Ivan Vasconcelos

Shearwater Health

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Matteo Ravasi

King Abdullah University of Science and Technology

Roel Snieder

Colorado School of Mines

Kees Wapenaar

Delft University of Technology

Joost van der Neut

Delft University of Technology

Yanadet Sripanich

Utrecht University

Andrew Curtis

University of Edinburgh

Paul Sava

Colorado School of Mines

Haorui Peng

Utrecht University

David Vargas

Shearwater Health

Leon Diekmann

Utrecht University

Cooperative Institutions

Colorado School of Mines

Utrecht University

Delft University of Technology

University of Edinburgh

Schlumberger (British Virgin Islands)

Shell (Netherlands)

Schlumberger (United Kingdom)

Shell (United States)

Schlumberger (Norway)

ExxonMobil (United States)

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Imaging Internal Multiples through Seismic Interferometry - Subsalt VSP Examples

75th EAGE Conference and Exhibition incorporating SPE EUROPEC 2013 (2008)

Ivan Vasconcelos R. Snieder Brian Hornby

Seismic interferometry has become a technology of growing interest for imaging from borehole seismic data. We demonstrate that interferometry of internal multiples can be used to image targets above a borehole receiver array. We use an interferometry technique that targets the reconstruction of specific primary reflections from multiply reflected waves. In this target-oriented interferometry approach, we rely on shot-domain wavenumber separation to select the directions of waves arriving at a given receiver. We provide a description of this method along with two conceptual applications, and compare it to other approaches to seismic interferometry. Using a numerical walkaway VSP experiment recorded by a subsalt borehole receiver array in the Sigsbee salt model, we use the interference of internal multiples to image the salt structure from below. In this numerical example, the interferometric image that targets internal multiples reconstructs the bottom and top salt reflectors above the receiver array, as well as subsalt sediment structure between the array and the salt.

Seismic interferometry

Multiple

Geophysical Imaging

Vertical seismic profile

10.3997/2214-4609.20147730

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Citations (1)

A Comparison of Strategies for Seismic Interferometry

Springer eBooks (2009)

Roel Snieder Masatoshi Miyazawa Evert Slob Ivan Vasconcelos Kees Wapenaar

Seismic interferometry

10.1007/978-90-481-3680-3_9

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Citations (2)

Scattering-based sensitivity kernels for time-lapse differential-waveform inversion

Daniel Leal Macedo Ivan Vasconcelos Jörg Schleicher

Time-lapse seismic surveys have become a powerful reservoir monitoring tool. The basic approach in time-lapse surveys is to image the changes in the reservoir by subtracting separated-in-time seismic images of the reservoir. Recently FWI has been used as an alternative time-lapse monitoring tool. However, in practice nonlinear gradient-based FWI is limited due to its notorious sensitivity to the choice of the starting model. Kernel decomposition based on scattering theory allows to break the acoustic-wavefield sensitivity kernels with respect to model parameters into background and singular parts, which should help to address model-convergence issues in FWI. In this work we apply scattering theory to the time-lapse problem, considering the time-lapse change as a perturbation of the singular part of the model. In the framework of time-lapse differentialwaveform inversion, and under application of scattering-based decomposition of the sensitivity kernel, we take advantage of the additional illumination of the time-lapse change provided by multiple-scattering phenomena to improve the perturbation estimates from FWI.

10.1190/segam2013-1292.1

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Interferometry by deconvolution: Part 2 — Theory for elastic waves and application to drill-bit seismic imaging

Geophysics (2008)

Ivan Vasconcelos Roel Snieder

Deconvolution interferometry successfully recovers the impulse response between two receivers without the need for an independent estimate of the source function. Here we extend the method of interferometry by deconvolution to multicomponent data in elastic media. As in the acoustic case, elastic deconvolution interferometry retrieves only causal scattered waves that propagate between two receivers as if one acts as a pseudosource of the point-force type. Interferometry by deconvolution in elastic media also generates artifacts because of a clamped-point boundary condition imposed by the deconvolution process. In seismic-while-drilling (SWD) practice, the goal is to determine the subsurface impulse response from drill-bit noise records. Most SWD technologies rely on pilot sensors and/or models to predict the drill-bit source function, whose imprint is then removed from the data. Interferometry by deconvolution is of most use to SWD applications in which pilot records are absent or provide unreliable estimates of bit excitation. With a numerical SWD subsalt example, we show that deconvolution interferometry provides an image of the subsurface that cannot be obtained by correlations without an estimate of the source autocorrelation. Finally, we test the use of deconvolution interferometry in processing SWD field data acquired at the San Andreas Fault Observatory at Depth (SAFOD). Because no pilot records were available for these data, deconvolution outperforms correlation in obtaining an interferometric image of the San Andreas fault zone at depth.

Seismic interferometry

Impulse response

Point spread function

10.1190/1.2904985

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Citations (124)

Band-limited scattered wavefield reconstruction beneath complex overburdens using the Marchenko method

David Vargas Ivan Vasconcelos Matteo Ravasi

Structural imaging beneath complex overburdens, such as sub-salt or sub-basalt, typically characterized by high-impedance contrasts represents a major challenge for state-of-the-art seismic methods. Reconstructing complex geological structures in the vicinity of and below salt bodies is challenging not only due to uneven, single-sided illumination of the target area but also because of the imperfect removal of surface and internal multiples from the recorded data, as required by traditional migration algorithms. In such tectonic setups, most of the downgoing seismic wavefield is reflected toward the surface when interacting with the overburden's top layer. Similarly, the sub-salt upcoming energy is backscattered at the salt's base. Consequently, the actual energy illuminating the sub-salt reflectors, recorded at the surface, is around the noise level. In diapiric trap systems, conventional seismic extrapolation techniques do not guarantee sufficient quality to reduce exploration and production risks; likewise, seismic-based reservoir characterization and monitoring are also compromised. In this regard, accurate wavefield extrapolation techniques based on the Marchenko method may open up new ways to exploit seismic data.The Marchenko redatuming technique retrieves reliable full-wavefield information in the presence of geologic intrusions, which can be subsequently used to produce artefact-free images by naturally including all orders of multiples present in seismic reflection data. To achieve such a goal, the method relies on the estimation of focusing operators allowing the synthesis of virtual surveys at a given depth level. Still, current Marchenko implementations do not fully incorporate available subsurface models with sharp contrasts, due to the requirements regarding the initialization of the focusing functions. Most importantly, in complex media, even a fairly accurate estimation of a direct wave as a proxy for the required initial focusing functions may not be enough to guarantee sufficiently accurate wavefield reconstruction.In this talk, we will discuss a scattering-based Marchenko redatuming framework which improves the redatuming of seismic surface data in highly complex media when compared to other Marchenko-based schemes. This extended version is designed to accommodate for band-limited, multi-component, and possibly unevenly sampled seismic data, which contain both free-surface and internal multiples, whilst requiring minimum pre-processing steps. The performance of our scattering Marchenko method will be evaluated using a comprehensive set of numerical tests on a complex 2D subsalt model.

Overburden

Multiple

Passive seismic

Seismic migration

Reflection

Geophysical Imaging

10.5194/egusphere-egu21-12557

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Elastic-wavefield Interferometry – Pseudo-source VSPs from 3D P-wave Vibrator Data, Wamsutter Field, WY, USA

71st EAGE Conference and Exhibition incorporating SPE EUROPEC 2009 (2009)

James Gaiser Ivan Vasconcelos Rosemarie Ramkhelawan

In this study we investigate methods of elastic-wavefield interferometry to obtain P- and S-wave velocity information from the 3D P-wave vibrator VSP atWamsutter Field inWyoming. Wamsutter field consists of naturally fractured tight gas sand reservoirs wh

Vibrator (electronic)

Seismic interferometry

10.3997/2214-4609.201400351

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The reciprocity theorem for the scattered field is the progenitor of the generalized optical theorem

The Journal of the Acoustical Society of America (2011)

Huub Douma Ivan Vasconcelos Roel Snieder

By analyzing correlation-type reciprocity theorems for wavefields in perturbed media, it is shown that the correlation-type reciprocity theorem for the scattered field is the progenitor of the generalized optical theorem. This reciprocity theorem, in contrast to the generalized optical theorem, allows for inhomogeneous background properties and does not make use of a far-field condition. This theorem specializes to the generalized optical theorem when considering a finite-size scatterer embedded in a homogeneous background medium and when utilizing the far-field condition. Moreover, it is shown that the reciprocity theorem for the scattered field is responsible for the cancellation of non-physical (spurious) arrivals in seismic interferometry, and as such provides the mathematical description of such arrivals. Even though here only acoustic waves are treated, the presented treatment is not limited to such wavefields and can be generalized to general wavefields. Therefore, this work provides the framework for deriving equivalents of the generalized optical theorem for general wavefields.

Reciprocity

Spurious relationship

Optical theorem

10.1121/1.3569728

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Citations (14)

Towards highly-sparse, autonomous imaging systems: high-resolution wavefield imaging for frontier exploration

Ivan Vasconcelos Jingming Ruan Dieuwertje Kuijpers Matteo Ravasi Patrick Putzky

Can we image and monitor the internal ocean structure at global scales? Can we monitor in vast expanses of the Earth&#8217;s cryosphere subsurface with meter-length resolution? Can we characterize the interior structures of asteroids and comets out in space efficiently and with high confidence? At the core of these questions lies the understanding and development of wave-based imaging systems, based on seismic or radar, that rely on highly-sparse, high-quality data, but whose output image quality is comparable to that of densely sampled, wide aperture array-based data. Traditionally, exploration seismology has long relied on wide aperture, dense data sets together with high-end imaging such as reverse-time migration and full-waveform inversion to produce high resolution subsurface models. Given the recent rise of drone-like, autonomous systems, in this talk, we present approaches that can take highly-sparse data as would be recorded by autonomous platforms, into accurate high-resolution images as if they had been acquired by densely-sampled, wide aperture source and receiver arrays. We demonstrate two approaches that could achieve this goal. The first is the use of sparse multicomponent sources and receivers capable of exciting/recording fields and their spatial gradients, together with a gradient-based wavefield reconstruction approach and subsequent imaging. The second approach relies on a new deep learning architecture, the so-called Recurrent Inference Machine, designed specifically for inverse problems &#8211; showing that it can surpass the capabilities of deterministic approaches to data reconstruction and imaging. We illustrate these approaches using a numerical model for oceanic turbulence, where we show the compressive sensing potential of these acquisition, reconstruction and imaging methods for acoustic imaging of the ocean's internal structure &#8211; overcoming current limitations in data acquisition and processing for seismic oceanography. Finally, we postulate that these approaches, though still in their early days, will pave the way in enabling breakthrough imaging systems at the frontiers of geo-imaging, e.g., for oceanography at global scales, in imaging the Earth&#8217;s cryosphere or for planetary exploration.

Aperture (computer memory)

10.5194/egusphere-egu2020-18782

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Student perspective: A young, 75-year-old geophysical community

The Leading Edge (2006)

Ivan Vasconcelos

Celebrating the 75th anniversary of the Society of Exploration Geophysicists is definitely no small deal. And of course, the best occasion to do so was the 2005 Annual Meeting of SEG that was, appropriately to the circumstances, held in Houston. From Saturday, 5 November, until the following Friday, attendees could experience a wide variety of activities like Continuing Education Short Courses, technical presentations, receptions (organized by the meeting or by companies), the exhibition hall (one highlight was the display of instruments and pictures that were part of our 75-year history), and so on. So, I guess that from a student perspective, one cannot help being overwhelmed with all that this meeting had to offer.

10.1190/tle25030266.1

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Elastic interferometry for ocean bottom cable data: Theory and examples^‡

Geophysical Prospecting (2009)

James Gaiser Ivan Vasconcelos

ABSTRACT Elastic imaging from ocean bottom cable (OBC) data can be challenging because it requires the prior estimation of both compressional‐wave (P‐wave) and shear‐wave (S‐wave) velocity fields. Seismic interferometry is an attractive technique for processing OBC data because it performs model‐independent redatuming; retrieving ‘pseudo‐sources’ at positions of the receivers. The purpose of this study is to investigate multicomponent applications of interferometry for processing OBC data. This translates into using interferometry to retrieve pseudo‐source data on the sea‐bed not only for multiple suppression but for obtaining P‐, converted P to S‐wave (PS‐wave) and possibly pure mode S‐waves. We discuss scattering‐based, elastic interferometry with synthetic and field OBC datasets. Conventional and scattering‐based interferometry integrands computed from a synthetic are compared to show that the latter yields little anti‐causal response. A four‐component (4C) pseudo‐source response retrieves pure‐mode S‐reflections as well at P‐ and PS‐reflections. Pseudo‐source responses observed in OBC data are related to P‐wave conversions at the seabed rather than to true horizontal or vertical point forces. From a Gulf of Mexico OBC data set, diagonal components from a nine‐component pseudo‐source response demonstrate that the P‐wave to S‐wave velocity ratio ( V P / V S ) at the sea‐bed is an important factor in the conversion of P to S for obtaining the pure‐mode S‐wave reflections.

Seabed

Synthetic data

10.1111/j.1365-2478.2009.00825.x

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Citations (12)