Numerical modeling of fluid flow and dissolved species transport in the subsurface is a challenging task, given variability and measurement uncertainty in the physical properties of the rock, the complexities of multi-fluid interaction, and limited computational resources. Nonetheless, this thesis seeks to expand our modeling capabilities in the context of contaminant hydrogeology. We describe the numerical simulator CompFlow Bio and use it to model invasion of a nonaqueous phase liquid (NAPL) contaminant through the vadose zone and below the water table in a fractured porous rock. CompFlow Bio is a three-phase, multicomponent, deterministic numerical model for fluid flow and dissolved species transport; it includes capillary pressure and equilibrium partitioning relationships. We have augmented the model to include randomly generated, axis-aligned, discrete fracture networks (DFNs). The DFN is coupled with the porous medium (PM) to form a single continuum. The domain is discretized using a finite-volume scheme in an unstructured mesh of rectilinear control volumes (CVs). Herein we present the governing equations, unstructured mesh creation scheme, algebraic development of fracture intersection CV elimination, and coupling of PM CVs over a fracture plane to permit asperity contact bridged flow. We include: small scale two-phase water-air and NAPL-water simulations to validate the practice of intersection CV elimination; small scale simulations with water-air, NAPL-water, and NAPL-water-air systems in a grid refinement exercise and to demonstrate the effect of asperity contact bridged flow; intermediate scale 3D simulations of NAPL invading the saturated zone, based on the Smithville, Ontario, site; intermediate scale 2D and 3D simulations of NAPL invading the vadose zone and saturated zone with transient recharge, based on the Santa Susana Field Laboratory site, California. Our findings indicate that: the formulation provides a practical and satisfactory way of modeling three-phase flow in discretely fractured porous rock; numerical error caused by spatial discretization manifests itself as several biases in physical flow processes; that asperity contact is important in establishing target water saturation conditions in the vadose zone; and simulation results are sensitive to relative permeability-saturation-capillary pressure relationships. We suggest a number of enhancements to CompFlow Bio to overcome certain computational limitations.

Numerical modeling of fluid flow and dissolved species transport in the subsurface is a challenging task, given variability and measurement uncertainty in the physical properties of the rock, the complexities of multi-fluid interaction, and limited computational resources. Nonetheless, this thesis seeks to expand our modeling capabilities in the context of contaminant hydrogeology. We describe the numerical simulator CompFlow Bio and use it to model invasion of a nonaqueous phase liquid (NAPL) contaminant through the vadose zone and below the water table in a fractured porous rock. CompFlow Bio is a three-phase, multicomponent, deterministic numerical model for fluid flow and dissolved species transport; it includes capillary pressure and equilibrium partitioning relationships. We have augmented the model to include randomly generated, axis-aligned, discrete fracture networks (DFNs). The DFN is coupled with the porous medium (PM) to form a single continuum. The domain is discretized using a finite-volume scheme in an unstructured mesh of rectilinear control volumes (CVs). Herein we present the governing equations, unstructured mesh creation scheme, algebraic development of fracture intersection CV elimination, and coupling of PM CVs over a fracture plane to permit asperity contact bridged flow. We include: small scale two-phase water-air and NAPL-water simulations to validate the practice of intersection CV elimination; small scale simulations with water-air, NAPL-water, and NAPL-water-air systems in a grid refinement exercise and to demonstrate the effect of asperity contact bridged flow; intermediate scale 3D simulations of NAPL invading the saturated zone, based on the Smithville, Ontario, site; intermediate scale 2D and 3D simulations of NAPL invading the vadose zone and saturated zone with transient recharge, based on the Santa Susana Field Laboratory site, California. Our findings indicate that: the formulation provides a practical and satisfactory way of modeling three-phase flow in discretely fractured porous rock; numerical error caused by spatial discretization manifests itself as several biases in physical flow processes; that asperity contact is important in establishing target water saturation conditions in the vadose zone; and simulation results are sensitive to relative permeability-saturation-capillary pressure relationships. We suggest a number of enhancements to CompFlow Bio to overcome certain computational limitations.

Orientador: Antonio Carlos Bannwart / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica, Instituto de Geociencias / Made available in DSpace on 2018-08-03T21:05:55Z (GMT). No. of bitstreams: 1 Trevisan_FranciscoExaltacao_M.pdf: 3270691 bytes, checksum: fe9889927a406d7a231ce2e2e37eb5cc (MD5) Previous issue date: 2003 / Resumo: Considerados de grande importância na indústria de petróleo, os óleos pesados constituem grande parte da reserva nacional, e mundial, a ser explotada e produzida. Devido a dificuldades associadas às características desfavoráveis deste tipo de óleo, como viscosidade e densidade, tem-se procurado métodos que viabilizem economicamente sua produção e transporte. Uma dessas técnicas é o core flow, que consiste basicamente na injeção lateral de pequenas quantidades de água junto ao óleo para que a primeira lubrifique o escoamento. Entretanto com a queda de pressão ao longo da tubulação, é inevitável que haja o desprendimento do gás inicialmente em solução no petróleo, o que altera as características do escoamento bifásico óleo pesado-água. Neste trabalho foram feitos testes experimentais para obter diversas informações sobre os padrões de fluxo em escoamento horizontal e as queda de pressão correspondentes. Foram elaborados mapas de fluxo onde se encontram os diversos padrões observados para cada trio de vazões de cada fase escoada. Os gradientes de pressão obtidos foram apresentados em forma de cartas e também comparados com outros tipos de fluxo, para melhor avaliar o comportamento das perdas de carga. Além disso, foi elaborado uma correlação matemática que prevê o gradiente de pressão estimando uma viscosidade equivalente do fluxo trifásico. A presença do gás aumentou o gradiente de pressão, porém o método de injeção de água para o transporte de óleos pesados provou ainda ser eficaz / Abstract: Considered to be of great importance to the oil industry, heavy oils represent a significant part of national, and worldwide, unexploited reserves. Do to the difficulties associated with the unfavorable characteristics ofthis type of oil, such as viscosity and density, heavy oil economic production and transportation techniques are being studied. One of these methods is the core flow, which consists on the lateral injection offew amounts ofwater that lubricates the oil flow. However, the pressure drop along the tube makes the gas dissociation inevitable, which wiIl alter the oil-water flow characteristics. This work presents an experimental study done to obtain more information on horizontal three-phase flow pattems and the corresponding pressure drop. Flow maps were developed, where the observed pattems were related to its corresponding superficial velocity trios. The obtained pressure gradients are presented in graphic forms and compared to other flow types, for a better evaluation of its behavior. A mathematical correlation that predicts the pressure loss by estimating an equivalent viscosity was also developed. Despite the pressure gradient increase, caused by the gaseous phase, the technique of water injection for the transport ofheavy oil has still proven to be efficient / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

Escoamentos gás-líquido assim como escoamento líquido-líquido-gás em duto de geometria anular estão presentes em muitas aplicações industriais, por exemplo, em poços de petróleo direcionais. No entanto, até mesmo características globais de escoamento gás-líquido nessa geometria, como os padrões de escoamento ou gradiente de pressão, não são ainda totalmente compreendidas. E ainda, informações são escassas quando se refere a escoamento trifásico nessa geometria, cuja aplicação está relacionada ao fenômeno de inversão de fase, que é de extrema importância não apenas para ao setor petrolífero, como para a indústria alimentícia. O presente estudo experimental tem como objetivo avaliar o escoamento líquido-gás, apresentar dados inéditos de escoamento gás-líquido para três viscosidades de óleo, além de avaliar o fenômeno de inversão de fase em escoamento ascendente vertical em duto anular de grande diâmetro. Um aparato experimental inclinável com 10,5 m de comprimento foi projetado e construído para este trabalho. As dimensões radiais do duto anular estão em escala real, conforme se verifica em poços de petróleo e gás. A investigação em escoamento gás-líquido foi conduzida utilizando água, óleo e ar comprimido como fluidos de trabalho em escoamento ascendente vertical em duas geometrias: (i) um tubo com diâmetro de 95 mm e (ii) um duto de configuração anular e concêntrico, com diâmetro hidráulico de valor igual ao diâmetro do tubo. A avaliação do fenômeno de inversão de fase em escoamento trifásico foi conduzida em condições equivalentes em três geometrias: (i) tubo vertical menor com diâmetro de 50 mm, (ii) tubo com diâmetro de 95 mm e (iii) um duto anular concêntrico. Padrões de escoamento, queda de pressão e fração volumétrica de fase foram obtidos para ambos os escoamentos gás-líquido e líquido-líquido-gás. Os dados coletados nesse trabalho são de grande importância para o desenvolvimento de novas correlações de fechamento, que são essenciais para o projeto otimizado de poços de petróleo. Dados inéditos de escoamento bifásico óleo-gás são apresentados, bem como um estudo pioneiro em inversão de fase em escoamento trifásico com velocidade superficial de gás e viscosidade do óleo elevadas. / Two-phase flows as well as three-phase flow in annular geometry are present in many industrial applications, for example in oil directional wells. However, even global characteristics of gas-liquid flow in this geometry, such as flow patterns and pressure gradient are not fully understood. Moreover, information is scarce when it refers to three-phase flow in this geometry, which application is related to the phase inversion phenomenon, which is of extreme importance and not only for the oil industry. This experimental study aims to evaluate the liquid-gas flow, present new data from gas-liquid flow for three oil viscosities and evaluate the phase inversion phenomenon in vertical upward flow in large diameter annular duct. An experimental apparatus with 10.5 m length was designed and built for this work. The radial dimensions of the annular duct are similar to full scale, as observed in oil and gas wells. The investigation into gas-liquid flow was conducted using water, oil and compressed air as working fluids in an ascending vertical flow in two geometries: (i) a tube with 95 mm diameter and (ii) a concentric annular duct with hydraulic diameter equivalent to the tube internal diameter. The evaluation of the phase inversion phenomenon in three-phase flow was conducted under equivalent conditions for three geometries: (i) smaller vertical tube with 50 mm of internal diameter, (ii) tube with 95 mm of internal diameter and (iii) concentric annular duct with hydraulic diameter of 95 mm. Flow patterns, pressure drop and volumetric phase fraction were obtained for both gas-liquid and gas-liquid-liquid flows. The data collected in this study are of great importance for the development of new closing correlations, which are essential for the optimized design of oil wells. New two-phase flow data for three oil viscosities, not found in the literature, are presented as well as a pioneer study in three-phase-flow phase inversion with high oil viscosity and high superficial gas velocity.

Dans le but de prédire l’évolution d’un hypothétique accident au sein d’un réacteur nucléaire, nous nous proposons au travers de cette étude de comprendre la dynamique de bulles de gaz évoluant dans un bain stratifié constitué de deux liquides superposés. Pour ce faire, un dispositif expérimental muni de caméras à haute cadence a été construit afin d’observer en détail la dynamique de bulles d’air isolées et de trains de bulles traversant une interface séparant deux liquides newtoniens immiscibles initialement au repos. En faisant varier la taille des bulles injectées ainsi que les contrastes de viscosité entre les liquides d’un et quatre ordres de grandeur respectivement, ce dispositif a permis d’observer une grande variété de régimes d’écoulement. Dans certaines situations, les bulles de taille millimétrique restent piégées à l’interface liquide-liquide, tandis que les bulles plus grosses parviennent à traverser l’interface, entraînant une importante colonne de liquide lourd derrière elles. Après que l’influence des paramètres physiques a été qualitativement établie à la lumière de modèles simples, des simulations numériques de plusieurs situations sélectionnées ont été réalisées. Celles-ci ont été menées à partir de deux approches basées sur les équations de Navier-Stokes incompressibles, l’une utilisant une technique de capture d’interface, l’autre une description de type « interface diffuse » de Cahn-Hilliard. Les comparaisons entre les résultats expérimentaux et numériques ont confirmé la fiabilité des prédictions numériques dans la plupart des cas, mais ont également souligné le besoin d’améliorer la capture de phénomènes physiques à petite échelle, en particulier ceux liés au drainage de film. / In order to predict the evolution of a hypothetical accident in pressurized water nuclear reactors, this study aims to understand the dynamics of gas bubbles ascending in a stratified mixture made of two superimposed liquids. To this aim, an experimental device equipped with two high-speed video cameras was designed, allowing us to observe isolated air bubbles and bubble trains crossing a horizontal interface separating two Newtonian immiscible liquids initially at rest. The size of the bubbles and the viscosity contrast between the two liquids were varied by more than one and four orders of magnitude respectively, making it possible to observe a wide variety of flow regimes. In some situations, small millimetric bubbles remain trapped at the liquid-liquid interface, whereas larger bubbles succeed in crossing the interface and tow a significant column of lower fluid behind them. After the influence of the physical parameters was qualitatively established thanks to simple models, direct numerical simulations of several selected experimental situations were performed with two different approaches. These are both based on the incompressible Navier-Stokes equations, one making use of an interfacecapturing technique, the other of a diffuse Cahn-Hilliard description. Comparisons between experimental and numerical results confirmed the reliability of the computational approaches in most situations but also highlighted the need for improvements to capture small-scale physical phenomena especially those related to film drainage.

Escoamentos gás-líquido assim como escoamento líquido-líquido-gás em duto de geometria anular estão presentes em muitas aplicações industriais, por exemplo, em poços de petróleo direcionais. No entanto, até mesmo características globais de escoamento gás-líquido nessa geometria, como os padrões de escoamento ou gradiente de pressão, não são ainda totalmente compreendidas. E ainda, informações são escassas quando se refere a escoamento trifásico nessa geometria, cuja aplicação está relacionada ao fenômeno de inversão de fase, que é de extrema importância não apenas para ao setor petrolífero, como para a indústria alimentícia. O presente estudo experimental tem como objetivo avaliar o escoamento líquido-gás, apresentar dados inéditos de escoamento gás-líquido para três viscosidades de óleo, além de avaliar o fenômeno de inversão de fase em escoamento ascendente vertical em duto anular de grande diâmetro. Um aparato experimental inclinável com 10,5 m de comprimento foi projetado e construído para este trabalho. As dimensões radiais do duto anular estão em escala real, conforme se verifica em poços de petróleo e gás. A investigação em escoamento gás-líquido foi conduzida utilizando água, óleo e ar comprimido como fluidos de trabalho em escoamento ascendente vertical em duas geometrias: (i) um tubo com diâmetro de 95 mm e (ii) um duto de configuração anular e concêntrico, com diâmetro hidráulico de valor igual ao diâmetro do tubo. A avaliação do fenômeno de inversão de fase em escoamento trifásico foi conduzida em condições equivalentes em três geometrias: (i) tubo vertical menor com diâmetro de 50 mm, (ii) tubo com diâmetro de 95 mm e (iii) um duto anular concêntrico. Padrões de escoamento, queda de pressão e fração volumétrica de fase foram obtidos para ambos os escoamentos gás-líquido e líquido-líquido-gás. Os dados coletados nesse trabalho são de grande importância para o desenvolvimento de novas correlações de fechamento, que são essenciais para o projeto otimizado de poços de petróleo. Dados inéditos de escoamento bifásico óleo-gás são apresentados, bem como um estudo pioneiro em inversão de fase em escoamento trifásico com velocidade superficial de gás e viscosidade do óleo elevadas. / Two-phase flows as well as three-phase flow in annular geometry are present in many industrial applications, for example in oil directional wells. However, even global characteristics of gas-liquid flow in this geometry, such as flow patterns and pressure gradient are not fully understood. Moreover, information is scarce when it refers to three-phase flow in this geometry, which application is related to the phase inversion phenomenon, which is of extreme importance and not only for the oil industry. This experimental study aims to evaluate the liquid-gas flow, present new data from gas-liquid flow for three oil viscosities and evaluate the phase inversion phenomenon in vertical upward flow in large diameter annular duct. An experimental apparatus with 10.5 m length was designed and built for this work. The radial dimensions of the annular duct are similar to full scale, as observed in oil and gas wells. The investigation into gas-liquid flow was conducted using water, oil and compressed air as working fluids in an ascending vertical flow in two geometries: (i) a tube with 95 mm diameter and (ii) a concentric annular duct with hydraulic diameter equivalent to the tube internal diameter. The evaluation of the phase inversion phenomenon in three-phase flow was conducted under equivalent conditions for three geometries: (i) smaller vertical tube with 50 mm of internal diameter, (ii) tube with 95 mm of internal diameter and (iii) concentric annular duct with hydraulic diameter of 95 mm. Flow patterns, pressure drop and volumetric phase fraction were obtained for both gas-liquid and gas-liquid-liquid flows. The data collected in this study are of great importance for the development of new closing correlations, which are essential for the optimized design of oil wells. New two-phase flow data for three oil viscosities, not found in the literature, are presented as well as a pioneer study in three-phase-flow phase inversion with high oil viscosity and high superficial gas velocity.

Afin de réduire les effets nocifs des inclusions d'alumine et d'améliorer la coulabilité de l'acier en fusion, le traitement au calcium est largement utilisé pour transformer les inclusions solides en inclusions liquides. Cependant, le traitement au calcium donne des résultats très irréguliers, difficilement explicables. Même si de nombreux efforts ont été déployés pour comprendre le comportement du calcium dans l’acier liquide, il n’a pas encore été prédit avec précision. Par conséquent, le mécanisme par lequel le calcium se dissout dans la masse fondue et transforme les inclusions solides doit être compris pour optimiser les conditions de traitement tels que la vitesse d'injection, la profondeur d'injection, le diamètre du fil d'injection, le temps d'agitation, etc. Afin de comprendre le mécanisme par lequel le calcium se dissout dans l'acier liquide, des expériences en laboratoire ont été effectuées dans un petit four à induction d'une capacité de 2,5 kg de métal. L'objectif est de confronter les résultats expérimentaux avec les résultats du modèle numérique développé. La remontée des gouttelettes de calcium ou des bulles dans l’acier liquide est un problème à trois phases (gouttelettes ou bulles de calcium/acier liquide/air au sommet). Par conséquent, une plateforme de calcul scientifique interne (ICI-tech) basée sur des méthodes par éléments finis est adaptée pour permettre la modélisation de telles solutions. Les écoulements triphasiques sont validés à l’aide de références classiques issues de la littérature. Le modèle de dissolution a été mis en oeuvre dans notre logiciel et la validation du modèle de dissolution a été réalisée. Les gouttelettes et les bulles de calcium sont étudiées dans l’acier liquide et leur coefficient de transfert de masse moyen est indiqué. Afin d'étudier le changement de phase calcium liquide/gaz, un modèle de nucléation a été implémenté dans le code ICI-tech. Un test typique est effectué où la croissance d'une bulle (vapeur d'eau) dans une eau uniformément surchauffée et la croissance d'une bulle de calcium dans du calcium liquide uniformément surchauffé sont calculées. / In order to diminish the harmful effects of aluminate inclusions and improve the castability of molten steel, calcium treatment is widely used in Aluminum killed steels. However, calcium treatment gives irregular results. Even with many efforts done to understand the behavior of calcium in liquid steel, it is not yet accurately predicted. Therefore, the mechanism by which the calcium dissolves into the liquid steel and transforms the solid inclusions must be understood to optimize the process conditions such as injection speed, injection depth, injection wire diameter, stirring time, etc. In order to understand the mechanism by which the calcium dissolves into the liquid steel, laboratory scale experiments have been performed in a small induction furnace of 2.5 kg metal capacity. The calcium injections are performed at the temperature below and above the boiling point of calcium. Then, the corresponding yields (calcium recovery) are compared. Rise of calcium droplet or bubble in liquid steel is a three-phase problem (calcium droplet or calcium bubble/liquid steel/air at the top). Therefore, an in-house scientific computational platform (ICI-tech) based on finite element methods is adapted to allow the modeling of such three-phase flows, which is validated using the classical benchmark issued from the literature. The dissolution model has been implemented in our software, and their validation has been performed. Thereafter, the rise of Calcium droplets and bubbles are studied in the liquid steel, and their respective average mass transfer coefficient in the liquid steel is reported. In order to study the calcium liquid/gas phase change, the nucleation model has been implemented in the code (ICI-tech). A typical test is performed where the growth of a bubble (water vapor) in uniformly superheated water and growth of a calcium bubble in uniformly superheated Ca liquid is computed.

[pt] O escoamento trifásico na indústria do petróleo é caracterizado pela presença das fases gás, óleo e água. A presença da terceira fase (água) traz complexidade a esse processo, visto que pode provocar a formação de diversos novos padrões de escoamento, além dos já conhecidos para escoamento bifásico. Adicionalmente, a presença de uma fase líquida dispersa na outra pode formar uma emulsão, alterando significativamente a viscosidade e, assim, influenciando diretamente na perda de carga. O foco do presente trabalho é na previsão do padrão de golfadas com dispersões de água e óleo utilizando um modelo transiente unidimensional de Dois Fluidos. A presença da água é modelada através da solução da equação de conservação de massa para a fase água. Visando prever com precisão a queda de pressão, assim como a distribuição das frações volumétricas de cada fase ao longo do domínio, desenvolveu-se um modelo de fechamento algébrico para avaliar o escorregamento entre as fases líquidas. Com o modelo proposto, os resultados obtidos para a velocidade de escorregamento no escoamento água/óleo foram comparados com dados experimentais e de outros modelos, apresentando um excelente desempenho. O modelo foi então utilizado para analisar o escoamento trifásico no padrão de golfadas. As previsões para a queda de pressão e características das golfadas (comprimento, frequência e velocidade de translação) foram comparadas com dados experimentais da literatura e os resultados são promissores. / [en] The three-phase flow in the oil industry is characterized by the presence of the gas, oil and water phases. The presence of the third phase (water) adds complexity to this process, since it can cause the formation of several new flow patterns in addition to those already known for two-phase flow. Additionally, the presence of a dispersed phase into another can form an emulsion, altering significantly the viscosity and consequently influencing directly the pressure drop. The focus of this job is in the prediction of the slug flow with dispersions of water and oil using a one-dimensional transient Two Fluid model. The presence of water in the flow is modelled with the solution of an equation of conservation of mass. Intending to predict with precision the pressure drop, as the volumetric phase distribution of each phase throw the domain, an algebraic closure model was inserted to assess the slip between the liquid phases. With the proposed model, the results obtained for the slip velocity of the water/oil flow were compared with experimental data and other models, showing excellent performance. The model was then used to analyze the three-phase flow in the slug pattern. The predictions for pressure drop and characteristics of the slugs (length, frequency and translation velocity) have been compared with experimental data from the literature and the results are promising.

A ocorrência frequente de escoamentos multifásicos em tubulações tem motivado um grande interesse acadêmico nas últimas décadas. O caso particular de escoamentos líquidolíquido é geralmente encontrado na indústria do petróleo, onde uma série de aplicações envolve escoamentos óleo-água, tais como a produção de petróleo e seu transporte. No entanto, ele não tem recebido a mesma atenção quando comparado com escoamentos gás-líquido. Ainda não existe uma explicação física razoável para um número significativo de fenômenos observados em escoamento óleo-água, como o fenômeno de redução de atrito, observado em escoamento disperso, e a estrutura interfacial ondulada em escoamento estratificado. Os escoamentos trifásicos têm sido ainda menos estudados. Há técnicas de medição, desenvolvidas para escoamento gás-líquido, que supostamente são adaptáveis aos escoamentos líquido-líquido, mas várias delas ainda precisam de validação adequada. O sensor wire-mesh, um método híbrido baseado na medição de resistência ou capacitância, que combina medição local intrusiva da fração de fase e imagens tomográficas transversais, oferece uma boa resolução espacial e alta resolução temporal em comparação com outras técnicas atuais. Porém, a literatura existente em aplicações do sensor wire-mesh cobre quase apenas o escoamento gás-líquido e, até agora, não é possível avaliar o limite de viscosidade do fluido para a sua aplicação. Neste contexto, este projeto propõe o estudo de aspectos importantes da fenomenologia de escoamentos líquido-líquido e líquido-líquido-gás com o auxílio da tecnologia wire-mesh. O principal objetivo prático é a validação da técnica wire-mesh como ferramenta de referência para o desenvolvimento de instrumentação para aplicações em campos petrolíferos, com especial atenção devotada ao efeito da viscosidade do óleo sobre a confiabilidade da medição e à extensão da tecnologia para lidar com escoamentos óleo-água-gás. / The frequent occurrence of multiphase flows in pipes has motivated a great research interest over the last decades. The particular case of liquid-liquid flow is commonly encountered in the petroleum industry, where a number of applications involve oil-water flow such as crude oil production and transportation. However, it has not received the same attention when compared to gas-liquid flow. There is no reasonable physical explanation for a significant number of phenomena observed in oil-water flow, as the drag reduction phenomenon observed in dispersed flow and the interfacial wavy structure of stratified flow. Much less has been investigated when it comes to three-phase flow. Several measurement techniques that are supposed to be adaptable to liquid-liquid flow have been proposed recently, but many of them still need proper validation. The wire-mesh sensor, a hybrid impedance-based method that combines intrusive local measurement of phase fraction and tomographic cross-sectional imaging, offers good spatial resolution and high temporal resolution in comparison with other current techniques. However, the existing literature on wire-mesh sensor applications covers almost only the gas-liquid flow and, so far, it is not possible to evaluate the fluid-viscosity limit for its application. In that context, this project proposes the study of important aspects of liquidliquid and liquid-liquid-gas flow phenomenology with the aid of the wire-mesh technology. The main goal is the validation of the wire-mesh technique as a reference tool for the development of instrumentation for oilfield application, with especial attention paid to the effect of oil viscosity on measurement reliability and the extension of the technology for dealing with oil-water-gas flow.

A maioria dos poços de petróleo offshore explorados no Brasil utilizam a técnica de elevação artificial de petróleo conhecida como gas-lift. Mais importante, há previsão de uso intensivo dessa técnica nos poços do pré-sal, sob pressões extremas e condições operacionais ainda não compreendidas completamente. O efeito de injetar gás em um escoamento em tubo vertical é o decréscimo do componente gravitacional do gradiente de pressão total. Por outro lado, os óleos pesados (10 < ºAPI < 19) são viscosos e difíceis de escoar. Em certas ocasiões, este tipo de petróleo não é extraído pela falta de tecnologia viável ou pelo alto custo do processo de produção. Alguns estudos recentes indicam que, para óleos ultra viscosos, o cisalhamento viscoso (componente \"friccional\") seria significativo no computo do gradiente de pressão total. Percebe-se, portanto, que deve existir, para cada condição de escoamento específica, um grau API ou uma viscosidade limite do fluido, acima do qual a técnica gas-lift torna-se ineficiente, quando não inútil. Dessa forma, o estudo do uso da água como fluido coadjuvante para a elevação artificial torna-se válido para óleos viscosos e pode ser indicado para melhorar a produtividade e reduzir a potência requerida de bombeamento. Outra questão é a possibilidade do escoamento trifásico gás-óleo-água ser promissor na redução do gradiente de pressão total. Dessa forma, para a prospecção dessa problemática e a avaliação dessas questões foram realizados testes em laboratório, utilizando misturas de óleos de diversas viscosidades (100 cP, 220 cP e 325 cP), onde foram quantificados os ganhos oferecidos pela injeção de gás, no caso ar, e de água em termos de fatores de redução de gradiente de pressão e fatores de desempenho. Além disso, com o intuito de melhor compreender a fenomenologia de escoamentos trifásicos, foram realizadas análises quanto ao deslizamento entre as fases e a aplicabilidade do modelo de deslizamento. Por fim, através de uma modelagem, foi verificado o efeito do deslizamento entre as fases na queda de pressão total em tubulações de elevado comprimento. / Most of the offshore oil wells operated in Brazil use the artificial lifting technique known as gas-lift. More importantly, an intensive use of this technique in the pre-salt wells under extreme pressures and operating conditions not yet completely understood is planned. The effect of injecting gas into the flow in a vertical pipe is the decrease of the gravitational component of the total pressure gradient. On the other hand, the heavy oils (10 < ºAPI < 19) are viscous and difficult to flow. In some occasions, this type of oil is not extracted by the lack of viable technology or by the high cost of the production process. Some recent studies indicated that for ultra-viscous oils, viscous shear stress (\"frictional\" component) would be significant in the total pressure gradient. Therefore, there must be an API degree or a fluid viscosity limit for each specific flow condition above which the \"gas-lift\" technique becomes inefficient. Thus, the study of water used as method of artificial lift becomes valid for viscous oils and can be indicated to improve productivity and reduce the pumping power required. Another issue is that the gas-oil-water three-phase flow can be advantageous in reducing the overall pressure gradient. Thus, for prospecting of this problems and the evaluation of these issues, tests were performed in laboratory using mixtures of oils with different viscosities (100 cP, 220 cP e 325 cP), at which the gains offered by gas (air) and water injection were quantified by pressure gradient reduction factors and performance factors. Furthermore, in order to better understand the phenomenology of three phase flows, analyzes were performed about the slip between the phases and the applicability of the drift flux model. Finally, the effect of slippage between the phases in the total pressure drop in long pipes was checked through modeling.