Relevant bibliographies by topics / Migration amplitudes

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  2. Dissertations / Theses
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Academic literature on the topic 'Migration amplitudes'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Migration amplitudes"

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Amazonas, Daniela, Rafael Aleixo, Gabriela Melo, Jörg Schleicher, Amélia Novais, and Jessé C. Costa. "Including lateral velocity variations into true-amplitude common-shot wave-equation migration." GEOPHYSICS 75, no. 5 (September 2010): S175—S186. http://dx.doi.org/10.1190/1.3481469.

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In heterogeneous media, standard one-way wave equations describe only the kinematic part of one-way wave propagation correctly. For a correct description of amplitudes, the one-way wave equations must be modified. In media with vertical velocity variations only, the resulting true-amplitude one-way wave equations can be solved analytically. In media with lateral velocity variations, these equations are much harder to solve and require sophisticated numerical techniques. We present an approach to circumvent these problems by implementing approximate solutions based on the one-dimensional analytic amplitude modifications. We use these approximations to show how to modify conventional migration methods such as split-step and Fourier finite-difference migrations in such a way that they more accurately handle migration amplitudes. Simple synthetic data examples in media with a constant vertical gradient demonstrate that the correction achieves the recovery of true migration amplitudes. Applications to the SEG/EAGE salt model and the Marmousi data show that the technique improves amplitude recovery in the migrated images in more realistic situations.
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Gray, Samuel H. "Spatial sampling, migration aliasing, and migrated amplitudes." GEOPHYSICS 78, no. 3 (May 1, 2013): S157—S164. http://dx.doi.org/10.1190/geo2012-0451.1.

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Seismic migration is a multichannel process, in which some of the properties depend on various grid spacings. First, there is the acquisition grid, which actually consists of two grids: a grid of source locations and, for each source location, a grid of receiver locations. In addition, there is a third grid, the migration grid, whose spacings also affect properties of the migration. Sampling theory imposes restrictions on migration, limiting the frequency content that can be migrated reliably given the grid spacings. The presence of three grids complicates the application of sampling theory except in unusual situations (e.g., the isolated migration of a single shot record). I analyzed the effects of the grids on different types of migration (Kirchhoff, wavefield extrapolation migration, and slant-stack migration), specifically in the context of migration operator antialiasing. I evaluated general antialiasing criteria for the different types of migration; my examples placed particular emphasis on one style of data acquisition, orthogonal source and receiver lines, which is commonly used on land and which presents particular challenges for the analysis. It is known that migration artifacts caused by inadequate antialiasing can interfere with velocity and amplitude analyses. I found, in addition, that even migrations with adequate antialiasing protection can have the side effect of inaccurate amplitudes resulting from a given acquisition, and I tested how this effect can be compensated.
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Vivas, Flor A., and Reynam C. Pestana. "True-amplitude one-way wave equation migration in the mixed domain." GEOPHYSICS 75, no. 5 (September 2010): S199—S209. http://dx.doi.org/10.1190/1.3478574.

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One-way wave equation migration is a powerful imaging tool for locating accurately reflectors in complex geologic structures; however, the classical formulation of one-way wave equations does not provide accurate amplitudes for the reflectors. When dynamic information is required after migration, such as studies for amplitude variation with angle or when the correct amplitudes of the reflectors in the zero-offset images are needed, some modifications to the one-way wave equations are required. The new equations, which are called “true-amplitude one-way wave equations,” provide amplitudes that are equivalent to those provided by the leading order of the ray-theoretical approximation through the modification of the transverse Laplacian operator with dependence of lateral velocity variations, the introduction of a new term associated with the amplitudes, and the modification of the source representation. In a smoothly varying vertical medium,the extrapolation of the wavefields with the true-amplitude one-way wave equations simplifies to the product of two separable and commutative factors: one associated with the phase and equal to the phase-shift migration conventional and the other associated with the amplitude. To take advantage of this true-amplitude phase-shift migration, we developed the extension of conventional migration algorithms in a mixed domain, such as phase shift plus interpolation, split step, and Fourier finite difference. Two-dimensional numerical experiments that used a single-shot data set showed that the proposed mixed-domain true-amplitude algorithms combined with a deconvolution-type imaging condition recover the amplitudes of the reflectors better than conventional mixed-domain algorithms. Numerical experiments with multiple-shot Marmousi data showed improvement in the amplitudes of the deepest structures and preservation of higher frequency content in the migrated images.
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BORTFELD, R., and M. KIEHN. "REFLECTION AMPLITUDES AND MIGRATION AMPLITUDES (ZERO-OFFSET SITUATION)1." Geophysical Prospecting 40, no. 8 (November 1992): 873–84. http://dx.doi.org/10.1111/j.1365-2478.1992.tb00557.x.

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Hanitzsch, Christian. "Comparison of weights in prestack amplitude‐preserving Kirchhoff depth migration." GEOPHYSICS 62, no. 6 (November 1997): 1812–16. http://dx.doi.org/10.1190/1.1444282.

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Three different theoretical approaches to amplitude‐preserving Kirchhoff depth migration are compared. Each of them suggests applying weights in the diffraction stack migration to correct for amplitude loss resulting from geometric spreading. The weight functions are given in different notations, but as is shown, all of these expressions are similar. A notation that is well suited for implementation is suggested: entirely in terms of Green's function quantities (amplitudes or point‐source propagators). For the most common prestack configurations (common‐shot and common‐offset) and 3-D, 2.5-D, and 2-D migrations, expressions of the weights are given in this notation. The quantities needed for calculation of the weights can be computed easily, e.g., by dynamic ray tracing.
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Nguyen, Bao D., and George A. McMechan. "Excitation amplitude imaging condition for prestack reverse-time migration." GEOPHYSICS 78, no. 1 (January 1, 2013): S37—S46. http://dx.doi.org/10.1190/geo2012-0079.1.

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An implicitly stable ratio imaging condition for prestack reverse-time migration (RTM) was defined using excitation criteria. Amplitude maxima and their corresponding occurrence times were saved at each grid point during forward source wavefield extrapolation. Application of the imaging condition involves dividing the amplitudes of the back-propagated receiver wavefield by the precomputed maximum source wavefield amplitude only at the grid points that satisfy the image time at each time step. The division normalizes by the source amplitude, so only the highest signal-to-noise ratio portion of the data is used. Provided that the source and receiver wavefield amplitudes are accurate at the reflection points, the peak wavelet amplitudes in the migrated image are the angle-dependent reflection coefficients and low wavenumber artifacts are significantly reduced compared to those in images calculated by crosscorrelation. Using excitation information and time-binning for the imaging condition improves computational and storage efficiency by three or more orders of magnitude when compared to crosscorrelation with the full source wavefield. Numerical tests with synthetic data for the Marmousi2 model have shown this method to be a cost-effective and practical imaging condition for use in prestack RTM.
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Dellinger, Joe A., Samuel H. Gray, Gary E. Murphy, and John T. Etgen. "Efficient 2.5-D true‐amplitude migration." GEOPHYSICS 65, no. 3 (May 2000): 943–50. http://dx.doi.org/10.1190/1.1444790.

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Kirchhoff depth migration is a widely used algorithm for imaging seismic data in both two and three dimensions. To perform the summation at the heart of the algorithm, standard Kirchhoff migration requires a traveltime map for each source and receiver. True‐amplitude Kirchhoff migration in 2.5-D υ(x, z) media additionally requires maps of amplitudes, out‐of‐plane spreading factors, and takeoff angles; these quantities are necessary for calculating the true‐amplitude weight term in the summation. The increased input/output (I/O) and computational expense of including the true‐amplitude weight term is often not justified by significant improvement in the final muted and stacked image. For this reason, some authors advocate neglecting the weight term in the Kirchhoff summation entirely for most everyday imaging purposes. We demonstrate that for nearly the same expense as ignoring the weight term, a much better solution is possible. We first approximate the true‐amplitude weight term by the weight term for constant‐velocity media; this eliminates the need for additional source and receiver maps. With one small additional approximation, the weight term can then be moved entirely outside the innermost loop of the summation. The resulting Kirchhoff method produces images that are almost as good as for exact true‐amplitude Kirchhoff migration and at almost the same cost as standard methods that do not attempt to preserve amplitudes.
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Yang, Jizhong, Yuzhu Liu, and Liangguo Dong. "Least-squares reverse time migration in the presence of density variations." GEOPHYSICS 81, no. 6 (November 1, 2016): S497—S509. http://dx.doi.org/10.1190/geo2016-0075.1.

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Least-squares migration (LSM) is commonly regarded as an amplitude-preserving or true amplitude migration algorithm that, compared with conventional migration, can provide migrated images with reduced migration artifacts, balanced amplitudes, and enhanced spatial resolution. Most applications of LSM are based on the constant-density assumption, which is not the case in the real earth. Consequently, the amplitude performance of LSM is not appropriate. To partially remedy this problem, we have developed a least-squares reverse time migration (LSRTM) scheme suitable for density variations in the acoustic approximation. An improved scattering-integral approach is adopted for implementation of LSRTM in the frequency domain. LSRTM images associated with velocity and density perturbations are simultaneously used to generate the simulated data, which better matches the recorded data in amplitudes. Summation of these two images provides a reflectivity model related to impedance perturbation that is in better accordance with the true one, than are the velocity and density images separately. Numerical examples based on a two-layer model and a small part of the Sigsbee2A model verify the effectiveness of our method.
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Chavent, Guy, and René‐Edouard Plessix. "An optimal true‐amplitude least‐squares prestack depth‐migration operator." GEOPHYSICS 64, no. 2 (March 1999): 508–15. http://dx.doi.org/10.1190/1.1444557.

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In order to define an optimal true‐amplitude prestack depth migration for multishot and multitrace data, we develop a general methodology based on the least‐squares data misfit function associated with a forward model. The amplitude of the migrated events are restored at best for any given geometry and any given preliminary filtering and amplitude correction of the data. The migrated section is then the gradient of the cost function multiplied by a weight matrix. A study of the Hessian associated with this data misfit shows how efficiently to find a good weight matrix via the computation of only few elements of this Hessian. Thanks to this matrix, the resulting migration operator is optimal in the sense that it ensures the best possible restoration of the amplitudes among the large class of least‐squares migrations. Applied to a forward model based on Born, ray tracing, and diffracting points approximation, this optimal migration outperforms or at least equals the classic Kirchhoff formula, since the latter belongs to the class of least‐squares migrations and is only optimal for one shot and an infinite aperture. Numerical results illustrate this construction and confirm the above expectations.
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Yue, Yubo, Yujin Liu, Yaonan Li, and Yunyan Shi. "Least-squares Gaussian beam migration in viscoacoustic media." GEOPHYSICS 86, no. 1 (December 16, 2020): S17—S28. http://dx.doi.org/10.1190/geo2020-0129.1.

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Because of amplitude decay and phase dispersion of seismic waves, conventional migrations are insufficient to produce satisfactory images using data observed in highly attenuative geologic environments. We have developed a least-squares Gaussian beam migration method for viscoacoustic data imaging, which can not only compensate for amplitude decay and phase dispersion caused by attenuation, but it can also improve image resolution and amplitude fidelity through linearized least-squares inversion. We represent the viscoacoustic Green’s function by a summation of Gaussian beams, in which an attenuation traveltime is incorporated to simulate or compensate for attenuation effects. Based on the beam representation of the Green’s function, we construct the viscoacoustic Born forward modeling and adjoint migration operators, which can be effectively evaluated by a time-domain approach based on a filter-bank technique. With the constructed operators, we formulate a least-squares migration scheme to iteratively solve for the optimal image. Numerical tests on synthetic and field data sets demonstrate that our method can effectively compensate for the attenuation effects and produce images with higher resolution and more balanced amplitudes than images from acoustic least-squares Gaussian beam migration.
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Dissertations / Theses on the topic "Migration amplitudes"

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Abdulkareem, Lamees Nazar. "Quantitative analysis of anomalous seismic amplitudes caused by fluid migration." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12886/.

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Two- (2D) and three- (3D) dimensional pre-stack and post-stack seismic reflection data are used to investigate the processes which have led to the development of amplitude anomalies on reflections in the faulted, Cenozoic overburden on the Laminaria High, Northwest Shelf of Australia. The integration of amplitude and seismic attribute maps for four key horizons (the seabed, Horizon H9, Horizon H10 and Horizon H13) with the corresponding two-way time (TWT) structure maps has identified the structural controls on the distribution of seismic anomalies. On the seabed, the main anomaly is located on the up-dip side of the fault trace, and is elongated parallel to the local time structure contours. These observations are consistent with the anomalies having developed in response to structurally-controlled fluid seepage along, and up-dip migration away from the fault trace. Amplitude anomalies associated with the deeper H9 reflector are also located adjacent to fault traces but are discordant to the local time structure contours. This observation suggests that the anomalies may be due to cemented hardgrounds that formed due to seepage when the faults intersected the palaeo-seafloor but were subsequently buried and deformed during ongoing sedimentation and fault growth/linkage. Reprocessing of the 2D and 3D seismic pre-stack data supports the seismic interpretation of amplitude anomalies at the seabed. It is concluded that these anomalies are robust – that is, they are likely to reflect geological processes and are not simply a function of the chosen seismic processing workflow – and are caused by localised changes in acoustic impedence in the subsurface. More important is that using processed data without the knowledge of the background processing sequence for the data could be an issue in any 2D or 3D seismic interpretation. For this reason the veracity of processing of any seismic data needs to be questioned, and should not be taken for granted especially if different surveys produce conflicting interpretations. 2D hydrocarbon migration modelling combined with fault slip- and dilation-tendency analyses were undertaken in order to investigate the impact of faults and host-rock lithologies on hydrocarbon seepage at the present-day sea floor. Results show that some active faults associated with amplitude anomalies (e.g. Fault F10) are critically stressed, assuming a static, and spatially homogeneous regional stress field. However, other faults associated with amplitude anomalies (e.g. Fault F11) appear not to be critically stressed. These results suggests that the “regional” stress field could, in fact, vary spatially and temporally allowing faults in different parts of the study area to become critically stressed – hence act as fluid migration pathways – at different times. The migration models show that hydrocarbon migration pathways are strongly influenced by fault-zone properties, specifically the capillary entry pressure (CEP) along faults. The dip of the sediment layers also influences hydrocarbon leakage from the subsurface to the seabed. In general, the migration models show vertical hydrocarbon migration along faults coupled with lateral migration below the seal layers and between faults. Fluids migrate along faults with two patterns of flow based on the CEP values along the faults: 1) focused – fluids migrate as a linear pattern along faults when the capillary entry pressure along the fault is within the lower range of the “background” CEP values; 2) diffuse – fluids are guided by faults when the capillary entry pressure along the fault is within the higher range of the “background” CEP values.
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Herrmann, Felix J. "Seismic data processing with curvelets: a multiscale and nonlinear approach." Society of Exploration Geophysicists, 2007. http://hdl.handle.net/2429/600.

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In this abstract, we present a nonlinear curvelet-based sparsity-promoting formulation of a seismic processing flow, consisting of the following steps: seismic data regularization and the restoration of migration amplitudes. We show that the curvelet's wavefront detection capability and invariance under the migration-demigration operator lead to a formulation that is stable under noise and missing data.
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P, Moghaddam Peyman. "Curvelet-based migration amplitude recovery." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/24421.

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Migration can accurately locate reflectors in the earth but in most cases fails to correctly resolve their amplitude. This might lead to mis-interpretation of the nature of reflector. In this thesis, I introduced a method to accurately recover the amplitude of the seismic reflector. This method relies on a new transform-based recovery that exploits the expression of seismic images by the recently developed curvelet transform. The elements of this transform, called curvelets, are multi-dimensional, multi-scale, and multi-directional. They also remain approximately invariant under the imaging operator. I exploit these properties of the curvelets to introduce a method called Curvelet Match Filtering (CMF) for recovering the seismic amplitude in presence of noise in both migrated image and data. I detail the method and illustrate its performance on synthetic dataset. I also extend CMF formulation to other geophysical applications and present results on multiple removal. In addition of that, I investigate preconditioning of the migration which results to rapid convergence rate of the iterative method using migration.
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Vanelle, Claudia. "Traveltime based true amplitude migration." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964567148.

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Joncour, Frédéric. "Migration profondeur avant sommation en amplitude préservée par extrapolation de forme d'onde." Phd thesis, École Nationale Supérieure des Mines de Paris, 2005. http://pastel.archives-ouvertes.fr/pastel-00001616.

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La migration est une étape clé de la chaîne de traitement des données de sismique réflexion. Intervenant après les phases de pré-traitement, et d'estimation du modèle de vitesse, elle peut servir de base à la caractérisation litho-sismique du réservoir. En effet lorsqu'elle est faîte avant sommation, en profondeur et en amplitude préservée, elle permet d'obtenir les réflectivités du sous-sol en fonction de l'angle d'incidence de l'onde sismique. Une inversion stratigraphique des paramètres élastiques du réservoir est alors possible permettant une caractérisation sismique plus détaillée du réservoir. Jusqu'à présent la migration en amplitude préservée était essentiellement basée sur des techniques de traçé de rayons, qui hélas présentent de réelles limitations pour les milieux géologiques complexes caractérisés par de fortes variations latérales de vitesse. L'utilisation d'approximations n one-way z paraxiales de l'équation d'onde permet de s'affranchir de ces limitations puisque, dans le cadre de la migration profondeur, elles fournissent des solutions précises et robustes pour l'ensemble de la bande de fréquences sismiques. En outre elles prennent en compte naturellement les trajectoires multiples induites par des modèles de vitesse complexes (en particulier dans le cas des structures salifères ). Longtemps pénalisées par leur coût numérique dans les applications 3D ces méthodes peuvent actuellement être appliquées sur données réelles. Elles portent le nom de migration par équation d'onde. Sur le plan de la préservation des amplitudes l'étude de la migration par équation d'onde n'a pas débouché jusqu'à présent sur une formulation aussi aboutie qu'avec l'utilisation de la théorie des raies. Dans ce domaine les efforts doivent porter tant sur la propagation numérique du champs d'onde, que sur la condition d'imagerie. Mon travail de thèse porte sur la définition et le développement numérique d'une méthode de migration par équation d'onde quantitative à 2D. Dans un premier temps, j'ai abordé l'étude de la préservation des amplitudes par l'approximation "one-way" paraxiale de l'équation des ondes. Je me suis familiarisé avec la technique en m'appuyant sur les travaux et les algorithmes développés à l'Institut Français du Pétrole. Dans un second temps, j'ai modifié le principe d'imagerie classique, de façon à constituer des collections migrées en fonction de l'angle de réflexion, et à retrouver l'information sur la dépendance angulaire de la réflectivité ou de la perturbation d'impédance. Cela devrait nous permettre de mieux caractériser le sous-sol dans le cas de milieux complexes ou les analyses classiques (AVO) ne donnent pas de résultats satisfaisants.
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Moghaddam, Peyman P., Felix J. Herrmann, and Christiaan C. Stolk. "Robust seismic amplitude recovery using curvelets." Society of Exploration Geophysicists, 2007. http://hdl.handle.net/2429/564.

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In this paper, we recover the amplitude of a seismic image by approximating the normal (demigrationmigration)operator. In this approximation, we make use of the property that curvelets remain invariant under the action of the normal operator. We propose a seismic amplitude recovery method that employs an eigenvalue like decomposition for the normal operator using curvelets as eigen-vectors. Subsequently, we propose an approximate non-linear singularity-preserving solution to the least-squares seismic imaging problem with sparseness in the curvelet domain and spatial continuity constraints. Our method is tested with a reverse-time ’wave-equation’ migration code simulating the acoustic wave equation on the SEG-AA salt model.
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Thierry, Philippe. "Migration/inversion 3d en profondeur a amplitude preservee : application aux donnees de sismique reflexion avant sommation." Paris 7, 1997. http://www.theses.fr/1997PA077081.

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L'obtention d'images tri-dimensionnelles du sous-sol est actuellement l'un des enjeux les plus importants en sismique petroliere. A l'aide d'ondes emises et propagees dans le sous-sol, et en se basant sur la physique de la propagation, on extrait des informations sur le milieu traverse pour en obtenir une image. Compte tenu des moyens de calculs actuels, on utilise des methodes de resolution qui ne tiennent pas ou tres peu compte de la complexite du milieu. En particulier, elles se basent sur l'hypothese d'une invariance laterale qui n'est pas acceptable dans les cas geologiquement complexes. Il devient alors indispensable d'utiliser un formalisme tri-dimensionnel. Au cours des dernieres annees, des travaux theoriques ont montre qu'il etait possible d'obtenir des images quantitatives en profondeur et avant sommation des donnees, par inversion linearisee au sens de born et avec l'approximation haute frequence (theorie des rais). Le principal but de cette these est donc l'etude et le developpement des aspects theoriques et pratiques d'une methode susceptible : ? de prendre en compte les variations tri-dimensionnelles du milieu ; ? d'utiliser toutes les donnees avant sommation ; ? de quantifier les contrastes d'un parametre physique caracterisant le sous-sol ; ? et de fournir des images 3d en fonction de la profondeur. Jusqu'a tres recemment, ce type de methodes semblait irrealisable avec les moyens de calculs actuels. Bien qu'il existe deja de nombreux algorithmes d'imagerie profondeur, aucun ne donne actuellement d'information quantitative. Nous montrons ici qu'il est en fait possible de developper, avec des ressources informatiques limitees, des algorithmes respectant la geometrie effective de la propagation d'ondes dans le milieu. Deux appplications sur donnees reelles de mer du nord fournies par la compagnie norsk hydro sont presentees pour tester les strategies de programmation et prouver la faisabilite d'une migration 3d en profondeur, a amplitude preservee et avant sommation des donnees (3d papsdm). Ces tests demontrent ainsi clairement que des applications realistes de la methode proposee sont possibles et qu'elles ameliorent grandement les resultats obtenus dans une meme zone avec l'approximation 2d.
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Haris, Abd. "Amplitude-preserving migration and its application to imaging of a BSR in marine multichannel seismic reflection data." [S.l.] : [s.n.], 2002. http://e-diss.uni-kiel.de/diss_671/d671.pdf.

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Haris, Abd [Verfasser]. "Amplitude-preserving migration and its application to imaging of a BSR in marine multichannel seismic reflection data / Abd Haris." Aachen : Shaker, 2003. http://d-nb.info/1172611572/34.

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Neto, Sílvio Beltramelli. "Amplitude das obrigações do empregador frente ao direito à moradia do trabalhador migrante." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/2/2138/tde-13022014-104700/.

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A frequência com que trabalhadores migrantes encontram-se submetidos a condições indignas de moradia despertou o interesse na investigação da existência e da extensão de obrigação jurídica do empregador em relação a seu correspondente direito. Como deixa entrever a jurisprudência a respeito, à exceção das ocasiões em que o empregador expressamente assume obrigação de tal natureza, o problema não encontra resposta normativa enunciada de forma específica. À vista dos direitos fundamentais, normas jurídicas nacionais e internacionais convergem no sentido de que o conteúdo do direito à moradia não se preenche com a simples existência de um abrigo ou alojamento; tem deveras maior alcance e abrange a concepção da moradia adequada. A inserção do direito à moradia do trabalhador migrante no âmbito do contrato de emprego pode suscitar colisão entre aquele direito fundamental e o de proteção à propriedade do empregador. A solução apresentada pretende oferecer uma resposta plausível e fundamentada à indagação central da pesquisa, dentre os possíveis encaminhamentos do problema.
The frequency with which migrant workers are subjected to degrading housing conditions has aroused the interest in investigating the existence and extent of the employer\'s legal obligation in relation to his/her corresponding right. As jurisprudence about it allows us to glimpse, except for occasions where the employer expressly assumes an obligation of such nature, the problem finds no normative response specifically set out. In view of fundamental rights, national and international legal standards converge in the sense that the content of the right to housing is not filled with the mere existence of a shelter; indeed has greater range and covers the conception of a dignifying housing. The insertion of the housing rights of migrant workers under the scope of the labor agreement may raise collision between that fundamental right and that of protecting the employer\'s property. The solution presented aims to provide a plausible answer and reasoned to the research central question, among the possible referrals of the problem.
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Book chapters on the topic "Migration amplitudes"

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Pleshkevich, Alexandr, Anton Ivanov, Vadim Levchenko, and Sergey Khilkov. "Kirchhoff-Type Implementation of Multi-Arrival 3-D Seismic Depth Migration with Amplitudes Preserved." In Communications in Computer and Information Science, 237–48. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-64616-5_21.

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Vanelle, Claudia, and Dirk Gajewski. "True Amplitude Migration Weights from Travel Times." In Seismic Waves in Laterally Inhomogeneous Media, 1583–99. Basel: Birkhäuser Basel, 2002. http://dx.doi.org/10.1007/978-3-0348-8146-3_10.

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"7. True-Amplitude Kirchhoff Migration." In Seismic True-Amplitude Imaging, 189–218. Society of Exploration Geophysicists, 2007. http://dx.doi.org/10.1190/1.9781560801672.ch7.

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"8. Further Aspects of Kirchhoff Migration." In Seismic True-Amplitude Imaging, 219–58. Society of Exploration Geophysicists, 2007. http://dx.doi.org/10.1190/1.9781560801672.ch8.

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"Advances in Fish Tagging and Marking Technology." In Advances in Fish Tagging and Marking Technology, edited by Anne-May Ilestad, T. hrond O. Haugen, and Jonathan E. Colman. American Fisheries Society, 2012. http://dx.doi.org/10.47886/9781934874271.ch18.

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<i>Abstract</i>.—Environmental variables and interspecific interactions influence fishes’ habitat use. The eurythermic and euryhaline European sea bass <i>Dicentrarchus labrax </i>is increasing in Norwegian waters. We compare diel- and seasonal habitat use and home ranges of this species with Atlantic cod <i>Gadus morhua </i>in the Oslo-fjord, Norway. Individual depth and horizontal positions were obtained using acoustic telemetry. Fish were tracked using both portable and stationary receivers. Both species displayed high site fidelity from June to October. In late October, the sea bass migrated out of the core area whereas the cod remained. Cod home ranges (11.4 ± 5.5 ha) were smaller than sea bass home ranges (42.6 ± 26.1 ha) throughout the study. Home range increased with individual body size in sea bass, but not cod. The two species had differential diel- and seasonal depth use. Sea bass used depths shallower than 4 m during June through September, with diel vertical migrations rarely exceeding 2 m. After September, sea bass sought deeper waters; stabilizing at 11 m in November with a diel migration amplitude of 7 m. Cod stayed deeper than the 9–10 m thermocline in August with vertical migration amplitude of 7 m and moved into daytime depths of 6.5 m with diel amplitude of 4.5 m in December. Sea bass actively selected warmer temperatures and the lowest salinities available, whereas cod avoided temperatures higher than 13°C and salinities below 24 ppt. The differential temperature preference for these species is likely the main driver for the differential depth utilization. A model using air temperatures as a predictor was constructed predicting daytime and night-time depth use. This study provides novel insights to the habitat use of the two species under Nordic fjord conditions—information to be included in upcoming management programs emerging due to the continuing northward colonization of sea bass along the Norwegian coast.
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Du, Qizhen, Gang Fang, Xufei Gong, and Mingqiang Zhang. "Wave-Propagation Operators for True-Amplitude Reverse-Time Migration." In Seismic Exploration of Hydrocarbons in Heterogeneous Reservoirs, 253–89. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-420151-4.00007-6.

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Bauer, Raymond T. "Life Cycle and Seasonal Migrations." In Life Histories, 203–31. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190620271.003.0008.

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Seasonal and life cycle migrations are mass movements in which individuals move horizontally for long distances to encounter favorable conditions for reproduction and development. Such migrations have been best studied in larger mobile decapod crustaceans, many of which are commercially important. Some decapod shrimps and brachyuran crabs are dependent on productive estuaries for completion of life cycles. In these species, planktonic larvae develop in oceanic waters. Postlarval stages utilize currents and appropriate behaviors to enter estuaries via selective tidal stream transport (STST). After growth, juveniles and subadults leave for the adult oceanic habitats, again using STST. Many subtropical and temperate zone neritic species make seasonal offshore migrations into deeper waters during the winter, with return nearshore in the spring; some high latitude species make these migrations but with seasons reversed. Numerous freshwater shrimps are amphidromic, that is, they live and reproduce in streams and rivers, but their planktonic larvae drift or are released directly into the sea for development and dispersal. Postlarvae find the mouths of streams, and then make spectacular mass migrations as juveniles back upstream to the adult habitat. Adults of terrestrial crabs live inland, but brooding females move into the littoral zone during new or full moon periods to hatch out larvae into high amplitude tides that carry the larvae out to sea for development and dispersal.
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Wang, Yani, Qingchun Li, and Guangzhou Shao. "The amplitude-preserving converted-wave pre-stack time imaging by Pseudo-Offset Migration." In Advances in Energy Equipment Science and Engineering, 1985–88. CRC Press, 2015. http://dx.doi.org/10.1201/b19126-384.

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van der Kruk, J., R. Streich, and M. Grasmueck. "6. Toward True-Amplitude Vector Migration of GPR Data Using Exact Radiation Patterns." In Advances in Near-surface Seismology and Ground-penetrating Radar, 97–116. Society of Exploration Geophysicists, American Geophysical Union, Environmental and Engineering Geophysical Society, 2010. http://dx.doi.org/10.1190/1.9781560802259.ch6.

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Brenner, H., S. A. Altobelli, A. L. Graham, J. R. Abbott, and L. A. Mondy. "HYDRODYNAMIC PARTICLE MIGRATION IN SMALL-AMPLITUDE, OSCILLATORY, CIRCULAR COUETTE FLOW: THE LIMITS OF REVERSIBILITY." In Theoretical and Applied Rheology, 585–87. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89007-8.50251-3.

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Conference papers on the topic "Migration amplitudes"

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Bloor, R., and G. Brown. "Depth Migration Velocity Models and Amplitudes." In EAGE/SEG Workshop - Depth Imaging of Reservoir Attributes. European Association of Geoscientists & Engineers, 1998. http://dx.doi.org/10.3997/2214-4609.201406684.

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Brink, M., N. Jones, J. Doherty, V. Vinje, and R. Laurain. "Infill decisions using simulated migration amplitudes." In SEG Technical Program Expanded Abstracts 2004. Society of Exploration Geophysicists, 2004. http://dx.doi.org/10.1190/1.1842412.

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R. Verdel, A., and D. W. van der Burg. "Depth Migration of Edge Diffractions by Adaptive Weighting of Migration Operator Amplitudes." In 73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011. Netherlands: EAGE Publications BV, 2011. http://dx.doi.org/10.3997/2214-4609.20149643.

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C. Alves, G., A. Bulco, and D. M. Soares Filho. "Normalized Depth Image Amplitudes from Reverse Time Migration." In 74th EAGE Conference and Exhibition incorporating EUROPEC 2012. Netherlands: EAGE Publications BV, 2012. http://dx.doi.org/10.3997/2214-4609.20148624.

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Kaschwich, Tina, and Joachim Mispel. "Simulated migration amplitudes of converted waves: First results." In SEG Technical Program Expanded Abstracts 2006. Society of Exploration Geophysicists, 2006. http://dx.doi.org/10.1190/1.2370055.

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Haney, Matthew M., Lewis C. Bartel, David F. Aldridge, and Neill P. Symons. "Insight into the output of reverse‐time migration: what do the amplitudes mean?" In SEG Technical Program Expanded Abstracts 2005. Society of Exploration Geophysicists, 2005. http://dx.doi.org/10.1190/1.2148088.

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Kelly, Steve, and Jiaxiang Ren. "Key elements in the recovery of relative amplitudes for pre‐stack, shot record migration." In SEG Technical Program Expanded Abstracts 2003. Society of Exploration Geophysicists, 2003. http://dx.doi.org/10.1190/1.1817469.

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Lester*, Ryan, Eric Liebes, Ross Hill, Steve Jenkins, and Andrey Makedonov. "Investigating mega-amplitudes in Tengiz carbonates through interactive model-building and Gaussian beam migration." In SEG Technical Program Expanded Abstracts 2015. Society of Exploration Geophysicists, 2015. http://dx.doi.org/10.1190/segam2015-5816162.1.

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Alde, Douglas M., Michael C. Fehler, Steven T. Hildebrand, Lianjie Huang, and Hongchuan Sun. "Comparison of Images of the Marmousi model for ray‐tracing based Kirchhoff migration using single‐ and multiple‐valued travel‐times, amplitudes, and KMAH phases." In SEG Technical Program Expanded Abstracts 2003. Society of Exploration Geophysicists, 2003. http://dx.doi.org/10.1190/1.1817656.

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Yao, Jianfeng, Xiang Li, Kai Zhao, and Hui Zhang. "Full-Waveform Inversion and Least-Squares Migration to Improve Images in Northern Carnarvon Basin." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21292-ms.

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Abstract Northern Carnarvon Basin is located in North West Shelf of Western Australia. The basin has over 10km sediments and owns both oil-prone and gas-prone sediments and is the current largest oil and gas producing basin in Australia. A geological section through this basin is shown in Figure 1, the complex geological settings from shallow to deep leads to significant processing challenges. In the vintage processing, the seismic image at reservoir level is deteriorated due to the presence of following geological complexities: 1) rugose water bottom, 2) shallow frequent canyons or channel systems, 3) shallow spatial-variant Tertiary carbonates, and 4) shallow gas chimneys and other geo-bodies. These complex overburdens plus limited small-angle coverage of primary reflections from narrow azimuth (NAZ) streamer surveys make it very difficult for ray-based reflection tomography to resolve the shallow velocity. As a result, the target image suffers from large well mis-ties, low signal-to-noise ratio (S/N) and severe event undulations. In addition, shallow fast-velocity layers cause severe illumination issues for deep targets which are compounded by limited offsets of NAZ surveys. Furthermore, localised absorption effects from gas pockets lead to dimming amplitudes for events beneath them. To deal with these issues, we propose to use time-lag full wave-form inversion (TLFWI) to resolve the velocity of complex overburdens and least-squares Q prestack depth migration (LS Q-PSDM) to compensate for illumination issues and absorption effects for the latest reprocessing. In the following sections, application procedure and results of these two technologies will be discussed. Seismic inversion was also conducted to assist the processing and analysis of the final result.
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Reports on the topic "Migration amplitudes"

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Milkereit, B., C. Spencer, and L. J. Mayrand. Migration and amplitude analysis of deep seismic reflection data: processing results of CCSS data sets II and III. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1990. http://dx.doi.org/10.4095/129023.

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