Conformance control has long been a compelling subject in improving waterflood oil recovery. By blocking the areas previously swept by water, subsequently injected water is allowed to sweep the remaining unswept portions of the reservoir and thereby increase the ultimate oil recovery. One technique that has received a great deal of attention recently in achieving this in-depth water shut-off is crosslinked gel injection. However, processing and predicting the performance of these gels in complex petroleum reservoirs is known to be extremely challenging. A model that accurately represents the reservoir features, chemical properties, and displacement mechanisms is, therefore, required. In this study, we further developed the UT in-house numerical reservoir simulator, branded as UTGEL. Our first focus was to enable UTGEL to simulate a new type of temperature-resistant and salt-tolerant pre-crosslinked swellable particle gel, known as Preformed Particle Gel or PPG. A series of numerical simulations have been conducted to match with experimental data and generate parameters for full field scale simulation. Five laboratory experimental matching attempts were successfully performed using the UTGEL simulator in this study. The matched experiments included a fracture model, two sandpack models, a sandstone coreflood experiment, and a parallel sandpack model. The second focus of this study was to investigate the applications of PPG in blocking high-permeability layers, fractures, and conduits. A number of synthetic and actual field cases were generated to study the performance of PPG in (1) reservoirs with various layered permeability contrasts, from extremely low to extremely high permeability contrasts, (2) reservoirs containing extensive conduits or channels, and (3) real field cases where heterogeneity had been identified unfavorable to the waterflood efficiency. The simulation outcomes indicated significant incremental oil recovery from PPG treatment ranging from less than 5% to almost 30%. A number of sensitivity analyses were also conducted to provide some insights on the optimal PPG treatment design. Lastly, to enhance the capability of UTGEL in simulating gel transport in diverse scenarios, a novel Embedded Discrete Fracture Modeling (EDFM) concept was implemented into UTGEL in this study, allowing multiple sets of fracture planes and conduits with dip angles and orientations to be modeled and simulated with gel treatments for the first time with a rather computationally inexpensive method. Although the developed simulator requires further improvement and validation against wider reservoir and fluid conditions, the representative results from a number of generated models in this study have suggested another step forward towards achieving realistic reservoir modeling and advanced gel transport simulation. / text

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Dióxido de estanho (SnO2) é um óxido com características semicondutoras, cujo comportamento de transporte elétrico tem interesse crescente de aplicação tecnológica, principalmente na utilização como filmes condutores transparentes. Neste trabalho, são produzidos xerogéis (pós) e filmes finos de SnO2 dopados com antimônio (Sb) pelo processo sol-gel, usando a técnica de molhamento (\"dip-coating\") na deposição dos filmes, com o intuito de se investigar os fenômenos envolvidos na condutividade elétrica do material. Os filmes finos são compostos por uma grande quantidade de pequenos grãos (3-6nm), tornando o espalhamento eletrônico na região do contorno de grão um fator determinante para a condução. Experimentos de fotocondutividade são feitos com luz monocromáticas advinda de uma fonte de deutério acoplada a um monocromador apropriado à baixas temperaturas, em filmes finos de Sn02, e mostram um aumento na fotocorrente que se inicia na transição de banda (\"bandgap\" ≅ 3,6eV) e continua aumentando mesmo para energias superiores ao bandgap. Este resultado está relacionado com a recombinação de pares elétron-buraco fotogerados com espécies de oxigênio adsorvidas no contorno de grão. Esta relação de recombinação também é observada em medidas de decaimento da condutividade fotoexcitada com o quarto harmônico de um laser de Nd:YAG (266nm), pelas quais se verifica o fenômeno de fotocondutividade persistente nos filmes. Resultados de resistência elétrica em função da temperatura (25-300K) indicam o caráter doador do dopante. Análises por Espectroscopia de Absorção de Raios X (XAS), feitas com radiação sincrotron, mostram que o antimônio em seu estado de oxidação Sb+5, entra na rede de SnO2 em sítios na superfície do cristalito, em substituição à átomos de estanho (Sn+4), levando a um aumento na concentração de elétrons livres. Medidas de Espectroscopia de Fotoemissão de Raios X (XPS) confirmam este comportamento substitucional de Sb e sugerem sua localização na superfície dos grãos. Em adição a isso, análises de Difração de Raios X (XRD) mostram as dimensões manométricas dos grãos e indicam que o dopante inibe o crescimento desses grãos. Caracterizações óticas mostram uma diminuição da transmitância dos filmes na região do infravermelho próximo (0,8-4,5&#181m), proporcionalmente à adição de Sb. Este fato pode ser explicado pela teoria de Drude e tem relação com a alta concentração de portadores (cerca de 1020cm-3) e alta reflexão ótica nesta região, promovida pela dopagem. As várias caracterizações feitas, indicam que filmes finos de SnO2:Sb depositados por este processo, apresentam baixa mobilidade eletrônica influenciando a condutividade elétrica do material / Tin dioxide (SnO2) is an oxide with semiconducting characteristics and electrical transport behavior of growing interest for technological applications, mainly as transparent conducting films. In this work, thin films and xerogels (powder) of Sb-doped SnO2 have been produced by the sol-gel process. Films are deposited by dip-coating technique. These samples aim at the investigation of electrical conductivity phenomena of this material. Thin films grown by this technique are composed of a huge amount of tiny grains (3-6nm), leading to high electron scattering at grain boundary region, which becomes the most relevant factor to the conduction. Photoconductivity experiments on SnO2 thin films are carried out with monochromatic light from a deuterium source coupled to an appropriate monochromator, at low temperature, and shows increase in the photocurrent, beginning about bandgap transition ≈ 3.6eV) and keep increasing even for higher energy than the bandgap. This result is related to electron and hole recombination with oxygen species adsorbed at grain boundary. This recombination is also observed in measurements of decay of photo-excited conductivity, where the sample is excited with the fourth harmonic of a ND:YAG laser (266nm). These results allow the verification of persistent photoconductivity phenomena in SnO2 thin films. Electrical resistance as function of temperature (25-300K) indicates the donor nature of antimony. X-ray absorption spectroscopy (XAS), done with sincrotron radiation, shows that antimony enters into the Iattice at surface crystallite sites, substitutional to tin atoms (Sn 4+) in the Sb5+ oxidation state, leading to an increase of the free electron concentration. X-ray photoemission spectroscopy (XPS) data confirm this behavior and suggest the Sb location at grain boundary surface. In addition, X-ray diffraction analysis (XRD) shows the nanoscopic dimensions of grains and indicates that doping inhibits grain growth. Optical characterization shows transmittance decrease in the near infrared (0.8-4.5µm), proportional to Sb concentration. It can be explained by Drude\'s theory and is related with a high electron concentration (about 1020 cm-3), which originates optical reflection, promoted by doping. AII the characterization done in this work, indicates that SnO2:Sb thin films, deposited by this process, present low electronic mobility, influencing the electrical conductivity of this material

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Orientador : Jose Francisco Hofling / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-09-11T20:48:39Z (GMT). No. of bitstreams: 1 Palomari_DeniseMadalena_M.pdf: 3176985 bytes, checksum: 76118d403e3be573a806e42857073b65 (MD5) Previous issue date: 1992 / Resumo: Com o proposito de se aplicar a tecnica de eletroforese em gel de poliacrilamida como contribuiçao aos estudos de identificação e caracterização de Streptococcus orais. amostras de culluras do grupo mutans.. idenlificadas bioquimicamenle. foram analisadas alravés da técnica de eletroforese em gel de poliacrilamida. empregando-se metodologias distinlas na oblençao de proteinas intracelulares. Os resultados obtidos na determinação dos perfis proteicos das amostras microbianas. analisadas pela técnica de solubilização direta. permitiram detectar diferenças entre as mesmas quando comparadas. Esses resultados demonstraram. que a ressuspensão diretà de células normais em mistura solubilizante. permite a possibilidade de se distinguir duas espéci.s como. mutans e S.sobrinus. ou descrever como semelhantes. cepas microbianas supostamente diferentes ou nao relacionadas como XI-3. XII-5. XII-3 e 1-4B / Abstract: As a contribuition to the identi:f'ication and caracterization o:f'oral 5treptococc'US. cul ture sampl es o:f' the mutans group identi:f'iedbyochemically. were analysed through the pol yacr yl ami de gel electrophoresis technique. using distinct methods to isol ate their intracellular proteins. These resul tS showed that the di rect resuspensi on o:f' the whole cell proteins in bu:f':f'ered solubilizing solution. allows to distinguish between species o:f'5. mutans and 5. sobrin'US. or to describe as similar. microbian strains supposely different not related. / Mestrado / Mestre em Biologia e Patologia Buco-Dental