parameter for the lossy reflection series so that the lossless Marchenko scheme can be applied. We propose a novel approach which makes it possible to calculate an effective temporal Q‐factor of the medium between a virtual source in the subsurface and receivers at the surface. This method is based on the minimization of the artefacts produced by the lossless Marchenko scheme. Artefacts have a very specific behavior: if the input data to the Marchenko equation are over‐ or under‐ compensated, the resulting artefacts will have an opposite polarity. Thus, they can be recognized. This approach is supported by a synthetic example for a 1D acoustic medium without a free surface.","","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","","","Applied Geophysics and Petrophysics","","","" "uuid:7f83193e-43f0-4d35-a334-98e56c0e73fc","http://resolver.tudelft.nl/uuid:7f83193e-43f0-4d35-a334-98e56c0e73fc","A single-sided representation for the homogeneous Green's function, accounting for all multiples","Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (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)","","2018","Marchenko imaging is a novel imaging technique that is capable to retrieve images from single-sided reflection measurements free of artefacts related to internal multiples (e.g. Behura et al., 2014; Broggini et al., 2012). An essential ingredient of Marchenko imaging is the so-called focusing function which can

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:013a0e81-3a84-4013-975c-4a2624fb4b0e","http://resolver.tudelft.nl/uuid:013a0e81-3a84-4013-975c-4a2624fb4b0e","Virtual seismology: from hydrocarbon reservoir imaging to induced earthquake monitoring","Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); Staring, M. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2018","Recent developments in exploration seismology have enabled the creation of virtual sources and/or virtual receivers in the subsurface from reflection measurements at the earth's surface. Unlike in seismic interferometry, no physical instrument (receiver or source) is needed at the position of the virtual source or receiver. Moreover, no detailed knowledge of the subsurface parameters and structures is required: a smooth velocity model suffices. Yet, the responses to the virtual sources, observed by the virtual receivers, fully account for multiple scattering. This new methodology, which we call virtual seismology, has led to a breakthrough in hydrocarbon reservoir imaging, as is demonstrated in a companion paper (Staring et al., Marchenko redatuming for multiple prediction and removal in situations with a complex overburden). The aim of the present paper is to discuss applications of virtual seismology beyond exploration seismology, in particular induced earthquake monitoring, and to highlight the connections between these applications. The ability to retrieve the entire wave field between (virtual or real) sources and receivers anywhere in the subsurface, without needing a detailed subsurface model, has large potential for monitoring induced seismicity, characterizing the source properties (such as the moment tensor of extended sources along a fault plane), and forecasting the response to potential future induced earthquakes. This will be demonstrated with numerical models and preliminary real-data results.","","en","conference paper","","","","","","Abstract S53A-03 presented at 2018 Fall Meeting, AGU, Washington, D.C., 10-14 Dec. Session: S53A On the Symbiosis Between Fundamental and Exploration Geophysics I","","2019-06-14","","","ImPhys/Acoustical Wavefield Imaging","","","" "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:ec82b4a8-3f09-45c2-9506-1453e3a8d6fe","http://resolver.tudelft.nl/uuid:ec82b4a8-3f09-45c2-9506-1453e3a8d6fe","Fast nonrecursive 1D inversion by filtering acoustic-reflection data","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); Treitel, Sven (Tridekon)","","2018","We derive a fast acoustic inversion method for a piecewise homogeneous horizontally layered medium. The method obtains medium parameters from the reflection response. The method can be implemented to obtain the parameters on either side of a reflector at an arbitrary depth. Three processing steps lead to the inversion result. First, we solve a modified Marchenko type equation to obtain a focusing wavefield. We then apply wavefield continuation across a reflecting boundary to the focusing wavefield and retrieve the reflection coefficient of a reflector as a function of horizontal slowness. Finally, we use the reflection coefficient to obtain the velocities and the ratio of the densities above and below the reflector. Because the two-way traveltime difference of the primary reflection and the one above it becomes known during the process, the thickness of the layer above the reflector is also found. The method can be applied multiple times in different zones, or recursively in a target zone without having to solve more Marchenko type equations. The numerical example illustrates that the method works well on modeled data without the need for a priori model information.","inversion; processing; acoustic","en","conference paper","SEG","","","","","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.","","2019-04-19","","","Applied Geophysics and Petrophysics","","","" "uuid:ee0b3190-beb4-4de6-bdc8-2a25c569dbbb","http://resolver.tudelft.nl/uuid:ee0b3190-beb4-4de6-bdc8-2a25c569dbbb","A lossless earth Green's function representation between any two subsurface points from surface reflection GPR data","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)","","2017","We present a three-dimensional scheme that can be used to compute the electromagnetic impulse response between any two subsurface points from surface reflection data measured at a single surface of a lossless medium. The scheme first computes a virtual vertical radar profile using the Marchenko scheme from which focusing wavefields are computed. With the aid of the Green's functions of the virtual vertical radar profiles these focusing wavefields are then used to compute the Green's function between any two points in the subsurface. One point is a virtual receiver and the other point is a virtual source. Virtual radar images can be created as well as the whole time evolution of the radar wave field throughout the subsurface generated by any subsurface virtual source. We show with a numerical example that the method works well in a one-dimensional configuration.","3D GPR; autofocusing; interferometry; virtual receiver; virtual source","en","conference paper","Institute of Electrical and Electronics Engineers Inc.","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:8b5b6fd7-8a4a-468c-91dd-77f6a3627a2e","http://resolver.tudelft.nl/uuid:8b5b6fd7-8a4a-468c-91dd-77f6a3627a2e","Snapshot wavefield decomposition for heterogeneous velocity media","Holicki, M.E. (TU Delft Applied Geophysics and Petrophysics); Drijkoningen, G.G. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","We propose a novel directional decomposition operator for wavefield snapshots in heterogeneous-velocity media. The proposed operator demonstrates the link between the amplitude of pressure and particlevelocity plane waves in the wavenumber domain. The proposed operator requires two spatial Fourier transforms (one forward and one backward) per spatial dimension and time slice. To illustrate the operator we demonstrate its applicability to heterogeneous velocity models using a simple velocity-box model and a more heterogeneous velocity model, based on real data, from close to the Annerveen gas field, The Netherlands.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:f12f14ab-7ad4-425c-8335-38daea5dce1d","http://resolver.tudelft.nl/uuid:f12f14ab-7ad4-425c-8335-38daea5dce1d","Time-lapse data prediction by Marchenko-based reservoir transplantation","Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","In a time-lapse experiment, changes in a reservoir cause changes in the reflection response. We discuss a method which predicts these changes from the baseline survey and a model of the changed reservoir. This method, which takes all multiple

scattering into account, is significantly more efficient than modeling the response of the entire medium containing the changed reservoir. This can be particularly attractive for applications in time-lapse full wave form inversion, which requires

repeated modelling of the reflection response.","","en","conference paper","SEG","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "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:8517ffa7-2f28-48f6-bb96-fe93885541fe","http://resolver.tudelft.nl/uuid:8517ffa7-2f28-48f6-bb96-fe93885541fe","Velocity analysis using surface-seismic primaries-only data obtained without removing multiples","Dokter, E. (University of Edinburgh); Meles, G.A. (TU Delft Applied Geophysics and Petrophysics; University of Edinburgh); Curtis, A (University of Edinburgh); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","A number of seismic processing methods, including velocity analysis (Sheriff and Geldart, 1999), make the assumption that recorded waves are primaries - that they have scattered only once (the Born approximation). Multiples then represent a source of coherent noise and must be suppressed to avoid artefacts. There are different approaches to mitigate free surface multiples (see Dragoset et al. (2010) for an overview), but internal multiples still pose a problem and usually cannot be removed without high computational cost or knowledge of the medium. Recently, Marchenko redatuming has been developed to image a medium in the presence of internal multiples (Wapenaar et al., 2014). Using Marchenko redatuming in combination with convolutional interferometry, Meles et al. (2016) have developed a method which allows the construction of a primaries-only data set from existing seismic reflection data and an initial velocity model. The method was proposed for the acoustic case and appears to be robust with respect to even huge inaccuracies in the employed velocity model. In this paper we investigate the impact of such primaries-only data on a simple velocity analysis workflow, as opposed to using the full data set with multiples. We use semblance analysis (Sheriff and Geldart, 1999) and compare the results obtained with three different data sets: the full reflection data with multiples, primaries data calculated with prior knowledge of the subsurface, and primaries data calculated with an entirely incorrect constant velocity model. We then use the velocity models that we construct to perform reverse time migration (RTM) of each of the data sets. We find that the velocities found are robust with respect to errors in the initial model used for Marchenko redatuming, and the method produces good results if non-hyperbolic moveout effects are avoided.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:6f56a5a1-f320-4b0e-8ae7-d4eada60ca08","http://resolver.tudelft.nl/uuid:6f56a5a1-f320-4b0e-8ae7-d4eada60ca08","Theory for Marchenko imaging of marine seismic data with free surface multiple elimination","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","The theory of data-driven true amplitude migration is presented for multicomponent marine seismic data. The Marchenko scheme is adapted to account for the ghost, free surface and internal multiple effects and works without the need to know the source wavelet. A true amplitude image is formed from the obtained focusing functions without ghost effects and artefacts from free surface and internal multiples. The resulting reflectivity at image times can be input for a final step of full waveform inversion. The numerical example shows the effectiveness of the method in a simple 1D problem.","","en","conference paper","EAGE","","","","","","","2018-01-01","","","Applied Geophysics and Petrophysics","","","" "uuid:65a6e1bc-fd87-4944-82d3-6551b2d973a2","http://resolver.tudelft.nl/uuid:65a6e1bc-fd87-4944-82d3-6551b2d973a2","Obtaining local reflectivity at two-way travel time by filtering acoustic reflection data","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Zhang, L. (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","A modified implementation of Marchenko redatuming leads to a filter that removes internal multiples from reflection data. It produces local reflectivity at two-way travel time. The method creates new primary reflections resulting from emitted events that eliminate internal multiples. We call these non-physical

primaries and their presence is a disadvantage. The advantage is that the filter is model free. We give the 3D filter and demonstrate with 1D arguments that starting the focusing wavefield with a unit impulse at zero time, while focusing below the bottom reflector, is the choice that leads to a model free implementation. The starting impulse generates the reflection data. Every later emitted pulse eliminates an internal multiple somewhere in the model and helps removing the transmission

amplitude effects in a physical primary. We show that

the amplitude of the non-physical primaries are a product of

three reflections, making them generally smaller than those of

the physical primaries. A 2D modeled shotgather at different

stages of filtering the data shows that the filter works well.","","en","conference paper","SEG","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "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: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:95ea33ec-4f45-4b19-9a85-fbef153ecb51","http://resolver.tudelft.nl/uuid:95ea33ec-4f45-4b19-9a85-fbef153ecb51","Elastodynamic single-sided homogeneous Green's function representation: Theory and examples","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); Reinicke Urruticoechea, C. (TU Delft Applied Geophysics and Petrophysics)","","2017","The homogeneous Green’s function is the Green’s function minus its timereversal. Many wavefield imaging applications make use of the homogeneous Green’s function in form of a closed boundary integral. Wapenaar et al. (2016a) derived an accurate single-sided homogeneous Green’s function representation that only requires sources/receivers on an open boundary. In this abstract we will present a numerical example of elastodynamic singlesided homogeneous Green’s function representation using a 2D laterally invariant medium. First, we will outline the theory of the single-sided homogeneous Green’s function representation. Second, we will show numerical results for the elastodynamic case.","","en","conference paper","EAGE","","","","","","","2018-01-01","","","","","","" "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:a6cb1a31-23c9-46f0-9a52-b1f68378d57f","http://resolver.tudelft.nl/uuid:a6cb1a31-23c9-46f0-9a52-b1f68378d57f","Time-slice wavefield decomposition","Holicki, M.E. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); Drijkoningen, G.G. (TU Delft Applied Geophysics and Petrophysics)","Sicking, Charles (editor); Ferguson, John (editor)","2016","We propose a novel acoustic decomposition operator for time slices, loosely based on conventional surface decomposition operators. The proposed operators hold for constant velocity models and require two 2D Fourier Transforms (one forward, one backward) per decomposed time slice per decomposition direction. We then demonstrate the capabilities of our operators on a constant velocity model and the Marmousi model. The decomposition results prove that we can decompose into up-, down-, left- and right-going waves for complex velocity media.","imaging; internal multiples","en","conference paper","SEG","","","","","","","","","","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: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: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:56af8349-c1ae-48f0-8bc1-beb4a15c4c7f","http://resolver.tudelft.nl/uuid:56af8349-c1ae-48f0-8bc1-beb4a15c4c7f","Full-field MDD for body-wave reflections from passive transient-sources under severely limited and irregular illumination conditions","Hartstra, I.E. (TU Delft Applied Geophysics and Petrophysics); Almagro Vidal, C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2016","Seismic interferometry (SI) presents a set of inexpensive and noninvasive methods that can be applied to any array at the surface to retrieve virtual body-wave reflection responses from earthquake recordings. Conventional SI by cross-correlation requires recordings of wavefields in lossless media generated by a smooth continuous distribution of passive sources with isotropic source radiation patterns and similar power spectra. These conditions are unlikely to be met in the lithosphere: earthquakes are distributed sparsely and generated by complex mechanisms. The resulting anisotropy in the illumination of the receiver array causes the retrieved virtual-source radiation patterns to be irregular, leading to artifacts which can obscure the desired body-wave reflections. SI by multidimensional deconvolution (MDD) can inherently correct for anisotropic illumination of the array and does not rely on the medium being lossless. We propose an alternative formulation of MDD for two-way wavefields: full-field MDD. Different from previous MDD methods for passive two-way wavefield recordings, full-field MDD uses multiples in the passive data to construct the reflection response without free-surface interaction. Therefore, this MDD method profits from additional wavenumbers provided by scattering to compensate for sparse earthquake distributions. Besides, this method does not require wavefield decomposition, which is sensitive to velocity variations at the receiver level. We compare the reflection retrieval by full-field MDD and cross-correlation for a limited passive source distribution in a lithospheric model with a discontinuous Moho at a depth of 50 km. We simulate earthquakes generated by dipole sources along a listric fault-system with power spectra varying within bandwidth 0.2-2.6 Hz. The reflection response retrieved by full-field MDD shows a continuous high-resolution Moho reflection, while cross-correlation yields a very low resolution response obscured by artifacts.","Geen BTA classificatie; Geen VSNU-classificatie","en","conference paper","AGU","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:8ea16a77-0ce5-4464-af8b-ba4e4a1c309d","http://resolver.tudelft.nl/uuid:8ea16a77-0ce5-4464-af8b-ba4e4a1c309d","Marchenko equations for acoustic Green's function retrieval and imaging in dissipative media","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (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 scheme for Marchenko imaging in a dissipative heterogeneous medium. The scheme requires measured reflection and transmission data at two sides of the dissipative medium. The effectual medium is the same as the dissipative medium, but with negative dissipation. We show how the measured double-sided data can be combined to obtain the single-sided reflection response of the effectual medium. Two sets of single-sided Marchenko equations follow that are used to compute to the focusing wavefield and the Green functions. Each uses single-sided reflection responses of the dissipative and effectual medium. To start the solution for these equations an initial estimate of the dissipation is required in addition to the estimate of the travel time of the first arrival. Avoiding the estimate of dissipation of the first arrival in a low-loss medium does not have a detrimental effects on the image quality. The numerical example shows the effectiveness of this strategy.","attenuation; autofocusing; multiples; 3D","en","conference paper","SEG","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:4f470bea-639d-49be-af8d-fa3556691801","http://resolver.tudelft.nl/uuid:4f470bea-639d-49be-af8d-fa3556691801","Reflection imaging of the Moho and the aseismic Nazca slab in the Malargüe region with global-phase seismic interferometry; abstract","Nishitsuji, Y.; Draganov, D.S.; Ruigrok, E.; Gomez, M.; Wapenaar, C.P.A.","","2015","","","en","conference paper","AGU","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","","","" "uuid:4df9ab66-7358-4539-b392-b43c09013030","http://resolver.tudelft.nl/uuid:4df9ab66-7358-4539-b392-b43c09013030","Estimating the location of a tunnel using interferometric times of Rayleigh-wave scattering","Kaslilar, A.; Harmankaya, U.; Wapenaar, C.P.A.; Draganov, D.S.","","2015","Inspired by a technique called seismic interferometry, we estimate the location of a scatterer using scattered waves. We isolate the scattered wavefield and evaluate the result of correlating scattered waves at different receiver locations. The cross-correlation eliminates the travel path between a source and a scatterer, making the estimation of the scatterers’ locations dependent only on properties between the receivers and the scatterer. We illustrate the potential of this method by locating a tunnel from seismic 23 field data, recorded along a line with multiple source and receiver locations. As near-surface scatterers are potential weak zones and may pose risk for the environment, to mitigate geo- and environmental hazards, this method can be an efficient alternative in detection of such structures.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:64f2fc04-f957-410d-bc10-a7b285ef4f06","http://resolver.tudelft.nl/uuid:64f2fc04-f957-410d-bc10-a7b285ef4f06","Creating virtual receivers from drill-bit noise","Liu, Y.; Draganov, D.S.; Wapenaar, C.P.A.; Arntsen, B.","","2015","In the field of seismic interferometry using noise, surface waves and body waves between receivers have been retrieved by crosscorrelating recordings of uncorrelated noise sources to extract useful subsurface information. When the positions of the noise sources are known, inter-source interferometry can be applied to retrieve the wavefileds between sources, thus turning sources into virtual receivers. Previous applications of this form of interferometry assume impulsive point sources or transient sources with similar signatures. We investigate the requirements of applying inter-source seismic interferometry using drill-bit noise to retrieve the reflection responses at those positions. We show that an accurate estimate of the source function is essential for such application. The preprocessing involves using standard seismicwhile-drilling procedures, such as pilot crosscorrelation and pilot deconvolution to remove the drill-bit signatures in the data, and then applying crosscorrelation interferometry. Provided that pilot signals are reliable, drill-bit data can be redatumed from surface to the depth of boreholes using this inter-source interferometry approach without any velocity information of the medium. We show that a well-positioned image below the borehole can be obtained with just a simple velocity model using these reflection responses. We also discuss some of the practical hurdles that restrict its application offshore.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5c46a3e3-4341-4689-8500-0d2408cda5df","http://resolver.tudelft.nl/uuid:5c46a3e3-4341-4689-8500-0d2408cda5df","Reflecting boundary conditions for interferometry by multidimensional deconvolution","Weemstra, C.; Wapenaar, C.P.A.; Van Dalen, K.N.","","2015","In this work we investigate a modification of the formulation of the theory underlying seismic interferometry (SI) by multidimensional deconvolution (MDD). The current formulation, and hence method, relies on separation of waves traveling inward and outward of a volume bounded by receivers. As a consequence, it is predominantly useful when receivers are illuminated from one side only. This puts constraints on the applicability of SI by MDD to omnidirectional wave fields. The proposed modification eliminates the requirement to separate inward-and outward propagating wave field and, consequently, improves the applicability of MDD to omnidirectional wave fields. We therefore envisage the modified MDD formulation to hold significant promise in the application to ambient-noise surface wave data.","illumination; deconvolution; passive; surface wave","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:26d929d6-05b8-4583-b13b-6a2fa0ef35fb","http://resolver.tudelft.nl/uuid:26d929d6-05b8-4583-b13b-6a2fa0ef35fb","Imaging and monitoring of subsurface structures using reflection retrieves from seismic interferometry","Draganov, D.S.; Wapenaar, C.P.A.","","2015","","","en","conference paper","","","","","","","","","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: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:d3a88b74-a158-4df2-ae3a-9bb8bc5b6cf6","http://resolver.tudelft.nl/uuid:d3a88b74-a158-4df2-ae3a-9bb8bc5b6cf6","Estimating the location of scatterers using correlation of scattered rayleigh waves","Harmankaya, U.; Kaslilar, A.; Van Wijk, K.; Wapenaar, C.P.A.; Draganov, D.S.","","2015","Inspired by a technique called seismic interferometry, we estimate the location of scatterers in a scaled model, where many near-surface scatterers are present. We isolate the scattered wavefield and evaluate correlation of scattered waves at different receiver locations. The cross-correlation eliminates the travel path between a source and a scatterer, making the estimation of the scatterers’ locations dependent only on properties between the receivers and the scatterer. We illustrate the potential of this method by locating scatterers with ultrasonic laboratory measurements of scattered Rayleigh waves recorded on two parallel and orthogonal lines of receivers. As near-surface scatterers are potential weak zones and may pose risk for the environment, to mitigate geo and environmental hazards, this method can be an efficient alternative that can be used in detection of such structures.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6d234427-0934-4f86-8f18-c17a4045293d","http://resolver.tudelft.nl/uuid:6d234427-0934-4f86-8f18-c17a4045293d","Elastodynamic Marchenko focusing, green's function retrieval and imaging","Wapenaar, C.P.A.; Slob, E.C.","","2015","Building on acoustic autofocusing in 1D media, we previously proposed acoustic Marchenko imaging for 1D and 3D media. Recently, the first steps have been set towards extending the single-sided Marchenko method to the elastodynamic situation. Here we discuss the extension of single-sided Marchenko focusing, Green's function retrieval and imaging to the elastodynamic situation. With numerical examples in a horizontally layered medium we show that, at least in principle, a true amplitude image can be obtained, free of artefacts related to multiple reflections and wave conversions. The method can be extended to 3D situations, in a similar way as we extended the acoustic 1D method to the 3D situation.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6debab43-6c38-48ce-acb7-55cbae48f654","http://resolver.tudelft.nl/uuid:6debab43-6c38-48ce-acb7-55cbae48f654","A method to retrieve an improved high resolution reflection response from HiCLIMB array recordings of local earthquake scattering coda (PPT)","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)","","2015","We discuss a method to interferometrically retrieve the body wave reflection response from local high-frequency scattering coda wave fields with the purpose to obtain an input dataset suitable for the application of advanced exploration-type imaging methods","scattering coda; interferometry; scattering mean free path; reflection response; impedance contrasts; advanced exploration-type imaging; coda attenuation factor; HiCLIMB array","en","conference paper","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:6d0ac8a1-3880-4df6-bfb4-d4b96563284a","http://resolver.tudelft.nl/uuid:6d0ac8a1-3880-4df6-bfb4-d4b96563284a","Creating virtual vertical radar profiles from surface reflection ground penetrating radar data","Slob, E.C.; Hunziker, J.W.; Thorbecke, J.W.; Wapenaar, C.P.A.","","2014","","virtual source; virtual receiver; interferometry; autofocusing; 3D GPR","en","conference paper","UCL , COST","","","","","","","","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:36fc8b48-3f70-4187-8993-0072d90ada9f","http://resolver.tudelft.nl/uuid:36fc8b48-3f70-4187-8993-0072d90ada9f","A method to suppress spurious multiples in virtual-source gathers retrieved using seismic interferometry with reflection data","Boullenger, B.; Wapenaar, C.P.A.; Draganov, D.S.","","2014","Seismic interferometry applied to surface reflection data (with source and receivers at the surface) allows to retrieve virtual-source gathers at the position of receivers, where no source was shot. As a result of the crosscorrelation of all primary and multiple reflections, the virtual-source gathers contain retrieved physical reflections as well as non-physical (ghost) reflections also called spurious multiples. We show that a significant part of the ghost reflections can be suppressed by using surface-related multiple elimination on the active data advantageously. The method that we propose consists in retrieving the strong ghost reflections mainly from the crosscorrelation of primaries only and in subtracting this result from the virtual-source gather retrieved from all the data. The resulting new virtual-source gathers provide a better estimate of the reflection response since it is now less polluted by undesired non-physical events that may bring ambiguity in the interpretation. This is better to make a more effective use of the virtual-source gathers, for example for imaging.","correlation; estimation; reflection; reconstruction; adaptive subtraction","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:f9b8ba0d-c83d-4b1c-9450-ca1cc2ae8bcb","http://resolver.tudelft.nl/uuid:f9b8ba0d-c83d-4b1c-9450-ca1cc2ae8bcb","Turning subsurface noise sources into virtual receivers by multi-dimensional deconvolution","Liu, Y.; Wapenaar, C.P.A.; Arntsen, B.","","2014","The retrieval of the Green's functions between receiver pairs by multi-dimensional deconvolution can be extended to extract the impulse response between source pairs through source-receiver reciprocity. However in general, the procedure requires the separation of the outgoing and incoming wavefields at the sources, which reduces to the separation of the direct waves and the reflected waves in the absence of free-surface and inter-layer multiples. We show that in theory, for non-transient noise sources where the separation may not be obvious in the data domain, the separation can be achieved by time-windowing in an intermediate crosscorrelation step, which can be readily included in the MDD scheme. We illustrate the method with a synthetic model.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "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:50734e45-3a08-4986-b8ba-5c711daa76bf","http://resolver.tudelft.nl/uuid:50734e45-3a08-4986-b8ba-5c711daa76bf","Locating cavities using ghost scattered waves in a scale-model experiment","Harmankaya, U.; Kaslilar, A.; Verstraeten, B.; Creten, S.; Glorieux, C.; Wapenaar, C.P.A.; Draganov, D.S.","","2014","The investigation and detection of near-surface structures (cavities, caves, tunnels, mineshafts, buried objects, archeological ruins, water reservoir, etc.) is important to mitigate geo- and environmental hazards. We use a method inspired by seismic interferometry to estimate the location of a cavity in a scaled ultrasonic experiment, representative for geophysical field problems. We use only one source at the surface and retrieve ghost scattered waves by evaluating the correlation of scattered waves at different receiver locations. As an exploitation of the ghost arrival information, the ghost travel times are determined and combined to estimate the location of a cavity with good accuracy.","","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:6954f84f-20e2-4a93-919b-41a26298ae02","http://resolver.tudelft.nl/uuid:6954f84f-20e2-4a93-919b-41a26298ae02","Overview of marine controlled-source electromagnetic interferometry by multidimensional deconvolution","Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.","","2014","Interferometry by multidimensional deconvolution for marine Controlled-Source Electromagnetics can suppress the direct field and the airwave in order to increase the detectability of the reservoir. For monitoring, interferometry by multidimensional deconvolution can increase the source repeatability. We give an overview over the method and discuss a possible path of research for the future.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:493d1089-c862-4cea-96b2-e4345cb41fe5","http://resolver.tudelft.nl/uuid:493d1089-c862-4cea-96b2-e4345cb41fe5","Inter-source seismic interferometry by multidimensional deconvolution (MDD) for borehole sources","Liu, Y.; Wapenaar, C.P.A.; Romdhane, A.","","2014","Seismic interferometry (SI) is usually implemented by crosscorrelation (CC) to retrieve the impulse response between pairs of receiver positions. An alternative approach by multidimensional deconvolution (MDD) has been developed and shown in various studies the potential to suppress artifacts due to irregular source distribution and intrinsic loss. Following previous theories on SI by MDD, we extend it to retrieve the impulse response between pairs of source positions by invoking source and receiver reciprocity. We verify the theory using a simple two-layered model and show that the retrieved response by MDD is more accurate than that by CC, and furthermore, it is free of free-surface multiples. We discuss the necessary pre-processing required for this method. This inter-source SI approach creates a virtual acquisition geometry with both borehole sources and receivers without the need to deploy receivers in the borehole, which might be of interest to applications such as seismic while drilling (SWD).","","en","conference paper","Chinese Petroleum Society / Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:43c97470-96cc-474a-a1ea-f61685040f49","http://resolver.tudelft.nl/uuid:43c97470-96cc-474a-a1ea-f61685040f49","Data-driven inversion of GPR surface reflection data for lossless layered media","Slob, E.C.; Wapenaar, C.P.A.","","2014","Two wavefields can be retrieved from the measured reflection response at the surface. One is the Green’s function at a chosen virtual receiver depth level in a layered model generated by a source at the surface. The other wavefield consists of the upgoing and downgoing parts of a wavefield that focuses at the virtual receiver depth level. From the upgoing part of the focusing wavefield an image can be computed at one-way vertical travel time and with correct amplitudes of the local reflection coefficients as a function of incidence angle. These reflection coefficient values can be used to invert for electric permittivity and magnetic permeability. From these values and the known image times the layer thickness values can be obtained for each layer. This method renders the full waveform inversion problem for horizontally layered media a linear problem.","antenna; propagation; measurement","en","conference paper","European Association on Antennas and Propagation","","","","","","","","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: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:f752f3d4-5f52-49e6-a309-5786f58dfae8","http://resolver.tudelft.nl/uuid:f752f3d4-5f52-49e6-a309-5786f58dfae8","3D Marine CSEM Interferometry by Multidimensional Deconvolution in the Wavenumber Domain for a Sparse Receiver Grid","Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.","","2013","We use interferometry by multidimensional deconvolution in combination with synthetic aperture sources in 3D to suppress the airwave and the direct field, and to decrease source uncertainty in marine Controlled-Source electromagnetics. We show with this numerical study that the method works for very large receiver spacing distances, even though the thereby retrieved reflection response may be aliased.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:d5828eb0-cde3-4ab5-adcc-07168d34c45e","http://resolver.tudelft.nl/uuid:d5828eb0-cde3-4ab5-adcc-07168d34c45e","Locating scatterers by non-physical scattered waves obtained by seismic interferometry","Harmankaya, U.; Kaslilar, A.; Thorbecke, J.W.; Wapenaar, C.P.A.; Draganov, D.S.","","2013","The investigation and detection of near-surface structures (such as cavities, caves, sinkholes, tunnels, mineshafts, buried objects, archeological ruins, water reservoir, etc.) is important to mitigate geo- and environmental hazards. In a former study, we suggested a method based on active-source seismic interferometry for locating the scatterers and we showed the applicability of the method in a simple model. In our method, we use only one source at the surface and non-physical scattered waves retrieved by seismic interferometry to estimate the location of the scatterer. In this paper, we show the effectiveness of the method in case of lateral variations. We use both scattered body and surface waves to estimate the location of a corner diffractor and a scatterer, respectively, and we obtain very good estimations. The method is promising for near-surface seismic field applications.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience and 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:757ea06c-4006-4a60-a03d-31388da7a94d","http://resolver.tudelft.nl/uuid:757ea06c-4006-4a60-a03d-31388da7a94d","Retrieving higher-mode surface waves using seismic interferometry by multidimensional deconvolution","Van Dalen, K.N.; Wapenaar, C.P.A.; Halliday, D.F.","","2013","Virtual-source surface-wave responses can be retrieved using the crosscorrelation of wavefields observed at two receivers. Higher-mode surface waves cannot be properly retrieved when there is a lack of subsurface sources, which is often the case. In this paper, we present a multidimensional-deconvolution scheme that introduces an additional processing step in which the crosscorrelation result is deconvolved by a point-spread function. The scheme is based on an approximate convolution theorem that includes pointforce responses only, which is advantageous for applications with contemporary field-acquisition geometries. The point-spread function captures the imprint of the lack of subsurface sources and quantifies the associated smearing of the virtual source in space and time. The function can be calculated from the same wavefields used in the correlation method, provided that one or more vertical arrays of subsurface receivers are present and the illumination is from one side. We show that the retrieved surface-wave response, including the higher modes, becomes much more accurate. The waveforms are properly reconstructed and there is only a small amplitude error, which is due to non-canceling cross terms in the employed approximate convolution theorem. The improved retrieval of the multi-mode surface waves can facilitate dispersion analyses and near-surface inversion algorithms.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:b67674f6-c10f-4815-8a44-a746b9510521","http://resolver.tudelft.nl/uuid:b67674f6-c10f-4815-8a44-a746b9510521","Creating the green's response to a virtual source inside a medium using reflection data with internal multiples","Broggini, F.; Snieder, R.; Wapenaar, C.P.A.; Thorbecke, J.W.","","2013","Seismic interferometry is a technique that allows one to reconstruct the full wavefield originating from a virtual source inside a medium, assuming a receiver is present at the virtual source location. We discuss a method that creates a virtual source inside a medium from reflection data measured at the surface, without needing a receiver inside the medium and, hence, presenting an advantage over seismic interferometry. An estimate of the direct arriving wavefront is required in addition to the reflection data. However, no information about the medium is needed. We illustrate the method with numerical examples in a lossless acoustic medium with laterally-varying velocity and density. We examine the reconstructed wavefield when a macro model is used to estimate the direct arrivals and we take into consideration finite acquisition aperture. Additionally, a variant of the iterative scheme allows us to decompose the reconstructed wave field into downgoing and upgoing fields. These wave fields are then used to create an image of the medium with either crosscorrelation or multidimensional deconvolution.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f911ba40-d510-42c8-a6bf-d64527330d67","http://resolver.tudelft.nl/uuid:f911ba40-d510-42c8-a6bf-d64527330d67","Seismic interferometry by midpoint integration","Ruigrok, E.N.; Almagro Vidal, C.; Wapenaar, C.P.A.","","2012","With seismic interferometry reflections can be retrieved between station positions. In the classical form, the reflections are retrieved by an integration over sources. For a specific dataset, however, the actual source distribution might not be sufficient to approximate the source integral. Yet, there might be a dense distribution of receivers allowing integration over the receiver domain. We rewrite the source integral to an integration over midpoints. With this formulation, a reflection can be retrieved even in the limiting case of only a single source. However, with respect to the classical formulation, an additional stationary-phase analysis is required.","","en","conference paper","Deutsche Geophysikalische Gesellschaft","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:aa01d8e7-7782-48c1-8552-c97bbfdbee67","http://resolver.tudelft.nl/uuid:aa01d8e7-7782-48c1-8552-c97bbfdbee67","Synthesized 2D CSEM-interferometry Using Automatic Source Line Determination","Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.","","2012","Interferometry by multidimensional deconvolution applied to Controlled-Source Electromagnetic data replaces the medium above the receivers by a homogeneous halfspace, suppresses the direct field and redatums the source positions to the receiver locations. In that sense, the airwave and any other interactions of the signal with the air-water interface and the water layer are suppressed and the source uncertainty is reduced. Interferometry requires grid data and cannot be applied to line data unless the source is infinitely long in the crossline direction. To create such a source, a set of source lines is required. We use an iterative algorithm to determine the optimal locations of these source lines and show that more source lines are required if the source is towed closer to the sea bottom and closer to the receivers.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:be874ea3-2151-43d9-b4f6-59dbd459e091","http://resolver.tudelft.nl/uuid:be874ea3-2151-43d9-b4f6-59dbd459e091","Estimating the Location of Scatterers by Seismic Interferometry of Scattered Surface Waves","Harmankaya, U.; Kaslilar, A.; Thorbecke, J.W.; Wapenaar, C.P.A.; Draganov, D.S.","","2012","In this study, non-physical (ghost) scattered surface waves are used to obtain the location of a near surface scatterer. The ghost is obtained from application of seismic interferometry to only one source at the surface. Different locations for virtual sources are chosen and ghost scattered surface waves for each of these virtual-source locations are retrieved. The retrieved ghost traveltimes are inverted by solving the inverse problem to determine the location of the scatterer. It is seen that the location of the scatterer is reasonably well estimated.","","en","conference paper","","","","","","","","","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:42a624a7-721a-4b12-a06c-b1254e16fff4","http://resolver.tudelft.nl/uuid:42a624a7-721a-4b12-a06c-b1254e16fff4","A proposal for 4D seismic imaging","Fokkema, J.T.; Dillen, M.W.P.; Wapenaar, C.P.A.","","1997","","development earthquakes elastic waves equations Europe four dimensional models geologic hazards geophysical methods Green function heavy oil induced earthquakes land subsidence measurement while drilling monitoring natural gas Netherlands northern Netherl","en","conference paper","European Association of Geoscientists and Engineers (EAGE), International","","","","","","","","","","","","","" "uuid:c31a699b-f406-4235-ac85-df9b933becbf","http://resolver.tudelft.nl/uuid:c31a699b-f406-4235-ac85-df9b933becbf","The reflectivity operator for curved interfaces","Fokkema, J.T.; Van Vroonhoven, M.; Wapenaar, C.P.A.; De Bruin, C.G.M.","","1993","","boundary conditions curved seismic interface elastic waves geophysical methods heterogeneous materials homogeneous materials mathematical methods reflection seismic methods seismic waves two dimensional models 20 Applied geophysics","en","conference paper","Society of Exploration Geophysicists","","","","","","","","","","","","","" "uuid:3db3eeb2-7663-42cc-bb72-a8aa1c10a67e","http://resolver.tudelft.nl/uuid:3db3eeb2-7663-42cc-bb72-a8aa1c10a67e","Extrapolation operators by beam tracing","Kremer, S.R.G.; Fokkema, J.T.; Wapenaar, C.P.A.","","1991","","amplitude beam tracing data processing extrapolation geophysical methods imagery seismic methods 20 Applied geophysics","en","conference paper","","","","","","","","","","","","","","" "uuid:68eea8de-85ef-4630-bae8-409e46402940","http://resolver.tudelft.nl/uuid:68eea8de-85ef-4630-bae8-409e46402940","Beam tracing for migration and inversion","Fokkema, J.T.; Kremer, S.R.G.; Wapenaar, C.P.A.","","1990","","accuracy direct problem evaluation geophysical methods Green function inverse problem propagation raypaths seismic methods seismic migration 20 Applied geophysics","en","conference paper","","","","","","","","","","","","","",""