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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo de sistemas multicomponentes no processo de inje??o c?clica de vapor

Carvalho, Tiago Pinheiro de 18 September 2010 (has links)
Made available in DSpace on 2014-12-17T14:08:43Z (GMT). No. of bitstreams: 1 TiagoPC_DISSERT.pdf: 1471839 bytes, checksum: 916c40a19572e874803d077f6852a370 (MD5) Previous issue date: 2010-09-18 / In Brazilian Northeast there are reservoirs with heavy oil, which use steam flooding as a recovery method. This process allows to reduce oil viscosity, increasing its mobility and consequently its oil recovery. Steam injection is a thermal method and can occurs in continues or cyclic form. Cyclic steam stimulation (CSS) can be repeated several times. Each cycle consisting of three stages: steam injection, soaking time and production phase. CSS becomes less efficient with an increase of number of cycles. Thus, this work aims to study the influence of compositional models in cyclic steam injection and the effects of some parameters, such like: flow injection, steam quality and temperature of steam injected, analyzing the influence of pseudocomponents numbers on oil rate, cumulative oil, oil recovery and simulation time. In the situations analyzed was compared the model of fluid of three phases and three components known as Blackoil . Simulations were done using commercial software (CMG), it was analyzed a homogeneous reservoir with characteristics similar to those found in Brazilian Northeast. It was observed that an increase of components number, increase the time spent in simulation. As for analyzed parameters, it appears that the steam rate, and steam quality has influence on cumulative oil and oil recovery. The number of components did not a lot influenced on oil recovery, however it has influenced on gas production / No Nordeste brasileiro existem reservat?rios de ?leos pesados, nos quais se utiliza a inje??o de vapor como m?todo de recupera??o. Este processo permite diminuir a viscosidade do ?leo, aumentando a sua mobilidade e melhorando o volume de ?leo a ser recuperado. A inje??o de vapor ? um m?todo t?rmico e ocorre na forma cont?nua ou c?clica. A inje??o c?clica de vapor pode ser repetida diversas vezes. Cada ciclo consiste de tr?s etapas distintas: a fase de inje??o, fase de fechamento (soaking) e fase de produ??o. A inje??o c?clica se torna menos eficiente ? medida que o n?mero de ciclos aumenta. Neste sentido, este trabalho visa estudar a influ?ncia de modelos composicionais na inje??o c?clica de vapor e os efeitos de alguns par?metros, tais como: vaz?o de inje??o, qualidade do vapor e temperatura do vapor injetado; analisando a influ?ncia do n?mero de pseudocomponentes, no que diz respeito ? vaz?o de ?leo, produ??o acumulada de ?leo, fator de recupera??o e tempo de simula??o. Nas situa??es analisadas foi comparado o modelo de fluido de tr?s fases e tr?s componentes conhecido como Black-oil . Foram realizadas simula??es, utilizando um simulador comercial a partir de um modelo de reservat?rio homog?neo com caracter?sticas similares ?s encontradas no Nordeste brasileiro. Observou-se que quanto maior o n?mero de componentes, maior ? o tempo gasto na simula??o. J? para os par?metros analisados, verifica-se que a vaz?o de inje??o de vapor e a qualidade do vapor influenciam na produ??o acumulada de ?leo e no fator de recupera??o. O n?mero de componentes n?o exerceu muita influ?ncia na produ??o acumulada, nem no fator de recupera??o de ?leo, por?m foi significativa na produ??o de g?s do sistema
2

Estudo de modelos composicionais de ?leo na inje??o cont?nua de vapor

Cavalcante, Liara Tavares 22 December 2011 (has links)
Made available in DSpace on 2014-12-17T14:08:51Z (GMT). No. of bitstreams: 1 LiaraTV_DISSERT.pdf: 1753803 bytes, checksum: 5e53187cb6e33e84a341ab8ca9fd48da (MD5) Previous issue date: 2011-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The objective of the thermal recovery is to heat the resevoir and the oil in it to increase its recovery. In the Potiguar river basin there are located several heavy oil reservoirs whose primary recovery energy provides us with a little oil flow, which makes these reservoirs great candidates for application of a method of recovery advanced of the oil, especially the thermal. The steam injection can occur on a cyclical or continuous manner. The continuous steam injection occurs through injection wells, which in its vicinity form a zone of steam that expands itself, having as a consequence the displace of the oil with viscosity and mobility improved towards the producing wells. Another possible mechanism of displacement of oil in reservoirs subjected to continuous injection of steam is the distillation of oil by steam, which at high temperatures; their lighter fractions can be vaporized by changing the composition of the oil produced, of the oil residual or to shatter in the amount of oil produced. In this context, this paper aims to study the influence of compositional models in the continuous injection of steam through in the analysis of some parameters such as flow injection steam and temperature of injection. Were made various leading comparative analysis taking the various models of fluid, varying from a good elementary, with 03 pseudocomponents to a modeling of fluids with increasing numbers of pseudocomponents. A commercial numerical simulator was used for the study from a homogeneous reservoir model with similar features to those found in northeastern Brazil. Some conclusions as the increasing of the simulation time with increasing number of pseudocomponents, the significant influence of flow injection on cumulative production of oil and little influence of the number of pseudocomponents in the flows and cumulative production of oil were found / O objetivo da recupera??o t?rmica ? aquecer o reservat?rio e o ?leo nele existente para aumentar a sua recupera??o. Na Bacia Potiguar existem v?rios reservat?rios de ?leos pesados cuja energia de recupera??o prim?ria nos fornece uma vaz?o de ?leo pequena, o que torna tais reservat?rios ?timos candidatos para aplica??o de um m?todo de recupera??o avan?ada de petr?leo, especialmente o t?rmico. A inje??o de vapor pode ocorrer de forma c?clica ou cont?nua. A inje??o de vapor cont?nua ocorre atrav?s de po?os injetores, pr?ximos aos quais se forma uma zona de vapor que se expande, tendo como conseq??ncia o deslocamento do ?leo com viscosidade e mobilidade melhoradas na dire??o dos po?os produtores. Outro mecanismo poss?vel de deslocamento do ?leo em reservat?rios submetidos ? inje??o cont?nua de vapor ? a destila??o do ?leo por vapor, o qual quando alcan?am altas temperaturas, suas fra??es mais leves podem ser vaporizadas alterando a composi??o do ?leo produzido, do ?leo residual ou impactar na quantidade de ?leo produzida. Nesse contexto, este trabalho objetiva estudar a influ?ncia de modelos composicionais na inje??o cont?nua de vapor atrav?s de uma an?lise de par?metros como vaz?o de inje??o de vapor e temperatura de inje??o. Foram realizadas diversas an?lises comparativas levando os diversos modelos de fluidos, variando de um bem elementar, com 03 pseudocomponentes at? modelagens de fluidos com n?meros crescentes de pseudocomponentes. Foi utilizado um simulador num?rico comercial para o estudo a partir de um modelo de reservat?rio homog?neo com caracter?sticas similares ?s encontradas no Nordeste brasileiro. Algumas conclus?es como o aumento do tempo de simula??o com o aumento do n?mero de pseudocomponentes, a influ?ncia significativa da vaz?o de inje??o na produ??o acumulada de ?leo e a pouca influ?ncia do n?mero de pseudocomponentes nas vaz?es e produ??o acumulada de ?leo foram constatadas
3

Mnoharozměrná pravděpodobnostní rozdělení: Struktura a učení / Multidimensional Probability Distributions: Structure and Learning

Bína, Vladislav January 2010 (has links)
The thesis considers a representation of a discrete multidimensional probability distribution using an apparatus of compositional models, and focuses on the theoretical background and structure of search space for structure learning algorithms in the framework of such models and particularly focuses on the subclass of decomposable models. Based on the theoretical results, proposals of basic learning techniques are introduced and compared.
4

Música Sacra, Discurso e Poder: Modelos Pré-Composicionais na Missa Luso-Brasileira / -

Christovam, Ozorio Bimbato Pereira 16 April 2018 (has links)
Compositores do século XVIII aplicaram processos de cópia e manipulação de modelos précomposicionais com o intuito de efetivar o discurso musical no processo de comunicação musical. Dentre esses modelos disponíveis, retórica e partimento participavam como ferramentas fundamentais na estruturação e resolução discursiva da música. A tese aqui apresentada tem como objetivo demonstrar como, através desses modelos pré-composicionais, a música sacra reproduzia ou alterava relações de poder no espaço luso-brasileiro. A justificativa para essa perspectiva baseia-se nas observações feitas pela musicologia lusófona sobre os problemas decorrentes da acomodação do ideal iluminista em um ambiente marcadamente católico, caracterizado pelo Despotismo Esclarecido, e que resultou nos embates de poder entre as esferas públicas, Estado e Igreja. Neste sentido, a nomeação do mestre de capela era um fator decisivo para a formação de zonas de influência ideológica e manutenção das relações de poder, pois era este ator social que produzia o discurso musical sacro. A metodologia empregada foi fundamentada na aplicação da Análise Crítica do Discurso na música, expondo como a manipulação dos modelos pré-composicionais, observadas no nível do texto musical, se alinhava e representava estruturas sociais em um nível contextual. A análise do corpus musical centrou-se sobre a Missa a 8 Vozes e Instrumentos, Missa a Cinco Vozes e Missa em Dó de André da Silva Gomes, focalizando, especialmente, o Kyrie por ser a primeira parte do ordinário. / Eighteenth-century composers applied processes of copying and manipulation of precompositional models with the intention of effecting the musical discourse in the process of musical communication. Among these available models, rhetoric and partimento participated as fundamental tools in the discoursive structuring and resolution of music. The thesis presented here aims to demonstrate how, through these pre-compositional models, sacred music reproduced or altered power relations in the Luso-Brasilian space. The justification for this perspective is based on the observations made by Lusophone musicology on the problems arising from the accomodation of the Enlightenment ideal in a markedly Catholic environment, characterized by the Enlightened absolutism, which resulted in the struggles of power between the public spheres, State and Church. In this sense, the appointment of the chapel master was a decisive factor for the formation of zones of ideological influences and maintenance of power relations, since it was this social actor who produced the sacred musical discourse. The methodology used was based on the application of Critical Discourse Analysis in music, exposing how the manipulation of the pre-compositional models, observed at the level of musical text, was aligned and represented social structures at a contextual level. The analysis of the musical corpus centered on the Eight Voices and Instruments Mass, Five Voice Mass and Mass in C by André da Silva Gomes, focusing especially on the Kyrie for being the first part of the ordinary.

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