2478.12280

Cited by 44 publications

(15 citation statements)

References 33 publications

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“…Silvestrov et al . () conclude their paper with the following wishful statement: “The ultimate solution that should allow us to image diffractions in velocity model of arbitrary complexity is to use prestack RTM and to construct dip‐angle CIGs in depth.”…”

Section: Introductionmentioning

confidence: 97%

“…There are few other authors that provide techniques for computing dip-angle CIGs based on space-shift extended waveequation migration methods (Browaeys 2008;Li, Tang and Ji 2012;Dafni and Symes 2016a). Another recent publication by Silvestrov, Baina and Landa (2016) involves poststack reversetime migration (RTM) and pseudo-dip-angle decomposition for diffraction imaging. It suggests a beamforming procedure to decompose the poststack seismic data into stack sections of constant horizontal slowness.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the decomposition is made in the poststack data space before the migration; hence, the method may not be as efficient in areas with structural complexity. Silvestrov et al (2016) conclude their paper with the following wishful statement: "The ultimate solution that should allow us to image diffractions in velocity model of arbitrary complexity is to use prestack RTM and to construct dip-angle CIGs in depth. "…”

Section: Introductionmentioning

confidence: 99%

“…The work in this study provides a method for diffraction imaging that addresses the need identified by Silvestrov et al (2016). We propose to compute and exploit dip-angle CIGs in depth based on prestack RTM (or any other waveequation migration method), as introduced by Dafni and Symes (2016a).…”

Section: Introductionmentioning

confidence: 99%

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Diffraction imaging by prestack reverse‐time migration in the dip‐angle domain

Dafni

Symes

2017

Geophysical Prospecting

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Prestack image volumes may be decomposed into specular and non‐specular parts by filters defined in the dip‐angle domain. For space‐shift extended image volumes, the dip‐angle decomposition is derived via local Radon transform in depth and midpoint coordinates, followed by an averaging over space‐shifts. We propose to employ prestack space‐shift extended reverse‐time migration and dip‐angle decomposition for imaging small‐scale structural elements, considered as seismic diffractors, in models with arbitrary complexity. A suitable design of a specularity filter in the dip‐angle domain rejects the dominant reflectors and enhances diffractors and other non‐specular image content. The filter exploits a clear discrimination in dip between specular reflections and diffractions. The former are stationary at the specular dip, whereas the latter are non‐stationary without a preferred dip direction. While the filtered image volume features other than the diffractor images (for example, noise and truncation artefacts are also present), synthetic and field data examples suggest that diffractors tend to dominate and are readily recognisable. Averaging over space‐shifts in the filter construction makes the reflectors‧ rejection robust against migration velocity errors. Another consequence of the space‐shift extension and its angle‐domain transforms is the possibility of exploring the image in a multiple set of common‐image gathers. The filtered diffractions may be analysed simultaneously in space‐shift, scattering‐angle, and dip‐angle image gathers by means of a single migration job. The deliverables of our method obviously enrich the processed material on the interpreter's desk. We expect them to further supplement our understanding of the Earth's interior.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diffraction imaging by prestack reverse‐time migration in the dip‐angle domain

Dafni

Symes

2017

Geophysical Prospecting

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“…Its principal advantage is the solving of the seismic wave equation to include all incident and converted or transmitted wave types that propagate through a reference model (Zhou et al, 2018). An important issue is whether the reflector is cast as a point diffractor or a specular reflector, that is, volumetric scattering versus reflections from smooth surfaces that separate different domains (Popovici et al, 2015;Schoepp et al, 2015;Silvestrov et al, 2015). RTM interpretational methods are usually dedicated to targeting one type of heterogeneity or the other but may include the capability to separate the contributions from the two scattering mechanisms (e.g., Koren & Ravve, 2011;Schoepp et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Surface Imaging Functions for Elastic Reverse Time Migration

Pollitz

2019

JGR Solid Earth

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Reverse time migration is often used to interpret acoustic or three‐component seismic recordings by creating an image of subsurface seismic reflectors. Here I describe elastic reverse time migration imaging functions that are cast as waveform misfit sensitivity kernels of contrasts in material parameters across hypothetical seismic discontinuities, that is, specular reflectors. The proposed “surface” imaging functions are theoretically applicable to either reflected or converted waves in order to estimate the location and reflectivity of these discontinuities. The surface imaging functions, as well as volumetric sensitivity kernels that target point diffractors, are tested on sets of synthetic surface array recordings that sample the 3‐D seismic wavefield on simple 2‐D structures generated using a 2.5‐D spectral element method. These tests illustrate that in contrast with the volumetric sensitivity kernels, the reflectivity is generally dominated by a high‐amplitude peak that coincides with input locations of discontinuities. Passive recordings of microseismicity, shot gathers, or a combination thereof can be potentially interpreted with the new surface imaging functions to yield useful reflectivity images.

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When there is no offset - a demonstration of seismic diffraction imaging and depth-velocity model building in the southern Aegean Sea

Preine

Schwarz

Bauer

et al. 2020

Preprint

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A vast majority of marine geological research is based on academic seismic data collected with single-channel systems or short-offset multichannel seismic cables, which often lack reflection moveout for conventional velocity analysis. Consequently, our understanding of Earth processes often relies on seismic time sections, which hampers quantitative analysis in terms of depth, formation thicknesses, or dip angles of faults. In order to overcome these limitations, we present a robust diffraction extraction scheme that models and adaptively subtracts the reflected wavefield from the data. We use diffractions to estimate insightful wavefront attributes and perform wavefront tomography to obtain laterally resolved seismic velocity information in depth. Using diffraction focusing as a quality control tool, we perform an interpretation-driven refinement to derive a geologically plausible depth-velocity model. In a final step, we perform depth migration to arrive at a spatial reconstruction of the shallow crust. Further, we focus the diffracted wavefield to demonstrate how these diffraction images can be used as physics-guided attribute maps to support the identification of faults and unconformities. We demonstrate the potential of this processing scheme by its application to a seismic line from the Santorini Amorgos Tectonic Zone, located on the Hellenic Volcanic Arc, which is notorious for its catastrophic volcanic eruptions, earthquakes, and tsunamis. The resulting depth image allows a refined fault pattern delineation and, for the first time, a quantitative analysis of the basin stratigraphy. We conclude that diffraction-based data analysis has a high potential, especially when the acquisition geometry of seismic data does not allow conventional velocity analysis. Plain Language SummaryThe active seismic method is a standard tool for studying and imaging the Earth's lithosphere. Proper imaging of complex geological targets requires seismic data of excellent quality, which are typically only acquired with expensive industrial surveys. Academic surveys, however, are often restricted to marine seismic equipment with limited illumination, which compromises imaging and interpretation. While most of the contemporary processing and interpretational routines are tailored to the reflected wavefield, recent research suggests that the often overlooked diffracted wavefield might help to overcome the gap between academic and industrial seismic imaging. Wave diffraction is the response of the seismic wavefield to small-scale subsurface structures and allows to estimate velocities even from single-channel seismic data.In this study, we use an academic seismic profile from the southern Aegean Sea and extract a rich diffracted wavefield from the data. We utilize these diffractions to estimate a velocity model that permits a reconstruction of the subsurface in depth and specifically highlight discontinuous features related to past dynamic processes. Such depth images allow us to reliably measure thicknesses and fault angles. We concl...

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Poststack diffraction imaging using reverse-time migration

Cited by 44 publications

References 33 publications

Diffraction imaging by prestack reverse‐time migration in the dip‐angle domain

Diffraction imaging by prestack reverse‐time migration in the dip‐angle domain

Surface Imaging Functions for Elastic Reverse Time Migration

When there is no offset - a demonstration of seismic diffraction imaging and depth-velocity model building in the southern Aegean Sea

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