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Mulder, W.A. (author)Migration velocity analysis for the two-way wave equation based on focusing extended migration images at zero subsurface offset are sensitive to the presence of multiples. Even after thorough multiple suppression, remnant multiple energy can lead to conflicting events that will focus at different velocities, one for the primary and another for...conference paper 2013
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Harmankaya, U. (author), Kaslilar, A. (author), Verstraeten, B. (author), Creten, S. (author), Glorieux, C. (author), Wapenaar, C.P.A. (author), Draganov, D.S. (author)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,...conference paper 2014
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Farajzadeh, R. (author), Lotfollahi, M. (author), Eftekhari, A.A. (author), Rossen, W.R. (author), Hirasaki, G.J. (author)Accurate modelling of foam rheology on the field scale requires detailed understanding of the correlation between the fundamental properties of foam and the scalable parameters of the porous medium. It has been experimentally observed that foam experiences an abrupt coalescence when the capillary pressure in the porous medium approaches a...conference paper 2015
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Bezerra, F.H. (author), Bertotti, G. (author), Cazarin, C.L. (author), Vieira, M.M. (author), Reijmer, J. (author), Srivastava, N. (author), Silva, A.T. (author), Nogueira, F.C. (author), Medeiros, W.E. (author), Silva, C.C. (author), Maia, R.P. (author)We investigated the Quaternary epigenic karst system in the Jandaíra Formation, a Turonian–Campanian carbonate platform in the Potiguar basin, northeastern Brazil. We concentrated our investigation in the vadose zone of the present-day karst, but also used borehole data. The leaching zones are preferentially concentrated along pre-solution...conference paper 2013
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Shamasundar, R. (author), Al-Khoury, R.I.N. (author), Mulder, W.A. (author)We investigated one-dimensional numerical dispersion curves and error behaviour of four finite-element schemes with polynomial basis functions: the standard elements with equidistant nodes, the Legendre-Gauss-Lobatto points, the Chebyshev-Gauss-Lobatto nodes without a weighting function and with. Mass lumping, required for efficiency reasons and...conference paper 2015
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Liu, Y. (author), Wapenaar, C.P.A. (author), Arntsen, B. (author)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...conference paper 2014
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Bertotti, G. (author), Arantegui, A. (author), Charton, R. (author), Luber, T. (author), Redfern, J. (author)The Morocco segment of the Central Atlantic passive continental margin experienced km-scale exhumation during the early post-rift (late Jurassic-Early Cretaceous). In the Meseta and the High Atlas this led to the development of a N-S trending ridge sourcing terrigenous sediments which were brought to the Atlantic sea via wide rivers flowing on...conference paper 2015
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Draganov, D.S. (author), Heller, H.K.J. (author), Ghose, R. (author)Time-lapse seismic monitoring is a fundamental part in most monitoring programmes involving CO2 storage. Even though the seismic method has proven its applicability for monitoring, there are two major causes of uncertainty in the estimation of changes in the reservoir properties: non-repeatability of the source positions and the difficulty in...conference paper 2013
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Justiniano, A. (author), Jaya, Y. (author), Diephuis, G. (author), Veenhof, R. (author), Pringle, T. (author)The objective of the study is to characterise the Triassic massive stacked sandstone deposits of the Main Buntsandstein Subgroup at Block Q16 located in the West Netherlands Basin. The characterisation was carried out through combining rock-physics modelling and seismic inversion techniques. The application of inversion on time-converted PSDM...conference paper 2015
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Khosrokhavar, R. (author), Eftekhari, A.A. (author), Farajzadeh, R. (author), Wolf, K.H.A.A. (author), Bruining, J. (author)The growing concern about global warming has increased interest in improving the technology for the geological storage of CO2 in aquifers. One important aspect for aquifer storage is the rate of transfer between the overlying gas layer and the aquifer below. It is generally accepted that density driven natural convection is an important...conference paper 2015
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Pisupati, P.B. (author), Mulder, W.A. (author), Drijkoningen, G.G. (author), Reijnen, R. (author)In the near-surface with unconsolidated soils, shear properties can be well imaged, sometimes better than P-wave properties. To facilitate ground prediction ahead of a tunnel boring machine (TBM), active ‘surveys’ with shear-wave vibrators are carried out during boring. In such surveys, only a few shear-wave vibrators can be placed in front of...conference paper 2015
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Blacquiere, G. (author), Berkhout, A.J. (author)In marine acquisition both a direct wavefield and a ghost wavefield are produced as well as recorded. Hence, the seismic data can be considered to be a natural blend of four wavefields related to the real sources, ghost sources, real detectors and ghost detectors respectively. We consider deghosting to be deblending ('echo-deblending'), leading...conference paper 2015
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Konstantaki, L.A. (author), Draganov, D.S. (author), Ghose, R. (author), Heimovaara, T.J. (author)In this study we investigate the application of seismic interferometry (SI) to seismic reflection data recorded over a landfill. Landfills represent strongly heterogeneous subsurfaces making the seismic reflection imaging challenging. We show that SI improves the imaging of high-density areas, which create scattering events in the recorded data....conference paper 2015
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Noorlandt, R.P. (author), Drijkoningen, G.G. (author), Schneider, R.M. (author)In this paper we present a newly developed vertical seismic vibrator driven by linear motors. We explain the different components the vibrator consists of. We show that the harmonic distortion of the linear-motor vibrator signal is very small. We also show that, without applying a feedback loop on the pilot signal, the weighted-sum ground force...conference paper 2012
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Shojai Kaveh, N. (author), Barnhoorn, A. (author), Wolf, K.H.A.A. (author)In recent years, the coupled UCG-CCS process has been considered as another potential CCS option, which can offer integrated energy recovery from coal and storage of CO2. However, existing potential problems may counteract its potential benefits. To develop a generic UCG-CCS site characterisation workflow, different aspects of this complex...conference paper 2015
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Donselaar, M.E. (author), Bouman, L. (author), Noordijk, N. (author), Van Toorenenburg, K.A. (author), Weltje, G.J. (author)The subsurface of the West European gas province contains up to several hundred meters thick continuous Upper Rotliegend and Lower Triassic mud rock sequences which have to date been labelled as nonreservoir ‘waste zone’. The mud rock formed as fluvial floodplain deposits in a semi-arid climate. The sequences contain thin-bedded porous and...conference paper 2015
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Bisdom, K. (author), Bertotti, G. (author), Gauthier, B.D.M. (author), Hardebol, N.J. (author)Presently adopted fracture-related permeability models of large folded reservoirs are simplistic and often unrelated to the geological setting and evolution of the considered structure. In order to improve predictions of fluid flow in more complex subsurface fractured reservoirs, we build a 3D fracture network model of an outcropping fold in...conference paper 2013
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Mulder, W.A. (author)Mass-lumped continuous finite elements provide accurate solutions of the second-order acoustic or elastic wave equation in complex geological settings, in particular in the presence of topography and large impedance contrasts. Elements of higher polynomial degree have better accuracy than those of lower degree but are also more costly. Here, the...conference paper 2013
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Hardebol, N.J. (author), Bertotti, G. (author)Our aim is to quantify the role of intermediate length scale pre-existing faults and fractures on the critical loading of first order faults and on the potential for enhancement of fracture network. The arrangement of smaller scale natural fractures relative to larger-scale faults is subject of our combined outcrop and numerical modelling study....conference paper 2014
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Berkhout, A.J. (author), Verschuur, D.J. (author)The next generation migration technology considers multiple scattering as vital information, allowing the industry to generate significantly better images of the subsurface. The proposed full wavefield algorithm (FWM) makes use of two-way wave theory that is formulated in terms of one-way wavefields. We show that the current migration algorithms...conference paper 2012