be retrieved from reflection data and a background model. Initially, the focusing function was defined such that it focuses inside the medium of interest as a point in time and in space (e.g. Wapenaar et al., 2014). The focusing property is used to retrieve the up- and downgoing Green’s functions associated to a virtual point source or receiver inside the medium. Subsequently, the retrieved Green’s functions are used to compute an image. Meles et al. (2017) introduced a new focusing function that focuses as a plane wave inside the medium. The new focusing function allows to retrieve medium responses associated to

virtual plane wave sources or receivers inside the medium. Hence, imaging based on areal-sources as suggested by Rietveld et al. (1992) becomes possible including the benefits of the Marchenko method. In the following we compare Marchenko imaging using point and plane wave focusing.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-15","","","ImPhys/Acoustical Wavefield Imaging","","","" "uuid:dfe1055f-645e-4753-96df-c49ba4df838d","http://resolver.tudelft.nl/uuid:dfe1055f-645e-4753-96df-c49ba4df838d","Passive body-wave interferometric imaging with directionally constrained migration","Almagro Vidal, C. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Verdel, Arie (TNO); Hartstra, I.E. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2018","Passive seismic interferometry enables the estimation of the reflection response of the subsurface using passive receiver recordings at the surface from sources located deep in the Earth. Interferometric imaging makes use of this retrieved reflection response in order to study the subsurface. Successful interferometric imaging relies on the availability of passive recordings from sufficient sources in the subsurface. Ideally, these sources should be homogeneously distributed, which is unlikely to happen in practical applications. Incomplete source distributions result in the retrieval of inaccurate reflection responses, containing artefacts which can disturb the interferometric imaging process. We propose an alternative imaging method for passive data based on illumination diagnosis and directionally constrained migration. In this method, passive responses from single transient sources are cross-correlated individually, and the dominant radiation direction from each virtual source is estimated. The correlated responses are imaged individually, thereby limiting the source wavefield to the dominant radiation direction of the virtual source. This constraint enables the construction of accurate images from individual sources with a significantly reduced amount of migrated interferometric artefacts. We also show that the summation of all individual imaging results improves the subsurface image by constructive interference, while migrated crosstalk and artefacts experience cancellation. This process, called Image Interferometry, shows that in case of limited subsurface illumination the interferometric integration can be applied in the image domain rather than in the virtual reflection-response domain, thus eliminating the need for the retrieval of the reflection response as an intermediate step.","Seismic Interferometry; Body waves; Crustal imaging","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:69b76fb7-85ff-46df-9865-2375ebda01de","http://resolver.tudelft.nl/uuid:69b76fb7-85ff-46df-9865-2375ebda01de","Artefact-Free Imaging by a Revised Marchenko Scheme","Zhang, L. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging)","","2018","A revised Marchenko scheme that avoids the need to compute the Green’s function is presented for artefact-free image of the subsurface with single-sided reflection response as input. The initial downgoing Green’s function which can be modelled from a macro model is needed for solving the revised Marchenko equations instead of its inverse. The retrieved upgoing focusing function can be correlated with the modelled initial downgoing Green’s function to image the medium without artefacts. The numerical example shows the effectiveness of the revised scheme in a 2D layered case.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-14","","","","","","" "uuid:74b21e40-6dfc-4ff4-be4d-dffdc8ffba34","http://resolver.tudelft.nl/uuid:74b21e40-6dfc-4ff4-be4d-dffdc8ffba34","Artifact-free reverse time migration","Zhang, L. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2018","We have derived an improved reverse time migration (RTM) scheme to image the medium without artifacts arising from internal multiple reflections. This is based on a revised implementation of Marchenko redatuming using a new time-truncation operator. Because of the new truncation operator, we can use the time-reversed version of the standard wavefield-extrapolation operator as initial estimate for retrieving the upgoing focusing function. Then, the retrieved upgoing focusing function can be used to directly image the medium by correlating it with the standard wavefieldextrapolation operator. This imaging scheme can be seen as an artifact-free RTM scheme with two terms. The first term gives the conventional RTM image with the wrong amplitude and artifacts due to internal multiple reflections. The second term gives a correction image that can be used to correct the amplitude and remove artifacts in the image generated by the first term. We evaluated the success of the method with a 2D numerical example.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:971090a1-d8f6-4e13-96cc-4f022707d87a","http://resolver.tudelft.nl/uuid:971090a1-d8f6-4e13-96cc-4f022707d87a","Source-receiver Marchenko redatuming on field data using an adaptive double-focusing method","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Pereira, Roberto (CGG, Rio de Janeiro); Douma, Huub (CGG, Rio de Janeiro); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2018","We have developed an adaptive double-focusing method that is specifically designed for the field-data application of source-receiver Marchenko redatuming. Typically, the single-focusing Marchenko method is combined with a multidimensional deconvolution (MDD) to achieve redatuming. Our method replaces the MDD step by a second focusing step that naturally complements the single-focusing Marchenko method. Instead of performing the MDD method with the directionally decomposed Green's functions that result from single-focusing, we now use the retrieved upgoing Green's function and the retrieved downgoing focusing function to obtain a redatumed reflection response in the physical medium. Consequently, we only remove the strongest overburden effects instead of removing all of the overburden effects. However, the gain is a robust method that is less sensitive to imperfections in the data and a sparse acquisition geometry than the MDD method. In addition, it is computationally much cheaper, more straightforward to implement, and it can be parallelized over pairs of focal points, which makes it suitable for application to large data volumes. We evaluate the successful application of our method to 2D field data of the Santos Basin.","Adaptive subtraction; Autofocusing; Datuming; Internal multiples; Subsalt","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:048b6e7c-398b-42ee-8d9b-53c693cc3023","http://resolver.tudelft.nl/uuid:048b6e7c-398b-42ee-8d9b-53c693cc3023","A new approach to separate seismic time-lapse time shifts in the reservoir and overburden","Liu, Y. (Norwegian University of Science and Technology); Landrø, Martin (Norwegian University of Science and Technology); Arntsen, Børge (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","For a robust way of estimating time shifts near horizontal boreholes, we have developed a method for separating the reflection responses above and below a horizontal borehole. Together with the surface reflection data, the method uses the direct arrivals from borehole data in the Marchenko method. The first step is to retrieve the focusing functions and the updown wavefields at the borehole level using an iterative Marchenko scheme. The second step is to solve two linear equations using a least-squares minimizing method for the two desired reflection responses. Then, the time shifts that are directly linked to the changes on either side of the borehole are calculated using a standard crosscorrelation technique. The method is applied with good results to synthetic 2D pressure data from the North Sea. One example uses purely artificial velocity changes (negative above the borehole and positive below), and the other example uses more realistic changes based on well logs. In the 2D case with an adequate survey coverage at the surface, the method is completely data driven. In the 3D case inwhich there is a limited number of horizontal wells, a kinematic correct velocity model is needed, but only for the volume between the surface and the borehole. Possible error factors related to the Marchenko scheme, such as an inaccurate source wavelet, imperfect surface multiples removal, and medium with loss are not included in this study.","","en","journal article","","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "uuid:459fdf96-c15d-45a3-aa93-89c03b17e985","http://resolver.tudelft.nl/uuid:459fdf96-c15d-45a3-aa93-89c03b17e985","Implementation of the marchenko method","Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","The Marchenko method makes it possible to compute subsurface-to-surface Green's functions from reflection measurements at the surface. Applications of the Marchenko method have already been discussed in many papers, but its implementation aspects have not yet been discussed in detail. Solving the Marchenko equation is an inverse problem. The Marchenko method computes a solution of the Marchenko equation by an (adaptive) iterative scheme or by a direct inversion. We have evaluated the iterative implementation based on a Neumann series, which is considered to be the conventional scheme. At each iteration of this scheme, a convolution in time and an integration in space are performed between a so-called focusing (update) function and the reflection response. In addition, by applying a time window, one obtains an update, which becomes the input for the next iteration. In each iteration, upgoing and downgoing focusing functions are updated with these terms. After convergence of the scheme, the resulting upgoing and downgoing focusing functions are used to compute the upgoing and downgoing Green's functions with a virtual-source position in the subsurface and receivers at the surface. We have evaluated this algorithm in detail and developed an implementation that reproduces our examples. The software fits into the Seismic Unix software suite of the Colorado School of Mines.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:b62de1a7-9e82-4b0a-b58f-c243e849b90f","http://resolver.tudelft.nl/uuid:b62de1a7-9e82-4b0a-b58f-c243e849b90f","Target-enclosed seismic imaging","van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Ravasi, Matteo (Statoil ASA); Liu, Y. (Norwegian University of Science and Technology); Vasconcelos, Ivan (Utrecht University)","","2017","Seismic reflection data can be redatumed to a specified boundary in the subsurface by solving an inverse (or multidimensional deconvolution) problem. The redatumed data can be interpreted as an extended image of the subsurface at the redatuming boundary, depending on the subsurface offset and time. We retrieve targetenclosed extended images by using two redatuming boundaries, which are selected above and below a specified target volume. As input, we require the upgoing and downgoing wavefields at both redatuming boundaries due to impulsive sources at the earth's surface. These wavefields can be obtained from actual measurements in the subsurface, they can be numerically modeled, or they can be retrieved by solving a multidimensional Marchenko equation. As output, we retrieved virtual reflection and transmission responses as if sources and receivers were located at the two target-enclosing boundaries. These data contain all orders of reflections inside the target volume but exclude all interactions with the part of the medium outside this volume. The retrieved reflection responses can be used to image the target volume from above or from below. We found that the images from above and below are similar (given that the Marchenko equation is used for wavefield retrieval). If a model with sharp boundaries in the target volume is available, the redatumed data can also be used for two-sided imaging, where the retrieved reflection and transmission responses are exploited. Because multiple reflections are used by this strategy, seismic resolution can be improved significantly. Because target-enclosed extended images are independent on the part of the medium outside the target volume, our methodology is also beneficial to reduce the computational burden of localized inversion, which can now be applied inside the target volume only, without suffering from interactions with other parts of the medium.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:0ec47f8d-06ec-4d2a-8cb6-2532fb2cd38c","http://resolver.tudelft.nl/uuid:0ec47f8d-06ec-4d2a-8cb6-2532fb2cd38c","A Marchenko equation for acoustic inverse source problems","van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Johnson, Jami L. (University of Auckland); van Wijk, K. (University of Auckland); Singh, S. (University of Edinburgh); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","From acoustics to medical imaging and seismology, one strives to make inferences about the structure of complex media from acoustic wave observations. This study proposes a solution that is derived from the multidimensional Marchenko equation, to learn about the acoustic source distribution inside a volume, given a set of observations outside the volume. Traditionally, this problem has been solved by backpropagation of the recorded signals. However, to achieve accurate results through backpropagation, a detailed model of the medium should be known and observations should be collected along a boundary that completely encloses the volume of excitation. In practice, these requirements are often not fulfilled and artifacts can emerge, especially in the presence of strong contrasts in the medium. On the contrary, the proposed methodology can be applied with a single observation boundary only, without the need of a detailed model. In order to achieve this, additional multi-offset ultrasound reflection data must be acquired at the observation boundary. The methodology is illustrated with one-dimensional synthetics of a photoacoustic imaging experiment. A distribution of simultaneously acting sources is recovered in the presence of sharp density perturbations both below and above the embedded sources, which result in significant scattering that complicates the use of conventional methods.","","en","journal article","","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:805c549b-44c0-4888-b56f-8b6fc06070f7","http://resolver.tudelft.nl/uuid:805c549b-44c0-4888-b56f-8b6fc06070f7","Retrieving Reservoir-only Reflection and Transmission Responses from Target-enclosing Extended Images","Vasconcelos, I. (Utrecht University); Ravasi, M. (Statoil); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Kritski, A. (Statoil); Cui, T. (Schlumberger Gould Research Center)","","2017","The Marchenko redatuming approach reconstructs wavefields at depth that contain not only primary reflections, but also multiply-scattered waves. While such fields in principle contain additional subsurface information, conventional imaging approaches cannot tap into the information encoded in internal multiples in a trivial manner. We discuss a new approach that uses the full information contained in Marchenko-redatumed fields, whose output are local reflection and transmission responses that fully enclose a target volume at depth, without contributions from over- or under-burden structures. To obtain the Target-Enclosing Extended Images (TEEIs) we solve a multi-dimensional deconvolution (MDD) problem that can be severely ill-posed, so we offer stable estimates to the MDD problem that rely on the physics of the Marchenko scheme. We validate our method on ocean-bottom field data from the North Sea. In our field data example, we show that the TEEIs can be used for reservoir-targeted imaging using reflection and, for the first time, local transmission responses, shown to be the direct by-product of using internal multiples in the redatuming scheme. Finally, we present local, TEEI-derived reflection and transmission images of the target volume at depth that are structurally consistent with a benchmark image from conventional migration of surface data.","","en","conference paper","EAGE","","","","","","","2017-11-01","","","Applied Geophysics and Petrophysics","","","" "uuid:2cc566bf-9d49-43b6-8abb-bdb6e2d4bcbd","http://resolver.tudelft.nl/uuid:2cc566bf-9d49-43b6-8abb-bdb6e2d4bcbd","Applying source-receiver Marchenko redatuming to field data, using an adaptive double-focusing method","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Pereira, Roberto (CGG, Rio de Janeiro); Douma, Huub; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","In this paper, we focus on the field data application of source-receiver Marchenko redatuming. Conventionally, a source-receiver redatumed reflection response is obtained by first applying the Marchenko method for receiver-redatuming and then performing a multi-dimensional deconvolution (MDD) for sourceredatuming (Wapenaar et al. (2014)). The obtained reflection response is free from any interactions with the overburden. However, the MDD solves an ill-posed inverse problem (van der Neut et al. (2011a)), which makes it sensitive to imperfections in the data and the acquisition geometry. This is a problem for the field data application, since neither the data nor the acquisition geometry are ever perfect. In addition, MDD is computationally expensive.","","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:61610d9a-db9e-44ef-aa18-a4b178fb620c","http://resolver.tudelft.nl/uuid:61610d9a-db9e-44ef-aa18-a4b178fb620c","Up-Down Wavefields Reconstruction in Boreholes Using Single-Component Data","Liu, Y. (Norwegian University of Science and Technology); Arntsen, B (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","A standard procedure in processing vertical seismic profile (VSP) data is the separation of up-and downgoing wavefields. We show that the up-down wavefields in boreholes can be reconstructed using only singlecomponent borehole data, given that a full set of surface reflection data is also available. No medium parameters are required. The method is wave-equation based for a general inhomogeneous lossless medium with moderately curved interfaces. It relies on a focusing wavefield from the Marchenko method, which gives the recipe for finding this wavefield that satisfies certain focusing conditions in a reference medium. The up-down wavefields are then reconstructed at borehole positions using this focusing wavefields and the surface reflection response. We show that the method is applicable to boreholes with any general orientation. The requirement is that the source positions in the surface data are regularized to be the same as those in the borehole data, and that source deconvolution and surface multiple removal are applied for the surface data. Numerical results from a field in the North Sea are shown, and three different borehole geometries (horizontal, deviated and vertical) are tested. The result shows that the reconstructed up-down wavefields agree well with those by conventional separation methods.","","en","conference paper","EAGE","","","","","","","2018-06-01","","","Applied Geophysics and Petrophysics","","","" "uuid:c3eb7eb2-27cf-43ae-8d99-0ae92fd057b0","http://resolver.tudelft.nl/uuid:c3eb7eb2-27cf-43ae-8d99-0ae92fd057b0","Why multiples do not contribute to deconvolution imaging","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2017","The question whether multiples are signal or noise is subject of ongoing debate. In this paper we consider correlation and deconvolution imaging methods and analyse to what extent multiples contribute to the image in these methods. Our starting point is the assumption that at a specific depth level the full downgoing and upgoing fields (both including all multiples) are available. First we show that by cross correlating the full downgoing and upgoing wave fields, primaries and multiples contribute to the image. This image is not true-amplitude and is contaminated by cross-talk artefacts. Next we show that by deconvolving the full upgoing field by the full downgoing field, multiples do not contribute to the image. We use minimum-phase arguments to explain this somewhat counterintuitive conclusion. The deconvolution image is true-amplitude and not contaminated by cross-talk artefacts. The conclusion that multiples do not contribute to the image applies to the type of deconvolution imaging analysed in this paper, but should not be extrapolated to other imaging methods. On the contrary, much research is dedicated to using multiples for imaging, for example in full wavefield migration, resonant migration and Marchenko imaging.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:b1b4381d-7219-40b9-84e7-6d7fb8a6120a","http://resolver.tudelft.nl/uuid:b1b4381d-7219-40b9-84e7-6d7fb8a6120a","Sparse Inversion for Solving the Coupled Marchenko Equations Including Free-surface Multiples","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Grobbe, N. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","We compare the coupled Marchenko equations without free-surface multiples to the coupled Marchenko equations including free-surface multiples. When using the conventional method of iterative substitution to solve these equations, a difference in convergence behaviour is observed, suggesting that there is a fundamental difference in the underlying dynamics. Both an intuitive explanation, based on an interferometric interpretation, as well as a mathematical explanation, confirm this difference, and suggest that iterative substitution might not be the most suitable method for solving the system of equations including free-surface multiples. Therefore, an alternative method is required. We propose a sparse inversion, aimed at solving an under-determined system of equations. Results show that the sparse inversion is indeed capable of correctly solving the coupled Marchenko equations including free-surface multiples, even when the iterative scheme fails. Using sparsity promotion and additional constraints, it is expected to perform better than iterative substitution when working with incomplete data or in the presence of noise. Also, simultaneous estimation of the source wavelet is a potential possibility.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:a6b425da-d877-43c1-ac28-8c1b3cd54f09","http://resolver.tudelft.nl/uuid:a6b425da-d877-43c1-ac28-8c1b3cd54f09","Accounting for free-surface multiples in Marchenko imaging","Singh, S.; Snieder, R; van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","Imagine placing a receiver at any location in the earth and recording the response at that location to sources on the surface. In such a world, we could place receivers around our reservoir to better image the reservoir and understand its properties. Realistically, this is not a feasible approach for understanding the subsurface. We have developed an alternative and realizable approach to obtain the response of a buried virtual receiver for sources at the surface. Our method is capable of retrieving the Green’s function for a virtual point in the subsurface to the acquisition surface. In our case, a physical receiver is not required at the subsurface point; instead, we require the reflection measurements for sources and receivers at the surface of the earth and a macromodel of the velocity (no small-scale details of the model are necessary). We can interpret the retrieved Green’s function as the response to sources at the surface for a virtual receiver in the subsurface. We obtain this Green’s function by solving the Marchenko equation, an integral equation pertinent to inverse scattering problems. Our derivation of the Marchenko equation for the Green’s function retrieval takes into account the free-surface reflections present in the reflection response (previous work considered a response without free-surface multiples). We decompose the Marchenko equation into up- and downgoing fields and solve for these fields iteratively. The retrieved Green’s function not only includes primaries and internal multiples as do previous methods, but it also includes freesurface multiples. We use these up- and downgoing fields to obtain a 2D image of our area of interest, in this case, below a synclinal structure.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:95b79ea8-bb03-41d3-8dea-96bdabc8bd41","http://resolver.tudelft.nl/uuid:95b79ea8-bb03-41d3-8dea-96bdabc8bd41","Deconvolution and correlation-based interferometric redatuming by wavefield inversion","Barrera Pacheco, D.F.; Schleicher, J.; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","Seismic interferometry is a method to retrieve Green’s functions for sources (or receivers) where there are only receivers (or sources, respectively). This can be done by correlationor deconvolution-based methods. In this work we present a

new approach to reposition the seismic array from the earth’s surface to an arbitrary datum at depth using the one-way reciprocity theorems of convolution and correlation type. The redatuming process is done in three steps: (a) retrieving the downward Green’s function for sources at the earth’s surface

and receivers at the datum, (b) retrieving the corresponding upward Green’s function, and (c) retrieving the reflected upward wavefield for sources and receivers at the datum. Input for steps (a) and (b) are the surface data and wavefields simulated in a velocity model of the datum overburden. Step (c)

uses the responses of steps (a) and (b) as input data in the convolution-based interferometric equation. The method accounts for inhomogeneities in the overburden medium, thus reducing anticausal events and artefacts as compared to a purely correlation-based procedure.","","en","conference paper","SEG","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "uuid:7226c2a4-f516-4b3c-aaed-1d2ea7da0ab2","http://resolver.tudelft.nl/uuid:7226c2a4-f516-4b3c-aaed-1d2ea7da0ab2","On the role of multiples in Marchenko imaging","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2017","","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:6990bd1b-f669-4dc0-ae21-5cf98c0261f4","http://resolver.tudelft.nl/uuid:6990bd1b-f669-4dc0-ae21-5cf98c0261f4","Decomposition of the Green's function using the Marchenko equation","Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","The Marchenko equation can be used to retrieve the Green’s function at depth as a full function or decomposed into its upand downgoing parts. We show that the equation can be rewritten to create a decomposition scheme that can decompose a full wavefield, that was recorded at depth, into its up- and downgoing parts. We show that this can be done without a smooth velocity model that the Marchenko scheme requires and without any knowledge of the medium properties that traditional decomposition methods require. Instead we only need a the reflection response and a wavefield that has been recorded at the

surface due to a source at depth or (by using source-receiver reciprocity) that was measured down in a borehole due to a source at the surface. We also validate our results by comparing them to directly modeled up- and downgoing wavefields.","","en","conference paper","SEG","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "uuid:81609a44-8217-47db-b672-2302af612d40","http://resolver.tudelft.nl/uuid:81609a44-8217-47db-b672-2302af612d40","Adaptive double-focusing method for source-receiver Marchenko redatuming on field data","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Pereira, R (CGG); Douma, H; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","We present an adaptive double-focusing method for applying source-receiver Marchenko redatuming to field data. Receiver redatuming is achieved by a first focusing step, where the coupled Marchenko equations are iteratively solved for the oneway Green’s functions. Next, source redatuming is typically performed by a multi-dimensional deconvolution of these Green’s functions. Instead, we propose a second focusing step for source Marchenko redatuming, using the upgoing Green’s function and the downgoing focusing function to obtain a redatumed reflection response in the physical medium. This method makes adaptive processing more straight-forward, making it less sensitive to imperfections in the data and the acquisition geometry and more suitable for the application to field data. In addition, it is cheaper and can be parallelized by pair of focal points.","","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:752f1f22-26f5-42e0-9d5e-70aaf95042aa","http://resolver.tudelft.nl/uuid:752f1f22-26f5-42e0-9d5e-70aaf95042aa","An interferometric interpretation of Marchenko redatuming including free-surface multiples","Staring, M. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","Sicking, Charles (editor); Ferguson, John (editor)","2016","We present an interferometric interpretation of the iterative Marchenko scheme including both free-surface multiples and internal multiples. Cross-correlations are used to illustrate the combination of causal and acausal events that are essential for the process of multiple removal. The first 4 steps in the scheme are discussed in detail, where the effect of different contributions on the result is displayed and the formation of individual events is illustrated. We highlight the events that are necessary to understand the process that removes both internal multiples and free-surface multiples from the data. We demonstrate that additional contributions are needed to correct for the presence of free-surface multiples.","multiples; seismic; autofocusing; correlation","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:aeefaee3-3d1f-48f8-b9a2-131971ca5e55","http://resolver.tudelft.nl/uuid:aeefaee3-3d1f-48f8-b9a2-131971ca5e55","Combination of surface and borehole seismic data for robust target-oriented imaging","Liu, Yi (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Arntsen, B; Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2016","A novel application of seismic interferometry (SI) and Marchenko imaging using both surface and borehole data is presented. A series of redatuming schemes is proposed to combine both data sets for robust deep local imaging in the presence of velocity uncertainties. The redatuming schemes create a virtual acquisition geometry where both sources and receivers lie at the horizontal borehole level, thus only a local velocity model near the borehole is needed for imaging, and erroneous velocities in the shallow area have no effect on imaging around the borehole level. By joining the advantages of SI and Marchenko imaging, a macrovelocity model is no longer required and the proposed schemes use only single-component data. Furthermore, the schemes result in a set of virtual data that have fewer spurious events and internal multiples than previous virtual source redatuming methods. Two numerical examples are shown to illustrate the workflow and to demonstrate the benefits of the method. One is a synthetic model and the other is a realistic model of a field in the North Sea. In both tests, improved local images near the boreholes are obtained using the redatumed data without accurate velocities, because the redatumed data are close to the target.","Inverse theory; Downhole methods; Interferometry; Wave propagation","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:170cc1de-39a6-4906-ad7a-935382da4232","http://resolver.tudelft.nl/uuid:170cc1de-39a6-4906-ad7a-935382da4232","New method for discriminating 4D time shifts in the overburden and reservoirr","Liu, Yi (Norwegian University of Science and Technology); Arntsen, B (Norwegian University of Science and Technology); Landrö, M (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","Sicking, Charles (editor); Ferguson, John (editor)","2016","Understanding seismic changes in the subsurface is important for reservoir management and health, safety and environmental (HSE) issues. Typically the changes are interpreted based on the time shifts in seismic time-lapse (4D) data, where sources are at the surface and receivers are either at the surface or in a borehole. With these types of acquisition geometry, it is more straightforward to detect and interpret changes in the overburden, close to the source and receivers, than changes in the deeper part close to the reservoir, because the time shift is accumulative along its ray path from source to receiver. We propose a new method for reconstructing the reflection responses of the overburden and the reservoir, separately, for 4D time shift analysis. This method virtually moves sources and receivers to a horizontal borehole level, which enables a more direct interpretation of the time shifts to the changes close to the borehole, instead of to the surface. A realistic field model is used to demonstrate the method, and we observe a clear discrimination of the different time shifts in the overburden and reservoir, which is not obvious in the original datasets.","reconstruction; time-lapse; traveltime; downhole receivers; internal multiples","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:0d0cf38b-e8ea-4b7a-9e8f-b0a0e81e97a1","http://resolver.tudelft.nl/uuid:0d0cf38b-e8ea-4b7a-9e8f-b0a0e81e97a1","Adaptive overburden elimination with the multidimensional Marchenko equation","van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2016","Imagine placing a receiver at any location in the earth and recording the response at that location to sources on the surface. In such a world, we could place receivers around our reservoir to better image the reservoir and understand its properties. Realistically, this is not a feasible approach for understanding the subsurface. We have developed an alternative and realizable approach to obtain the response of a buried virtual receiver for sources at the surface. Our method is capable of retrieving the Green’s function for a virtual point in the subsurface to the acquisition surface. In our case, a physical receiver is not required at the subsurface point; instead, we require the reflection measurements for sources and receivers at the surface of the earth and a macromodel of the velocity (no small-scale details of the model are necessary). We can interpret the retrieved Green’s function as the response to sources at the surface for a virtual receiver in the subsurface. We obtain this Green’s function by solving the Marchenko equation, an integral equation pertinent to inverse scattering problems. Our derivation of the Marchenko equation for the Green’s function retrieval takes into account the free-surface reflections present in the reflection response (previous work considered a response without free-surface multiples). We decompose the Marchenko equation into up- and downgoing fields and solve for these fields iteratively. The retrieved Green’s function not only includes primaries and internal multiples as do previous methods, but it also includes freesurface multiples. We use these up- and downgoing fields to obtain a 2D image of our area of interest, in this case, below a synclinal structure.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:9289514b-58c6-4e80-948b-fed8dcafa4e1","http://resolver.tudelft.nl/uuid:9289514b-58c6-4e80-948b-fed8dcafa4e1","Unified double- and single-sided homogeneous Green's function representations","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2016","In wave theory, the homogeneous Green’s function consists of the impulse response to a point source, minus its time-reversal. It can be represented by a closed boundary integral. In many practical situations, the closed boundary integral needs to be approximated by an open boundary integral because the medium of interest is often accessible from one side only. The inherent approximations are acceptable as long as the effects of multiple scattering are negligible. However, in case of strongly inhomogeneous media, the effects of multiple scattering can be severe. We derive double- and single-sided homogeneous Green’s function representations. The single-sided representation applies to situations where the medium can be accessed from one side only. It correctly handles multiple scattering. It employs a focusing function instead of the backward propagating Green’s function in the classical (double-sided) representation. When reflection measurements are available at the accessible boundary of the medium, the focusing function can be retrieved from these measurements. Throughout the paper, we use a unified notation which applies to acoustic, quantum-mechanical, electromagnetic and elastodynamic waves. We foresee many interesting applications of the unified single-sided homogeneous Green’s function representation in holographic imaging and inverse scattering, time-reversed wave field propagation and interferometric Green’s function retrieval.","","en","journal article","","","","","","","","2017-07-31","","","Applied Geophysics and Petrophysics","","","" "uuid:0527c923-f2f4-422f-928c-c8fd3d9e6295","http://resolver.tudelft.nl/uuid:0527c923-f2f4-422f-928c-c8fd3d9e6295","Beyond Marchenko: Obtaining virtual receivers and virtual sources in the subsurface","Singh, S. (Colorado School of Mines); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Snieder, R (Colorado School of Mines)","Sicking, Charles (editor); Ferguson, John (editor)","2016","By solving the Marchenko equations, the Green’s function can be retrieved between a virtual receiver in the subsurface to points at the surface (no physical receiver is required at the virtual location). We extend the idea of these equations to retrieve the Green’s function between any two points in the subsurface; i.e, between a virtual source and a virtual receiver (no physical source or physical receiver is required at either of these locations). This Green’s function is called the virtual Green’s function and includes all the primaries, internal and free-surface multiples. Similar to the Marchenko Green’s function, we require the reflection response at the surface (single-sided illumination) and an estimate of the first arrival travel time from the virtual location to the surface.","multiples; scattering; downhole sources; downhole receivers; autofocusing","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:3b45c9ec-e3da-4997-8f92-e89271b442c9","http://resolver.tudelft.nl/uuid:3b45c9ec-e3da-4997-8f92-e89271b442c9","A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics)","","2016","Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's function of the wave equation without a singularity on the right-hand side) is represented by a closed boundary integral. In practical applications, sources and/or receivers are usually present only on an open surface, which implies that a significant part of the closed boundary integral is by necessity ignored. Here we derive a homogeneous Green's function representation for the common situation that sources and/or receivers are present on an open surface only. We modify the integrand in such a way that it vanishes on the part of the boundary where no sources and receivers are present. As a consequence, the remaining integral along the open surface is an accurate single-sided representation of the homogeneous Green's function. This single-sided representation accounts for all orders of multiple scattering. The new representation significantly improves the aforementioned wavefield imaging applications, particularly in situations where the first-order scattering approximation breaks down.","Controlled source seismology; Interferometry; Wave scattering and diffraction","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:55668444-8773-44ce-a542-b28883d3654c","http://resolver.tudelft.nl/uuid:55668444-8773-44ce-a542-b28883d3654c","Marchenko wavefield redatuming, imaging conditions, and the effect of model errors","de Ridder, Sjoerd (University of Edinburgh); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Curtis, A (University of Edinburgh); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","Sicking, Charles (editor); Ferguson, John (editor)","2016","Recently, a novel method to redatum the wavefield in the sub-surface from a reflection response measured at the surface has gained interest for imaging primaries in the presence of strong internal multiples. A prerequisite for the algorithm is an accurate and correct estimate of the direct-wave Green's function. However, usually we use an estimate for the direct-wave Green's function computed in a background velocity medium. Here, we investigate the effect of amplitude and phase errors in that estimate. We formulate two novel imaging conditions based on double-focusing the measured reflection response inside the subsurface. These yield information on the amplitude error in the estimate for the direct-wave Green's function which we can then correct, but the phase error remains elusive.","inversion; autofocusing; imaging; internal multiples; velocity","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:e5a47613-6f6c-48a6-a81e-16430c319586","http://resolver.tudelft.nl/uuid:e5a47613-6f6c-48a6-a81e-16430c319586","Electromagnetic Marchenko imaging in 1D for dissipative media","Zhang, L. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Staring, M. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","Sicking, Charles (editor); Ferguson, John (editor)","2016","We present a one-dimensional lossless scheme to compute an image of a dissipative medium from two single-sided reflection responses. One reflection response is measured at or above the top reflector of a dissipative medium and the other reflection response is computed as if measured at or above the top reflector of a medium with negative dissipation which we call the effectual medium. These two reflection responses together can be used to construct the approximate reflection data of the corresponding lossless medium by multiplying and taking the square root in time domain. The corresponding lossless medium has the same reflectors as the dissipative medium. Then the constructed reflection data can be used to compute the focusing wavefield which focuses at the chosen location in subsurface of the dissipative medium. From the focusing function and constructed reflection response the Green’s function for a virtual receiver can be obtained. Because the up- and downgoing parts of the Green’s function are retrieved separately, these are used to compute the image. We show with an example that the method works well for a sample in a synthesized waveguide that could be used for measurements in a laboratory.","electromagnetic; conductivity; internal multiples; permeability; GPR","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:37a5a787-e388-49f5-9c22-579dee5aa1ef","http://resolver.tudelft.nl/uuid:37a5a787-e388-49f5-9c22-579dee5aa1ef","From closed-boundary to single-sided homogeneous Green's function representations","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Singh, Satyan (University of the West Indies)","Sicking, Charles (editor); Ferguson, John (editor)","2016","The homogeneous Green’s function (i.e., the Green’s function and its time-reversed counterpart) plays an important role in optical, acoustic and seismic holography, in inverse scattering methods, in the field of time-reversal acoustics, in reversetime migration and in seismic interferometry. Starting with the classical closed-boundary representation of the homogeneous Green’s function, we modify the configuration to two parallel boundaries. We discuss step-by-step a process that eliminates the integral along the lower boundary. This leads to a single-sided representation of the homogeneous Green’s function. Apart from imaging, we foresee interesting applications in inverse scattering, time-reversal acoustics, seismic interferometry, passive source imaging, etc.","imaging; internal multiples","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:28ababd6-a8bb-46b8-8145-699d1b07106b","http://resolver.tudelft.nl/uuid:28ababd6-a8bb-46b8-8145-699d1b07106b","Imaging the earth's interior with virtual sources and receivers","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Snieder, R (Extern)","","2016","","","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:d70af4b3-b5b7-40e6-b1bc-0a7b08880bac","http://resolver.tudelft.nl/uuid:d70af4b3-b5b7-40e6-b1bc-0a7b08880bac","Seismic reflection imaging, accounting for primary and multiple reflections","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Broggini, F.; Slob, E.C.; Snieder, R.","","2015","","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","","","" "uuid:ef15255e-c92c-4615-bd63-b9525f7e25db","http://resolver.tudelft.nl/uuid:ef15255e-c92c-4615-bd63-b9525f7e25db","Marchenko imaging: Imaging with primaries, internal multiples, and free-surface multiples","Singh, S.; Snieder, R.; Behura, J.; van der Neut, J.R.; Wapenaar, C.P.A.; Slob, E.C.","","2015","Recent work on retrieving the Green’s function with the Marchenko equation shows how these functions for a virtual source in the subsurface can be obtained from reflection data. The response to the virtual source is the Green’s function from the location of the virtual source to the surface. The Green’s function is retrieved using only the reflection response of the medium and an estimate of the first arrival at the surface from the virtual source. Current techniques, however, only include primaries and internal multiples. Therefore, all surface-related multiples must be removed from the reflection response prior to Green’s function retrieval. We have extended the Marchenko equation to retrieve the Green’s function that includes primaries, internal multiples, and free-surface multiples. In other words, we have retrieved the Green’s function in the presence of a free surface. The information needed for the retrieval is the same as the current techniques, with the only difference being that the reflection response now also includes free-surface multiples. The inclusion of these multiples makes it possible to include them in the imaging operator, and it obviates the need for surface-related multiple elimination. This type of imaging with Green’s functions is called Marchenko imaging.","multiples; scattering; imaging; reflectivity; reciprocity","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:54461b72-390d-4755-ad4d-51a80c1bd352","http://resolver.tudelft.nl/uuid:54461b72-390d-4755-ad4d-51a80c1bd352","Geophysical noise interferometry: Repairing the broken mirror","Wapenaar, C.P.A.; Van der Neut, J.R.; Draganov, D.S.","","2015","Under conditional circumstances, the correlation of noise at two receivers is approximately proportional to the Green’s function between these receivers. Hence, the correlation process turns one of the receivers into a virtual source, of which the response is observed by the other receiver. This principle, also known as ambient-noise interferometry, is used by researchers in geophysics, ultrasonics and underwater acoustics to infer information about an unknown object from passive noise measurements. In geophysics, ambient-noise interferometry is used for tomographic velocity inversion when surface waves are dominant, or for high-resolution reflection imaging when a significant amount of body waves is present in the noise field. The virtual-source response obtained with geophysical noise interferometry is accurate when the medium is lossless and the noise field is equipartitioned. In practice these assumptions are often violated: the medium of interest is often illuminated from one side only, the sources may be irregularly distributed and losses may be significant. For those cases, it is as if the virtual source is viewed in a broken (time-reversal) mirror, which causes blurring of the source. This blurring is quantified by the so-called point-spread function, which, like the correlation function, can be derived from the observed data (that is, without the need to know the actual sources and the medium). The broken mirror can be repaired by deconvolving the correlation function for the point-spread function. As a result, the virtual source is refocused and hence the virtual-source response becomes more reliable.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:835a8461-b853-46e4-9a70-7d8e19a95485","http://resolver.tudelft.nl/uuid:835a8461-b853-46e4-9a70-7d8e19a95485","An illustration of adaptive Marchenko imaging","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Slob, E.C.; Vasconcelos, I.","","2015","In Marchenko imaging, wavefields are retrieved at specified focal points in the subsurface through an iterative scheme derived from the multidimensional Marchenko equation. The method requires seismic-reflection data at the earth’s surface (after free-surface multiple elimination) and an estimate of the direct wavefield from the surface to each focal point, which can be computed, for instance, in a macrovelocity model. In the first iteration, the direct wavefield is crosscorrelated with the reflection data. This operation is identical to inverse-wavefield extrapolation as is applied commonly in various imaging schemes, for instance, in reverse time migration (RTM). At each succeeding iteration, the result of the previous iteration is truncated in time and crosscorrelated with the reflection data again. To obtain a seismic image, a multidimensional deconvolution-based imaging condition can be applied to the retrieved wavefields. By this approach, both primary reflections and internal multiples contribute to the construction of the image. Alternatively, a crosscorrelation-based imaging condition can be used in which only the primary reflections are imaged and the contributions of internal multiples are subtracted. The latter strategy offers more flexibility because the subtraction of redatumed internal multiples can be implemented adaptively. Through this approach, the artifacts from internal multiples can be removed effectively from a conventional RTM image.","","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6884147a-f7b2-499a-a9ab-68591ea6d074","http://resolver.tudelft.nl/uuid:6884147a-f7b2-499a-a9ab-68591ea6d074","Improving repeatability of land seismic data using virtual source approach based on multidimensional deconvolution","Alexandrov, D.; Van der Neut, J.R.; Bakulin, A.; Kashtan, B.","","2015","We present a new redatuming workflow developed for improving the repeatability of seismic data and designed specifically to account for changes in the source signatures or variations in downgoing fields in general. The new approach is based on the virtual source method with the same potential for reducing nonrepeatability, associated with acquisition geometry changes and variations in the near surface. To correct for changes in the source wavelet between surveys, we suggest deconvolving the virtual source gather of the monitor survey with the point-spread function (PSF) of the same survey, and immediately convolving with the PSF of the base or reference survey. The PSF governs the radiation pattern of the virtual source. Trying to completely deconvolve the effects of individual PSFs on each virtual source response may degrade repeatability due to possible amplification of noise. Instead, we try to equalize radiation patterns of the virtual sources across all repeat surveys by reassigning a new reference PSF to all surveys. We apply the deconvolution-convolution method to a field 4D dataset with buried receivers and demonstrate significant improvement in repeatability.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f5b72d69-b9ee-4e27-be15-3751a68ca753","http://resolver.tudelft.nl/uuid:f5b72d69-b9ee-4e27-be15-3751a68ca753","Inversion of the multidimensional marchenko equation","Van der Neut, J.R.; Thorbecke, J.W.; Wapenaar, C.P.A.; Slob, E.C.","","2015","Focusing functions are defined as wavefields that focus at a specified location in a heterogeneous subsurface. These functions can be directly related to Green's functions and hence they can be used for seismic imaging of complete wavefields, including not only primary reflections but all orders of internal multiples. Recently, it has been shown that focusing functions can be retrieved from single-sided reflection data and an initial operator (which can be computed in a smooth background velocity model of the subsurface) by iterative substitution of the multidimensional Marchenko equation. In this work, we show that the Marchenko equation can also be inverted directly for the focusing functions. Although this approach is computationally more expensive than iterative substitution, additional constraints can easily be imposed. Such a flexibility might be beneficial in specific cases, for instance when the recorded data are incomplete or when additional measurements (e.g. from downhole receivers) are available.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c27b50de-0d8a-4a8c-923d-a64633ec9568","http://resolver.tudelft.nl/uuid:c27b50de-0d8a-4a8c-923d-a64633ec9568","On Green’s function retrieval by iterative substitution of the coupled Marchenko equations","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2015","Iterative 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.","controlled source seismology; wave scattering and diffraction","en","journal article","Oxford University Press","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:a26e5c46-b6a2-4692-96bc-43656b9a2ad4","http://resolver.tudelft.nl/uuid:a26e5c46-b6a2-4692-96bc-43656b9a2ad4","Combining inter-source seismic interferometry and source-receiver interferometry for deep local imaging","Liu, Y.; Arntsen, B.; Wapenaar, C.P.A.; Van der Neut, J.R.","","2014","The virtual source method has been applied successfully to retrieve the impulse response between pairs of receivers in the subsurface. This method is further improved by an updown separation prior to the crosscorrelation to suppress the reflections from the overburden and the free surface. In a reversed situation where the sources are in the subsurface and receivers are on the surface, in principle, one can apply the same logic to retrieve the virtual response between pairs of sources by source-receiver reciprocity, turning the physical borehole sources into virtual receivers. However, since the up-down separation is not applicable on the source side, the simple crosscorrelation of the total fields results in spurious events due to the incomplete receiver coverage around the sources. We show with a numerical example that for this configuration of borehole sources and surface receivers, one can replace such an updown separation at the source side by that of the direct and reflected waves as a first order approximation. This procedure produces the virtual receiver data that is adequate for local imaging below the source depth and is completely independent of the accuracy of the overburden velocity model. We implement this inter-source type of interferometry by multidimensional deconvolution (MDD). Further, if the conventional surface survey data is available, we test the methodology from source-receiver interferometry (SRI) for this reverse configuration with borehole sources to retrieve the virtual receiver data with reflections coming from above, using also only the separation of the direct and reflected waves. By migrating the two sets of virtual receiver data, one can create a local image around the borehole sources in a deep area with better focusing and localization without a sophisticated velocity model.","","en","conference paper","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:7b0b9d5d-7895-4d46-9b03-d618bd9734fa","http://resolver.tudelft.nl/uuid:7b0b9d5d-7895-4d46-9b03-d618bd9734fa","Internal multiple suppression by adaptive Marchenko redatuming","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Vasconcelos, I.","","2014","Recently, a novel iterative scheme was proposed to retrieve Green's functions in an unknown medium from its single-sided reflection response and an estimate of the propagation velocity. In Marchenko imaging, these Green's functions are used for seismic imaging with complete wavefields, including internal multiple reflections. In this way, common artifacts from these internal reflections are avoided and illumination of the subsurface can potentially be improved. However, Marchenko imaging requires accurate input data, with correct amplitudes, a deconvolved source signature, without free-surface multiples and source / receiver ghosts. Hence, a significant amount of preprocessing is required, which should be done accurately. To relax these requirements, we propose a scheme to remove artifacts due to internal multiples from inverse-extrapolated wavefields, by adaptively subtracting an estimate of these artifacts that is constructed with the Marchenko equation.","autofocusing; internal multiples","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:097d4a01-a0ae-4741-8bbf-023b10226dfb","http://resolver.tudelft.nl/uuid:097d4a01-a0ae-4741-8bbf-023b10226dfb","On the focusing conditions in time-reversed acoustics, seismic interferometry, and Marchenko imaging","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Vasconcelos, I.; Van Manen, D.J.; Ravasi, M.","","2014","Despite the close links between the fields of time-reversed acoustics, seismic interferometry and Marchenko imaging, a number of subtle differences exist. This paper reviews the various focusing conditions of these methods, the causality/acausality aspects of the corresponding focusing wavefields, and the requirements with respect to omnidirectional/single-sided acquisition.","imaging; internal multiples","en","conference paper","SEG","","","","","","","","Applied Sciences","ImPhys/Imaging Physics","","","","" "uuid:a3762abc-0fae-4b0b-bea6-aa571f2db3e2","http://resolver.tudelft.nl/uuid:a3762abc-0fae-4b0b-bea6-aa571f2db3e2","Autofocusing imaging: Imaging with primaries, internal multiples and free-surface multiples","Singh, S.; Snieder, R.; Behura, J.; van der Neut, J.R.; Wapenaar, C.P.A.; Slob, E.C.","","2014","Recent work on autofocusing with the Marchenko equation has shown how the Green's function for a virtual source in the subsurface can be obtained from reflection data. The response to the virtual source is the Green's function from the location of the virtual source to the surface. The Green's function is retrieved using only the reflection response of the medium and an estimate of the first arrival at the surface from the virtual source. Current techniques, however, only include primaries and internal multiples. Therefore, all surface-related multiples must be removed from the reflection response prior to Green's function retrieval. Here, we extend the Marchenko equation to retrieve the Green's function that includes primaries, internal multiples, and free-surface multiples. In other words, we retrieve the Green's function in the presence of a free surface. We use the associated Green's function for imaging the subsurface. The information needed for the retrieval are the reflection response at the surface and an estimate of the first arrival at the surface from the virtual source. The reflection response, in this case, includes the free-surface multiples; this makes it possible to include these multiples in the imaging operator and it obviates the need for surface-related multiple elimination.","imaging; multiples; scattering; autofocusing; internal multiples","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:84266f03-b9e6-4fe6-9e74-a727c641d9f5","http://resolver.tudelft.nl/uuid:84266f03-b9e6-4fe6-9e74-a727c641d9f5","Marchenko imaging","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","","","en","lecture notes","","","","","","","","","","","","","","" "uuid:640f712d-dd99-4a5c-a65f-6e2fdcc50ba9","http://resolver.tudelft.nl/uuid:640f712d-dd99-4a5c-a65f-6e2fdcc50ba9","Wavefield decomposition of field data, using a shallow horizontal downhole sensor array and a free-surface constraint","Grobbe, N.; van der Neut, J.R.; Almagro Vidal, C.; Drijkoningen, G.G.; Wapenaar, C.P.A.","","2014","Separation of recorded wavefields into downgoing and upgoing constituents is a technique that is used in many geophysical methods. The conventional, multi-component (MC) wavefield decomposition scheme makes use of different recorded wavefield components. In recent years, land acquisition designs have emerged that make use of shallow horizontal downhole sensor arrays. Inspired by marine acquisitiondesigns that make use of recordings at multiple depth levels for wavefield decomposition, we have recently developed a multi-depth level (MDL) wavefield decomposition scheme for land acquisition. Exploiting the underlying theory of this scheme, we now consider conventional, multi-component (MC) decomposition as an inverse problem, which we try to constrain in a better way. We have overdetermined the inverse problem by adding an MDL equation that exploits the Dirichlet free-surface boundary condition. To investigate the successfulness of this approach, we have applied both MC and combined MC-MDL decomposition to a real land dataset acquired in Annerveen, the Netherlands. Comparison of the results of overdetermined MC-MDL decomposition with the results of MC wavefield decomposition, clearly shows improvements in the obtained one-way wavefields, especially for the downgoing fields.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:e1657f41-faa4-4d63-a407-a34dc49cdbd0","http://resolver.tudelft.nl/uuid:e1657f41-faa4-4d63-a407-a34dc49cdbd0","Marchenko imaging below an overburden with random scatterers","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Vasconcelos, I.; Slob, E.C.","","2014","Marchenko imaging is a new way to deal with internal multiple scattering in migration. It has been designed for layered media with smooth interfaces. Here we analyze the performance of the Marchenko scheme for a medium with many point scatterers. Although the conditions for Marchenko imaging are violated, we observe from a numerical experiment that the signal-to-noise ratio of the obtained image is significantly higher than with standard imaging.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8c2fce50-b63b-4eac-99ad-70265c9f275e","http://resolver.tudelft.nl/uuid:8c2fce50-b63b-4eac-99ad-70265c9f275e","An interferometric interpretation of Marchenko redatuming","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2014","Recently, an iterative scheme was introduced to retrieve up- and downgoing Green’s functions at an arbitrary location F in the subsurface. The scheme uses the reflection data as acquired at the surface as input, together with an estimate of the direct arrival from the surface to location F, which is referred to as the initial focusing function. We interpret the overall action of the scheme as the successive actions of various linear filters, acting on the initial focusing function. These filters involve multidimensional crosscorrelations with the reflection response, time reversals and truncations in time. Inspired by literature on seismic interferometry, we interpret multidimensional crosscorrelation in terms of the subtraction of traveltimes along stationary raypaths. The scheme has been designed for layered media with smooth interfaces. Our interferometric interpretation reveals some of the scheme’s limitations when it is applied to more complex configurations. It can be concluded that (downgoing or upgoing) internal multiples that arrive at F with a particular angle can be retrieved only if the initial focusing function (i.e., the direct wave) has visited F with this angle. Consequently, shadow zones that cannot be imaged with primary reflections can theoretically also not be imaged with internal multiples, when the current iterative scheme is used for their retrieval. Finally, we observe that the current scheme does not yet optimally perform in media with point scatterers, since an underlying assumption (generally referred to as the ansatz) is not perfectly obeyed in this case. It is envisioned that this can be improved if truncations in time that are implemented after each iteration are replaced by more advanced filtering methods.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8e8655c9-4b23-4f9e-9339-37c372be931b","http://resolver.tudelft.nl/uuid:8e8655c9-4b23-4f9e-9339-37c372be931b","An interferometric interpretation of Marchenko redatuming","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2014","","","en","lecture notes","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:61ad5e42-e10d-470c-a500-382090e1bff5","http://resolver.tudelft.nl/uuid:61ad5e42-e10d-470c-a500-382090e1bff5","Marchenko imaging","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","Traditionally, the Marchenko equation forms a basis for 1D inverse scattering problems. A 3D extension of the Marchenko equation enables the retrieval of the Green’s response to a virtual source in the subsurface from reflection measurements at the earth’s surface. This constitutes an important step beyond seismic interferometry. Whereas seismic interferometry requires a receiver at the position of the virtual source, for the Marchenko scheme it suffices to have sources and receivers at the surface only. The underlying assumptions are that the medium is lossless and that an estimate of the direct arrivals of the Green’s function is available. The Green’s function retrieved with the 3D Marchenko scheme contains accurate internal multiples of the inhomogeneous subsurface. Using source-receiver reciprocity, the retrieved Green’s function can be interpreted as the response to sources at the surface, observed by a virtual receiver in the subsurface. By decomposing the 3D Marchenko equation, the response at the virtual receiver can be decomposed into a downgoing field and an upgoing field. By deconvolving the retrieved upgoing field with the downgoing field, a reflection response is obtained, with virtual sources and virtual receivers in the subsurface. This redatumed reflection response is free of spurious events related to internal multiples in the overburden. The redatumed reflection response forms the basis for obtaining an image of a target zone. An important feature is that spurious reflections in the target zone are suppressed, without the need to resolve first the reflection properties of the overburden.","multiples; migration; reciprocity","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c9d6af44-5c03-4d03-b5b7-a9895cc37864","http://resolver.tudelft.nl/uuid:c9d6af44-5c03-4d03-b5b7-a9895cc37864","Green's function retrieval from reflection data, in absence of a receiver at the virtual source position","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","The methodology of Green’s function retrieval by cross-correlation has led to many interesting applications for passive and controlled-source acoustic measurements. In all applications, a virtual source is created at the position of a receiver. Here a method is discussed for Green’s function retrieval from controlled-source reflection data, which circumvents the requirement of having an actual receiver at the position of the virtual source. The method requires, apart from the reflection data, an estimate of the direct arrival of the Green’s function. A single-sided three-dimensional (3D) Marchenko equation underlies the method. This equation relates the reflection response, measured at one side of the medium, to the scattering coda of a so-called focusing function. By iteratively solving the 3D Marchenko equation, this scattering coda is retrieved from the reflection response. Once the scattering coda has been resolved, the Green’s function (including all multiple scattering) can be constructed from the reflection response and the focusing function. The proposed methodology has interesting applications in acoustic imaging, properly accounting for internal multiple scattering.","","en","journal article","Acoustical Society of America","","","","","","","2014-11-01","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8e10d71b-962d-47c1-8a88-a00a02331765","http://resolver.tudelft.nl/uuid:8e10d71b-962d-47c1-8a88-a00a02331765","Marchenko redatuming below a complex overburden","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Vasconcelos, I.","","2014","Complex overburdens can severely distort transmitted wavefields, posing serious challenges for seismic imaging. In Marchenko redatuming, we use an iterative scheme to estimate so-called focusing functions, which can be used to redatum seismic wavefields to a specified level below the major complexities in the subsurface. Unlike in conventional redatuming methods, internal scattering in the overburden is accounted for by this methodology. Through Marchenko redatuming, internal multiple reflections are effectively utilized and common artefacts that are caused by these multiples are suppressed. The redatumed data can be interpreted as if it were acquired at the redatuming level and as if the medium above this level were non-reflecting. We provide an interpretation of the iterative scheme that is used for Marchenko redatuming and we evaluate its performance in a medium with a strongly heterogeneous overburden.","","en","conference paper","KAUST","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f1750374-9a25-4f81-a5d5-e99279aec31e","http://resolver.tudelft.nl/uuid:f1750374-9a25-4f81-a5d5-e99279aec31e","Data-driven Green's function retrieval and application to imaging with multidimensional deconvolution","Broggini, F.; Wapenaar, C.P.A.; Van der Neut, J.R.; Snieder, R.","","2014","An iterative method is presented that allows one to retrieve the Green's function originating from a virtual source located inside a medium using reflection data measured only at the acquisition surface. In addition to the reflection response, an estimate of the travel times corresponding to the direct arrivals is required. However, no detailed information about the heterogeneities in the medium is needed. The iterative scheme generalizes the Marchenko equation for inverse scattering to the seismic reflection problem. To give insight in the mechanism of the iterative method, its steps for a simple layered medium are analyzed using physical arguments based on the stationary phase method. The retrieved Green's wavefield is shown to correctly contain the multiples due to the inhomogeneities present in the medium. Additionally, a variant of the iterative scheme enables decomposition of the retrieved wavefield into its downgoing and upgoing components. These wavefields then enable creation of a ghost-free image of the medium with either cross correlation or multidimensional deconvolution, presenting an advantage over standard prestack migration.","autofocusing; Marchenko; scattering; interferometry; Green's function","en","journal article","American Geophysical Union","","","","","","","2014-07-17","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5ac5be23-4fc0-4b2d-9ec5-1b799e8944f1","http://resolver.tudelft.nl/uuid:5ac5be23-4fc0-4b2d-9ec5-1b799e8944f1","Green's function retrieval with Marchenko equations: A sensitivity analysis","Thorbecke, J.W.; Van der Neut, J.R.; Wapenaar, C.P.A.","","2013","Recent research showed that the Marchenko equation can be used to construct the Green’s function for a virtual source position in the subsurface. The method requires the reflection response at the surface and an estimate of the direct arrival of the wavefield, traveling from the virtual source location to the acquisition surface. In this paper, we investigate the sensitivity of this method. We demonstrate its robustness with respect to significant amplitude and phase errors in the direct arrival. The erroneous operators introduce low amplitude artefacts. The main reflections and internal multiples are still presents and disturbing ghost events are not introduced. In case the reflection data is modeled in a medium with losses, ghost events seem to be visible in the upgoing wavefield, but not in the downgoing wavefield.","imaging; migration; multiples; decomposition; reconstruction","en","conference paper","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f9f4a019-9537-4040-b1d5-4c33a2093c18","http://resolver.tudelft.nl/uuid:f9f4a019-9537-4040-b1d5-4c33a2093c18","Data-driven green's function retrieval from reflection data: Theory and example","Wapenaar, C.P.A.; Slob, E.C.; Broggini, F.; Snieder, R.; Thorbecke, J.W.; Van der Neut, J.R.","","2013","Recently we introduced a new approach for retrieving the Green's response to a virtual source in the subsurface from reflection data at the surface. Unlike in seismic interferometry, no receiver is needed at the position of the virtual source. Here we present the theory behind this new method. First we introduce the Green's function G and a so-called fundamental solution F of an inhomogeneous medium. Next we derive a relation between G and F, using reciprocity theorems. This relation is used as the basis for deriving a 3D single-sided Marchenko equation. We show that this equation is solved by a 3D autofocusing scheme and that the Green's function is obtained by combining the focusing wave field and its response in a specific way. We illustrate the method with a numerical example.","","en","conference paper","Eage","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:b7664c48-8b2a-4ca7-9cc1-2fab32183a87","http://resolver.tudelft.nl/uuid:b7664c48-8b2a-4ca7-9cc1-2fab32183a87","Turning One-sided Illumination into Two-sided Illumination by Target-enclosing Interferometric Redatuming","Van der Neut, J.R.; Almagro Vidal, C.; Grobbe, N.; Wapenaar, C.P.A.","","2013","We present a novel method to transform seismic data with sources at the surface and receivers above and below a selected target zone in the subsurface into virtual data with sources and receivers located at the initial receiver locations. The method is based on inverting a series of multidimensional equations of the convolution- and the correlation-type. The required input data can be computed from surface seismic data with a new iterative scheme that is currently being developed. The output data contains virtual sources that illuminate the target not only from above (as in the original data), but also from below, facilitating the needs of seismic imaging and inversion in an optimal way. The method is nonlinear in the sense that all internal multiples are correctly accounted for and true amplitude in the sense that the virtual sources are forced to inherit uniform radiation patterns even though the overburden is strongly heterogeneous.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:ebb7789d-93a5-4f49-b119-f230f910d123","http://resolver.tudelft.nl/uuid:ebb7789d-93a5-4f49-b119-f230f910d123","Separation of PS-wave Reflections from Ultrashallow Water OBC Data Using Elastic Wavefield Decomposition","El Allouche, N.; Van der Neut, J.R.; Drijkoningen, G.G.","","2013","Elastic wave decomposition, aiming at separating the converted modes from the P waves, is applied to high-resolution OBC data acquired in the River Danube, Hungary. The decomposition relies on accurate knowledge of the water-bottom elastic parameters and on a perfect sensor calibration and coupling. The available decomposition schemes require an adaptation to account for the shallow water depth in the survey area. In the presented method, the medium parameters are obtained from the inversion of the Scholte waves dispersion curves and the coupling filter was determined from the data. The coupling filter accounts for the imperfections in the geophone coupling and was corrected for by minimizing the contribution of the pressure and vertical component to the upgoing S-wave potential at near offsets. This criterion implies that these two components contain no converted energy at these offsets. The estimated coupling filter is applied to the geophone data used as an input to the decomposition scheme. The decomposed S-wave potential showed an improvement in the visibility of some converted modes, mainly at later arrivals.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:76f58e0e-0c37-4a86-8f51-452d3ed65f08","http://resolver.tudelft.nl/uuid:76f58e0e-0c37-4a86-8f51-452d3ed65f08","Interferometric redatuming by multidimensional deconvolution","Van der Neut, J.R.","Wapenaar, C.P.A. (promotor); Slob, E.C. (promotor)","2012","Seismic reflection imaging is a popular method to image, characterize and monitor the Earth's subsurface. In this method, seismic signals are sent into the subsurface and their reflections are collected. Strong heterogeneities in upper sections of the subsurface often pose a problem for imaging deeper sections. To overcome these problems, it has been proposed to place receivers in a horizontal, deviated or vertical borehole and to turn these receivers into virtual sources by seismic interferometry. In this thesis, the correlation-based formalism that undergirds seismic interferometry is replaced by multidimensional deconvolution, yielding several important advantages. It is shown that multidimensional deconvolution improves the radiation pattern of the generated virtual sources and that it removes undesired artifacts. A range of applications is being discussed, including the retrieval of signals from background noise, subsalt imaging and reservoir monitoring.","seismic interferometry; redatuming","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:65483e5b-d171-4c8f-88f5-5347dad5abea","http://resolver.tudelft.nl/uuid:65483e5b-d171-4c8f-88f5-5347dad5abea","Data matching for free-surface multiple attenuation by multidimensional deconvolution","Van der Neut, J.R.; Frijlink, M.; Borselen, R.","","2012","A common strategy for surface-related multiple elimination of seismic data is to predict multiples by a convolutional model and subtract these adaptively from the input gathers. Problems can be posed by interfering multiples and primaries. Removing multiples by multidimensional deconvolution (MDD) (inversion) does not suffer from these problems. However, this approach requires data to be consistent, which is often not the case, especially not at interpolated near-offsets. A novel method is proposed to improve data consistency prior to inversion. This is done by backpropagating first-order multiples with a time-gated reference primary event and matching these with early primaries in the input gather. After data matching, multiple elimination by MDD can be applied with a deterministic inversion scheme.","image processing; controlled source seismology; wave propagation","en","journal article","Wiley","","","","","","","2013-04-10","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8edf39dd-4eeb-426c-af42-faf7c7e63d01","http://resolver.tudelft.nl/uuid:8edf39dd-4eeb-426c-af42-faf7c7e63d01","Estimation of Imageable Dip Range of Target Structures in Interferometric Salt Flank Imaging with Limited Illumination","Loureiro, A.; Van der Neut, J.R.; Alves, D.; Carvalho, J.; Afilhado, A.; Draganov, D.S.; Matias, L.; Martins, T.","","2012","When applying seismic interferometry to image sub-vertical salt flanks or structures with large dips from vertical or deviated wells, we are often confronted with poor target illumination. Strong directionalillumination footprints caused by non-ideal placement of sources at the surface degrade the interferometric image quality and may prevent the retrieval of particular dips in the image. The effect of the well's orientation on the interferometric image is investigated. Moreover, a method is presented to estimate the imageable dips in an interferometric image, which can be used to design a more favorable shooting geometry and to gain additional knowledge about the target structures.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:637658ba-009b-42a3-afeb-5ba5b8505330","http://resolver.tudelft.nl/uuid:637658ba-009b-42a3-afeb-5ba5b8505330","Up/down wavefield decomposition by sparse inversion","Van der Neut, J.R.; Herrmann, F.J.","","2012","","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:569fa57f-bd3f-4e26-9c74-f544326125bd","http://resolver.tudelft.nl/uuid:569fa57f-bd3f-4e26-9c74-f544326125bd","Creating Virtual Sources Inside an Unknown Medium from Reflection Data: A New Approach to Internal Multiple Elimination","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Snieder, R.","","2012","It has recently been shown that the response to a virtual source in the subsurface can be derived from reflection data at the surface and an estimate of the direct arrivals between the virtual source and the surface. Hence, unlike for seismic interferometry, no receivers are needed inside the medium. This new method recovers the complete wavefield of a virtual source, including all internal multiple scattering. Because no actual receivers are needed in the medium, the virtual source can be placed anywhere in the subsurface. With some additional processing steps (decomposition and multidimensional deconvolution) it is possible to obtain a redatumed reflection response at any depth level in the subsurface, from which all the overburden effects are eliminated. By applying standard migration between these depth levels, a true amplitude image of the subsurface can be obtained, free from ghosts due to internal multiples. The method is non-recursive and therefore does not suffer from error propagation. Moreover, the internal multiples are eliminated by deconvolution, hence no adaptive prediction and subtraction is required.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:419c882f-51cc-4723-af40-4ef71fd4b3cd","http://resolver.tudelft.nl/uuid:419c882f-51cc-4723-af40-4ef71fd4b3cd","Deblending by direct inversion","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.","","2012","Deblending of simultaneous-source data is usually considered to be an underdetermined inverse problem, which can be solved by an iterative procedure, assuming additional constraints like sparsity and coherency. By exploiting the fact that seismic data are spatially band-limited, deblending of densely sampled sources can be carried out as a direct inversion process without imposing these constraints. We applied the method with numerically modeled data and it suppressed the crosstalk well, when the blended data consisted of responses to adjacent, densely sampled sources","acquisition; inversion","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:55fabcd8-0435-48ba-aba0-a0bad1e05033","http://resolver.tudelft.nl/uuid:55fabcd8-0435-48ba-aba0-a0bad1e05033","Controlled-source interferometric redatuming by crosscorrelation and multidimensional deconvolution in elastic media","Van der Neut, J.R.; Thorbecke, J.W.; Mehta, K.; Slob, E.C.; Wapenaar, C.P.A.","","2011","Various researchers have shown that accurate redatuming of controlled seismic sources to downhole receiver locations can be achieved without requiring a velocity model. By placing receivers in a horizontal or deviated well and turning them into virtual sources, accurate images can be obtained even below a complex near-subsurface. Examples include controlled-source interferometry and the virtual-source method, both based on crosscorrelated signals at two downhole receiver locations, stacked over source locations at the surface. Because the required redatuming operators are taken directly from the data, even multiple scattered waveforms can be focused at the virtual-source location, and accurate redatuming can be achieved. To reach such precision in a solid earth, representations for elastic wave propagation that require multicomponent sources and receivers must be implemented. Wavefield decomposition prior to crosscorrelation allows us to enforce virtual sources to radiate only downward or only upward. Virtual-source focusing and undesired multiples from the overburden can be diagnosed with the interferometric point-spread function (PSF), which can be obtained directly from the data if an array of subsurface receivers is deployed. The quality of retrieved responses can be improved by filtering with the inverse of the PSF, a methodology referred to as multidimensional deconvolution.","acoustic wave interferometry; correlation methods; deconvolution; filtering theory; geophysical signal processing; geophysical techniques; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5aee14ca-5e05-4fec-9138-dc6f306c1b7c","http://resolver.tudelft.nl/uuid:5aee14ca-5e05-4fec-9138-dc6f306c1b7c","Deghosting, demultiple, and deblurring in controlled-source seismic interferometry","Van der Neut, J.R.; Tatanova, M.; Thorbecke, J.W.; Slob, E.C.; Wapenaar, C.P.A.","","2011","With controlled-source seismic interferometry we aim to redatum sources to downhole receiver locations without requiring a velocity model. Interferometry is generally based on a source integral over cross-correlation (CC) pairs of full, perturbed (time-gated), or decomposed wavefields. We provide an overview of ghosts, multiples, and spatial blurring effects that can occur for different types of interferometry. We show that replacing cross-correlation by multidimensional deconvolution (MDD) can deghost, demultiple, and deblur retrieved data. We derive and analyze MDD for perturbed and decomposed wavefields. An interferometric point spread function (PSF) is introduced that can be obtained directly from downhole data. Ghosts, multiples, and blurring effects that may populate the retrieved gathers can be locally diagnosed with the PSF. MDD of perturbed fields can remove ghosts and deblur retrieved data, but it leaves particular multiples in place. To remove all overburden-related effects, MDD of decomposed fields should be applied.","","en","journal article","Hindawi Publishing Corporation","","","","","","","","Civil Engineering and Geosciences","Applied Geophysics and Petrophysics","","","","" "uuid:db579f8a-3b14-4c1e-949e-d63f883cca2e","http://resolver.tudelft.nl/uuid:db579f8a-3b14-4c1e-949e-d63f883cca2e","Improved surface?wave retrieval from ambient seismic noise by multi?dimensional deconvolution","Wapenaar, C.P.A.; Ruigrok, E.N.; Van der Neut, J.R.; Draganov, D.S.","","2011","The methodology of surface?wave retrieval from ambient seismic noise by crosscorrelation relies on the assumption that the noise field is equipartitioned. Deviations from equipartitioning degrade the accuracy of the retrieved surface?wave Green's function. A point?spread function, derived from the same ambient noise field, quantifies the smearing in space and time of the virtual source of the Green's function. By multidimensionally deconvolving the retrieved Green's function by the point?spread function, the virtual source becomes better focussed in space and time and hence the accuracy of the retrieved surface?wave Green's function may improve significantly. We illustrate this at the hand of a numerical example and discuss the advantages and limitations of this new methodology.","Green's function; ambient noise; surface wave","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:fdd34e74-03a7-458f-bb89-40640a312e74","http://resolver.tudelft.nl/uuid:fdd34e74-03a7-458f-bb89-40640a312e74","Methodology for dense spatial sampling of multicomponent recording of converted waves in shallow marine environments","El Allouche, N.; Drijkoningen, G.G.; Van der Neut, J.R.","","2010","A widespread use of converted waves for shallow marine applications is hampered by spatial aliasing and field efficiency. Their short wavelengths require dense spatial sampling which often needs to be achieved by receivers deployed on the seabed. We adopted a new methodology where the dense spatial sampling is achieved in the common-receiver domain by reducing the shot spacing. This is done by shooting one track multiple times and merging the shot lines in an effective manner in a separate processing step. This processing step is essential because positioning errors introduced during the field measurement can become significant in the combined line, particularly when they exceed the distance between two adjacent shot positions. For this processing step, a particular shot line is used as a reference line and relative variations in source and receiver positions in the other shot lines are corrected for using crosscorrelation. The combined shot line can subsequently be regularized for further processing. The methodology is adopted in a field experiment conducted in the Danube River in Hungary. The aim of the seismic experiment was to acquire properly sampled converted-wave data using a multicomponent receiver array. The dense spatial sampling was achieved by sailing one track 14 times. After correcting for the underwater receiver positions using the direct arrival, the crosscorrelation step was applied to merge the different shot lines. The successfully combined result is regularized into a densely sampled data set free of visible spatial aliasing and suitable for converted-wave processing.","geophysical techniques; rivers; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:7b865e3f-1f3b-4225-b3d6-97d5f4fca724","http://resolver.tudelft.nl/uuid:7b865e3f-1f3b-4225-b3d6-97d5f4fca724","A representation for Green’s function retrieval by multidimensional deconvolution","Wapenaar, C.P.A.; Van der Neut, J.R.","","2010","Green’s function retrieval by crosscorrelation may suffer from irregularities in the source distribution, asymmetric illumination, intrinsic losses, etc. Multidimensional deconvolution (MDD) may overcome these limitations. A unified representation for Green’s function retrieval by MDD is proposed. From this representation, it follows that the traditional crosscorrelation method gives a Green’s function of which the source is smeared in space and time. This smearing is quantified by a space–time point-spread function (PSF), which can be retrieved from measurements at an array of receivers. MDD removes this PSF and thus deblurs and deghosts the source of the Green’s function obtained by correlation.","","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:015bf386-811f-4587-b50b-9bac69f19699","http://resolver.tudelft.nl/uuid:015bf386-811f-4587-b50b-9bac69f19699","Passive seismic interferometry by multidimensional deconvolution","Wapenaar, C.P.A.; Van der Neut, J.R.; Ruigrok, E.N.","","2008","We introduce seismic interferometry of passive data by multidimensional deconvolution (MDD) as an alternative to the crosscorrelation method. Interferometry by MDD has the potential to correct for the effects of source irregularity, assuming the first arrival can be separated from the full response. MDD applications can range from reservoir imaging using microseismicity to crustal imaging with teleseismic data.","deconvolution; geophysical techniques; multidimensional signal processing; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","",""