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1
Moghaddam, Peyman P., Felix J. Herrmann, and Christiaan C. Stolk. "Seismic Amplitude Recovery with Curvelets." European Association of Geoscientists & Engineers, 2007. http://hdl.handle.net/2429/543.
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A non-linear singularity-preserving solution to the least-squares seismic imaging problem with
sparseness and continuity constraints is proposed. The applied formalism explores curvelets as
a directional frame that, by their sparsity on the image, and their invariance under the imaging
operators, allows for a stable recovery of the amplitudes. Our method is based on the estimation
of the normal operator in the form of an ’eigenvalue’ decomposition with curvelets as the
’eigenvectors’. Subsequently, we propose an inversion method that derives from estimation
of the normal operator and is formulated as a convex optimization problem. Sparsity in the
curvelet domain as well as continuity along the reflectors in the image domain are promoted as
part of this optimization. Our method is tested with a reverse-time ’wave-equation’ migration
code simulating the acoustic wave equation.
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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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Tsang, Hing-ho. "Probabilistic seismic hazard assessment direct amplitude-based approach /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36783456.
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Tsang, Hing-ho, and 曾慶豪. "Probabilistic seismic hazard assessment: direct amplitude-based approach." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36783456.
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The Best PhD Thesis in the Faculties of Dentistry, Engineering, Medicine and Science (University of Hong Kong), Li Ka Shing Prize, 2005-2006.published_or_final_version
abstract
Civil Engineering
Doctoral
Doctor of Philosophy
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Wang, Yanghua. "Co-operative inversion of seismic traveltime and amplitude data." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267299.
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PAMPANELLI, PATRICIA CORDEIRO PEREIRA. "SEISMIC AMPLITUDE SMOOTHING BY ANISOTROPIC DIFFUSION PRESERVING STRUCTURAL FEATURES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25824@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A interpretação sísmica consiste em um conjunto de metodologias que visam compreender o modelo estrutural e estratigráfico de uma determinada região. Durante este processo, o intérprete analisa a imagem sísmica buscando identificar estruturas geológicas como falhas, horizontes e canais, dentre outras. Dada a baixa razão sinal-ruído, os algoritmos que dão suporte à interpretação precisam de uma etapa de pré-processamento onde o ruído é reduzido. Esta tese propõe um novo método de filtragem por difusão anisotrópica que melhor preserva as feições sísmicas de interesse. A formulação do processo de difusão permite que os atributos identificadores de horizontes e de falhas sejam incorporados ao método a fim de evitar que estas estruturas sejam corrompidas durante a difusão da amplitude sísmica. O método proposto implementado apresenta resultados aplicados a dados reais disponíveis na literatura. Para estes resultados, é apresentada uma análise da influência do método de filtragem anisotrópica proposta nas medidas de correlação ao longo de horizontes previamente rastreados. Finalmente, a tese apresenta algumas conclusões e sugestões para trabalhos futuros.
Seismic interpretation can be viewed as a set of methodologies to enhance the understanding of the structural and stratigraphic model of a given region. During this process, the interpreter analyzes the seismic imaging seeking to identify geological structures such as faults, horizons and channels, among others. Given the low signal to noise ratio, the algorithms that support the interpretation require a pre-processing stage where the noise is reduced. This thesis proposes a new filtering method based on the anisotropic diffusion of the amplitude field. The formulation of the diffusion process proposed here uses seismic attributes to identify horizons and faults that are preserved in the diffusion process. The proposed method implemented in this thesis also presents results applied to real and synthetic data. Based on these results, we present an analysis of the influence of the proposed method in correlation measurements over horizons previously tracked. Finally the thesis presents some conclusions and suggestions for future work.
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Herrmann, Felix J., Peyman P. Moghaddam, and Christiaan C. Stolk. "Just diagonalize: a curvelet-based approach to seismic amplitude recovery." European Association of Geoscientists & Engineers, 2007. http://hdl.handle.net/2429/523.
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Herrmann, Felix J., Gilles Hennenfent, and Peyman P. Moghaddam. "Seismic imaging and processing with curvelets." European Association of Geoscientists & Engineers, 2007. http://hdl.handle.net/2429/552.
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In this paper, we present a nonlinear curvelet-based sparsity-promoting formulation for
three problems in seismic processing and imaging namely, seismic data regularization
from data with large percentages of traces missing; seismic amplitude recovery for subsalt
images obtained by reverse-time migration and primary-multiple separation, given
an inaccurate multiple prediction. We argue why these nonlinear formulations are beneficial.
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Pila, Matheus Fabiano 1979. "A redatumação de Kirchhoff de empilhamento único em amplitude verdadeira." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307297.
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Orientadores: Joerg Dietrich Wilhelm Schleicher, Maria Amelia Novais SchleicherTese (doutorado - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica
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Resumo: Entende-se por datum a superfície onde estão posicionados os pares fonte-receptor usados na aquisição sísmica. Este datum pode ser plano ou irregular e sua profundidade pode variar. O objetivo da redatumação é transformar o dado sísmico adquirido na superfície original em um dado simulado adquirido em outra superfície. Obtém-se assim um novo dado, como se tivesse sido adquirido em uma superfície de geometria e profundidade diferentes. A vantagem deste processo seria eliminar a propagação indesejada da onda sísmica em camadas com forte variação na velocidade. A transformação correta das amplitudes, do dado na superfície original para os dados no novo datum, é de importância fundamental. Um dado com esta propriedade poderia ser usado em diversos processos que necessitam de um dado com amplitude verdadeira, possibilitando melhor caracterização de possíveis reservatórios, por exemplo. Um destes processos seria a migração Kirchhoff em amplitude verdadeira. Na literatura, existem trabalhos que discutem e comprovam que uma transformação de configuração em amplitude verdadeira pode ser obtida encadeando os processos de migração e demigração com funções peso. Nesta tese, nós estendemos este resultado e derivamos um operador de redatumação em amplitude verdadeira, ao considerar que neste encadeamento podemos também mudar a profundidade dos pares fonte-receptor, tanto no dado sísmico de entrada quanto no simulado de saída. Processos Kirchhoff como este dependem de um bom modelo de velocidades para poder calcular as correções de tempo de trânsito de cada traço. Ao longo deste trabalho, foi possível verificar como a cinemática da redatumação independe da velocidade abaixo do novo datum. Esta velocidade afeta apenas a função peso que corrige as amplitudes. No entanto, após alguns testes foi possível verificar que pequenas incertezas inseridas nesta variável produzem pouco erro relativo na amplitude final
Abstract: The surface where the source-receiver pairs used in the seismic aquisition are positioned is called a datum. This datum can be flat or irregular and the depth may vary. The main goal of redatuming is to transform the seismic data acquired on the original surface into simulated data as if acquired on another datum. The advantage of this process is that it can eliminate undesired seismic wave propagation in layers with strong velocity variation or strong topography. The correct amplitude transformation, from the original surface data to the new datum, is of fundamental importance if the data are to be used in subsequent true-amplitude processes that allow better characterization of potential reservoirs, for example. One of these processes is the true-amplitude migration. In the literature, there are studies that argue and prove that a true-amplitude configuration transform can be obtained by chaining the weighted migration and demigration integral operators. In this thesis, we extend this result and derive a true-amplitude redatuming operator. For this purpuse, we consider that in this chaining procedure, we can also change the depth of the source-receiver pairs, either in the input or simulated output configuration. Kirchhoff processes like this one depend on a good velocity model in order to calculate traveltime corrections for each trace. Throughout this work, we demonstrated that the kinematics of redatuming is independent of the velocity below the new datum. This velocity affects only the weight function that corrects the amplitudes. However, our numerical tests indicated that small uncertainties inserted in this variable resulted in little relative error in the final amplitude
Doutorado
Matematica Aplicada
Doutor em Matemática Aplicada
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Mills, Stephanie Maria. "The effect of grout and casing on amplitude measurements for borehole seismic testing." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/20194.
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Linkimer, Lepolt. "Discrimination between earthquakes and chemical explosions in Eastern Russia using amplitude ratios obtained from analog records." Diss., Connect to online resource - MSU authorized users, 2006.
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Varela, Gutierrez Isabel. "Fracture studies from amplitude versus offset and azimuth and vertical seismic profile data." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4080.
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In this thesis I address the problem of determining fracture properties of subsurface rocks from geophysical surface seismic and vertical seismic profile (VSP) data. In the first part of this thesis I perform multi-attribute analysis, including frequency content, amplitude, travel time and angle of rotation studies on field VSP data from two different carbonate fields, both containing time-lapse surveys. I compare the findings to independent data available in the region and find that the interpreted fracture orientations from the attribute analyses correlate with independent fracture studies in the area, the principal axis of major faults, or the maximum horizontal stress of the area studied. Although I show the existence of these correlations, due to the limited knowledge of the rock properties, these correlations are only qualitative. A more robust inversion of fracture properties requires more knowledge of the physical properties of the medium and forward modelling of the seismic response. A rock physics theory would be required to model the elastic response of the fractured rock; hence a more quantitative fracture characterisation is necessary. In the second part of this thesis I address this need by developing and testing a method for fracture density inversion. Linearised approximations are commonly used in azimuthal amplitude versus offset (AVO) analysis. However, these approximations perform poorly at large angles of incidence where the effect of fractures is more significant. The method proposed here uses a model based approach that does not use these approximations but calculates the exact azimuthal AVO response based on prior knowledge of the elastic constants of the medium, assumed to be known, and a range of fracture densities. A rock physics theory is used for modelling the elastic constants of the fractured rock. I then create a linearized relationship for a specific model that separates the effect due to fracture density from the modelled AVOZ responses. This separation is key to the method, as it provides both a new set of orthogonal basis functions that can be used to express the AVOZ response of field data, and a set of coefficients that are related to fracture density. In general, the inversion is based on these coefficients. The coefficient or coefficients which present the highest correlation with fracture density must be determined on a case by case basis, as they will vary depending on the contrast between the elastic constants across the boundary of interest. I develop and test the method on synthetic surface seismic data and then apply it to seismic data acquired from a laboratory-scale physical geological model. Due to the prior knowledge of the rock properties and structure of the physical geological model, I am able to corroborate that the inverted fracture density from the seismic data matches that of the physical model within the error. I compare the inversion for two different levels of uncertainty in the velocities and densities of the modelled reflection coefficients and show that the inversion results are more precise and accurate when there is less uncertainty in the rock properties of the modelled reflection coefficients. In both the synthetic and physical geological model studies I find that the inversion is optimal for a certain range of offsets/angles of incidence. This means that the optimal range for inversion must be found on a case by case basis, as it depends on the behaviour of the data. Finally, as the inversion relies on the input modelled azimuthal AVO curves, a careful choice of the input rock properties is essential for the inversion process. The inverted fracture density values will only be valid if the rock properties of the field data fall within the range of the modelled ones. This is a limitation of the method, as adequate knowledge of the rock properties is not always available.
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Hennenfent, Gilles, and Felix J. Herrmann. "Application of stable signal recovery to seismic interpolation." Society of Exploration Geophysicists, 2006. http://hdl.handle.net/2429/529.
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We propose a method for seismic data interpolation based on 1) the reformulation of the problem as a stable signal recovery problem and 2) the fact that seismic data is sparsely represented by curvelets. This method does not require information on the seismic velocities. Most importantly, this formulation potentially leads to an explicit recovery condition. We also propose a large-scale problem solver for the l1-regularization minimization involved in the recovery and successfully illustrate the performance of our algorithm on 2D synthetic and real examples.
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Nugent, Andrew Thomas. "USE OF SEISMIC REFRACTION TO DELINEATE AND CHARACTERIZE FRACTURES IN CARBONATE BEDROCK AND GLACIAL OVERBURDEN OF NORTHWEST OHIO." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1147205868.
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Al, Mazro'ey Mohamed Ahmed Salim. "Fluid characterisation using 4-D seismic amplitude and choherence anaylsis : application to Oseberg gas/oil field." Thesis, Imperial College London, 2003. http://hdl.handle.net/10044/1/8416.
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Nguyen, Thanh Tung. "Amplitude and AVO properties of seismic reflections from boundaries with small scale topography : a modelling study." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435809.
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Zeiler, Cleat Philip. "Improving nuclear explosion detection using seismic and geomorphic data sets." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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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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Ohl, Derek Robert. "Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates fields, Sumner County, Kansas, USA." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13637.
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Master of ScienceDepartment of Geology
Abdelmoneam Raef
Amid increasing interest in geological sequestration of carbon dioxide (CO2), detailed rock formation characterization has emerged as priority to ensure successful sequestration. Utilizing recent advances in the field of 3D seismic attributes analysis, offers improved opportunities to provide more details when characterizing reservoir formations. In this study, several post-stack seismic attributes integrated with seismic modeling for highlighting critical structural elements and petrophysical facies variation of rock formations at Wellington and Anson-Bates fields, Sumner County, Kansas. A newly acquired 3D Seismic data set and several geophysical well logs are also used to achieve the objectives of this study. Results sought in this study are potentially important for understanding pathways for CO2 to migrate along. Seismic amplitude, coherency, and most negative curvature attributes were used to characterize the subsurface for structural effects on the rock formations of interest. These attributes detect multiple anomaly features that can be interpreted as small throw faults. However, in this study, there is a larger anomalous feature associated with the Mississippian formation that can be interpreted as a small throw fault or incised channel sand. Determining which of the two is very important for flow simulation models to be more exact. Modeling of the seismic was undertaken to help in the interpretation of the Mississippian amplitude anomaly. An artificial neural network, based on well log porosity cross-plots and three seismic attributes, was trained and implemented to yield a seismic petrophysical facies map. The neural network was trained using three volume seismic waveform attributes along with three wells with difference in well log porosity. A reworked lithofacies along small throw faults has been revealed based on comparing the seismic structural attributes and the seismic petrophysical facies. Arbuckle formation characterization was successful to a certain degree. Structural attributes showed multiple faults in the northern half of the survey. These faults are in agreement with known structure in the area associated with the Nemaha uplift. Further characterization of the Arbuckle was hindered by the lack of well data. This study emphasizes the need for greater attention to small-scale features when embarking upon characterization of a reservoir for CO2 based geosequestration.
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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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Murchek, Jacob T. "Pre-Stack Seismic Inversion and Amplitude Variation with Offset (AVO) Attributes as Hydrocarbon Indicators in Carbonate Rocks: A Case Study from the Illinois Basin." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1620214269732212.
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Bokhonok, Oleg. "Sísmica de reflexão rasa multicomponente: Aquisição e inversão de tempos de trânsito e amplitudes." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-06062018-155544/.
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Neste trabalho avaliou-se a potencialidade do uso da sísmica rasa de reflexão multicomponente para investigação geológica-geotécnica. Foram abordados vários aspectos relacionados à aquisição dos dados sísmicos de reflexão multicomponente, com o objetivo de entender as vantagens e limitações do método para aplicação em investigações de subsuperfície rasa. Os ensaios de campo foram realizados em duas áreas, ambas em terrenos da Bacia Sedimentar de São Paulo, em área urbana da cidade de São Paulo. Para a interpretação dos dados sísmicos multicomponente foram investigados procedimentos para a inversão não-linear dos tempos de trânsito e das amplitudes. O testes realizados orientaram a escolha da aproximação não-hiperbólica mais apropriada para calculo dos tempos de trânsito visando à análise de velocidades do pacote acima do refletor. O estudo numérico desenvolvido para a inversão das amplitudes mostrou a viabilidade da estimativa das velocidades e densidades, acima e abaixo do refletor, empregando-se as equações de Zoeppritz para as ondas refletidas PP, PSv, SvP e SvSv, antes e depois do ângulo crítico. Dada a complexidade da inversão nao-linear das amplitudes, se fez necessário elaborar uma estratégia estocástica de otimização e desenvolver uma nova abordagem para análise da função objetivo multi-dimensional, garantindo confiabilidade ao resultado da inversão não-linear. Os resultados deste trabalho mostraram o potencial da sísmica de reflexão rasa multicomponente para caracterização geológica-geotécnica, possibilitando um melhor entendimento das camadas superficiais.This thesis aims to evaluate the useful of the multicomponent seismic methods for shallow investigations, mainly its potential for the geotechnical and geological characterization of the nearsurface. Several aspects regarding the acquisition and processing data of multicomponent seismic data are discussed. They were based on data set acquired in the urban area of Sao Paulo city, Brazil. Two different areas were investigated. Both located in sedimentary terrains belonging to the Sao Paulo Sedimentary Basin. We present a non-linear travel time and seismic amplitude inversion scheme to quantitative interpretation of multicomponent seismic data. Several tests were performed to guide the choice of non-hyperbolic equation more suitable for travel time inversion aiming the velocity analysis above the reflector. A numerical experiment developed to solve the nonlinear inversion of seismic amplitudes showed the feasibility to estimate seismic interval velocities and layer densities above and below the reflector using the exact Zoeppritz equations for PP, PSv, SvP e SvSv reflected waves, before and after critical angle. Due to the apparent complexity of the nonlinear seismic amplitude inversion, it was necessary elaborate the strategy for stochastic optimization and develop a new approach to analyze the multi-dimensional objective function, with different implications for the accuracy and efficiency of the non-linear inversion. The study show the benefits of using the multicomponent seismic method for shallow geological-geotechnical characterization, improving the nearsurface understanding, once allows an integrated analyzes of a more complete record of the wave field.
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Santiago, Tania Maria Godinho. "Migração Kirchhoff 2,5D em tempo no dominio de angulo comum e em amplitude verdadeira." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/262965.
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Orientador: Martin TygelDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias
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Resumo: Atualmente, a indústria do petróleo, tanto na área de caracterização de reservatórios quanto na de exploração, tem feito cada vez mais uso do estudo da variação da amplitude sísmica com o afastamento fonte-receptor, ou com o ângulo de reflexão, como ferramenta auxiliar na previsão da existência de hidrocarbonetos nos reservatórios. Como o método, rotineiramente utilizado, de transformação de afastamento para ângulo de reflexão, em dados migrados na configuração afastamento comum, envolve erros que podem diminuir a confiabilidade deste estudo, toma-se necessário uma nova maneira para a obtenção de dados que produzam curvas mais acuradas da variação da amplitude com o ângulo de reflexão (AVA). Neste sentido, apresenta-se nesta dissertação a migração Kirchhoff no domínio de ângulo comum 2,5D por empilhamento em tempo e em amplitude verdadeira, e os resultados de sua aplicação em dados sísmicos sintéticos de três modelos geológicos. Discute-se a influência, nos resultados, dos parâmetros de aquisição dos dados sísmicos e a parametrização da migração, especificamente a abertura e intervalo entre os ângulos de mergulho da migração. São feitas comparações das curvas de amplitude versus o ângulo de reflexão oriundas dos conjuntos de dados migrados no domínio de ângulo comum e no domínio de afastamento comum, e mostra-se a maior eficiência da primeira migração em obter curvas de AVA que se aproximam mais das curvas teóricas
Abstract: The analysis of amplitude variation with offset or reflection angle is of great importance in the oil industry to predict hydrocarbon presence in the reservoir. This analysis is applied to both reservoir and exploration areas. The usual transformation method from offset to reflection angle, for common-offset migrated data, involves errors that may produce unreliable results. Thus, it becomes necessary to find altemative procedures to obtain appropriate data to provide more reliable curves of amplitude versus reflection angle (AVA). This work considers 2.5D true amplitude Kirchhoff-time migration in the common-angle domain, and its application to synthetic seismic data. It also examines the influence of seismic acquisition and migration parameters, aperture and migration dip-angle increment, on the migration results. Comparison between AVA curves obtained from common-angle and common-offset migrated data confirms that the former is a more reliable procedure
Mestrado
Mestre em Ciências e Engenharia de Petróleo
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Gafeira, Gonçalves Joana. "Submarine mass movement processes on the North Sea Fan as interpreted from the 3D seismic data." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4714.
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This research has been focused on the characterisation and analysis of the deposits of large-scale mass movement events that shaped the North Sea Fan since the Mid-Pleistocene. Located at the mouth of the cross-shelf trough Norwegian Channel, the North Sea Fan is one of the largest through-mouth fans in the glaciated european margin with an area of approximately 142,000 km2. Submarine mass movement processed have occurred intermittenrly throughout the Quarternary history of the North Sea Fan, related to recurrent climate-related episodes of growth and retreat of the ice sheets. These processes can transport large amounts of sediment from the upper shelf up to the abyssal basins, playing an important role on the evolution of continental margins and can also reporesnet major geological hazards. This thesis uses mainly 3D seismic data to investigate the external geometry and internal structure of large-scale mass movement deposits. The high spatial resolution provided by the 3D seismic data has allowed a detailed geomorpholocial analysis of these deposits, This study involved the interpretation of the seismic data and the detailed pickling of key reflectors followed by tge extraction of both horizon and window-based seismic attributes. Digital elevation models of the key reflectors and their seismic attribute maps were then transferred to a geographical information system (GIS) where they were interactively interpreted using spatial analysis tools and the full visualisation potential of the software. The outcomes of this study highlight the importance of detailed horizon pickling and interactice interpretation followed by spatial analysis and visualisation in GIS environment. The identification of acoustic patterns within deposits that are normally described from 2D seismic as chaotic or acoustically transparent emphasizes the potential of detailed analysis of 3D seismic data. It gives an example of how this type of data can provide new insights into the mechanisms and processes associated with mass movements. In particular, amplitude and RMS amplitude maps provide remarkable detailed information of internal deformation structures whereas slope, shaded-relief and thickness maps allowed detailed characterisation of the external geometry. Various types of kinematic indicators can be recognized within the mass movement deposits through combined seismic analysis and detaield morphological mapping.
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Syed, Riaz. "Development of Computational Tools for Characterization, Evaluation, and Modification of Strong Ground Motions within a Performance-Based Seismic Design Framework." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/36435.
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One of the most difficult tasks towards designing earthquake resistant structures is the determination of critical earthquakes. Conceptually, these are the ground motions that would induce the critical response in the structures being designed. The quantification of this concept, however, is not easy. Unlike the linear response of a structure, which can often be obtained by using a single spectrally modified ground acceleration history, the nonlinear response is strongly dependent on the phasing of ground motion and the detailed shape of its spectrum. This necessitates the use of a suite (bin) of ground acceleration histories having phasing and spectral shapes appropriate for the characteristics of the earthquake source, wave propagation path, and site conditions that control the design spectrum. Further, these suites of records may have to be scaled to match the design spectrum over a period range of interest, rotated into strike-normal and strike-parallel directions for near-fault effects, and modified for local site conditions before they can be input into time-domain nonlinear analysis of structures. The generation of these acceleration histories is cumbersome and daunting. This is especially so due to the sheer magnitude of the data processing involved.
The purpose of this thesis is the development and documentation of PC-based computational tools (hereinafter called EQTools) to provide a rapid and consistent means towards systematic assembly of representative strong ground motions and their characterization, evaluation, and modification within a performance-based seismic design framework. The application is graphics-intensive and every effort has been made to make it as user-friendly as possible. The application seeks to provide processed data which will help the user address the problem of determination of the critical earthquakes. The various computational tools developed in EQTools facilitate the identification of severity and damage potential of more than 700 components of recorded earthquake ground motions. The application also includes computational tools to estimate the ground motion parameters for different geographical and tectonic environments, and perform one-dimensional linear/nonlinear site response analysis as a means to predict ground surface motions at sites where soft soils overlay the bedrock.
While EQTools may be used for professional practice or academic research, the fundamental purpose behind the development of the software is to make available a classroom/laboratory tool that provides a visual basis for learning the principles behind the selection of ground motion histories and their scaling/modification for input into time domain nonlinear (or linear) analysis of structures. EQTools, in association with NONLIN, a Microsoft Windows based application for the dynamic analysis of single- and multi-degree-of-freedom structural systems (Charney, 2003), may be used for learning the concepts of earthquake engineering, particularly as related to structural dynamics, damping, ductility, and energy dissipation.Master of Science
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Lumley, David Edward. "A generalized Kirchhoff-WKBJ depth migration theory for multi-offset seismic reflection data : reflectivity model construction by wavefield imaging and amplitude estimation." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27588.
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This thesis embodies a mathematical, physical, and quantitative investigation into the imaging and amplitude estimation of subsurface earth reflectivity structure within the framework of pre stack wave-equation depth migration of multi-offset seismic reflection data.
Analysis is performed on five prestack depth migration reflectivity "imaging conditions" with respect to image quality and quantitative accuracy of recovered reflectivity amplitudes. A new computationally efficient and stable prestack depth migration imaging method is proposed which is based upon a geometric approximation to the theoretically correct, but unstable, "dynamic" imaging condition. The "geometric" imaging condition has the desirable property of true-amplitude reflectivity recovery in regions of both 1-D and 2-D velocity variation, while fully retaining and optimizing the favorable imaging characteristics of current, non-true amplitude formulations. The currently predominant "crosscorrelation" and "excitation-time" migration imaging methods are shown to possess significantly less accurate imaging and amplitude-recovery characteristics relative to the proposed geometric migration. The respective signal-to-noise recovery of their imaged amplitudes deteriorates approximately linearly (excitation-time) and quadratically (crosscorrelation) with depth.
As a necessary prerequisite to the imaging analysis, a true-amplitude prestack depth migration equation is derived which appears to be new to the literature. This result is obtained in the form of a 2.5-D farfield Kirchhoff integral solution to the acoustic wave equation, after the application of a dynamic imaging condition to the reconstructed upgoing and downgoing wavefields. This solution is in harmony with zeroth order asymptotic ray theory (ART) assumptions, and depends upon WKBJ Green's functions which can be numerically evaluated for arbitrary migration models by raytracing methods.
A new and "generalized" Kirchhoff prestack depth migration equation is subsequently obtained by the introduction of a weighting function into the true-amplitude migration integral. The weight is a function of both the reconstructed upgoing and downgoing wavefields, and is determined analytically by a mathematical application of each specific reflectivity imaging condition. This generalized equation is significant in that it provides a common mathematical, physical and computational basis for the comparative analytical and quantitative analysis of reflectivity image quality and amplitude recovery among current prestack migration philosophies and variants of those migration themes.
In addition, three ancillary research objectives are achieved. The first achievement is the development of a Kirchhoff prestack depth migration computer algorithm to implement the generalized imaging of surface-recorded seismic reflection data. This algorithm can be readily modified to perform seismic wavefield imaging for other recording geometries such as cross-borehole or vertical seismic profiling, and may be suitable to non-seismic applications such as the imaging of electromagnetic wavefields and satellite-acquired synthetic aperture radar data. The second result is the development of a fast two-point raytracing computer algorithm which provides accurate computation of a subsurface grid of traveltimes and 1.5-D zeroth order ART amplitudes in a 1-D acoustic medium. This algorithm is useful for subsurface wavefield reconstruction and imaging, and for inversion applications such as geotomography. The third objective is the detailed quantitative examination of migration imaging quality and true relative-amplitude normal-incidence reflectivity recovery from numerically migrated depth images. This is achieved successfully in an extensive 2.5-D synthetic data analysis, using a challenging 2-D structural model, synthetic multifold reflection seismogram shot gathers, and the numerical imaging and modelling algorithms developed as part of this thesis research.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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ONeal, Ryan J. "Seismic and Well Log Attribute Analysis of the Jurassic Entrada/Curtis Interval Within the North Hill Creek 3D Seismic Survey, Uinta Basin, Utah, A Case History." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1025.
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3D seismic attribute analysis of the Jurassic Entrada/Curtis interval within the North Hill Creek (NHC) survey has been useful in delineating reservoir quality eolian-influenced dune complexes. Amplitude, average reflection strength and spectral decomposition appear to be most useful in locating reservoir quality dune complexes, outlining their geometry and possibly displaying lateral changes in thickness. Cross sectional views displaying toplap features likely indicate an unconformity between Entrada clinoforms below and Curtis planar beds above. This relationship may aid the explorationist in discovering this important seismic interval. Seismic and well log attribute values were cross plotted and have revealed associations between these data. Cross plots are accompanied by regression lines and R2 values which support our interpretations. Although reservoir quality dune complexes may be delineated, the Entrada/Curtis play appears to be mainly structural. The best producing wells in the survey are associated with structural or stratigraphic relief and the thickest Entrada/Curtis intervals. Structural and stratigraphic traps are not always associated with laterally extensive dune complexes. Time structure maps as well as isochron maps have proven useful in delineating the thickest and/or gas prone portions of the Entrada/Curtis interval as well as areas with structural and stratigraphic relief. We have observed that the zones of best production are associated with low gamma ray (40-60 API) values. These low values are associated with zones of high amplitude. Thus, max peak amplitude as a seismic attribute may delineate areas of higher sand content (i.e. dune complexes) whereas zones of low amplitude may represent areas of lower sand content (i.e. muddier interdune or tidal flat facies). Lack of significant average porosity does not seem to be related to a lack of production. In fact, the best producing wells have been drilled in Entrada/Curtis intervals where average porosity is near 4 %. There are however zones within the upper portion of the Entrada/Curtis that are 40 ft. (12.2 m) thick and have porosities between 14% and 20%. By combining derived attribute maps with observed cross plot relationships, it appears that the best producing intervals within the Entrada/Curtis are those associated with high amplitudes, API values from 40-60 and structural relief.
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Butterfield, Andrei. "Characterization of a Utica Shale Reflector Package Using Well Log Data and Amplitude Variation with Offset Analysis." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401462908.
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Hennenfent, Gilles, and Felix J. Herrmann. "Sparseness-constrained data continuation with frames: Applications to missing traces and aliased signals in 2/3-D." Society of Exploration Geophysicists, 2005. http://hdl.handle.net/2429/524.
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We present a robust iterative sparseness-constrained interpolation algorithm using 2/3D curvelet frames and Fourier-like transforms that exploits continuity along reflectors in seismic data. By choosing generic transforms, we circumvent the necessity to make parametric assumptions (e.g. through linear/parabolic Radon or demigration) regarding the shape of events in seismic data. Simulation and real data examples for data with moderately sized gaps demonstrate that our algorithm provides interpolated traces that accurately reproduce the wavelet shape as well as the AVO behavior. Our method also shows good results for de-aliasing judged by the behavior of the (f-k)-spectrum before and after regularization.
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Krehel, Austin. "Investigation of time-lapse 4D seismic tuning and spectral responses to CO₂-EOR for enhanced characterization and monitoring of a thin carbonate reservoir." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34628.
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Master of ScienceDepartment of Geology
Abdelmoneam Raef
Advancements, applications, and success of time-lapse (4D) seismic monitoring of carbonate reservoirs is limited by these systems’ inherent heterogeneity and low compressibility relative to siliciclastic systems. To contribute to the advancement of 4D seismic monitoring in carbonates, an investigation of amplitude envelope across frequency sub-bands was conducted on a high-resolution 4D seismic data set acquired in fine temporal intervals between a baseline and eight monitor surveys to track CO₂-EOR from 2003-2005 in the Hall-Gurney Field, Kansas. The shallow (approximately 900 m) Plattsburg ‘C Zone’ target reservoir is an oomoldic limestone within the Lansing-Kansas City (LKC) supergroup – deposited as a sequence of high-frequency, stacked cyclothems. The LKC reservoir fluctuates around thin-bed thickness within the well pattern region and is susceptible to amplitude tuning effects, in which CO₂ replacement of initial reservoir fluid generates a complex tuning phenomena with reduction and brightening of amplitude at reservoir thickness above and below thin-bed thickness, respectively. A thorough analysis of horizon snapping criteria and parameters was conducted to understand the sensitivity of these autonomous operations and produce a robust horizon tracking workflow to extend the Baseline Survey horizon data to subsequent Monitor Surveys. This 4D seismic horizon tracking workflow expedited the horizon tracking process across monitor surveys, while following a quantitative, repeatable approach in tracking the LKC and maintaining geologic integrity despite low signal-to-noise ratio (SNR) data and misties between surveys. Analysis of amplitude envelope data across frequency sub-bands (30-80 Hz) following spectral decomposition identified geometric features of multiple LKC shoal bodies at the reservoir interval. In corroboration with prior geologic interpretation, shoal boundaries, zones of overlap between stacked shoals, thickness variation, and lateral changes in lithofacies were delineated in the Baseline Survey, which enhanced detail of these features’ extent beyond capacity offered from well log data. Lineaments dominated by low-frequency anomalies within regions of adjacent shoals’ boundaries suggest thicker zones of potential shoal overlap. Analysis of frequency band-to-band analysis reveals relative thickness variation. Spectral decomposition of the amplitude envelope was analyzed between the Baseline and Monitor Surveys to identify spectral and tuning changes to monitor CO₂ migration. Ambiguity of CO₂ effects on tuning phenomena was observed in zones of known CO₂ fluid replacement. A series of lineaments highlighted by amplitude brightening from the Baseline to Monitor Surveys is observed, which compete with a more spatially extensive effect of subtle amplitude dimming. These lineaments are suggestive of features below tuning thickness, such as stratigraphic structures of shoals, fractures, and/or thin shoal edges, which are highlighted by an increased apparent thickness and onset of tuning from CO₂. Detailed analysis of these 4D seismic data across frequency sub-bands provide enhanced interpretation of shoal geometry, position, and overlap; identification of lateral changes in lithofacies suggestive of barriers and conduits; insight into relative thickness variation; and the ability of CO₂ tuning ambiguity to highlight zones below tuning thickness and improve reservoir characterization. These results suggest improved efficiency of CO₂ -EOR reservoir surveillance in carbonates, with implications to ensure optimal field planning and flood performance for analogous targets.
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Yang, Can. "Time-lapse Analysis of Borehole and Surface Seismic Data, and Reservoir Characterization of the Ketzin CO2 Storage Site, Germany." Doctoral thesis, Uppsala universitet, Geofysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-163013.
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The CO2SINK (and CO2MAN) project is the first onshore CO2 storage project in Europe. The research site is located near the town of Ketzin, close to Potsdam in Germany. Injection started in June 2008, with a planned injection target of 100,000 tonnes of CO2. In February 2011, around 45, 000 tons of CO2 had been injected into the saline aquifer at an approximate depth of 630 m. This thesis focuses on time-lapse analysis of borehole seismic data, surface seismic data and reservoir characterization at the Ketzin site. Baseline Moving Source Profiling (MSP) data were acquired in the borehole Ketzin 202/2007 (OW2), along seven lines in 2007. The zero-offset Vertical Seismic Profile (VSP) data were acquired in the same borehole. The main objective of the VSP and MSP survey was to generate high-resolution seismic images around the borehole. After modeling and data processing, the sandy layers within the Stuttgart Formation can potentially be imaged in the VSP and MSP data whereas reflections from these layers are not as clearly observed in the 3D surface seismic data. 2D and pseudo-3D time-lapse seismic surveys were conducted at the Ketzin site. Interpretation of 2D baseline and repeat stacks shows that no CO2 leakage related time lapse signature is observable where the 2D lines allow monitoring of the reservoir. This is consistent with the time-lapse results of the 3D surveys showing an increase in reflection amplitude just centered around the injection well. The results from the pseudo-3D surveys are also consistent with the 3D seismic time-lapse studies and show that the sparse pseudo-3D geometry can be used to qualitatively map the CO2 in the reservoir with significantly less effect than the full 3D surveying. The 2nd pseudo-3D repeat survey indicates preferential migration of the CO2 to the west. There are no indications of migration into the caprock on either of the repeat surveys. Amplitude Versus Offset (AVO) analysis was performed on both 2D and 3D repeat surveys. A Class 3 AVO anomaly is clearly observed on the 3D repeat data and matches the synthetic modeling well. No AVO anomaly was observed on the 2D repeat data, which was anticipated, but the result shows signs of a pressure response at the reservoir level in the data. Reflection coefficients were calculated using surface seismic data (3D and pseudo-3D) at the site. Pre-injection calculations agree well with calculations from logging data. Post-injection calculations are in general agreement with the seismic modeling, but generally show higher amplitudes than those expected. The full 3D data show a better image of the reflection coefficients before and after injection than the pseudo-3D data and can potentially be used to make quantitative calculations of CO2 volumes. The pseudo-3D data only provide qualitative information.
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Brinkerhoff, Alonzo R. "Mapping Middle Paleozoic Erosional and Karstic Patterns with 3-D Seismic Attributes and Well Data in the Arkoma Basin, Oklahoma." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/907.
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Newly available industry well data and seismic attribute analysis reveal that late Ordovician-early Devonian Hunton Group strata are more widespread (i.e., not removed by mid-Devonian erosion) in the central and southern portions of the Arkoma Basin in eastern Oklahoma than previously thought. This study demonstrates the value of applying seismic attribute analysis to problems of quantifying and mapping stratigraphic features caused by erosions and/or karstification. Well and seismic isochron data in the Red Oak petroleum field for the Viola-Woodford interval (the units that lie stratigraphically beneath and above, respectively, the Huton Group) show isolated ~40-m thick lenses of Hunton rocks, on average measuring 3 km in diameter, with a surrounding halo of karsted rock. This distribution can be explained in two different ways: 1) Hunton occurrences could represent isolated erosional remnants reflecting incomplete removal of the Hunton Group during Middle Devonian time (pre-Woodford unconformity) or 2) due to karsting and collapse of stratigraphically lower units (Viola or Bromide carbonates), lenses of Hunton rocks would have sagged into sinkholes where they were preserved beneath regional base level. Using formation tops from a well data set correlated with attribute and structure maps from a proprietary 3-D seismic data set, we identify three seismic characteristics in the middle Paleozoic interval that correlate well with: 1) absent Hunton seismic markers, indicating that Hunton rocks were completely removed, 2) the Hunton contacts, indicating where a seismically visible section of Hunton rocks remains, 3) absent Hunton but with a thin horizon included within lower carbonate strata that is interpreted to be an incipient karst zone, which is consistently adjacent to areas containing Hunton rocks. The base of the Sylvan Shale and the top of the Woodford Shale, the respective lower and upper adjoining units, form significant chronostratigraphic surfaces. As such, anomalous thicknesses of these units are depositionally related; thick Woodford sections often correlate to thin or absent Hunton rocks, possibly indicating back-filled pre-Woodford channels eroded into or through the Hunton Group. Conversely, when there is little or no Woodford thickening over Hunton lenses and when adjacent areas show thinning and partially karsted Viola rocks, we propose that karstic collapse of Viola strata was responsible for the Hunton rocks preservation. A combination of these models may be necessary to account for areas where we see thinning both in the Woodford and Viola, suggesting that a Hunton lens is structurally lowered due to karsting, but due to its erosionally resistive nature, the lens forms a depositional high, causing the Woodford to thin over it. The 3-D approach is absolutely necessary to reveal the subtle waveform details that illustrate the karstic and erosional processes involved in the preservation of the Hunton wedges. These findings were interpolated, constrained by well data, over the entire Oklahoma portion of the Arkoma basin in order to produce a new Hunton isopach map and 20 separate cross-sections (two shown herein). These show a broad linear region of absent Hunton. Eustatic sea levels rose throughout the middle and late Devonian, so this large area of eroded Hunton is interpreted as a post-Hunton, pre-Woodford structural uplift. Other Hunton wedges, similar in size and extant to that seismically imaged in this study, were also found in the well data. The karstic collapse of the Viola and subsequent preservation of Hunton rocks occurred on both limbs of the arch.
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Ravenna, Matteo. "A reversible jump markov chain Monte Carlo inversion method for layering and amplitude of seismic velocity variations : an application to 1-D structure of the lower mantle." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510764.
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Stafford, Peter James. "Engineering seismological studies and seismic design criteria for the Buller Region, South Island, New Zealand." Thesis, University of Canterbury. Civil Engineering, 2006. http://hdl.handle.net/10092/1078.
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This thesis addresses two fundamental topics in Engineering Seismology; the application of Probabilistic Seismic Hazard Analysis (PSHA) methodology, and the estimation of measures of Strong Ground Motion. These two topics, while being related, are presented as separate sections. In the first section, state-of-the-art PSHA methodologies are applied to various sites in the Buller Region, South Island, New Zealand. These sites are deemed critical to the maintenance of economic stability in the region. A fault-source based seismicity model is developed for the region that is consistent with the governing tectonic loading, and seismic moment release of the region. In attempting to ensure this consistency the apparent anomaly between the rates of activity dictated by deformation throughout the Quaternary, and rates of activity dictated by observed seismicity is addressed. Individual fault source activity is determined following the application of a Bayesian Inference procedure in which observed earthquake events are attributed to causative faults in the study region. The activity of fault sources, in general, is assumed to be governed by bounded power law behaviour. An exception is made for the Alpine Fault which is modelled as a purely characteristic source. The calculation of rates of exceedance of various ground motion indices is made using a combination of Poissonian and time-dependent earthquake occurrence models. The various ground motion indices for which rates of exceedance are determined include peak ground acceleration, ordinates of 5% damped Spectral Acceleration, and Arias Intensity. The total hazard determined for each of these ground motion measures is decomposed using a four dimensional disaggregation procedure. From this disaggregation procedure, design earthquake scenarios are specified for the sites that are considered. The second part of the thesis is concerned with the estimation of ground motion measures that are more informative than the existing scalar measures that are available for use in New Zealand. Models are developed for the prediction of Fourier Amplitude Spectra (FAS) as well as Arias Intensity for use in the New Zealand environment. The FAS model can be used to generate ground motion time histories for use in structural and geotechnical analyses. Arias Intensity has been shown to be an important strong motion measure due to its positive correlation with damage in short period structures as well as its utility in predicting the onset of liquefaction and landslides. The models are based upon the analysis of a dataset of New Zealand Strong Motion records as well as supplementary near field records from major overseas events. While the two measures of ground motion intensity are strongly related, different methods have been adopted in order to develop the models. As part of the methodology used for the FAS model, Monte Carlo simulation coupled with a simple ray tracing procedure is employed to estimate source spectra from various New Zealand earthquakes and, consequently, a magnitude - corner-frequency relationship is obtained. In general, the parameters of the predictive equations are determined using the most state-of-the-art mixed effects regression procedures.
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Wilson, Adam. "Theory and methods of frequency-dependent AVO Inversion." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4740.
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Amplitude-versus-offset, AVO, approximations allow the estimation of various properties from pre-stack seismic gathers. Recently it has been suggested that fluid mobility is a controlling factor in pore pressure equalisation and can result in anomalous velocity dispersion in the seismic bandwidth. However, current approximations all assume an elastic subsurface and are unable to account for velocity dispersion. I have applied existing methodologies to a real dataset to qualitatively detect and interpret spectral amplitude anomalies. Three areas had AVO and spectral signature consistent with frequency-dependent AVO theory. The results suggest that it is feasible to measure such effects on real data in the presence of random noise. It would imply that the relaxation parameter, tau, is larger in the field than has been measured in water-saturated real and synthetic sandstones in the laboratory. I extended a two-term AVO approximation by accounting for velocity dispersion and showed how the resultant reflection coefficient becomes frequency-dependent. I then used this to measure P- and S-wave reflectivity dispersion using spectrally-balanced amplitudes. The inversion was able to quantify the affect of the P-wave velocity dispersion as an instantaneous effect on the reflection. NMO stretch was an issue at the far offsets and I limited myself to the near offsets and effectively measured only the P-wave reflectivity dispersion. I showed how the P-wave reflectivity dispersion signs depend on the AVO classification of the reflection whilst the magnitude depends on the crack density of my model. I showed how the effect of noise and thin-bed tuning can enter uncertainties into the interpretation of spectral anomalies. Whilst it is possible to detect frequency-dependent AVO signatures on pre-stack gathers, the interpretation remains non-unique. I have quantitatively measured a new physical property, reflectivity dispersion, from pre-stack seismic data. I have presented a method of detecting and measuring velocity dispersion in pre-stack gathers but there remain ambiguities in the interpretation of such results. The approach incorporates spectrally decomposed data in an extended AVO inversion scheme. Future work should investigate the application of the methodology to a real seismic dataset.
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Haneberg-Diggs, Dominique Miguel. "Seismic attributes of the Clinton interval reservoir in the Dominion East Ohio Gabor gas storage field near North Canton, Ohio." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1418759184.
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Côte, Philippe. "Tomographies sismiques en génie civil." Grenoble 1, 1988. http://www.theses.fr/1988GRE10122.
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Une nouvelle méthode géométrique itérative de tomographie est décrite (PRIAM-2D). Elle s'apparente à une technique d'inversion sans blocs. Le calcul au sein de chacune des zones comporte des pondérations visant à discriminer les rais entre eux. Dans le domaine du génie civil, plusieurs applications sont envisagées. Des sols, ainsi que certains ouvrages d'art peuvent être auscultes. Il est possible d'obtenir des cartes de la vitesse des ondes de compression ou de facteur de qualité
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Lasisi, Ayodele Oluwatoyin. "Pore pressure prediction and direct hydrocarbon indicator: insight from the southern pletmos basin, offshore South Africa." Thesis, University of the Western Cape, 2014. http://hdl.handle.net/11394/4255.
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>Magister Scientiae - MScAn accurate prediction of pore pressure is an essential in reducing the risk involved in a well or field life cycle. This has formed an integral part of routine work for exploration, development and exploitation team in the oil and gas industries. Several factors such as sediment compaction, overburden, lithology characteristic, hydrocarbon pressure and capillary entry pressure contribute significantly to the cause of overpressure. Hence, understanding the dynamics associated with the above factors will certainly reduce the risk involved in drilling and production. This study examined three deep water drilled wells GA-W1, GA-N1, and GA-AA1 of lower cretaceous Hauterivian to early Aptian age between 112 to 117.5 (MA) Southern Pletmos sub-basin, Bredasdorp basin offshore South Africa. The study aimed to determine the pore pressure prediction of the reservoir formation of the wells. Eaton’s resistivity and Sonic method are adopted using depth dependent normal compaction trendline (NCT) has been carried out for this study. The variation of the overburden gradient (OBG), the Effective stress, Fracture gradient (FG), Fracture pressure (FP), Pore pressure gradient (PPG) and the predicted pore pressure (PPP) have been studied for the selected wells. The overburden changes slightly as follow: 2.09g/cm3, 2.23g/cm3 and 2.24g/cm3 across the selected intervals depth of wells. The predicted pore pressure calculated for the intervals depth of selected wells GA-W1, GA-N1 and GA-AA1 also varies slightly down the depths as follow: 3,405 psi, 4,110 psi, 5,062 psi respectively. The overpressure zone and normal pressure zone were encountered in well GA-W1, while a normal pressure zone was experienced in both well GA-N1 and GA-AA1. In addition, the direct hydrocarbon indicator (DHI) was carried out by method of post-stack amplitude analysis seismic reflectors surface which was used to determine the hydrocarbon prospect zone of the wells from the seismic section. It majorly indicate the zones of thick hydrocarbon sand from the amplitude extraction grid map horizon reflectors at 13AT1 & 8AT1 and 8AT1 & 1AT1 of the well GA-W1, GA-N1 and GA-AA1 respectively. These are suggested to be the hydrocarbon prospect locations (wet-gas to Oil prone source) on the seismic section with fault trending along the horizons. No bright spot, flat spot and dim spot was observed except for some related pitfalls anomalies
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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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Macedo, Daniel Leal 1975. "Uma proposta de método de análise de velocidade em seções sísmicas de ponto médio comum baseada no paradigma de espalhamento de amplitudes." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287734.
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Orientadores: Rodrigo de Souza Portugal, Joerg Dietrich Wilhelm SchleicherDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
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Resumo: Técnicas que usam dados sísmicos organizados em famílias de ponto médio comum (CMP), como correção de sobretempo normal (NMO), empilhamento e análise de velocidade, estão no núcleo do processamento sísmico. Elas são combinações de procedimentos que se baseiam na física, processamento de sinais e leis básicas da estatística. Em geral, todas elas presupõem a existência de um modelo de velocidades do qual derivam-se expressões para o tempo de trânsito e esquemas numéricos para alcançar seus objetivos. Como exemplo, tem-se espectros de velocidade, os quais são tradicionalmente construídos somando-se as amplitudes - empilhando-se - ao longo de hipérboles parametrizadas pelo tempo de afastamento nulo e velocidade sísmica. Neste trabalho foi mostrado que os mesmos espectros obtidos pelo processo convencional, ou seja, de empilhamento, podem ser construídos por aquele de espalhamento. Além disso, modificando-se ligeiramente o processo de espalhamento, outros tipos de espectros de velocidade podem ser obtidos. Nos experimentos numéricos realizados, alguns desses espectros de velocidade alternativos apresentaram picos de velocidade mais destacados
Abstract: Techniques that use seismic data sorted in Common Mid-Point (CMP) gathers, such as normal moveout (NMO) correction, stacking and velocity analysis are at the core of seismic processing. They are a combination of procedures that rely on physics, signal processing and the basic laws of statistics. In general, they all use an underlying velocity model, which gives a traveltime expression, and numerical schemes to acomplish their goals. For instance, velocity spectra are traditionally constructed by summing up - stacking - amplitudes along auxiliary hyperbolae, which are parameterized by zero-offset time and seismic velocity. In this work, we demonstrate that the same velocity spectra obtained by the conventional stacking procedure can be constructed by the smearing one. Moreover, by slightly modifying the smearing process, other types of velocity spectra can be obtained. In our numerical experiments, some of these alternative velocity spectra showed more distinctive velocity peaks
Mestrado
Geologia e Recursos Naturais
Mestre em Geociências
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Nosjean, Nicolas. "Management et intégration des risques et incertitudes pour le calcul de volumes de roches et de fluides au sein d’un réservoir, zoom sur quelques techniques clés d’exploration Integrated Post-stack Acoustic Inversion Case Study to Enhance Geological Model Description of Upper Ordovicien Statics : from imaging to interpretation pitfalls and an efficient way to overcome them Improving Upper Ordovician reservoir characterization - an Algerian case study Tracking Fracture Corridors in Tight Gas Reservoirs : An Algerian Case Study Integrated sedimentological case study of glacial Ordovician reservoirs in the Illizi Basin, Algeria A Case Study of a New Time-Depth Conversion Workflow Designed for Optimizing Recovery Proper Systemic Knowledge of Reservoir Volume Uncertainties in Depth Conversion Integration of Fault Location Uncertainty in Time to Depth Conversion Emergence of edge scenarios in uncertainty studies for reservoir trap analysis Enhancing geological model with the use of Spectral Decomposition - A case study of a prolific stratigraphic play in North Viking Graben, Norway Fracture corridor identification through 3D multifocusing to improve well deliverability, an Algerian tight reservoir case study Geological Probability Of Success Assessment for Amplitude-Driven Prospects, A Nile Delta Case Study." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS085.
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En tant que géoscientifique dans le domaine de l’Exploration pétrolière et gazière depuis une vingtaine d’années, mes fonctions professionnelles m’ont permis d’effectuer différents travaux de recherche sur la thématique de la gestion des risques et des incertitudes. Ces travaux de recherche se situent sur l’ensemble de la chaîne d’analyse Exploration, traitant de problématiques liées à l’acquisition et au traitement sismique, jusqu’au placement optimal de forages d’exploration. Un volet plus poussé de mes travaux s’est orienté sur la gestion des incertitudes géophysiques en Exploration pétrolière, là où l’incertitude est la plus importante et paradoxalement la moins travaillée.On peut regrouper mes travaux de recherche en trois grands domaines qui suivent les grandes étapes du processus Exploration : le traitement sismique, leur interprétation, et enfin l'analyse et l'extraction des différentes incertitudes qui vont nous permettre de calculer les volumes d’hydrocarbures en place et récupérables, ainsi que l’analyse de ses risques associés. L’ensemble des travaux de recherche ont été appliqués avec succès sur des cas d’études opérationnelles. Après avoir introduit quelques notions générales et détaillé les grandes étapes du processus Exploration et leur lien direct avec ces problématiques, je présenterai quatre grands projets de recherche sur un cas d’étude algérienIn the last 20 years, I have been conducting various research projects focused on the management of risks and uncertainties in the petroleum exploration domain. The various research projects detailed in this thesis are dealing with problematics located throughout the whole Exploration and Production chain, from seismic acquisition and processing, until the optimal exploration to development wells placement. Focus is made on geophysical risks and uncertainties, where these problematics are the most pronounced and paradoxically the less worked in the industry. We can subdivide my research projects into tree main axes, which are following the hydrocarbon exploration process, namely: seismic processing, seismic interpretation thanks to the integration with various well informations, and eventually the analysis and extraction of key uncertainties, which will be the basis for the optimal calculation of in place and recoverable volumes, in addition to the associated risk analysis on a given target structure. The various research projects that are detailed in this thesis have been applied successfully on operational North Africa and North Sea projects. After introducing risks and uncertainty notions, we will detail the exploration process and the key links with these issues. I will then present four major research projects with their theoretical aspects and applied case study on an Algerian asset
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Dev, Ashwani. "Seismic amplitude processing and inversion /." 2008. http://proquest.umi.com/pqdweb?did=1642922061&sid=3&Fmt=2&clientId=10361&RQT=309&VName=PQD.
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Deng, Feng. "True amplitude prestack depth migration /." 2007. http://proquest.umi.com/pqdweb?did=1441191561&sid=9&Fmt=2&clientId=10361&RQT=309&VName=PQD.
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Contreras, Arturo Javier. "Spatial delineation, fluid-lithology characterization, and petrophysical modeling of deepwater Gulf of Mexico reservoirs through joint AVA deterministic and stochastic inversion of 3D partially-stacked seismic amplitude data and well logs." Thesis, 2006. http://www.lib.utexas.edu/etd/d/2006/contrerasd42954/contrerasd42954.pdf#page=3.
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Haris, Abd [Verfasser]. "Amplitude-preserving migration and its application to imaging of a BSR in marine multichannel seismic reflection data / vorgelegt von Abd Haris." 2002. http://d-nb.info/971989656/34.
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Alemie, Wubshet M. "Regularization of the AVO inverse problem by means of a multivariate Cauchy probability distribution." Master's thesis, 2010. http://hdl.handle.net/10048/914.
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Thesis (M. Sc.)--University of Alberta, 2010.Title from pdf file main screen (viewed on Mar. 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Geophysics, Department of Physics, University of Alberta. Includes bibliographical references.
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Casey, Michael Chase. "Integrated Reservoir Characterization: Offshore Louisiana, Grand Isle Blocks 32 & 33." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9363.
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This thesis integrated geology, geophysics, and petroleum engineering data to build a detailed reservoir characterization models for three gas pay sands in the Grand Isle 33 & 43 fields, offshore Louisiana. The reservoirs are Late Miocene in age and include the upper (PM), middle (QH), and lower (RD) sands. The reservoir models address the stratigraphy of the upper (PM) sand and help delineate the lower (RD) reservoir. In addition, this research addresses the partially depleted QH-2 reservoir compartment. The detailed models were constructed by integrating seismic, well log, and production data. These detailed models can help locate recoverable oil and gas that has been left behind.
The upper PM model further delineated that the PM sand has several areas that are shaled-out effectively creating a flow barrier within reservoir compartments. Due to the barrier in the PM-1 reservoir compartment, an area of potentially recoverable hydrocarbons remains. In Grand Isle 33, the middle QH sand was partially depleted in the QH-2 reservoir compartment by a series of development wells. Bottom hole pressure data from wells in Grand Isle 32 & 33 reveal that the two QH fault compartments are in communication across a leaking fault. Production wells in the QH-1 compartment produced reserves from the QH-2 compartment. The lower RD sand model helped further delineate the reservoir in the RD-2 compartment and show that this compartment has been depleted. The RD model also shows the possible presence of remaining recoverable hydrocarbons in the RD-1 compartment. It is estimated that about 6.7 billion cubic feet of gas might remain within this reservoir waiting to be recovered. A seismic amplitude anomaly response from the QH and RD sands is interpreted to be a lithologic indicator rather than the presence of hydrocarbons. Amplitude response from the PM level appears to be below the resolution of the seismic data. A synthetic seismogram model was generated to represent the PM and surrounding sands. This model shows that by increasing the frequency of the seismic data from 20 Hz to a dominant frequency of 30 Hz that the PM and surrounding sands could be seismically resolvable. Also the PM-1 compartment has possible recoverable hydrocarbons of 1.5 billion cubic feet of gas remaining.
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Luo, Yi-Jing, and 羅翊菁. "Topography Effect on Seismic Travel Times and Amplitudes: the Case of Northern Taiwan." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/59258306408752917456.
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碩士國立臺灣大學
地質科學研究所
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The resolution and accuracy of the crustal models obtained from seismic tomography is very important in making reliable estimations of strong ground motions of earthquakes for both post-earthquake disaster relief and assessing future seismic risk purposes. Drastic topography changes have significant effects on the propagation of seismic waves, which leads to perturbations in waveforms and therefore the arrival times and amplitudes of seismic phases. Various factors contribute to the topography-induced waveform changes, including not only the fixed geometrical shape of the surface itself, but also the path-related incidence angles and azimuths of the seismic waves which are dependent on the location of the receiver site as well as the back azimuth, epicentral distance and depth of the earthquake. In order to assess the potential bias in crustal models obtained by traveltime tomography when the effect of surface topography is neglected, we carry out a systematic analysis of the surface topography effect on the traveltimes and amplitudes of seismic waves using accurate synthetics calculated by the finite-difference method in three-dimensional structure with realistic surface topography and quantify the topography-induced delay times and amplitude anomalies by cross-correlations of waveforms obtained with realistic topography and those with topography ignored. The quantitative measurements of topography effect is used to assess the potential biases in seismic tomography due to the omission of topography in modeling regional seismic waveforms. The results show that for the topography relief of northern Taiwan, these biases can be up to 0.4 s for P- and 0.6 s for S-wave delay times and more than 100% for S-wave amplitudes, which we demonstrate to be significant in tomography inversions for crustal structure. Our results also suggest that in PGV and PGA predictions for hazard purposes, results from a few scenario earthquakes are insufficient in producing the complete picture.
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Chand, Shyam. "GAS HYDRATE ANOMALIES IN SEISMIC VELOCITIES, AMPLITUDES AND ATTENUATION: WHAT DO THEY IMPLY?" 2008. http://hdl.handle.net/2429/1393.
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Gas hydrates are found worldwide and many studies have been carried out to develop an efficient method to identify and quantify them using various geophysical as well as other anomalies. In this study, various seismic anomalies related to gas hydrates and the underlying gas are analysed, and correlated them to rock physics properties. Observations of velocities in sediments containing gas hydrates show that the rigidity, and hence the velocity of sediments increases with increase of hydrate saturation. The increase of velocity due to the presence of gas hydrate can be explained in terms of gradual cementation of the sediment matrix. In the case of seismic attenuation, gas hydrate bearing sediments are quite different from common sedimentary rock behaviour of low seismic attenuation with high rigidity. In contrary gas hydrate bearing sediments is observed to have increased seismic attenuation of higher frequencies with increase of hydrate saturation. This strange phenomenon can be explained in terms of differential fluid flow within sediment and hydrate matrix. Also it is observed that the presence of large amount of gas hydrate can result in an increase of seismic amplitudes, a signature similar to the presence of small amount of gas. Hence misinterpretation of these enhanced amplitudes could result in the under estimation of gas present not only as shallow drilling hazard but also on the resource potential of the region. The increase of seismic reflection amplitude results from the formation of gas hydrates in selective intervals causing strong positive and negative impedance contrasts across the formations with and without gas hydrates.