Acoustic full-waveform inversion in an elastic world

Agudo, Òscar Calderón; Silva, Nuno da; Warner, Michael; Morgan, Joanna

doi:10.1190/segam2016-13843013.1

Cited by 5 publications

(9 citation statements)

References 16 publications

(22 reference statements)

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“…The proposed method consists of suppressing viscoacoustic effects from the observed data by computing matching filters that match modeled viscoacoustic to modeled acoustic data generated from estimates of the subsurface P-wave velocity and Q models, followed by the application of the filters to the observed data. This is analogous to the method proposed by Agudo et al (2016Agudo et al ( , 2017 to mitigate elastic effects in acoustic FWI, but with three main differences:…”

Section: Methodsmentioning

confidence: 99%

“…The first difference in the methodology with respect to that of Agudo et al (2016Agudo et al ( , 2017 is a consequence of having to model viscoacoustic wave propagation. For this purpose, an estimated Q model is required, which can be obtained independently from an inversion.…”

Section: Methodsmentioning

confidence: 99%

“…Here, we implement an alternative scheme by adapting the method of Agudo et al (2016Agudo et al ( , 2017, originally designed to mitigate elastic effects, to address viscous effects. The aim of this modified method is not to obtain an intrinsic attenuation model of the subsurface, but to mitigate viscous effects and improve the estimated P-wave velocity models from FWI.…”

Section: Introductionmentioning

confidence: 99%

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Addressing Viscous Effects in Acoustic Full-waveform Inversion

Agudo¹,

Silva²,

Warner³

et al. 2017

Proceedings

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In conventional full-waveform inversion (FWI), viscous effects are typically neglected, and this is likely to adversely affect the recovery of P-wave velocity. We have developed a strategy to mitigate viscous effects based on the use of matching filters with the aim of improving the performance of acoustic FWI. The approach requires an approximate estimate of the intrinsic attenuation model, and it is one to three times more expensive than conventional acoustic FWI. First, we perform 2D synthetic tests to study the impact of viscoacoustic effects on the recorded wavefield and analyze how that affects the recovered velocity models after acoustic FWI. Then, we apply the current method on the generated data and determine that it mitigates viscous effects successfully even in the presence of noise. We find that having an approximate estimate for intrinsic attenuation, even when these effects are strong, leads to improvements in resolution and a more accurate recovery of the P-wave velocity. Then, we implement and develop our method on a 2D field data set using Gabor transforms to obtain an approximate intrinsic attenuation model and inversion frequencies of up to 24 Hz. The analysis of the results indicates that there is an improvement in terms of resolution and continuity of the layers on the recovered P-wave velocity model, leading to an improved flattening of gathers and a closer match of the inverted velocity model with the migrated seismic data.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Addressing Viscous Effects in Acoustic Full-waveform Inversion

Agudo¹,

Silva²,

Warner³

et al. 2017

Proceedings

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“…As a rule of thumb, by moving from RBI to FWI, the spatial resolution can improve by up to one order of magnitude for and for borehole applications, it can reach to one of borehole logging methods (Wu and Toksöz, 1987;Dickens, Page 4 of 49 Geophysics Manuscript, Accepted Pending: For Review Not Production Confidential manuscript submitted to Geophysics 2.5D crosshole GPR full-waveform inversion 1994; Pratt and Shipp, 1999;Dessa and Pascal, 2003;Belina et al, 2009;Virieux and Operto, 2009;Warner et al, 2013). Since the pioneering work by Tarantola (1984), a large number of FWI approaches for acoustic and elastic waves have been proposed using time-domain, frequency-domain, and hybrid methods (Sirgue et al, 2008;Butzer et al, 2013;Lavoué et al, 2013;Warner et al, 2013;Agudo et al, 2016). Despite the existence of an elastic solution for crosshole seismic FWI, many applications are still restricted to acoustic-wave solutions due to the high computational costs of both the forward modeling and inversion (Pratt et al, 1998;Hollender et al, 1999;Ernst et al, 2007a;Butzer et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

2.5D crosshole GPR full-waveform inversion with synthetic and measured data

et al. 2020

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Full-waveform inversion (FWI) of cross-borehole ground-penetrating radar (GPR) data is a technique with the potential to investigate subsurface structures. Typical FWI applications transform 3D measurements into a 2D domain via an asymptotic 3D to 2D data transformation, widely known as a Bleistein filter. Despite the broad use of such a transformation, it requires some assumptions that make it prone to errors. Although the existence of the errors is known, previous studies have failed to quantify the inaccuracies introduced on permittivity and electrical conductivity estimation. Based on a comparison of 3D and 2D modeling, errors could reach up to 30% of the original amplitudes in layered structures with high-contrast zones. These inaccuracies can significantly affect the performance of crosshole GPR FWI in estimating permittivity and especially electrical conductivity. We have addressed these potential inaccuracies by introducing a novel 2.5D crosshole GPR FWI that uses a 3D finite-difference time-domain forward solver (gprMax3D). This allows us to model GPR data in 3D, whereas carrying out FWI in the 2D plane. Synthetic results showed that 2.5D crosshole GPR FWI outperformed 2D FWI by achieving higher resolution and lower average errors for permittivity and conductivity models. The average model errors in the whole domain were reduced by approximately 2% for permittivity and conductivity, whereas zone-specific errors in high-contrast layers were reduced by approximately 20%. We verified our approach using crosshole 2.5D FWI measured data, and the results showed good agreement with previous 2D FWI results and geologic studies. Moreover, we analyzed various approaches and found an adequate trade-off between computational complexity and accuracy of the results, i.e., reducing the computational effort while maintaining the superior performance of our 2.5D FWI scheme.

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“…These papers showed inversion examples of 2D and 3D models and noted that artefacts exist on the P-wave velocity inversion result when acoustic inversion is carried out using elastic data. Several authors have proposed methods to help mitigate the artefacts on the P-wave image that resulted from applying acoustic inversion to elastic data (Agudo et al 2016;Albertin et al 2016;Willemsen et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Elastic versus acoustic inversion for marine surveys

Móra¹,

2018

Geophysical Journal International

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Acoustic full-waveform inversion in an elastic world

Cited by 5 publications

References 16 publications

Addressing Viscous Effects in Acoustic Full-waveform Inversion

Addressing Viscous Effects in Acoustic Full-waveform Inversion

2.5D crosshole GPR full-waveform inversion with synthetic and measured data

Elastic versus acoustic inversion for marine surveys

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