The principal goal of this research is to clarify the structure and tectonic setting of the Southern Alaska and, specifically, the offshore area close to Kayak Island. Seismic reflection data collected in 1976 in the offshore region of Kayak Island in the Gulf of Alaska were reprocessed in order to improve the quality of the signal by applying seismic data processing techniques that were not available at the time in which the data were obtained. The processed data were then interpreted, focusing on identifying patterns that indicate the direction, as well as the intensity of deformation. The deformation pattern observed in this research suggests that the major deformation of the region is located at the northwest side of Kayak Island.

IGeoS is an integrated open-source software framework for geophysical data processing under development at the UofS seismology group. Unlike other systems, this processing monitor supports structured multicomponent seismic data streams, multidimensional data traces, and employs a unique backpropagation execution logic. This results in an unusual flexibility of processing, allowing the system to handle nearly any geophysical data.<p> In this project, a modern and feature-rich Graphical User Interface (GUI) was developed for the system, allowing editing and submission of processing flows and interaction with running jobs. Multiple jobs can be executed in a distributed multi-processor networks and controlled from the same GUI. Jobs, in their turn, can also be parallelized to take advantage of parallel processing environments such as local area networks and Beowulf clusters.<p> A 3D/2D interactive display server was created and integrated with the IGeoS geophysical data processing framework. With introduction of this major component, the IGeoS system becomes conceptually complete and potentially bridges the gap between the traditional processing and interpretation software.<p> Finally, in a specialized application, network acquisition and relay components were written allowing IGeoS to be used for real-time applications. The completion of this functionality makes the processing and display capabilities of IGeoS available to multiple streams of seismic data from potentially remote sites. Seismic data can be acquired, transferred to the central server, processed, archived, and events picked and placed in database completely automatically.

IGeoS is an integrated open-source software framework for geophysical data processing under development at the UofS seismology group. Unlike other systems, this processing monitor supports structured multicomponent seismic data streams, multidimensional data traces, and employs a unique backpropagation execution logic. This results in an unusual flexibility of processing, allowing the system to handle nearly any geophysical data.<p> In this project, a modern and feature-rich Graphical User Interface (GUI) was developed for the system, allowing editing and submission of processing flows and interaction with running jobs. Multiple jobs can be executed in a distributed multi-processor networks and controlled from the same GUI. Jobs, in their turn, can also be parallelized to take advantage of parallel processing environments such as local area networks and Beowulf clusters.<p> A 3D/2D interactive display server was created and integrated with the IGeoS geophysical data processing framework. With introduction of this major component, the IGeoS system becomes conceptually complete and potentially bridges the gap between the traditional processing and interpretation software.<p> Finally, in a specialized application, network acquisition and relay components were written allowing IGeoS to be used for real-time applications. The completion of this functionality makes the processing and display capabilities of IGeoS available to multiple streams of seismic data from potentially remote sites. Seismic data can be acquired, transferred to the central server, processed, archived, and events picked and placed in database completely automatically.

[pt] Ondas superficiais são uma fonte comum de ruído nos dados sísmicos. O rolamento superficial pode ser definido como um conjunto de eventos que contaminam os dados sísmicos formando um cone de alto mergulho (baixa velocidade) e alta amplitude, podendo dominar as componentes do sinal que estão perto da fonte. Ondas de superfície são um problema tão significativo na aquisição de dados terrestres que no desenvolvimento dos parâmetros de aqusição é levado em consideração a necessidade de suprimí- las. Este trabalho propõe a remoção do ruído de rolamento superficial a partir da transformada wavelet em uma dimensão. Este método obteve melhores resultados que a transformada f-k. O algoritmo foi testado em dados sintético e real. / [en] Surface waves are a common source of unwanted noise in the seismic record. Ground roll can be defined as a group of events that contaminates seismic data and makes a high dip (low velocity) and high amplitude cone, this can dominate near-source on seismic records. Surface waves are such a problem in land seismic record acquisition that the design of acquisition parameters is dominated by the need to suppress them. In this work we propose to remove ground roll by employing Wavelet Transforms in 1-D. This method gives better results than the f-k transform. The procedure was tested in synthetic and real data.

Made available in DSpace on 2015-03-13T17:08:35Z (GMT). No. of bitstreams: 1 MarcosALL_DISSERT.pdf: 5173840 bytes, checksum: 26fa2fd6ccf8445fa5e27cbfeebf642c (MD5) Previous issue date: 2012-12-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The seismic reflection is used on a large scale in oil exploration. In case of marine acquisition the presence of high impedance contrast at the interfaces water/air generates multiple reflections events. Such multiple events can mask primary events; thus from the interpretational viewpoint it is necessary to mitigate the multiples. In this manuscript we compare two methods of multiple attenuation: the predictive multichannel deconvolution (DPM) and the F-K filtering (FKF). DPM is based in the periodicity of the multiples while FKF is based in multiples and primaries splitting in F-K domain. DPM and FKF were applied in common-offset and CDP gathers, respectively. DPM is quite sensible to the correct identification of the period and size of the filter while FKF is quite sensible to an adequate choice of the velocity in order to split multiples and primaries events in the F-K domain. DPM is a method that is designed to act over a specific event. So, when the parameters are well selected, DPM is very efficient in removing the specified multiple. Then DPM can be optimized by applying it several times, each time with a different parameterization. A deficiency of DPM occurs when a multiple is superposed to a primary event: in this situation, DPM can attenuate also the primary event. On the other hand, FKF presents almost the same performance to all multiples that are localized in the same sector of the F-K domain. The two methods can be combined in order to take advantage of their associated potentials. In this situation, DPM is firstly applied, with a focus in the sea bed multiples. Then FKF is applied in order to attenuate the remaining multiples / A s?smica de reflex?o ? utilizada em grande escala na explora??o de petr?leo. No caso de aquisi??o marinha, devido ao alto contraste de imped?ncia nas interfaces ?gua/ar, podem ocorrer eventos de reflex?o m?ltipla. Tais m?ltiplas podem mascarar eventos prim?rios, sendo necess?rio atenu?-las para facilitar o processo de interpreta??o. Neste trabalho faremos a compara??o usando dados sint?ticos e reais de duas t?cnicas de atenua??o de m?ltiplas: a deconvolu??o preditiva multicanal do tipo Wiener-Levinson (DPM) e a filtragem F-K. A primeira t?cnica ? baseada na periodicidade das m?ltiplas enquanto a segunda ? baseada nas diferen?as de mergulho dos eventos. A DPM foi aplicada em fam?lias de afastamento comum e a filtragem F-K em fam?lias CDP. Constatamos que a efici?ncia da t?cnica DPM ? bastante sens?vel ? identifica??o correta do per?odo e do tamanho do filtro. Por sua vez, a filtragem F-K ? bastante sens?vel ? escolha da velocidade adequada para separar as m?ltiplas dos eventos prim?rios. A DPM ? uma t?cnica que ? focada num dado evento; quando bem parametrizada, ela ? bastante eficiente para remover a m?ltipla especificada, podendo ter atua??o menos eficiente em outras m?ltiplas. A DPM pode ser ent?o otimizada aplicando-se a t?cnica v?rias vezes, em cada vez com uma diferente parametriza??o. Uma defici?ncia da t?cnica DPM ? quando h? sobreposi??o de m?ltiplas com eventos prim?rios, em que a DPM pode remover tamb?m uma parcela do evento prim?rio. Por sua vez, a filtragem F-K tem aproximadamente o mesmo desempenho em todas as m?ltiplas que estejam localizadas em um mesmo setor do espectro F-K. As duas t?cnicas podem ser combinadas de modo a tomar partido do potencial de cada uma delas, aplicando-se primeiro a t?cnica DPM, focada na m?ltipla do fundo do mar, seguida da filtragem F-K para a atenua??o das demais m?ltiplas

Orientador: Martin Tygel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-04T20:27:31Z (GMT). No. of bitstreams: 1 Santiago_TaniaMariaGodinho_M.pdf: 6170921 bytes, checksum: fb1caa1410e2409aa2455f02c3c86e58 (MD5) Previous issue date: 2004 / 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

[pt] Este trabalho quantifica o erro que se comete durante o processamento sísmico quando uma abordagem isotrópica é utilizada na análise de velocidade e correção de sobretempo normal (NMO) em dados anisotrópicos. Esta quantificação é realizada através da repetição do experimento de análise de velocidade em dados sísmicos sintéticos construídos a partir de um modelo geológico simples (porém realista) representando uma seqüência sedimentar típica de águas profundas com camadas horizontais onde uma delas é anisotrópica (VTI). A variação da anisotropia é conhecida e a diferença entre as velocidades NMO encontradas para cada modelo é quantificada. O resultado também é quantificado através da diferença na profundidade de uma camada resultante da conversão tempo- profundidade a partir da velocidade obtida no procedimento e mostra que, dependendo da anisotropia, o erro na velocidade (e/ou profundidade) por não se considerar anisotropia pode chegar a 10-15 porcento para valores de anisotropia que são encontrados habitualmente na natureza. A análise desta quantificação também mostra que o parâmetro de anisotropia delta é muito mais influente sobre o erro da velocidade que o parâmetro e e que a espessura da camada utilizada no experimento. Para complementar o trabalho, é verificada a melhor abordagem anisotrópica de correção de sobretempo normal para dados reais a partir de equações existentes na literatura, tanto para a correção de NMO quanto para a estimativa de parâmetros de anisotropia. A utilização de equações que incluem anisotropia permitem uma melhor correção do sobretempo normal e uma boa estimativa dos parâmetros de anisotropia épsilon e delta. Os parâmetros estimados foram utilizados em um algoritmo de migração para meio anisotrópico pré-empilhamento em profundidade e foi verificado que quando existe uma boa estimativa de delta, a profundidade migrada do refletor sofre uma distorção, desprezível em comparação à sua posição original. Em conjunto com este estudo, também é proposta uma técnica alternativa para análise de velocidade utilizando uma função de discriminantes lineares chamada gradiente descendente. Esta metodologia permite adaptar várias equações de NMO e obter todos os parâmetros da equação de uma única vez (t0 ,VNMO e eta), diferentemente do método de coerência geralmente utilizado para realizar análise de velocidade e que só permite a obtenção de dois parâmetros ao mesmo tempo (t0 e VNMO), tornando necessária uma segunda análise de velocidade. O método do gradiente descendente proposto neste trabalho foi testado para quatro funções de sobretempo normal com dados sintéticos e um dado real e foi considerado rápido, robusto e eficiente. / [en] This work quantifies the error created during seismic processing when isotropic approach is used to normal moveout correction and velocity analysis and the seismic data is anisotropic. This quantification is made by performing velocity analysis in several synthetic seismograms built from a simple (but realistic) geological model with some horizontal layers, one of them being anisotropic (VTI), representing a common deep water sedimentary sequence. The anisotropy in the model is known and the difference between the NMO velocities found by seismic processing (semblance analysis) is quantified for each model. The result is also shown through the difference in depth obtained from time-depth conversion with NMO velocity. Depending on the anisotropic degree, the velocity (and/or depth) error produced when the anisotropy is not considered can be up to 10-15 percent for anisotropic values commonly found in nature. This quantification analysis also concludes that delta parameter influences more on velocity error than e parameter and layer depth. To complement this work, the best anisotropic approach for normal moveout correction to be used in real data is investigated, by comparing some NMO functions found in technical papers, analyzing the data correction and the parameter estimation. The usage of NMO equation with anisotropic approach in anisotropic seismic data allows a better normal moveout correction and the anisotropic parameters ( épsilon and delta) can be estimated from velocity analysis. The estimated anisotropic parameters were applied in a pre-stack anisotropic depth migration algorithm and it was verified that when delta is well estimated, the migrated position of a seismic reflector is not very distorted from its real position. It is also proposed in this Thesis one alternate technique for velocity analysis using one linear discriminant function called gradient descendent. This methodology allows adopting several normal moveout functions and obtaining all the equation parameters (t0 , VNMO and eta) at once, differently from semblance method used in conventional velocity analysis that only allows obtaining two parameters at the same time (t0 and VNMO ), which requires a second velocity analysis to obtain all equation parameters. The proposed gradient descendent method was tested with four NMO equations and it was shown to be fast, robust and efficient.

No description available.

An extensive multi-channel seismic dataset acquired between 1970 and 1990 by Oljeprospektering AB (OPAB) has recently been made available by the Geological Survey of Sweden (SGU). This thesis summarizes four papers, which utilize this largely unpublished dataset to improve our understanding of the geology and CO2 storage capacity of the Baltic and Hanö Bay basins in southern Sweden. A range of new processing workflows were developed, which typically provide an improvement in the final stacked seismic image, when compared to the result obtained with the original processing. A method was developed to convert scanned images of seismic sections into SEGY files, which allows large amounts of the OPAB dataset to be imported and interpreted using modern software. A new method for joint imaging of multiples and primaries was developed, which is shown to provide an improvement in signal to noise for some of the seismic lines within the OPAB dataset. For the first time, five interpreted regional seismic profiles detailing the entire sedimentary sequence within these basins, are presented. Depth structure maps detailing the Outer Hanö Bay area and the deeper parts of the Baltic Basin were also generated. Although the overall structure and stratigraphy of the basins inferred from the reprocessed OPAB dataset are consistent with previous studies, some new observations have been made, which improve the understanding of the tectonic history of these basins and provide insight into how the depositional environments have changed throughout time. The effective CO2 storage potential within structural and stratigraphic traps is assessed for the Cambrian Viklau, När and Faludden sandstone reservoirs. A probabilistic methodology is utilized, which allows a robust assessment of the storage capacity as well as the associated uncertainty. The most favourable storage option in the Swedish sector of the Baltic Basin is assessed to be the Faludden stratigraphic trap, which is estimated to have a mid case (P50) storage capacity of 3390 Mt in the deeper part of the basin, where CO2 can be stored in a supercritical phase.

3D time-lapse seismics, also known as 4D seismics, have great potential for monitoring the migration of CO2 at underground storage sites. This thesis focuses on time-lapse analysis of 3D seismic reflection data acquired at the Ketzin CO2 geological storage site in order to improve understanding of the reservoir and how CO2 migrates within it. Four 3D seismic surveys have been acquired to date at the site, one baseline survey in 2005 prior to injection, two repeat surveys in 2009 and 2012 during the injection period, and one post-injection survey in 2015. To accurately simulate time-lapse seismic signatures in the subsurface, detailed 3D seismic property models for the baseline and repeat surveys were constructed by integrating borehole data and the 3D seismic data. Pseudo-boreholes between and beyond well control were built. A zero-offset convolution seismic modeling approach was used to generate synthetic time-lapse seismograms. This allowed simulations to be performed quickly and limited the introduction of artifacts in the seismic responses. Conventional seismic data have two limitations, uncertainty in detecting the CO2 plume in the reservoir and limited temporal resolution. In order to overcome these limitations, complex spectral decomposition was applied to the 3D time-lapse seismic data. Monochromatic wavelet phase and reflectivity amplitude components were decomposed from the 3D time-lapse seismic data. Wavelet phase anomalies associated with the CO2 plume were observed in the time-lapse data and verified by a series of seismic modeling studies. Tuning frequencies were determined from the balanced amplitude spectra in an attempt to discriminate between pressure effects and CO2 saturation. Quantitative assessment of the reservoir thickness and CO2 mass were performed. Time-lapse analysis on the post-injection survey was carried out and the results showed a consistent tendency with the previous repeat surveys in the CO2 migration, but with a decrease in the size of the amplitude anomaly. No systematic anomalies above the caprock were detected. Analysis of the signal to noise ratio and seismic simulations using the detailed 3D property models were performed to explain the observations. Estimation of the CO2 mass and uncertainties in it were investigated using two different approaches based on different velocity-saturation models.