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1
Karpathakis, George. "Rock stories: The discourse of rocks and rock-collecting". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/218.
Testo completoAbstract (sommario):
Humanity's relationship with rocks is a long-standing one. Belk (1995, p.2) describes archaeological evidence of early assemblages of rocks found in Cro-Magnon caves that would not be out of place in contemporary rock-collections. Historically, apart from being used as material for tools and buildings. rocks were also used for magical, pharmaceutical and decorative purposes. During the Renaissance and Enlightenment, the practice of collecting rocks became associated with the sense of discovery and the colonial expansion of western European civilization across world, and with advances in mining, science and industry. It is a practice that continues through to the present day. This thesis is an ethnography that asks contemporary rock collectors: why do they collect rocks? How do they collect rocks? And, how do they talk about them? Adapting Foucault's theoretical framework on discourse (1970) and utilising positions on collecting put forward by Baudrillard ( 1994), Belk ( 1995), Benjamin (1999), and others, the thesis analyses interviews and images of rock-collectors and their collections and puts forward a snapshot of the discourse of rocks and rock-collecting as currently practiced. The thesis's theoretical framework is first tested on texts of popular culture on rocks and rock-collecting to locate and identify the statements and discursive formations that make up the discourse, and then it is applied to the interviews of contemporary collectors talking about their collections. While some rock collectors practice alone and their approaches may appear idiosyncratic, others, sharing knowledge and experience, practice in a club environment. The collectors' approaches to rock collecting range from the taxonomic and scientific to the aesthetic and utilitarian, personal and historical, and, for some, to the metaphysical. In Australia some aspects of rock-collecting are allied to prospecting and mining. For some collectors the rocks are souvenirs, and are connected to travel. For other collectors rock-collecting is associated with understandings of nature, time and space. The interviews reveal that in a consumer society rocks are also commodities, with many of the collectors not only acquiring their rocks in the field, but also buying what they cannot find, or trade, for their collection. The analysis of the collectors' interviews demonstrates that the discourse does not stand as an isolated figure, but shares statements and configurations of statements with many other discourses in the field of knowledge, including science, history, archaeology and metaphysics. The interviews also illustrate how discourse and their associated practices are subject to external and internal rules and regulations, imposed by the State, and by institutions of academia and cultural and scientific practices, such as museums and universities. Some collectors aspire to emulate museums, and wish to share with others knowledge about to their collection through exhibition. The variety of themes and practices found in the interviews reinforce Foucault's proposition that within a discourse statements and configurations of statements may arise that are incompatible and form diffractions in the discourse. While apparently incompatible themes, variations and differences exist within the discourse, the analysis of the interviews and the conclusion of the thesis underscore the underlying unities of the discourse of rocks and rock-collecting.
2
Nejedlik, John. "Petrographic image analysis as a tool to quantify porosity and cement distribution". Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09SM/09smn417.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 153-157). Petrographic image analysis proved particularly useful in determining the parameters for statistical analysis for the simple mineralogies displayed in the samples from the Hutton Sandstone. Concentrates on establishing techniques for statistical study of data collected by PIA to subdivide the framework grains from the porosity or cement.
3
Pressler, Rebecca E. "An integrated petrofabric study of the high-pressure Orlica-Śnieźnik Complex, Czech Republic and Poland". Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1149180445.
Testo completo
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SPAGNOLO, RODRIGO ALVES. "ANALYSIS OF RESERVOIR ROCKS PLUGGING DURING WATER INJECTION OPERATIONS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2001. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2206@1.
Testo completoAbstract (sommario):
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO presente trabalho apresenta um estudo paramétrico de alguns fatores intervenientes no processo de entupimento de formações rochosas por sólidos em suspensão, sob injeção de água. Primeiramente se fez uma revisão das formulações mais comumente utilizadas em se tratando de modelos de redução de permeabilidade na literatura técnica especializada. Em seguida, a partir de dois simuladores numéricos, executou- se vários casos de injeção de água,e tais resultados foram comparados entre si e comentários foram feitos a respeito da validade das informações por eles fornecidas. Uma campanha de ensaios foi executada de forma a avaliar alguns parâmetros intervenientes na retenção de partículas em suspensão quando injetadas em um meio poroso, como a rocha. Inicialmente foi feita uma revisão bibliográfica sobre ensaios de injeção já realizados em diversos centros de pesquisas do mundo. Os resultados desses experimentos de injeção, conjugados a análises complementares de microscopia eletrônica, fornecem informações bastantes úteis para determinados aspectos a serem considerados na execução de injeção de água produzida em poços offshore.
The present work presents a parametric study of some intervening factors in the blockage process of rocky formations for solids in suspension, under injection of water.Firstly it was made a review in the specialized technical literature on the formulations more commonly used for modelling the permeability reduction. Next, using two numeric simulators, several examples of water injection were executed, and the results were compared amongst each other. A series of laboratory tests was performed in order to evaluate some intervening parameters in the retention of particles in suspension when injected in a porous medium. Initially it was made a bibliographical review on injection tests carried out in several research centers of the world. The results of the injection experiments, with associated analyses of electronic microscopy, were able to supply useful information for certain aspects to be considered when injecting produced water in offshore wells.
5
Ponce, Escudero Carlos. "Structural analysis of tectonic lozenges in anisotropic rocks: fied analysis and experimental modelling". Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283937.
Testo completo
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Mánica, Malcom Miguel Ángel. "Analysis of underground excavations in argillaceous hard soils : weak rocks". Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/663452.
Testo completoAbstract (sommario):
Materiales arcillosos rígidos, que se encuentran en la zona de transición entre suelos duros y rocas blandas, están siendo considerados actualmente en varios países como la roca huésped para el almacenamiento geológico profundo de residuos nucleares de alta actividad y larga vida. Esta posibilidad a derivado en la construcción de laboratorios de investigación subterráneos (LIS), excavados en estos materiales arcillosos rígidos, para estudiar su comportamiento bajo condiciones reales de trabajo. Entre los diferentes aspectos estudiados en los LIS, el comportamiento hidromecánico de la roca huésped es el más relevante para la presente investigación. Observaciones in situ han revelado que las excavaciones inducen daño alrededor de los túneles, en la forma de redes de fracturas, contenidas dentro de una zona llamada la zona de daño de la excavación (ZDE). La ZDE se ha identificado como una de las principales causas afectando el comportamiento de las excavaciones. En este contexto, el principal objetivo de la presente investigación es la simulación numérica del comportamiento hidromecánico de excavaciones experimentales llevadas a cabo en el LIS Meuse/Haute-Marne (Francia). Para lograrlo, se desarrolló un modelo constitutivo para caracterizar la roca huésped. El modelado de estos materiales es una tarea desafiante. Estos materiales exhiben características más propias de los suelos como considerables deformaciones plásticas, dependencia con la velocidad de carga, y creep, aunque también muestran características más típicas de las rocas como un considerable reblandecimiento y deformaciones plásticas localizadas. Además, debido a su origen sedimentario, también exhiben anisotropía en propiedades como su rigidez, resistencia, y permeabilidad. Se prestó especial atención a la reproducción de la ZDE y, por lo tanto, a la simulación objetiva de deformaciones localizadas; se empleó un enfoque no local para la regularización del continuo, el cual evita la dependencia con la malla empleada. Los resultados obtenidos proporcionan importantes conclusiones respecto al comportamiento hidromecánico de estos materiales arcillosos rígidos, e indican los principales aspectos que afectan la respuesta de las excavaciones subterráneas. En particular, se demuestra la importancia de la ZDE.Stiff clayey materials, lying in the transition between hard soils and weak rocks, are being currently considered in several countries as possible host medium for deep geological disposal of high active and long-lived nuclear waste. This possibility has led to the construction of underground research laboratories (URL), excavated in these indurated clayey materials, to study their behaviour under real working conditions. Among the very different topics addressed in the URLs, the hydromechanical behaviour of the host rock is the one that most concerns the present research. In situ observations have revealed that excavation operations induce damage around the galleries, in the form of fracture networks, contained within a zone called excavation damaged zone (EDZ). The EDZ has been identified as one of the main aspects affecting the behaviour of the excavations. In this context, the main objective of the present study is the numerical simulation of the hydromechanical behaviour of experimental excavations performed at the Meuse/Haute-Marne URL (France). For this purpose, a constitutive model has been developed to characterise the host formation. The modelling of these stiff argillaceous materials is a quite challenging task. They exhibit soil-like features like considerable plastic strains, rate-dependency, and creep, although they also show characteristics more typical of a rock such as significant softening and localised deformations. In addition, due to their sedimentary origin, they often exhibit anisotropy in properties like stiffness, strength, and permeability. Special attention has been paid to the reproduction of the EDZ and, therefore, to the objective simulation of localised deformations; a nonlocal approach has been employed for the regularisation of the continuum, avoiding the dependence on the employed mesh. The obtained results provide relevant insights into the hydromechanical behaviour of these stiff clayey materials, and they indicate the main aspects affecting the response of the underground excavations. In particular, the relevance of the EDZ has been demonstrated.
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Eggen, Katharina Banschbach. "AVO Analysis of Turbidite Reservoir Rocks in the Alvheim Field". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18727.
Testo completoAbstract (sommario):
The Alvheim reservoir is a turbidite reservoir, which means that the complex deposition makes it a difficult reservoir to perform predictions regarding reservoir content on. In the preceding project work (Eggen 2012) AVO analyses were performed on the twelve modelled scenarios that can be present in a turbidite reservoir. These modelled scenarios were to be compared with the analyses performed on the real data in this master’s thesis to see if the modelled scenarios can help to predict what answers to expect from the analyses performed on the real data. One post-stack data set consisting of Near and Far stacks covering the whole Alvheim field including all three hydrocarbon discoveries, and one pre-stack data set focusing on the oil discovery named Kneler were available for this thesis in addition to well logs from well 25/4-7. Naturally, it was the Kneler oil discovery that was focused on, and on the gathers from the pre-stack data the top reservoir could be identified by a clear AVO effect. Different AVO analyses were performed on this AVO effect and the results were compared with the results obtained from the project work. In addition to performing AVO analyses on the data it was interesting to see if it was possible to see how the reservoir changed when moving away from the well location on the seismic data. To increase the signal to noise ratio, super gathers around the well location were created in addition to super gathers at some distance away from the well to see if there were changes that were noticeable on the seismic.The AVO analysis was performed on the top oil sand (top reservoir) in the Heimdal Member located in the Lista Formation. An AVO crossplot was created from both data sets, where the area around the Kneler discovery was picked by hand on the post-stack data set to match the area that was plotted from the pre-stack data. The crossplot created from the post-stack data showed the best deviation from the background trend out of the two, and the anomaly could be classified as a class III AVO anomaly. It was also performed an AVO gradient analysis on the AVO effect on a pre-stack seismic gather and on a synthetic seismic gather created with a normal Ricker wavelet and velocities taken from well 25/4-7. Both AVO curves from these analyses had a negative intercept and a negative gradient, which also could classify them as a class III AVO anomaly. It was known in advance that the upper part of the reservoir consisted of unconsolidated interbedded sand-shale and it was expected that the results would match the results obtained from the modelled scenario of the unconsolidated interbedded sand-shale. However, this was not completely the case and the results from the analyses of the real data turned out to match the analyses for the modelled unconsolidated massive sandstone. Even if the analyses from this master’s thesis do not match the expected analyses performed in the preceding project work, they can be said to be correct. The error in comparison is due to the fact that the analyses in this master’s thesis are performed on the top of a section of unconsolidated interbedded sand-shale, but the top layer is actually a layer of unconsolidated massive sandstone. This means that when making assumptions it should not be taken for granted that the real data will match the modelled data, especially not if there are uncertainties related to the assumptions the modelling is based on.
8
PESSOA, THIAGO FIGUEIREDO POLARI. "NUMERICAL ANALYSIS OF SAND CONTROL METHODS IN OIL-PRODUCING ROCKS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19293@1.
Testo completoAbstract (sommario):
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORDurante a vida produtiva de um poço de petróleo, problemas devido à produção de sólidos podem ocasionar gastos excessivos por danos nos equipamentos ou redução de produtividade do poço. Por causa destes problemas, a instalação de sistemas de contenção de sólidos na etapa de completação é uma das mais complexas e fundamentais fases na construção do poço. A alteração no estado de tensões atuante sobre a formação é uma das principais fontes de carregamento dos sistemas de contenção mecânica de sólidos. Este trabalho visa simular as tensões atuantes no sistema de contenção de sólidos (gravel packing e stand alone) instalados em uma formação com potencial de produção de sólidos, permitindo a otimização de projetos para este tipo de sistemas. Para isso foi utilizado o modelo de Mohr Coulomb solucionado numericamente no software comercial de elementos finitos Abaqus que foi escolhido devido a sua enorme capacidade de resolver problemas não lineares. Os resultados obtidos foram então comparados com ensaios experimentais que apresentaram comportamento bastante semelhante com os obtidos numericamente. Além disso, foi observada a capacidade do gravel packing de suportar as tensões até determinado estado de tensões.
During the production steps of a petroleum well, issues regarding sand production may have hight costs due to damages in the equipment or reduction of the well’s productivity. Such problems make the application of sand control systems in the completion phase one of the most complex and essential parts in the construction of the well. This work aims to simulate the behavior of different sand control methods (gravel packing and stand alone) taking into account mechanical interaction between the formation and sand control screens. For the development of the present study, elastoplastic (Mohr Coulomb) models are used to represent granular materials with the commercial FEM software Abaqus, chosen due to its versality in the solution of non-linear problems named out previously. Numerical simulations were compared to experimental tests which presented similar behavior regarding the numerical analysis. In addition, it was observed the capability of the gravel packing to withstand the stresses up to a certain state of stress.
9
SOBREIRA, GUSTAVO HENRIQUE OLIVEIRA. "EVALUATION OF ELASTIC PROPERTIES OF CARBONATIC ROCKS FROM MICROSTRUCTURAL ANALYSIS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29612@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Reservatórios carbonáticos contêm entre 50 e 60 porcento de petróleo e gás do mundo. No entanto, estas rochas têm apresentado problemas operacionais consideráveis durante as etapas de perfuração e produção. Tais problemas são originados pelas dificuldades na caracterização adequada destas rochas em função da complexa distribuição espacial de suas micro e macro estrutura. Enquanto ambas as escalas possuem importância no entendimento do comportamento de carbonatos, o presente trabalho trata da análise da microestrutura. Nesse âmbito, a proposta deste trabalho integra o processamento e análises de imagens digitais, elaboração de malhas de elementos finitos e simulação numérica de forma a prever propriedades elásticas, com o objetivo de correlacionar a microestrutura e o módulo de Young. Foram utilizadas imagens digitais de amostras de afloramento (travertinos) considerados como possíveis análogas a rochas carbonáticas de reservatório. A metodologia implementada permitiu obter subamostras que incluem uma gama de microestruturas e porosidades numa única amostra para assim simular numericamente o módulo de Young. Conclui-se neste estudo que os poros maiores (vuggys) são os principais responsáveis pelo comportamento do material quando o mesmo é carregado, e também a influência da estrutura porosa nos resultados, foi possível observar que a posição dos poros afeta o módulo de elasticidade do corpo de prova.
Carbonate reservoirs contain between 50 and 60 percent of oil and gas reserves in the world. However, these rocks have presented considerable operating problems during the phases of drilling and production. Such problems are originated by the difficulties in the proper characterization of these rocks due to the complex spatial distribution of its micro and macro structure. While both scales have importance on the carbonate behavior understanding, this paper deals with the analysis of the microstructure. In this context, the aim of this work is part of the processing and digital image analysis, mesh preparation and finite element numerical simulation to predict elastic properties, in order to correlate the microstructure and the Young s modulus. Using digital images of outcrop samples (travertine) considered as possible analogous to carbonate rocks reservoir. The methodology implemented afforded sub-samples that include a range of porosities and microstructures for a single sample well numerically simulate the Young s modulus. It is concluded in this study that the larger pores (vuggys) are mainly responsible for the behavior of the material when it is loaded, and also the influence of the porous structure in the results, it was observed that the position of pores affects the modulus of elasticity of sample.
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AMARO, RENATO. "ANALYSIS OF THE FEASIBILITY OF DRILLING OF ROCKS WITH LASERS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=37208@1.
Testo completoAbstract (sommario):
Um dos maiores desafios na perfuração das rochas carbonáticas, situadas a grandes profundidades, é superar as baixas taxas de penetração que vem sendo obtidas na perfuração de poços verticais e direcionais. Para vencer este desafio, um grande esforço vem sendo desenvolvido em várias linhas de pesquisa, tanto no desenvolvimento de novos conceitos de brocas como na seleção de um sistema de perfuração que apresente um melhor desempenho. Para atingir este objetivo, estão sendo priorizados procedimentos e sistemas de perfuração que apresentem menores níveis de vibração, pois este fenômeno além de reduzir a eficiência da perfuração, também compromete o tempo de vida útil dos equipamentos e, por consequência, acarreta a redução da confiabilidade do sistema e eleva o custo por metro da perfuração. Por conseguinte, novas tecnologias de brocas e sistemas de perfuração estão em desenvolvimento e, dentre as novas tecnologias, podemos diferenciar aquelas que promovem melhorias nas tecnologias convencionais e as tecnologias francamente inovadoras, aquelas que utilizam novos mecanismos para cortar ou fragilizar a rocha. Dentre as tecnologias inovadoras, a perfuração assistida por laser é uma das mais promissoras, nesta versão o feixe da energia radiante tem a função principal de fragilizar a rocha, facilitando o avanço da perfuração. Esta dissertação tem por objetivo realizar uma avaliação das possibilidades de aplicação da tecnologia laser na perfuração de rochas. O meio através do qual o laser deverá atuar nas aplicações futuras é analisado sobre o enfoque das suas propriedades físico-químicas. Dessa forma, o conhecimento da interação com o fluido de perfuração é o ponto de partida para a análise de viabilidade. Inicialmente, análises de absorção ótica foram realizadas em alguns tipos de fluido utilizados na indústria do petróleo e, na sequência, foram realizados testes de bancada com um dispositivo eletro-mecânico, especialmente desenvolvido, para servir de base para o laser, com potência máxima de 1500 W, direcionado sobre amostras de rochas carbonáticas. A análise de absorção ótica tem por
objetivo compreender melhor o processo de interação do laser com o fluido de perfuração. Os testes de absorção ótica foram realizados para avaliar a absorção da luz, na faixa de comprimento de onda entre 800 nm até 1200 nm. A partir destas informações foi dado o primeiro passo no conhecimento da interação com o fluido de perfuração. Na seqüência da abordagem, um resumo, em nível de pesquisa bibliográfica é apresentado com os estudos, análises e testes de bancada já realizados por vários pesquisadores para verificar o estágio de desenvolvimento desta tecnologia inovadora. A partir deste conhecimento, será possível fazer uma inferência sobre as reais possibilidades desta tecnologia e iniciar um levantamento preliminar sobre os pontos considerados críticos para a sua aplicação, no cenário de perfuração de um poço de petróleo. O cenário de perfuração, como se sabe, é um ambiente agressivo, sujeito a altas vibrações, temperaturas e pressões elevadas. Para concluir, serão apresentados os resultados obtidos em teste de bancada com dispositivo especificamente construído para a fundamentação das conclusões da dissertação. Dentre os aspectos mais relevantes, podemos mencionar: a determinação da durabilidade do sistema, considerando a resistência da lente de focalização ao aquecimento provocado pelo laser e, também, uma avaliação da eficiência do processo sob o ponto de vista do valor obtido para a energia específica. Em resumo, o objetivo final dessa dissertação é o de concentrar em um documento as informações mais atualizadas sobre a utilização do laser na perfuração de rochas e apresentar uma análise, ainda que preliminar, sobre os possíveis pontos de melhoria que permitam viabilizar esta tecnologia no futuro.One of the biggest challenges in drilling the carbonate rocks located at great depths is to overcome low penetration drilling rates that have been obtained in vertical and directional wells. To overcome this challenge, a great effort is being developed on multiple lines of research. All of them are focused in new concepts of drilling procedures and the selection of a drilling system that presents a better performance. To achieve this goal, new procedures are being designed and drilling systems with lower vibration levels are under development. Vibration reduces the efficiency of drilling, also decreases the lifetime of equipment and consequently causes a reduction in reliability of all system and raises the drilling costs. Consequently, new drill bit technologies and drilling systems are being developed and, among the new technologies we can differentiate those that only promote improvements in conventional technologies and those innovative technologies, in which new mechanisms to cut or weaken the rock are used. The drilling assisted laser is one of the most promising mechanism in which the radiant energy beam has the primary function to weaken the rock increasing the performance of drilling process. This dissertation aims to perform an assessment of the possibilities of laser technology in rock drilling applications. The laser will have to pass through the drilling fluid in the future applications so it is very important to understand their physicochemical properties and their mutual interaction. For this reason, the knowledge of the interaction with the drilling fluid is the starting point for this work. First of all, it will be accomplished an analysis of optical absorption in some types of fluid used in the oil industry. After that, it will be performed bench testing with an electro-mechanical device that will support a laser whose maximum power can reach 1500 W and it will be pointed to carbonate rock samples. The optical absorption analysis aims to better understand the interaction of the laser with the drilling fluid. The optical absorption tests are performed to evaluate the absorption of light in the wavelength range from 800 nm to 1200 nm. From this information, it will be taken the first step to understand the interaction with the drilling fluid, which is the starting point for the feasibility study of the use of lasers. Following the approach, a literature review will be presented with the studies, analysis and bench testing already conducted by various researchers to check the stage of development of this new technology. Taking into account this knowledge, it will be possible to make an initial approach about the actual possibilities of this technology and initiate a preliminary survey on the questions that are critical to its application in a drilling scenario in the well construction, an aggressive environment which is subject to high vibrations, high temperatures and pressures. To conclude, we present the results obtained in bench testing with device specifically built for supporting the conclusions of the dissertation. Among the most relevant aspects, we can mention the durability of the system, considering the focusing lens lifetime under the heating effects caused by the laser. Another point, it is to make an evaluation of the performance of drilling process, considering the specific energy. In summary, the ultimate goal of this dissertation is to concentrate in a single document the most current information about the use of laser drilling and present an analysis, though preliminary, about the possible improvement points that will allow the feasibility of this technology in the future.
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葉社榮 e Sair-wing Yip. "Discontinuity survey using laser scanning technology". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B30431670.
Testo completo
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Li, Lian, e 李煉. "Microscopic study and numerical simulation of the failure process of granite". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242005.
Testo completo
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Ersoy, A. "Performance analysis of polycrystalline diamond compact (PDC) core bits in rocks". Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309552.
Testo completo
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PARRA, DARIO PRADA. "NUMERICAL AND EXPERIMENTAL ANALYSIS OF LASER-BASED PERFORATION IN CARBONATE ROCKS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33675@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Atualmente, os lasers de alta potência estão sendo testados pela indústria de petróleo como ferramentas de perfuração. Isto ocorre visando dois objetivos fundamentais: (i) aumentar a eficiência na perfuração de poços (maior taxa de penetração) e (ii) melhorar o controle da geometria do corte de revestimento no processo de canhoneio de poço. Este trabalho tem como objetivo contribuir para a tecnologia de canhoneio a laser em rochas carbonáticas através do desenvolvimento de técnicas para aumentar o volume de rocha removida por unidade de tempo. Estudou-se o comportamento termomecânico das rochas carbonáticas quando um laser é utilizado como ferramenta de perfuração no processo de canhoneio. Este conhecimento, obtido através de experimentos e simulações, forneceu dados para a otimização dos parâmetros de perfuração. Foram investigadas as condições de perfuração estática (não há movimentação do feixe do laser) e dinâmica (o feixe do laser percorre uma trajetória espiral). Além disso, foram investigados os resultados da perfuração sob pressão atmosférica e também utilizando uma câmara de pressão projetada para emular a pressão confinante do reservatório. Foram realizados testes experimentais de perfuração a laser com corpos de prova feitos a partir da rocha Bege Bahia. O Bege Bahia é um afloramento utilizado para simular as rochas encontradas nos reservatórios do Pré-sal. A análise destes corpos de prova foi feita através de inspeção e da caracterização por microtomografia, permitindo observar e caracterizar as propriedades da rocha, além da zona termicamente afetada (ZTA), características geométricas do furo, e valores da energia específica da perfuração. Estes resultados foram comparados com resultados obtidos através de simulações. Na modelagem numérica, o processo de canhoneio foi simulado pelo método de elementos finitos através de um modelo termomecânico elástico transiente axissimétrico que verificou as condições de perfuração. O modelo numérico permitiu observar o comportamento das tensões e temperaturas nos testes que envolvem altas temperaturas e altas pressões. Estas grandezas são usualmente difíceis de serem medidas em ensaios experimentais e, portanto, não foram observadas nos ensaios experimentais discutidos nesta tese. Também foram obtidos através da modelagem numérica valores para propriedades da rocha e da zona termicamente afetada (ZTA), características geométricas do furo, e valores da energia específica da perfuração. Os resultados numéricos obtidos foram comparados com resultados dos ensaios experimentais. Os resultados obtidos mostraram que a condição de perfuração dinâmica consegue remover uma quantidade maior de material e produzir uma ZTA maior em Comparação com o teste estático, gerando uma melhor relação tempo x potência. Os testes estáticos e dinâmicos permitiram se chegar às condições de canhoneio mais eficientes para a perfuração da rocha. A análise de tensões do modelo mostrou uma correlação compatível com o perfil do dano encontrado nos ensaios experimentais.
Currently, the petroleum industry is testing high power lasers as drilling tools. The use of these lasers for this application has two main reasons: (i) to increase the efficiency of well drilling (higher penetration rate) and (ii) to improve the control of the geometry of the hole in the casing during the perforation process of the well. The present thesis has the purpose of contributing to the laser perforation technology in carbonate rocks by developing techniques to increase the volume of rock removed by unit of time. The thermo-mechanical behavior of the carbonate rocks was studied when a laser is used as the drilling tool in the perforation process. This knowledge, obtained through experiments and simulations, supplied data for the optimization of the drilling parameters. Both static (the laser beam does not move) and dynamic (the laser beam moves in a spiral trajectory) drilling conditions were investigated. Also investigated were drilling conditions under atmospheric pressure and under high pressure, where a pressure chamber designed to emulate pressure conditions of reservoirs was used. Experimental tests were performed by laser drilling samples made of Bege Bahia rock. This rock is used to simulate rocks found in pre-salt reservoirs. The analysis of these samples was performed through inspection and microtomography characterization, allowing the observation of properties of the rocks and of the heat affected zone (HAZ), geometric characteristics of the hole, and values of the drilling specific energy. These results were compared to the results obtained by simulations. In the numerical modeling, the perforation process was simulated with the finite element method through a transient axisymmetric thermo-mechanical elastic model that verified the drilling conditions. The numerical model allowed the observation of the behavior of the tensions and temperatures in tests involving high temperatures and pressures. These properties are usually difficult to measure in experimental tests and, therefore, were not measured during the experimental tests discussed in this thesis. Also obtained by numeric modeling were: properties of the rock and of the HAZ, geometric characteristics of the hole, and values of the drilling specific energy. The numeric results obtained were compared to the experimental results. The results obtained showed that the dynamic drilling condition is able to remove a larger amount of material and produce a larger HAZ, compared to the static condition, thus generating a better time x power relation. The static and dynamic tests allowed reaching more efficient conditions for rock drilling. The analysis of the tension of the model showed a compatible correlation with the damage profile found in the experimental tests.
15
Jade, (B) Sridevi. "Numerical Modeling Of Jointed Rock Mass". Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/257.
Testo completoAbstract (sommario):
The behavior of jointed rock mass is very complex and is influenced by many factors such as location of joints, joint frequency, joint orientation and joint strength. A thorough review of literature on different aspects of jointed rock mass indicate that the discontinuities or planes of weakness present in rock mass significantly influence its behavior. Numerous experimental tests were conducted to study the behavior of natural as well as artificial joints in rocks. Laboratory tests are time consuming and give results applicable to specific joint fabric and confining pressure. Numerical methods are the best alternative to laboratory tests to study the behavior of jointed rock mass. With the advent of computers numerical methods of analysis have become very popular, as they are highly flexible and can represent all complex geometries and material behavior. The accuracy of a numerical model depends upon the how well constitutive relations for the jointed rock mass are defined in the analysis. Empirical relationships for describing the mechanical behavior of discontinuities obtained from scaling the laboratory data is crucial unresolved problem, which will affect the quality of results obtained. One more important aspect in the numerical model is strength criteria used for jointed rock mass. The applicability of existing strength criteria to a particular jointed rock has to be carefully examined before they are used.
Equivalent continuum approach simplifies the modeling of jointed rock mass as the joints are not modeled separately. Instead in equivalent continuum approach the jointed rock mass is represented by an equivalent continuum whose properties are defined by a combination of intact rock properties and joint properties. The accuracy of this kind of modeling depends upon the relationships used to define the jointed rock mass properties as a function of intact rock properties and joint properties. In the present study, an effort has been made (i) to establish empirical relations to define the properties of jointed rock mass as a function of intact rock properties and joint factor (ii) to develop a numerical model based on equivalent continuum approach using the empirical relations derived above, for easy and efficient modeling of jointed rock mass (iii) comparison of existing strength criteria for jointed rock masses using the equivalent continuum model developed above (iv) Modeling of joints explicitly and comparing these results with the equivalent continuum model results.
Empirical relationships expressing the uniaxial compressive strength and elastic modulus of jointed rock as a function of corresponding intact rock properties and joint factor have been derived based on the statistical analysis of large amount of experimental data of uniaxial and triaxial tests collected from the literature. The effect of joints in the jointed rock is taken in to account by the joint factor. A comparative study of the empirical relationships arrived by the above analysis has been made to choose the best relation for the numerical analysis. Empirical relationships thus arrived for jointed rock mass are used in the equivalent continuum approach to represent the jointed rock properties as a combination of intact rock properties and joint factor. Equivalent continuum model developed is thoroughly tested, validated and applied for single, multiple and block jointed rocks. The equivalent continuum model developed has been applied for analysis of the power cavern for Shiobara power station. Different strength criteria available for jointed rock namely Mohr-Coulomb, Hoek and Drown, Yudhbir et al. and Rarnamurthy are incorporated in the equivalent continuum model to evaluate their applicability for jointed rock masses. Ramarnurthy's strength criterion gives the best values of failure stress for almost all the test cases and hence used in the equivalent continuum model.
Alternatively, the joints in jointed rock mass are represented explicitly using interface element in the nonlinear finite element analysis. The explicit finite element model has been tested and validated using the experimental stress strain curves and failure stress values. Comparison of results obtained using equivalent continuum analysis and explicit modeling of joints has been given in the form of stress strain curves and failure stress plots for jointed rock masses along with the experimental results.
Some of the major conclusions from the present study are as follows. Statistical relationships arrived to express the properties of the jointed rock as a function of intact rock and joint factor give a fair estimate of jointed rock in the absence of experimental data. Equivalent continuum model developed using statistical relations arrived above simplifies the numerical modeling of jointed rock to a large extent and also gives a fair estimate of jointed rock behavior with minimum input data. From the equivalent continuum analysis of Shiobara power cavern, it can be concluded that this approach is very advantageous for modeling highly discontinuous systems provided the joint factor is estimated properly so that it represents the real fabric of the joints present in the system. Comparison of different strength criteria shows that Ramamurthy's strength criterion is the best for jointed rocks. When the rock mass has one or two major joints it is advantageous to model it explicitly so that the behavior of the joint can be studied in detail. Explicit representation of the joints in the finite element analysis gives a lair estimate of the zones most susceptible to failure in a jointed rock. From comparison of experimental values, equivalent continuum model results and the explicit joint model results, it can be concluded that results obtained using equivalent continuum model are nearest to the experimental results in almost all the cases.
16
Kortz, Karen Melissa. "Alternative conceptions of introductory geoscience students and a method to decrease them /". View online ; access limited to URI, 2009. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3367995.
Testo completo
17
LINS, JOAS P. "Determinacao de hafnio e zirconio em materiais geologicos por analise por ativacao com neutrons". reponame:Repositório Institucional do IPEN, 1992. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10289.
Testo completoAbstract (sommario):
Made available in DSpace on 2014-10-09T12:36:56Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:56:25Z (GMT). No. of bitstreams: 1 04451.pdf: 1033007 bytes, checksum: 54e030bafa03853c9dedda585e3f53db (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
18
Vennemann, Torsten Walter. "A geochemical and stable isotope study of some rocks from the Bandelierkop formation, southern marginal zone of the Limpopo Belt, South Africa( vol.1 Text)". Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/23476.
Testo completoAbstract (sommario):
The Bandelierkop Formation of the Southern Marginal Zone (SMZ) of the Limpopo Belt consists of metamorphosed ultramafic, mafic and sedimentary rocks. Metamorphic conditions indicated by the petrography of these different rock groups are consistent with upper amphibolite to granulite facies. The ultramafic and mafic rocks are geochemically akin to peridotitic-pyroxenitic intrusive rocks and high-Mg basalts respectively. Metamorphism of these two rock groups in the SMZ was an essentially closed system process, except for the highly volatile phases such as H₂O and CO₂. The metasediments appear to represent a sequence of high (Mg+Fe)-greywackes and/or deep-water shales with minor amounts of iron formation material. The unusually mafic character of the metasediments can be ascribed to a high ultramafic + mafic source component to the original sediment. Some modification of the major and trace element compositions of the pelitic rocks has been caused by the removal of partial melts and the metamorphism of the pelitic rocks is not therefore considered to have occurred under closed system conditions. Variable extraction of partial melts is implied by the chemical variations shown by the pelitic rocks and is also suggested by the presence of large pegmatitic felsic bodies which are commonly found close to the pelitic rocks. Detailed petrographic study of the Bandelierkop Formation rocks suggests an increase in metamorphic grade, and/or a decrease in water activity, from south to north within the Southern Marginal Zone. Peak metamorphic conditions of 730°C + 65°C at pressures of 6.1 ± 1.5 kbars may be deduced from a careful application of several cation thermometers and barometers on selected mineral analyses. A rigorous application of garnet-biotite thermometry to the pelitic rocks indicates that the transition from orthoamphibole gneisses in the south to orthopyroxene-bearing rocks in the north of the SMZ terrane, is a function of changing biotite composition and/or decreasing water activities rather than an increase in metamorphic temperatures. In contrast to the major and trace element data, the stable isotope data for the ultramafic and mafic rocks in the SMZ indicate open system behaviour for some of these rocks, but closed system behaviour for the pelites. Extraction of SO to 70% partial melts from the pelitic rocks, should not, however, have affected the δ¹⁸O value of the restite. Petrological and stable isotope data in the SMZ rocks are consistent with retrogression in all these rocks and open system behaviour for oxygen in some ultramafic and mafic rocks, being caused by the crystallization and accompanying fluid release of melts produced during prograde metamorphism of the pelitic rocks. Small scale (-5 to 30m's) heterogeneity is implied by both oxygen and carbon stable isotope compositions of closely spaced rock samples, even for those collected from within large "shear zones", suggesting small fluid/rock ratios for most of the samples in the high-grade terrane or heterogeneous stable isotopic compositions of the fluids. Furthermore, a similarity in mineral-mineral stable isotope fractionation factors is observed for all the pelitic rocks, including the orthoamphibole gneisses found immediately south of the orthopyroxene isograd. These features preclude the presence of pervasive fluid infiltration after peak metamorphism. Two implications are, that granulite facies metamorphism in the SMZ terrane was not caused by an influx of mantle derived CO₂-rich fluid and, that the orthoamphibole gneisses are not retrogressed equivalents of the granulites found to the north of the orthopyroxene isograd. It is suggested that this isograd represents a change in the water activities of the rocks during metamorphism. Apparent disequilibria in mineral - mineral stable isotope fractionations observed amongst different minerals within any one pelitic rock, may be explained by a combination of the crystallization of residual melt within these rocks and oxygen diffusion amongst minerals which have not reached their oxygen-closure. The concordant quartz-plagioclase, quartz-biotite and plagioclase-biotite oxygen isotope equilibration temperatures are taken to represent minimum crystallization temperatures for the melts (-560°C), while successively higher quartz-orthopyroxene, quartz-amphibole and quartz-garnet oxygen isotope equilibration temperatures are a function of increasing closure temperatures for the orthopyroxene, amphibole and garnet respectively. The minimum estimate to peak metamorphic temperatures is given by the quartz-garnet oxygen isotope temperature averaging 736 + 52°C. If oxygen diffusion experiments performed in hydrothermal systems are appropriate for the SMZ rocks, then cooling rates for the SMZ terrane could have been as low as 12 to 25°C/My over a temperature range of 480 to 600°C. Stable isotope modeling of hypothetical fluids that may have been in equilibrium with the high-grade rocks, suggests that a mixture of CO₂ and H₂O, with CO₂/H₂O mole ratios > 0.1 can precipitate both quartz and carbonate of stable isotope composition similar to those determined for quartz and carbonate from the mineralized Archaean lode gold deposits of the Murchison and Pietersburg greenstone belts. A model involving granulite facies metamorphism, partial melt extraction and subsequent release of fluids, Au, K and S upon crystallization of such melts, appears to be viable for gold mineralization occuring in the adjacent lower grade greenstone belts and in the high-grade terrane of the Southern Marginal Zone.
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Zhang, Wenbing. "A method and program for quantitative description of fracture data and fracture data extrapolation from scanline or wellbore data /". May be available electronically:, 2001. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Testo completo
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Tourchi, Saeed. "THM analysis of argillaceous rocks with application to nuclear waste underground storage". Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/670899.
Testo completoAbstract (sommario):
Argillaceous rocks (Stiff sedimentary clays) provide the geological background to many civil engineering projects. In recent years, interest in these types of material has increased, because they are being considered as potential host geological media for underground repositories of high-level radioactive waste (HLW). The possible use of these types of clay as geological hosts for radioactive waste has prompted the construction of several underground laboratories. Among the very different topics addressed in the Underground Research Laboratories (URLs), the thermo-hydro-mechanical (THM) behaviour of the host rock is the one that most concerns the present research. In situ observations have revealed a considerable number of coupled THM processes in the operation of an HLW repository.
In this context, the main objective of the present study is to describes the performance, observations and interpretation of the full-scale in situ heating test conducted on Callovo-Oxfordian (COx) claystone in the Meuse / Haute-Marne URL simulating a heat-emitting, high-level radioactive waste disposal concept. The test is fully instrumented, and attention is focused on the near-field region's the THM behaviour consisting of the sleeve surrounding the heater and the host rock. The interpretation of the test is assisted by the performance of a coupled numerical analysis based on a coupled formulation incorporating the relevant THM phenomena. The calculations have used a reference isothermal constitutive model especially developed for this type of material. The reference model later has been extended to non-isothermal condition by incorporating thermal dependency of strength parameters and stiffness. The thermomechanical model has been successfully used in the simulation of triaxial tests on COx claystone. The numerical analysis performed has proved able to represent the progress of the experiment very satisfactorily. The performance and analysis of the in-situ test has significantly enhanced the understanding of a complex THM problem and have proved the capability of the numerical formulation and non-isothermal constitutive model to provide adequate predictive capacity.Las rocas argiláceas (arcillas sedimentarias rígidas) proporcionan el trasfondo geológico de muchos proyectos de ingeniería civil. En los últimos años, ha aumentado el interés por este tipo de materiales, porque están siendo considerados como posibles medios geológicos hospedadores de depósitos subterráneos de desechos radiactivos de alta actividad (HLW). El posible uso de este tipo de arcilla como hospedante geológico de residuos radiactivos ha impulsado la construcción de varios laboratorios subterráneos. Entre los muy diferentes temas que se abordan en los Laboratorios de Investigación Subterránea (URL), el comportamiento termo-hidromecánico (THM) de la roca huésped es el que más preocupa a la presente investigación. Las observaciones in situ han revelado un número considerable de procesos THM acoplados en el funcionamiento de un depósito de HLW. En este contexto, el objetivo principal del presente estudio es describir el rendimiento, las observaciones y la interpretación de la prueba de calentamiento in situ a gran escala realizada en piedra arcillosa Callovo-Oxfordian (COx) en la URL de Mosa / Haute-Marne simulando un calor- concepto de eliminación de desechos radiactivos de alto nivel emisor. La prueba está totalmente instrumentada y la atención se centra en el comportamiento del THM de la región de campo cercano que consiste en la manga que rodea el calentador y la roca anfitriona. La interpretación de la prueba es asistida por la realización de un análisis numérico acoplado basado en una formulación acoplada que incorpora los fenómenos de THM relevantes. Los cálculos han utilizado un modelo constitutivo isotérmico de referencia especialmente desarrollado para este tipo de material. Posteriormente, el modelo de referencia se ha ampliado a condiciones no isotérmicas incorporando la dependencia térmica de los parámetros de resistencia y rigidez. El modelo termomecánico se ha utilizado con éxito en la simulación de ensayos triaxiales en arcillas COx. El análisis numérico realizado ha demostrado ser capaz de representar de forma muy satisfactoria el avance del experimento. El rendimiento y el análisis de la prueba in situ ha mejorado significativamente la comprensión de un problema THM complejo y ha demostrado la capacidad de la
21
Hodge, Martin Owen Petroleum Engineering Faculty of Engineering UNSW. "Avoiding borehole failure by time-dependent stability analysis of stressed poroelastic rocks". Awarded by:University of New South Wales. School of Petroleum Engineering, 2006. http://handle.unsw.edu.au/1959.4/27270.
Testo completoAbstract (sommario):
Wellbore stability is a critical issue when drilling through tectonically stressed and complex geological conditions. Understanding wellbore stability issues before a well is drilled enables better planning of the drilling operation and helps to avoid borehole failure. This is of particular importance in underbalanced drilling where we are limited with our choice of drilling mud densities. This thesis examines the impact of fluid pressure change on wellbore stability during underbalanced drilling by using a timedependent poroelastic model. The poroelastic behaviour is analysed using numerical and analytical models. The finite element method (FEM) is used for the numerical model. Some simple techniques are developed and implemented to increase the speed and stability of the FEM solution. The common assumptions of plane strain and plane stress are explored. It is shown that the plane strain assumption results in high error while the error for plane stress is low. It is also shown that use of plane strain predicts more instability than use of plane stress and the stability difference is significant. From this it is concluded that the plane stress assumption should be used instead of the commonly used plane strain assumption. A sensitivity analysis is conducted to demonstrate the effect of several variables on wellbore stability during underbalanced drilling. These variables include mean in-situ horizontal stress, deviatoric in-situ horizontal stress, bulk compressibility and permeability. I various ways changes in these variables were shown to change the chance of shear failure, early time tensile failure through exfoliation and late time tensile failure through hydraulic fracture initiation.
22
Chen, Youqing. "Observation and analysis on features of microcracks and pore spaces in rocks". Kyoto University, 2002. http://hdl.handle.net/2433/150150.
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23
Pereira, Janaina Luiza Lobato. "Permeability prediction from well log data using multiple regression analysis". Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3368.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains xiii, 82 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 41).
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Yang, Ying Ping. "Electromagnetic characteristics of synthetic rocks, and sulphide and oxide mineral assemblages". Thesis, The University of Sydney, 1995. https://hdl.handle.net/2123/26849.
Testo completoAbstract (sommario):
An understanding of the electromagnetic characteristics of sulphide-bearing and magnetite-bearing rock and ore samples is important in the interpretation of electromagnetic (EM) exploration data. In this research study of electromagnetic conductivity characteristics, a theoretical measurement basis was developed, synthetic analogue materials were studied and the theory and analogue results were related to rock samples of varied mineralogy, texture and mineral concentration.
The theory developed for cylindrical core sample EM measurements agreed with experiments performed on standard conductive samples using a multi-frequency coilbridge system in the 10 kHz to 4 MHz range. Skin effect was an important limitation to EM measurements on conductive (o > 1000 S/m) core samples but can be effectively monitored by spectral measurements.
Measurements on 104 synthetic cores, of five types, revealed the relationship between apparent EM conductivity and the structure and arrangement of the conducting materials. These analogue cores contained a range of conductors, including copper wires, graphite powder, aluminium particles and magnetite/ilmenite grains, set in a matrix of insulating plaster or wax, representing models of layered, stringer, disseminated, network, massive and magnetite-rich mineralisation. A mechanism attributed to magnetic loss produced unrealistically high EM apparent conductivities for magnetite—bearing samples, especially at low frequencies (f < 100 kHz). For a conductive magnetite sample (6 > 1 S/m), the effect of magnetic loss can be eliminated at high frequencies (f > 400 kHz) and the ohmic conductivity of the magnetite sample can then be estimated.
A total of 254 sulphide—bearing and magnetite-rich samples from 15 different geological environments constituted the natural materials used in this research. The sulphides, including chalcopyrite, pyrite, galena, sphalerite and pyrrhotite, and magnetite occurred in varying proportions and diverse fabrics in these samples. Complementary measurements of galvanic conductivity, density and magnetic susceptibility and thin section mineralogy results provided essential auxiliary information for the analysis of the EM data. The electrical conductivity of a rock is controlled by its mineralogy, mineral habit, mode of connectivity of conducting minerals and rock fabric. Texture may have an overwhelming effect on the EM and galvanic conductivities of rock samples. The conductivities of the massive sulphides studied ranged from thousands of S/m to a few tens of thousands of S/m for pyrrhotite, hundreds of S/m to thousands of S/m for chalcopyrite and galena, and a few S/m to hundreds of S/m for pyrite. Sulphide-free magnetite-bearing rocks generally are, at best, only moderate conductors (l S/m to 10 S/m) and then only with a large proportion of magnetite. Coarse grainsize in massive magnetite significantly enhances conductivity (up to hundreds of S/m). There is a clear contrast in the conductivity behaviour of networks and discrete aggregations of conducting minerals. When pyrrhotite is present, it usually dominates the conductivity response. Chalcopyrite also makes an effective contribution, whereas pyrite and magnetite often do not.
Conductivity modelling of concentration variations can be achieved using appropriate
empirical relations for different cases. For dispersed conducting euhedral cubic minerals such as pyrite or magnetite, Maxwell's mixing law can be applied. When a conducting material, such as pyrite or magnetite, changes from a dispersed phase to conductive channels with increasing concentration, percolation theory can be applied The observed critical concentrations, where the conducting minerals start to change from dispersed phases to continuous phases electrically, are 20 percent to 50 percent for pyrite, 40 percent to 80 percent for magnetite. For pyrrhotite or Chalcopyrite, present as continuous conducting minerals, it appears that a power law can be applied and the power exponent may vary between 1.5 and 5.5, depending on the conducting network structure.
For a laboratory core sample with dispersed conducting particles, the calculated and
observed diminution of measured EM conductivity with an increase in diameter of the
sample suggests that EM exploration methods may not work well in conductivity
prospecting for a disseminated target. For a heterogeneous mineralised rock sample,
applications of laboratory—determined EM conductivity to field situations generally need to take account of the structure or texture of the conducting minerals.
The research results of this thesis are intended as a contribution to the understanding of laboratory electromagnetic conductivity measurements. The results have important applications to the designs and evaluations of field-based EM systems in the exploration for metallic lustre sulphide and oxide economic mineral deposits in a variety of geological settings.
25
Keene, David G. "An analysis of fracture systems, lithologic character and kinematic history of Paleozoic rock formations in a portion of southeastern Indiana". Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/722793.
Testo completoAbstract (sommario):
This is an analysis of fractures occurring within the Paloezoic sedimentary rocks in a portion of southeastern Indiana. Fifteen hundred seventy-two fractures were used in analysis of distribution, orientation, pervasiveness, persistence, and intensity. The data collected is representative of eight counties and seventeen different collection sites.All fracture data were given an associated numerical value identifying each variable used for analysis and recorded into computer data files. A computer program was used for statistical analysis and construction of equal area nets which graphically displayed the distribution of variables. The compilation of the fracture data allowed for close interpretative analyses of variables and correlation of the orientation and distribution of the fractures within the study area.This study revealed that two orthogonal fracture systems exist in southeastern Indiana. The fracture set containing the largest percentage of those measured is oriented N11W with its compliment oriented N73W. The orientation of the second largest fracture set is N8E with its compliment oriented N82°W.The effects of the tectonic history as well as contemporary stress on the area are discussed relative to their effects on the overall distribution of fracture sets.Evidence is presented to substantiate a reactivation of the Cincinnati Arch as indicated in the Devonian-Mississippian lithologic units from data collected in the southeastern portion of the study area. Fracture data correlating to these units displays a rotation of the major fracture set maxima 90w. This data is supported by radiometric dates from the Belfast member of the Brassfield Limestone in which Laskouski, et.al., correlated a reactivation of the arch.Also within this study are lithologic descriptions of all the Paleozoic formations used for data collection. These descriptions were developed over a three year period from extensive field observation.A map of the study area is presented displaying the distribution and orientation of the fractures recorded at each data collection site.Department of Geology
26
Johnson, Aaron W. "Regional-scale geochemical analysis of carbonate cements : reconstructing multiple fluid interactions related to dolomitization and mineralization in lower carboniferous rocks of the Irish Midlands /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3101027.
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Arns, Christoph Hermann Petroleum Engineering Faculty of Engineering UNSW. "The influence of morphology on physical properties of reservoir rocks". Awarded by:University of New South Wales. Petroleum Engineering, 2002. http://handle.unsw.edu.au/1959.4/18257.
Testo completoAbstract (sommario):
We consider the structural and physical properties of complex model morphologies and microstructures obtained by Xray-CT imaging. The Minkowski functionals, a family of statistical measures based on the Euler-Poincaré characteristic of n-dimensional space, are shown to be sensitive measures of the morphology of disordered structures. Analytic results for the Boolean model are given and used to devise a reconstruction scheme, which allows one to accurately reconstruct a complex Boolean structure given at any phase fraction for all other phase fractions. The percolation thresholds of either phase are obtained with good accuracy. From the reconstructions one can subsequently predict property curves for the material across all phase fractions from a single 3D image. We illustrate this for transport and mechanical properties of complex Boolean systems and for experimental sandstone samples. By extending the Minkowski functionals to parallel surfaces using operations from mathematical morphology, a powerful discrimination of structure is obtained. Further the sensitivity of the Minkowski functionals under experimental conditions is analysed. Accurate calculations of conductive and elastic properties directly from tomographic images are achieved by estimating and minimising several sources of numerical error. Simulations of electrical conductivity and linear elastic properties on microtomographic images of Fontainebleau sandstone are in excellent agreement with experimental measurements over a wide range of porosity. The results show the feasibility of combining digitised images with transport and elasticity calculations to accurately predict physical properties of individual material morphologies. We show that measurements of properties based on microtomographic images are more accurate than those based on conventional theories for disordered materials. We study the elastic behaviour of model clean and cemented sandstones. Results are in excellent agreement with available experimental data, and are compared to conventional theoretical and empirical laws. A new predictive empirical method is given for predicting the elastic moduli of sandstone morphologies. The method gives an excellent match to numerical and experimental data.
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Zack, Thomas. "Trace element mineral analysis in high pressure metamorphic rocks from Trescolmen, Central Alps". [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=963753924.
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CARRAPATOSO, CARLA MASSIGNANI. "ANALYSIS OF OPTIMIZATION ANALYTICAL MODELS BASED ON SPECIFIC ENERGY APPLIED TO EVAPORITE ROCKS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=17928@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A indústria do petróleo sempre investiu em pesquisa de modo a otimizar as operações de perfuração. O objetivo é desenvolver tecnologia para aumentar a taxa de penetração e reduzir o tempo não produtivo durante a perfuração. As recentes descobertas de campos de petróleo localizados em camadas profundas, cobertas por espessas camadas de evaporitos aumentaram a importância dos estudos associados com a otimização nas bacias marítimas brasileiras do pré-sal. Existem muitos modelos para a previsão da taxa de penetração baseados em parâmetros operacionais tais como peso sobre a Broca (WOB), taxa de penetração (ROP), torque a rotação da broca (RPM), e resistência à compressão da rocha. A energia mecânica específica é o parâmetro freqüentemente usado como referência para estabelecer a eficiência das operações de perfuração assim como identificar o que deve ser modificado de modo a melhorar a perfuração. Esta dissertação analisa diferente métodos de otimização de perfuração baseados na energia mecânica específica. Estes métodos são aplicados a um conjunto de dados que consiste nos parâmetros de perfuração (WOB, T, RPM, ROP) obtidos ao longo dos trechos de evaporitos em 6 poços perfurados com broca PDC. Dados de ensaios de perfuração de grande escala realizados em laboratório também foram analisados nesta dissertação. Este estudo conclui que a energia mecânica específica ideal em muitas das operações está relacionada com uma parcela da resistência à compressão confinada da rocha.
The oil industry has always invested in research in order to optimize drilling operation. The aim is to develop technology to increase the rate of penetration and reduce the non-productive time during drilling. The recent discovery of large oil reserves located in very deep layers that are covered with thick salt layers has increased the importance of studies associated with drilling optimization in Brazilian offshore sub-salt oil fields. There are many models to predict rate of penetration based on operational parameters, drill bit type and rock properties. The specific mechanical energy is the parameter often used as reference to guide the efficiency of the drilling operation as well as to identify what has to be changed in order to improve the drilling. This dissertation analyses different methods for drilling optimization based on the specific mechanical energy. These methods are applied to a data set that consists of drilling parameters (weight-onbit, torque, rate of penetration, rotation per minute) for 6 wells along the sections of evaporites. Large-scale drilling experiments carried out at the laboratory were also used. The study concludes that the ideal specific mechanical energy on most operations is related to a fraction of the confined compressive strength of the rock.
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Halliday, Jennifer M. "Magnetic characterisation and palaeointensity analysis of rocks from selected I-type granitic plutons". Thesis, Kingston University, 2008. http://eprints.kingston.ac.uk/20395/.
Testo completoAbstract (sommario):
Absolute palaeointensity data are crucial to investigating the behaviour of the geomagnetic field. Long-term global palaeomagnetic databases are compiled with the aim of documenting the evolution of the geomagnetic field. However the temporal and spatial distribution remains limited, partly due to a lack of 'suitable' material in critical time windows, or poor magnetic behaviour of these rocks during experiments. Therefore it would be useful to have other potential sources of palaeointensity data in the surface rock record. Granitic intrusions occur frequently throughout the geological record, are often well exposed and well dated. However, granitic rocks have not previously been fully exploited in palaeointensity studies, due to their perceived lower primary magnetic content and problems associated with the stability of their magnetic signatures. Plutons show an internal grain-size variation and contain mafic enclaves, xenoliths and sheets derived from the primary melt. Therefore a range of magnetic behaviour, and hence a range of potential suitability for palaeointensity work can be expected within a single pluton. To our knowledge, there are no recorded rock magnetic or palaeomagnetic investigations addressing the question of whether granites are generically unsuitable, for palaeointensity work. To test this hypothesis, three I-type granitic plutons were characterised in terms of their magnetic suitability for palaeointensity analysis - including the Ross of Mull Pluton and Loch Doon Complex, SW Scotland and selected intrusions from the Coastal Batholith, Peru. Characterisation was achieved though extensive rock magnetic, palaeomagnetic and SEM analysis which enabled the magnetic properties of the samples to be determined. 180 samples were investigated using the Coe-modified Thellier technique to determine whether reliable palaeointensity data can be obtained. Magnetic characterisation and SEM analysis reveal that the magnetic mineralogy of the granitic intrusions is dominated by multidomain (MD) Ti-poor titanomagnetite. Exsolution textures observed in the Fe-Ti oxide grains are responsible for creating grains with SD-MD grain sizes. Stable univectoral remanences are usually accompanied by narrow unblocking temperatures where most NRM is lost between 560- 580°C. This makes obtaining acceptable PI data difficult, but by no means impossible. PI experiments were of variable success. Experiments including pTRM and pTRM tail checks and standard acceptance criteria were used to assess the quality of the results. The Ross of Mull rocks yielded no PI determinations. However, the Loch Doon Complex and intrusions from the Coastal Batholith were more triumphant with success rates of 28% and 57% respectively. The Loch Doon pluton (408Ma) is calculated to have a pluton average 8.2[mu]T with standard deviation 4[mu]T. The main reasons for failure of PI experiments are weak NRM, alteration and unstable MD behaviour. Experimental success correlates with the perceived geological complexity at each field area, where it is observed that simpler intrusions with less complicated cooling histories yield rocks with a: more stable magnetic signature and allow PI data to be derived. Results indicate that the more mafic rocks sampled in each pluton produced the best quality PI data. PI estimates were made on samples from Peruvian intrusives. The Anta ring dyke and Chasquitambo pluton give a site average of 15[mu]T with standard deviation 13.5[mu]T. Large deviation is caused by a single estimate, which at 46.7±18.4[mu]T is significantly different from the values found from other sites. Remaining sites have PI within error, however it should be noted that according to the K-Ar dates (Wilson, 1975) emplacement of the two separate intrusions occurred millions of years apart, 70.7±1.6Ma and 61±0.7Ma respectively. Samples from the Sayan pluton (61.2±0.4Ma) yield an average PI 25.4[mu]T ±7.7[mu]T. Arai plots are dominated by curvature, pTRM checks and rock magnetic experiments indicate that curvature is not caused by alteration and can be attributed to MD phenomena. PI estimates are made using the end-point method and from linear segments were possible, consistency between the two methods was demonstrated. This research reveals the potential of I-type plutons to provide reliable palaeointensity data.However, the PI data presented here must be considered as preliminary as no cooling rate or anistropy corrections have been applied.
31
Ruth, Dawn C. S. "Impact Spherules From Western Australia : A Textural Analysis of Really Old Tiny Rocks". Oberlin College Honors Theses / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1411722854.
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Zangerl, Christian Josef. "Analysis of surface subsidence in crystalline rocks above the Gotthard highway tunnel, Switzerland /". [Zurich] : [s.n.], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15051.
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Louchnikov, Vadim. "A numerical investigation into the stress memory effect in rocks". Click here to access, 2004. http://hdl.handle.net/2440/37740.
Testo completoAbstract (sommario):
Reliable and inexpensive methods of in-situ stress measurement have been sought for more than 40 years. A number of non-destructive core-based methods of in-situ stress determination are currently available, among which Deformation Rate Analysis ' DRA ' and Acoustic Emissions ' AE ' method have the most promising potential due to their ability to measure stress as opposed to strain, which is measured by strain recovery techniques. The DRA and AE method are similar in their utilisation of a phenomenon termed Kaiser effect in the case of AE and deformation memory effect in the case of DRA. The KE/DME is defined as a recollection of a maximum stress a rock core had been subjected prior to its retrieval from the in-situ environment. The physical nature of this phenomenon has not however been universally established. In this study, interaction of microcracks as the most probable cause of the KE/DME, was investigated. To reproduce the damage that occurs to rock at the micro level, a discrete element modelling code was required, which enabled dynamic failure propagation to be modelled. Commercially available code PFC [ superscript 2D ] was found to be suitable for this purpose due to its ability to explicitly model mechanical damage in rocks. The numerical model was based on a real prototype - a sandstone rock core, which had also been previously subjected to the DRA. Although the bulk of the numerical tests were conducted on intact rock models, it was found that changes in the lithology and introduction of discontinuities did not have significant effect on the DME. Influence of the confining stress on the DME was confirmed. It was assumed that only the highest historical stress could be determined reliably using the DRA technique. The ability of the numerical model to reproduce the DME was validated. The link between the DME and development of microcracks was established. The results of the study encourage further use of the code for understanding the micromechanical behaviour of rocks under loading.Thesis (M.Eng.Sc.)--Australian School of Petroleum, 2004.
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Hasenohr, Edward Joseph. "Statistical analysis of trace element distributions in rocks and soils of the Breckenridge Mining District Summit County, Colorado /". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487327695621244.
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35
Fang, Zhi. "A local degradation approach to the numerical analysis of brittle fractures in heterogeneous rocks". Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/8122.
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36
Hutchison, Courtney Louise. "Stratigraphy, micropalaeontology and stable isotope analysis of Tertiary rocks in the North Canterbury region". Thesis, University of Canterbury. Geological Sciences, 2012. http://hdl.handle.net/10092/7647.
Testo completoAbstract (sommario):
Stable isotope, stratigraphic and micropalaeontological studies provide an insight into the preservation of Tertiary global cooling episodes in shelf carbonate rocks from the Mandamus-Pahau District in North Canterbury. Local shelf carbonate isotope analysis (δ13C and δ18O) shows these shelf rocks have not retained the original sea-water isotopic signature but have been altered during burial diagenesis. The Palaeocene to Late Eocene Coal Creek Formation from this district is a glauconite-rich, inner shelf unit transitioning to a mid-outer shelf environment. Separation of this unit from the Mid-Late Oligocene Cookson Volcanic Group is marked by a ~3-4 Ma hiatus representative of the Marshall Paraconformity. The Marshall Paraconformity is inferred throughout the district due to a distinct break in style and sedimentation from the Late Eocene until the Mid-Late Oligocene. Cookson Volcanic Group tuffaceous beds and pillow basalts represent localised intra-plate volcanism that occurred prior to the deposition of the Late Oligocene Flaxdown Limestone. This Oligocene limestone represents a mid shelf, bryozoan and algal-rich grainstone. Widespread development of this carbonate unit illustrates the absence of tectonically derived sediments prior to the deposition of the Pahau Siltstone Member. The Early Miocene marks the initiation of a new tectonic regime in New Zealand, with the deposition of the inner shelf, quartz-rich Pahau Siltstone Member due to tectonic associated uplift and erosion.
These shelf sediments proved inadequate as a record of global climate excursions, with grainsize and the dominance of burial diagenesis limiting their use in global isotope records. Shelf sediments seen in this study mostly consist of grainstones or sandstones with the coarse grainsize of these units allowing a high flow of pore fluids through sediments. These pore fluids occurred out of equilibrium with bioclasts within these Tertiary units, increasing the alteration potential of bioclasts. This thesis provides strong evidence for problematic global isotopic signatures in local shelf sediments due to grainsize and diagenesis, yet other studies have proved it is possible to reconstruct the global isotope curve from shelf sediment records. Accurate shelf records depend on proxies less prone to diagenetic alteration that act as a reliable gauge of local and global environmental change.
37
Tadesse, Tarekegn. "A stratigraphic, structural and metamorphic analysis of Dalradian Rocks west of Ballater, northeast Scotland". Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241492.
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Eriksson, Sarah. "Tracing the Origin of Metasedimentary Rocks in the Faroe-Shetland Basin". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-297082.
Testo completoAbstract (sommario):
The Faroe-Shetland region has been exposed to a long history of tectonic events and the geology in the area is rather complex. This history has led to the formation large metasedimentary deposits, though the origin of these deposits is not yet fully understood. Possible source areas are Greenland, Norway and Scotland. To give a further understanding of the geology in the Faroe-Shetland basin and its regional relationship this study will analyze metasediments to classify them and compare them with other related sediments. Geochemical, petrographical and isotopic data will be for classification. Through this comparison it is evident that the metasediments from the Faroe-Shetland basin contain remnants from several different deposits and cannot be rated to one specific origin. This is shown by the 143Nd/ 144Nd , 87Sr/ 86Sr and 206Pb/204Pb , 207Pb/204Pb, 208Pb/204Pb isotope ratios found in the Faroe-Shetland basin compared with other possible source areas from Greenland, Norway and Scotland. This has shown that the isotope from the Faroe region correlate well with Caledonian traces from both Greenland and Scotland. Though the Torridonian sandstone from Scotland can also be correlated with the metasediments in the Faroe-Shetland basin.Regionen kring Färö-Shetland bassängen har blivit utsatt för en lång historia av tektoniska orogeneser och extensioner vilket har lett till geologisk komplexitet i området. Metasediment täcker stora delar av bassängen, men ursprunget av dessa avsättningar är ännu inte helt fastställt. Grönland, Skottland och Norge är några av de föreslagna ursprungsområdena till de sedimentära avsättningarna. För att fördjupa förståelsen kring dessa metasediment och deras regionala relationer till andra platser, så fokuserar denna studie på att jämföra och klassificera metasediment från Färö-Shetland bassängen. Geokemisk, petrologisk och isotopdata kommer användas för klassifikation, medan isotopdata huvudsakligen kommer att ligga till grund för jämförelsen av troliga sedimentära källor. Genom denna jämförelse så har det blivit tydligt att metasedimenten från Färö-Shetland bassängen innehåller spår från flertalet olika områden och avsättningarna kan inte enbart förklaras utifrån ett ursprungsområde. Detta framgår genom isotopförhållandena 143Nd/144Nd , 87Sr/86 Sr and 206Pb/204Pb , 207Pb/204Pb, 208Pb/204Pb, vilka hittats i Färö-Shetland bassängen i jämförelse med andra möjliga källor från Grönland, Skottland och Norge. Detta påvisar en komplex metasedimentär sekvens, en sekvens efter den komplexa tektoniska historian.
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Kassos, Gabriel Philip Steltenpohl Mark G. "Structural, isotropic, and kinematic analysis of eclogite-facies shear zones and associated structures, Lofoten, North Norway". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Geology_and_Geography/Thesis/Kassos_Gabriel_39.pdf.
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Millett, John Michael. "Geochemical stratigraphy and correlation within the Faroe Islands Basalt Group with developments in the analysis of large igneous province deposits from well data". Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215221.
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Sorber, Samuel C. "Geologic Map and Structural Analysis of the Twin Rocks 7.5 Minute Quadrangle, Wayne County, Utah". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1352.pdf.
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Jurgawczynski, Mathieu. "Predicting absolute and relative permeabilities of carbonate rocks using image analysis and effective medium theory". Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441333.
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Nejati, Houshin. "Analysis of physical properties and thermo – mechanical induced fractures of rocks subjected to microwave radiation". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123156.
Testo completoAbstract (sommario):
This doctoral thesis investigates the microwave heating process, and its influence upon the physical properties and propagation of fractures in Rocks Under Illumination (RUI).In order to best understand microwave-assisted rock fracturing, it is critical to investigate the different aspects of this process. These range from the electromagnetic study (i.e., dielectric heating and heat generation), to the mechanical aspects (i.e., heat transfer, strength reduction material mechanics and fracture mechanics), and finally to the final fracturing behaviour of RUIs (i.e., fractography). In order to understand the various elements of the microwave fracturing of rocks, this research is divided into three investigations: 1) An investigation of the magnitude of heat generation within a rock body, and the extent to which illumination parameters can influence the efficiency of a microwave rock fracturing system. In addition, this research sought to expand the scope of microwave rock fracturing beyond the basaltic rocks utilized, and to apply this technique to other rock samples. This research investigates the possibility of substantially reducing the required energy input for a microwave-assisted rock fracturing system. This is made possible when operating at the optimal illumination parameters, with regard to each material property of the rock. To study the microwave heating process of rocks over a wide frequency range, the dielectric properties of some rocks are measured over frequencies ranging from 200 MHz to 20 GHz; with various water content, from fully dried to fully saturated; and at elevated temperatures ranging from 23ºC to 80oC.2) An investigation of the mechanical aspects of microwaves. This study sought to evaluate the influence of microwave illumination properties (i.e., input microwave power and exposure duration) on the fracture toughness of basalt samples and fracturing. It also attempted to experimentally quantify the fracture strength reduction of Chinese basalt after microwave illumination, at a variety of power levels and durations of exposure. Finally, the investigation sought to evaluate any correlation between the density of micro-cracks caused by microwave heating and any reduction in fracture toughness. This correlation was then modeled with the aid of numerical modeling (i.e., Discrete Element Modeling).3) A quantitative and qualitative investigation of the fracture development of Basalt Specimens Under Microwave Illuminations (BSUI) at macroscopic and microscopic scales. This research describes results of the visual investigations of the Fracture Growth Path (FGP) and the fracturing behaviour of SCBs after being exposed to microwave illuminations. FGPs are classified via their surface temperature level and the required input of microwave power. The Petrography Standard Test aided this approach, and allowed me to best describe fracture behaviour and the interactions between the fractures and mineralogical composition of Chinese basalt. A comprehensive fractographic investigation using Scanning Electron Microscopy (SEM) investigated microwave induced fracturing (i.e., fracture morphologies, fracture behaviours and the interaction of micro-fractures with rock forming minerals) in Chinese basalt fracture surfaces.Microwaves rock fracturing has potential to be employed for space applications: In Situ Resource Utilization (ISRU), sampling and In Situ material analysis sampling, in addition to mining and full face tunnelling applications on earth.Cette thèse de doctorat examine le procédé de chauffage par micro-ondes, et son influence sur les propriétés physiques et la propagation de fractures de roche sous illumination micro-onde (RUI). Pour bien comprendre la fracturation de roche avec assistance d'illumination micro-onde, il est essentiel de se pencher sur différents aspects du procédé. Ceux-ci vont de l'étude électromagnétique (chauffage diélectrique et génération de chaleur), jusqu'aux aspects mécaniques (transfère de chaleur, réduction de la résistance mécanique, mécanique de fracturation), et finalement jusqu'au comportement de fracturation final de la roche sous illumination micro-onde (fractographie). En tout, l'étude est divisée en trois parties :1) Une étude sur la magnitude de la génération de chaleur dans un corps rocheux, et dans quelle mesure les paramètres de l'illumination micro-ondes peut influencer l'efficacité d'un système de fracturation de roche avec chauffage par micro-ondes. Cette recherche tente d'élargir l'utilisation de chauffage par micro-ondes au-delà des roches basaltiques en appliquant cette technique à d'autres spécimens de roche. Cette recherche étudie aussi la possibilité de réduire substantiellement l'énergie d'entrée requise pour un système de fracturation de roche avec chauffage par micro-ondes. Ceci est possible lorsque les paramètres d'illumination micro-ondes sont optimisés par rapport aux propriétés de la roche. Pour étudier le processus de chauffage par micro-ondes à travers une ample gamme de fréquences, les propriétés diélectriques de plusieurs roches sont mesurées entre des fréquences de 200MHz à 20GHz. Le contenu d'eau varie entre parfaitement séché et complètement saturé, et la température varie entre la température de la pièce et 80oC.2) Une étude des aspects mécaniques des micro-ondes. Cette étude tente d'évaluer l'influence des propriétés de l'illumination micro-onde (puissance d'entrée micro-onde, durée d'exposition) sur la résistance de rupture de spécimens de basalte. L'étude tente aussi de quantifier expérimentalement la réduction de la résistance de rupture de spécimens de basalte chinois après l'illumination aux micro-ondes, en variant la puissance d'illumination ainsi que la durée d'exposition. Finalement, l'étude cherche à évaluer la corrélation entre la densité des micro-fractures causées par le chauffage par micro-ondes et la réduction de la résistance de rupture de la roche. La corrélation est ensuite modélisée à l'aide de modélisation numérique.3) Une étude qualitative et quantitative du développent de fractures dans des spécimens de basalte sous illumination micro-onde à l'échelle macroscopique et microscopique. Cette recherche décrit les résultats the l'étude visuelle du chemin de rupture (FGP) et le comportement de fracturation des SCBs après l'illumination par micro-ondes. Les FGP sont classifiés par rapport à la température de surface et la puissance d'entrée de micro-ondes requise. Le test standard de pétrographie aide à cette approche, et permet de mieux décrire le comportement de fracturation, et l'interaction entre les fractures et la composition minéralogique du basalte chinois. Une étude fractographique compréhensive sur la surface des ruptures induites dans le basalte chinois par l'illumination micro-onde (morphologie de rupture, comportement de rupture) est conduite en utilisant un microscope électronique à balayage (MEB). Cette recherche discute la possibilité d'utiliser les micro-ondes pour des applications spatiales : l'utilisation de ressources in-situ, l'échantillonnage et l'analyse d'échantillons in-situ, ainsi que des applications sur terre tel que l'extraction minière et la construction de tunnels.
44
Savage, Jeni Ellen. "Provenance Analysis of the Sperm Bluff Formation, southern Victoria Land, Antarctica". Thesis, University of Canterbury. Geological Sciences, 2005. http://hdl.handle.net/10092/1497.
Testo completoAbstract (sommario):
Beacon Supergroup rocks of probable Devonian age, containing conglomerate clasts of lithologies unknown in outcrop in southern Victoria Land (SVL) occur in the St Johns Range to Bull Pass Region, SVL, Antarctica. The Lower Taylor Group sedimentary rocks, herein called the Sperm Bluff Formation, unconformably rest on the regionally extensive Kukri Erosion Surface that truncates local basement. The basement complex includes three Plutonic Suites, Dry Valley (DV) 1a, DVIb and DV2 of the Granite Harbour Intrusives that intrude metasedimentary rocks of the Koettlitz Group. Allibone et al. (1993b) suggested a SVL terrane accretion event may have occurred about the same time as accretion of a terrane known as the Bowers terrane in northern Victoria Land (NVL) based on changing chemistry of the CambroOrdovician granitoids. Further, it is suggested that conglomerate clasts of the Sperm Bluff Formation may have been derived from this postulated terrane (Allibone et al., 1993b; and Turnbull et al., 1994). Following extensive fieldwork provenance studies and basin analysis of the sedimentary Sperm Bluff Formation are used here to test these ideas. The Sperm Bluff Conglomerate of Turnbull et al. (1994) is re-interpreted as the Sperm Bluff Formation and described using a lithofacies-based approach. The Sperm Bluff Formation is divided into six lithofacies including 1) Conglomerate Lithofacies; 2) Pebbly Sandstone Lithofacies; 3) Crossbedded Sandstone Lithofacies; 4) Parallelbedded Lithofacies; 5) Low-angle Crossbedded Lithofacies; and 6) Interbedded Siltstone/Sandstone Lithofacies. The intimate field association of the Conglomerate, Pebbly Sandstone and Crossbedded Sandstone Lithofacies ties them to the Conglomerate Lithofacies Association whereas the other three units are independent. The Conglomerate Lithofacies Association is interpreted to represent a wavedominated deltaic environment, based on the presence of broad channels, pervasive crossbedding, paleocurrent and trace fossil data. Both Parallel-bedded and Low-angle Crossbedded Sandstone Lithofacies are interpreted as a foreshore-shore face shallow marine setting on the basis of low-angle crossbeds and trace fossil assemblages. The Interbedded Siltstone and Sandstone Lithofacies is interpreted as an estuarine environment based on alternating siltstone/sandstone beds and the presence of flaser and lenticular bedding, small crossbedded dune sets, mud drapes, syneresis cracks and diverse paleocurrent directions. An estuarine setting is tentatively favoured over a lagoonal setting due to the presence of syneresis cracks small channels and the proximity to a river delta. I suggest that the Sperm Bluff Formation is likely a lateral correlative of the Altar Mt Formation of the Middle Taylor Group, in particular the Odin Arkose Member. This interpretation is based on arkosic nature of the sedimentary rocks, regional paleocurrent patterns, the presence of salmon pink grits at Gargoyle Turrets and trace fossil assemblages. The upper most lithofacies at Mt Suess, the Low-angle Crossbedded Sandstone Lithofacies that only occurs at this site is- suggested as a lateral correlative to the Arena Sandstone, which stratigraphically overlies the Altar Mt Formation, based on quartzose composition, clay matrix, stratigraphic position and trace fossils present. Provenance analysis was carried out on sedimentary rocks and conglomerate clasts using clasts counts of conglomerates, petrographic analysis of clasts, point counts of sandstones and clasts, geochemistry and V-Pb detrital zircon analysis. Conglomerate clasts lithologies include dominantly silicic igneous clasts and finely crystalline quartzite clast amongst other subordinate lithologies such as vein quartz, schist, schorl rock, gneiss and sandstone. Despite past identification of granitoid clasts in the Sperm Bluff Formation (Turnbull et al., 1994), none were found. Rhyolitic clasts of the Sperm Bluff Formation have compositions typical of highly evolved subduction related rocks, although they have undergone post-emplacement silicification. Wysoczanski et al. (2003) date rhyolite and tuff clasts between 497±17 Ma and 492±8 Ma, placing them within error of all three Dry Valley Magmatic Suites and removing the likelihood of correlation to NVL volcanic rocks. Petrographic analysis suggests they are components of a silicic magmatic complex. Chemically the volcanic clasts appear to represent a single magmatic suite (Sperm Bluff Clast Suite), and are clearly related to the Dry Valley Plutonic Suites. Although clasts are not constrained beyond doubt to one Suite, DV2 is the best match. Quartzite clasts of the Sperm Bluff Formation are too pure and old to be derived from a local source. Detrital zircon V-Pb ages for the quartzite suggest zircons were derived from the East Antarctic Craton, and that the quartzite source rocks were deposited prior to the Ross-Delamarian Orogeny. Quartzite with a similar age signature has not been identified; however, the Junction Formation sandstone of northwest Nelson has a similar age spectrum. Sandstones from the Sperm Bluff Formation indicate derivation from a felsic continental block provenance, which contain elements of volcanic, hyperbyssal and plutonic rocks. They are arkosic to quartzose in composition and conspicuously lack plagioclase. Detrital zircon analyses give a strong 500 Ma peak in all 3 samples, characteristic of a Ross-Delamarian Orogen source, with few other peaks. The dominance of a single peak is highly suggestive oflocal derivation. The sedimentary rocks of the Sperm Bluff Formation are interpreted to be derived predominantly from the basement rocks they now overlie. The presence of the regionally extensive Kukri Erosion Surface at the lower contact of the Beacon Supergroup rocks implies an intermediate source must have existed. This most likely contained all components of the formation. I suggest that the DV2 Suite was emplaced in a subsiding, extensional intra-arc setting. Erosion of the uplifted arc region probably occurred from Late Ordovician to Silurian times with deposition of sediments in a subsiding intra-arc basin. Erosion of the rhyolitic complex in this region probably occurred, however, it is likely that some was preserved. Inversion of this basin prior to the Devonian probably provided the means for these sediments to be deposited as the Sperm Bluff Fonnation.
45
Jones, Marilyn Gail 1963. "Clay mineralogy and petrology of the Lower Cretaceous fine-grained clastic rocks, southeastern Arizona". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/558100.
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46
ALCALA, ANTONIO L. "Determinacao de elementos terras raras em rochas por analise por ativacao com neutrons com separacao pre-irradiacao". reponame:Repositório Institucional do IPEN, 1991. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10261.
Testo completoAbstract (sommario):
Made available in DSpace on 2014-10-09T12:36:39Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:59:09Z (GMT). No. of bitstreams: 1 04223.pdf: 1419857 bytes, checksum: c459646dde6311c48fc0d2d70d417684 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Vidana, Pathiranagei Savani Madusanka. "Study on the thermal behaviour of common rocks in South East Queensland". Thesis, Griffith University, 2022. http://hdl.handle.net/10072/413309.
Testo completoAbstract (sommario):
The thermal behaviour of rocks has recently become an important topic for rock engineering due to developments in deep underground applications. Because of the extensive depth of these applications, more hazards occur such as rock bursts, external fires and gas explosions. The main reasons behind these underground rock disasters are the high temperatures and pressures. Therefore, the research focus on the thermal behaviour of rock is important for the safety and maintenance of underground applications. A good deal of research has been conducted so far about the thermal behaviour of rocks. The existing literature on the thermal behaviour of rocks in Australia is currently restricted to a few regions, largely in New South Wales and Victoria. The literature suggests that the mechanical properties of heated rock behave differently due to various geological and stress conditions, even for the same rock types. The thermal behaviour of common rocks (basalt, argillite, and sandstone) in South East Queensland has not yet been identified. The aim of the present research is to study the thermal behaviour of common rocks in South East Queensland and to develop a damage model. In this, the physical and mechanical properties of thermally treated rocks have been investigated by conducting porosity tests, point load tests, uniaxial compressive strength tests, and triaxial tests. These outcomes were further examined in X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC), derivative thermogravimetry (DTG), scanning electron microscopy (SEM) and micro-computed tomography (CT) analyses of the mineral composition and microstructure. It was found that the mineral composition and microstructure determine the engineering properties of rock under high temperatures. The critical temperature obtained using a thermal damage coefficient may vary significantly from the threshold temperature, and thus, for deep geological applications, it is recommended to determine both parameters. It was observed that high temperature treatment can significantly affect rock damage, more so than thermal cycle treatment. To predict the total damage of the rock, a thermomechanical damage model was proposed and applied to sandstone. This research will contribute to both theory and practice by providing a laboratory database, empirical correlations, and coupled thermo-mechanical damage model for common rocks in South East Queensland. More importantly, the outcome of this research will help to enhance the safety of deep underground projects.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
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Pizarro, Nicolás. "Magnetic susceptibility scaling of rocks using geostatistical analysis : an approach to geologic and geophysical model integration". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2483.
Testo completoAbstract (sommario):
Rock physical properties are usually associated with important geologic features within mineral deposits and can be used to define the location, depth and size of the deposit, type of ore, or physical property contrast between the host and country rock. Geophysical surveys are sensitive to physical properties and therefore are widely used in mining exploration, especially in concealed terrains. The surveys can be performed at multiple scales, resulting in corresponding physical property datasets at different scales. Survey scale can vary from core or hand sample, involving few cubic centimeters, to regional-scale surveys providing information about physical property contrasts between distinct regional geological features. The understanding of the relationship between the physical property distributions with the sample volume (e.g. district, deposit, and drill-hole scale) is required where point scale physical property measurements are going to be consistent with measurements at larger volumetric scales during the integration of data for geophysical modeling
The approach used to address the problem of understanding the scaling relations of physical properties, was achieved by considering them as second order stationary regionalized variables and then applying the random function formalism, provided by geostatistics theory. Geostatistics provide the required framework to characterize, quantify, model and link the spatial variability of the random variable at the different volumetric scales. The aim of this study is to apply geostatistics to effectively integrate data collected at several scales and bring knowledge to the understanding of the scaling relations of magnetic susceptibility. For this purpose, measurements of magnetic susceptibility available from Flin Flon copper-zinc district in Canada will be used. The data available at point scale were collected with hand portable magnetic susceptibility meter. The larger volumetric scale dataset were acquired using frequency domain electromagnetic instruments capable of measuring larger sample volumes, and then used to obtain magnetic susceptibility models using geophysical inversion algorithms. Once different scale models of magnetic susceptibility were available, quantification of the scaling relation using geostatistics, specifically variogram models and dispersion variance were determined.
The understanding provided by the scaling analysis of the Flin-Flon magnetic data is applied to data from the Rio Blanco copper district in central Chile. Magnetic susceptibility measurements collected with a hand magnetic susceptibility meter on drill-core is integrated in larger scale volumes used for geophysical inversion modeling of regional scale airborne magnetic field measurements to recover magnetic susceptibility models.
The methodology resulting from this application of geostatistics is used to address the problem of integrating multiple scales of physical property data in an effective way. The resulting physical property models capture the small-scale magnetic susceptibility variability observed and can guide larger-scale variability within geophysical inversion models. Establishing reliable statistical correlations between physical properties and rock units controlling ore within deposits are crucial steps leading predictive mine exploration tools. Any numerical modeling approach to establish these correlations should consider in some way the scaling nature of both physical property and ore content.
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Shim, Moojoon. "Techniques for the analysis of carbonate-associated sulfate (CAS) concentrations in modern and ancient limestones and dolostones /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426105.
Testo completo
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Bowen, Michael Peter. "The petrogenesis of the volcanic rocks of the Witwatersrand triad in the Klerksdorp area, Transvaal". Thesis, Rhodes University, 1985. http://hdl.handle.net/10962/d1001569.
Testo completoAbstract (sommario):
Several hundred chemical analyses of early Proterozoic lavas of the Witwatersrand triad (incorporating the Dominion Group, Witwatersrand Supergroup and Ventersdorp Supergroup) in the Klerksdorp area, have revealed the presence of various distinct magma types. These essentially correspond to formally defined lithostratigraphic units, but several inconsistencies have necessitated the use of informal nomenclature. The lavas have been regionally metamorphosed to low-grade, greenschist facies assemblages. Original igneous textures are preserved, despite a metamorphic overprint. Metamorphism has resulted in a certain degree of random chemical remobilization. Ba, Sr, Rb, K₂0, Na₂0 and CaO have been highly mobile, and their usefulness in petrogenetic modelling is extremely limited. In contrast, Zr, Nb, Y, LREE's, Cr, Ni, Ti0₂ P₂0₅ and Al₂0₃ have remained immobile. Ti/Zr and Ti/P ratios together constitute efficient discriminating variables for characterizing the different magma types. Lava compositions range from primitive Mg-rich tholeiites to rhyolites, the bulk being tholeiitic andesites. Al₂0₃ contents do not exceed 15%, a feature which reflects the tholeiitic, as opposed to calcalkaline, character of these lavas. Two magma-types are present within the Dominion Group, which is a typical example of bimodal volcanism. The Dominion basic lavas are overlain by the Dominion acid porphyries, with a limited amount of interfingering. The basic lava suite is highly fractionated, with compositions ranging from Mg-, Cr- and Ni-rich tholeiites (close to primary mantle melts) to evolved tholeiitic andesites. The most primitive liquids evolved by 45% fractional crystallization of hornblende, followed by a further 70% crystallization of an orthopyroxene-plagioclase assemblage containing up to 3% sulphides. The Dominion porphyries are rhyolitic, display very limited compositional variation, and probably represent a crustal melt related to the same magmatic event which produced the basic lavas. The only lavas from the Witwatersrand Supergroup present in the Klerksdorp area are those of the Crown Formation (Jeppestown amygdaloid). These are tholeiitic dacites which display extremely limited compositional variation, and are unrelated to any of the other magmas of the Witwatersrand triad. The Ventersdorp Supergroup comprises 4 magma-types: The Kliprivierberg Group lavas at the base are subdivisible into 3 sub-types on the basis of Zr contents. (Zr>11Oppm) are the most evolved. They are tholeiitic andesites which display fairly limited compositional variation. It is likely that more evolved compositions are present in other areas where the porphyritic lavas which characterize this unit are better developed. The overlying Orkney lavas are characterized by 110ppm>Zr>90ppm. They are tholeiitic andesites of similar composition to the Alberton lavas, but have lower incompatible element levels, higher siderophile element levels, and are of extremely uniform composition. The uppermost Loraine/Edenville lavas range from magnesian tholeiites to tholeiitic andesites. They are distinguished by Zr< 90ppm, and contain the most primitive magmas af the Witwatersrand triad, with up to 17,5% MgO, 2600ppm Cr, 600ppm Ni and M-values up to 77. The most primitive liquids evolved by 38% fractional crystallization of orthopyroxene ∓ chromite, followed by 35% fractional crystallization of an extract containing clinopyroxene and plagioclase. The absence of olivine precipitation is a result of the inherently high Si0₂ content of the magma. The Loraine/Edenville, Orkney and Alberton lavas do not lie on a common liquid line of descent, but are probably consanguinous. The Platberg Group overlies the Kliprivierberg Group, and has a coarse-clastic sedimentary unit, the Kameeldoorns Formation, at the base. Three petrographically distinct porphyritic lava sequences overlie the Kameeldoorns Formation, namely the informal "Goedgenoeg formation", the Makwassie quartz-feldspar porphyries and the Rietgat Formation. Despite petrographic differences, the Goedgenoeg and Rietgat lavas are chemically indistinguishable and thus form a single magma-type. The Makwassie porphyries are dacitic in composition with a high proportion of feldspar and quartz phenocrysts. Rational variation trends are attributed to a nett loss of Si0₂ during secondary alteration. The porphyries are probably of crustal origin. The Goedgenoeg/Rietgat lavas display unusual chemistry and a broad, irrational compositional spectrum. They contain very high incompatible element levels, high nonnative quartz, as well as high MgO, M-values, Cr and Ni relative to the other tholeiitic andesites of the Witwatersrand triad. It is tentatively suggested that they are hybrid magmas containing both crust and mantle components, the former possibly represented by the Makwassie porphyries. Field evidence suggests that Platberg volcanism commenced directly after Klipriviersberg volcanism ceased, and was accompanied by a period of enhanced tectonic activity. The Platberg lavas thus probably reflect a crustal melting cycle associated with the Klipriviersberg magmatic event. The Allanridge lavas are the youngest rocks of the Witwatersrand triad. They are separated from the Platberg Group by a unit of flat-lying sediments, the Bothaville Formation, which was deposited after an extended period of peneplanation. The Allanridge lavas form a separate magma-type. They are tholeiitic andesites of similar composition to the Alberton lavas, but have higher incompatible element levels and are not consanguinous. The compositional similarities amongst the basic magma-types of the Witwatersrand triad suggests that all were generated in an hydrous mantle. Interelement ratio differences between the various magma-types nevertheless support the concept that the mantle was chemically heterogeneous during the early Proterozoic.