An Interferometry-Based, Subsurface-Domain Objective Function for Targeted Waveform Inversion

Vasconcelos, I.; Ravasi, Matteo; Neut, Joost van der

doi:10.3997/2214-4609.20141090

Cited by 5 publications

(2 citation statements)

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“…By applying the methodology at each depth level in the subsurface and taking the response at zero time lag and zero space lag, an image with accurate amplitudes can be obtained without artefacts from internal multiple reflections Broggini et al 2014a;Behura et al 2014). By including non-zero lags, equivalent extended images can also be created (Vasconcelos & Rickett 2013), which can be useful input for migration velocity analysis (Sava & Vasconcelos 2011), reservoir characterization (De Bruin et al 1990;Thomson 2012) and novel schemes for nonlinear imaging (Fleury & Vasconcelos 2012;Ravasi & Curtis 2012) and waveform inversion (Vasconcelos et al 2014a). Alternatively, we can use the Marchenko equations to retrieve internal multiples at the acquisition level, which could then be adaptively subtracted from the recorded data .…”

Section: Introductionmentioning

confidence: 99%

On Green's function retrieval by iterative substitution of the coupled Marchenko equations

Neut¹,

Vasconcelos

Wapenaar³

2015

Geophys. J. Int.

118

114

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S U M M A R YIterative substitution of the coupled Marchenko equations is a novel methodology to retrieve the Green's functions from a source or receiver array at an acquisition surface to an arbitrary location in an acoustic medium. The methodology requires as input the single-sided reflection response at the acquisition surface and an initial focusing function, being the time-reversed direct wavefield from the acquisition surface to a specified location in the subsurface. We express the iterative scheme that is applied by this methodology explicitly as the successive actions of various linear operators, acting on an initial focusing function. These operators involve multidimensional crosscorrelations with the reflection data and truncations in time. We offer physical interpretations of the multidimensional crosscorrelations by subtracting traveltimes along common ray paths at the stationary points of the underlying integrals. This provides a clear understanding of how individual events are retrieved by the scheme. Our interpretation also exposes some of the scheme's limitations in terms of what can be retrieved in case of a finite recording aperture. Green's function retrieval is only successful if the relevant stationary points are sampled. As a consequence, internal multiples can only be retrieved at a subsurface location with a particular ray parameter if this location is illuminated by the direct wavefield with this specific ray parameter. Several assumptions are required to solve the Marchenko equations. We show that these assumptions are not always satisfied in arbitrary heterogeneous media, which can result in incomplete Green's function retrieval and the emergence of artefacts. Despite these limitations, accurate Green's functions can often be retrieved by the iterative scheme, which is highly relevant for seismic imaging and inversion of internal multiple reflections.

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Section: Introductionmentioning

confidence: 99%

On Green's function retrieval by iterative substitution of the coupled Marchenko equations

Neut¹,

Vasconcelos

Wapenaar³

2015

Geophys. J. Int.

118

114

View full text Add to dashboard Cite

show abstract

“…The ability to separate upgoing from downgoing waves when VA data are opportunely injected along the receiver array is not limited to back propagation (or propagation backward in time): The downgoing component can be propagated downward (and the upgoing component upward) by injecting the full recorded VA data forward in time and interchanging the sign of equation 4 (Robertson and Chapman, 2000;van Manen et al, 2007;Amundsen and Robertsson, 2014;Vasconcelos et al, 2014;Ravasi et al, 2015c).…”

Section: Discussionmentioning

confidence: 99%

Vector-acoustic reverse time migration of Volve ocean-bottom cable data set without up/down decomposed wavefields

et al. 2015

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Methods for wavefield injection are commonly used to extrapolate seismic data in reverse time migration (RTM). Injecting a single component of the acoustic field, for example, pressure, leads to ambiguity in the direction of propagation. Each recorded wavefront is propagated both upward and downward, and spurious (or ghost) reflectors are created alongside real reflectors in the subsurface image. Thus, wavefield separation based on the combination of pressure and particle velocity data is generally performed prior to imaging to extract only the upgoing field from multicomponent seabed or towed marine seismic recordings. By instead combining vector-acoustic (VA) data with monopoleand dipole-type propagators in the extrapolation of shot or receiver gathers, we show that wavefield separation (or deghosting) can instead be performed "on-the-fly" at limited additional cost. This strategy was successfully applied to a line of a North Sea ocean-bottom cable data set, acquired over the Volve field. We then evaluate additional advantages over standard RTM with decomposed fields such as improved handling of the directivity information contained in the acquired VA data for clearer shallow sections and better focused space-lag common image gathers, and imaging of the downgoing component without the need for additional finite-difference modeling via mirror migration. Finally, we prove the robustness of our method with respect to sparse and irregular receiver sampling.

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Seismic interferometry by multidimensional deconvolution without wavefield separation

Ravasi¹,

Meles²,

Curtis³

et al. 2015

Geophysical Journal International

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An Interferometry-Based, Subsurface-Domain Objective Function for Targeted Waveform Inversion

Cited by 5 publications

References 0 publications

On Green's function retrieval by iterative substitution of the coupled Marchenko equations

On Green's function retrieval by iterative substitution of the coupled Marchenko equations

Vector-acoustic reverse time migration of Volve ocean-bottom cable data set without up/down decomposed wavefields

Seismic interferometry by multidimensional deconvolution without wavefield separation

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