Chemical enhanced oil recovery has regained its attention because of high oil price and the depletion of conventional oil reservoirs. This process is more complex than the primary and secondary recovery flooding and requires detailed engineering design for a successful field-scale application. An effective alkaline/co-solvent/polymer (ACP) formulation was developed and corefloods were performed for a cost efficient alternative to alkaline/surfactant/polymer floods by the research team at the department of Petroleum and Geosystems Engineering at The University of Texas at Austin. The alkali agent reacts with the acidic components of heavy oil (i.e. 170 cp in-situ viscosities) to form in-situ natural soap to significantly reduce the interfacial tension, which allows producing residual oil not contacted by waterflood or polymer flood alone. Polymer provides mobility control to drive chemical slug and oil bank. The cosolvent added to the chemical slug helps to improve the compatibility between in-situ soap and polymer and to reduce microemulsion viscosity. An impressive recovery of 70% of the waterflood residual oil saturation was achieved where the remaining oil saturation after the ACP flood was reduced to only 13.5%. The results were promising with very low chemical usage for injection. The UTCHEM chemical flooding reservoir simulator was used to model the coreflood experiments to obtain parameters for pilot scale simulations. Geological model was based on unconsolidated reservoir sand with multiple seven spot well patterns. However, facility capacity and field logistics, reservoir heterogeneity as well as mixing and dispersion effects might prevent coreflood design at laboratory from large scale implementation. Field-scale sensitivity studies were conducted to optimize the design under uncertainties. The influences of chemical mass, polymer pre-flush, well constraints, and well spacing on ultimate oil recovery were closely investigated. This research emphasized the importance of good mobility control on project economics. The in-situ soap generated from alkali-naphthenic acid reaction not only mobilizes residual oil to increase oil recovery, but also enhances water relative permeability and increases injectivity. It was also demonstrated that a closer well spacing significantly increases the oil recovery because of greater volumetric sweep efficiency. This thesis presents the simulation and modeling results of an ACP process for a viscous oil in high permeability sandstone reservoir at both coreflood and pilot scales. / text

Fractured viscous oil resources hold great potential for continued oil production growth globally. However, many of these resources are not accessible with current commercial technologies using steam injection which limits operations to high temperatures. Several steam-solvent processes have been proposed to decrease steam usage, but they still require operating temperatures too high for many projects. There is a need for a low temperature injection strategy alternative for viscous oil production. This dissertation discusses scoping experimental work for a low temperature solvent injection strategy targeting fractured systems. The strategy combines three production mechanisms – gas-oil gravity drainage, liquid extraction, and film gravity drainage. During the initial heating period when the injected solvent is in the liquid phase, liquid extraction occurs. When the solvent is in the vapor phase, solvent-enhanced film gravity drainage occurs. A preliminary simulation of the experiments was developed to study the impact of parameter uncertainty on the model performance. Additional work on reducing uncertainty for key parameters controlling the two solvent production mechanisms will be necessary. In a natural fracture network, the solvent would not be injected uniformly throughout the reservoir. Preferential injection into the higher conductivity fracture areas would result in early breakthrough leaving unswept areas of high oil saturation. Conformance control would be necessary to divert subsequent solvent injection into the unswept zones. A variety of techniques, including polymer and silica gel treatments, have been designed to block flow through the swept zones, but all involve initiating gelation prior to injection. This dissertation also looks at a strategy that uses the salinity gradient between the injected silica nanoparticle dispersion and the in-situ formation water to trigger gelation. First, the equilibrium phase behavior of silica dispersions as a function of sodium chloride and nanoparticle concentration and temperature was determined. The dispersions exhibited three phases – a clear, stable dispersion; gel; and a viscous, unstable dispersion. The gelation time was found to decrease exponentially as a function of silica concentration, salinity, and temperature. During core flood tests under matrix and fracture injection, the in-situ formed gels were shown to provide sufficient conductivity reduction even at low nanoparticle concentration. / text

There is a vast deposit of viscous and heavy oil, especially in Canada and Venezuela. Typically thermal methods are used to recover heavy oil. However, thermal methods are inefficient when the depth of the reservoir is high and pay thickness is low. Non-thermal methods need to be developed for viscous and heavy oils. Alkaline-surfactant-polymer (ASP) floods can be used for improving the displacement efficiency, but its effect on sweep efficiency in viscous oil recovery has not been studied. The objective of this research was to investigate 2D ASP floods in a quarter five-spot pattern. Through careful phase behavior screening, the surfactant formulation was developed that produced ultra-low interfacial tension with reservoir viscous oil (100 cp). After verifying that the design of surfactant formulation was robust and can recover more than 90% of oil in a 1D ASP sandpack flood, it was tested in a 2D geometry. Both stable and unstable tertiary ASP floods were performed in a 2D quarter five-spot sandpack using the surfactant formulation developed in 1D ASP sandpack flood. In a stable ASP quarter five-spot sandpack flood, the oil recovery was excellent (~97% of ROIP). Oil recovery in the stable 2D ASP flood behaved similar to oil recovery in the 1D stable ASP flood. However, pressure drop obtained was high which would be unsustainable in field applications. Interestingly, unstable 2D flood performed well even with an adverse mobility ratio between oil/water bank and ASP slug with a recovery of 80% ROIP. Decreasing the viscosity of ASP slug 6 times decreased the maximum pressure drop 5 times; thus, the maximum pressure drop was almost proportional to the ASP slug viscosity in a 2D pattern. This research showed that unstable ASP flood in a 2D geometry can recover significant amount of oil with a practical pressure gradient. / text

“Introduction to the Canadian Oil Sands”, “Canada’s Oil Sand Industry: An Overview”, “Heavy Oil Technologies”, and so many other topics about heavy oil have become the hotcakes in the oil industry. A number of new projects are in Execute phase for the development of heavy oil assets. This clearly shows the increasing demand for heavy oil. An oil industry is working hard to meet the world oil demand by developing deep water, HPHT, heavy oil, shale sands and all other non-conventional reservoirs but the main challenge is to develop and operate them in a risk free environment. Understanding the reservoir and fluid properties and developing new technologies help the industry to reduce the risk in developing non-conventional fields. A major problem in heavy oil field is to understand the behaviour of heavy oil. The viscous oil flows sluggishly in the formations and hence it is difficult to transport through unconsolidated formations and is very difficult to produce by conventional methods. Viscous oil recovery entails neatly designed enhanced oil recovery processes like Steam Assisted Gravity Drainage and the success of such technologies are critically dependent on accurate knowledge of reservoir, well and fluid properties of oil under variety of pressure and temperature conditions. This research project has provided some solutions to the challenges in heavy oil field development and can help the oil industry to optimise heavy oil production. Detailed experimental understanding of PVT properties has allowed this project to contribute to the knowledge. Reservoir, well and fluid properties were studied thoroughly and demonstrated the criticality of each parameter on the efficiency of Steam Assisted Gravity Drainage. An user friendly SAGD simulator is a big output of this research which allows the user to optimise the heavy oil recovery and enables to do risk assessments quickly during design phase of SAGD. A SAGD simulator is developed.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21352号 / 工博第4511号 / 新制||工||1702(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 八木 知己, 教授 清野 純史, 教授 高橋 良和 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Ce travail porte sur la description et la compréhension de l’inversion de phase catastrophique utilisée pour l’émulsification de produits visqueux, à travers l’analyse des effets de formulation et de procédé sur la fraction de phase dispersée à laquelle le processus se produit et sur les mécanismes mis en jeu. Les suivis rhéologique et conductimétrique simultanés in situ de l’émulsification ont permis, du point de vue procédé, de mettre en avant l’influence du débit d’addition de la phase aqueuse sur la formation d’émulsions multiples du type e/H/E lesquelles, en augmentant notablement la fraction de phase dispersée apparente, sont responsables de l’inversion dès de faibles fractions de phase dispersée ajoutée. Au niveau formulation, l’augmentation de la viscosité de l’huile induit de manière remarquable la tendance de cette phase à devenir le milieu dispersé, conduisant à une inversion pour de très faibles fractions de phase aqueuse et donc à des émulsions finales très concentrées (de 80 à 95% en volume). Le suivi au microscope du phénomène d’inversion de phase par l’intermédiaire d’un écoulement de type « squeezing flow », a permis d’établir les conditions et les mécanismes conduisant à une inversion complète ou seulement partielle. La viscosité relative des phases aqueuse et huileuse est responsable d’une inversion catastrophique suivant un mécanisme de type agglomération – coalescence plutôt que de type inclusion/fuite tel que généralement admis. L’établissement d’un modèle mathématique basé sur les bilans de population et le caractère fractal du phénomène a permis de décrire l’évolution de la taille des gouttes multiples ainsi que la fraction de phase dispersée ajoutée à laquelle l’inversion se produit / This study deals with the description and understanding of catastrophic phase inversion during high viscous oil emulsification, through the analysis of the effects of formulation and process variables on the dispersed phase fraction at which the inversion is triggered and on the involved mechanisms. The simultaneous follow – up in situ of viscosity and conductivity measurements allowed, from a process point of view, to emphasize on the effect that the aqueous phase addition rate has on the formation of multiple w/O/W emulsions. Due to the formation of w/o/W emulsions, the volume of the effective dispersed phase greatly increases while at the same time, if the aqueous phase is added by very small fractions inversion of the w/o/W system can occur. In relation with formulation, an increase in oil viscosity greatly increased the tendency of the oily phase to become the dispersed phase. At the same time, it promoted the formation of highly concentrated emulsions (about 80 to 95 % in volume) after the inversion had occurred. The microscopical follow-up of emulsion morphology by means of squeezing flow, allowed us to establish the conditions and mechanisms that lead to partial or complete inversion. Even though literature sources lead us believe that inversion will occur through the “inclusion/escape” mechanism, experimental results showed that the relative viscosity between the phases promoted inversion through the mechanism of “agglomeration – coalescence” rather than “inclusion/escape”. A mathematical model based on population balances and on the fractal nature of multiple emulsions allowed us to describe the multiples drop size and effective dispersed phase evolution until inversion phenomena

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 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.

[pt] O atual esgotamento de campos de petróleo tradicionais tem aumentado a demanda pela produção e transporte óleos não convencionais, que podem possuir uma alta viscosidade dinâmica. Neste contexto, o estudo do escoamento simultâneo de gás e óleos viscosos em tubulações é de grande importância para a indústria de Óleo e Gás. Simulações numéricas uni-dimensionais desempenham um papel essencial nestes estudos, especialmente aquelas baseadas no Modelos de Dois-Fluidos 1D, cuja solução numérica em malhas refinadas consiste na Metodologia de Captura de Regimes. O propósito deste trabalho é utilizar esta abordagem para reproduzir dados experimentais de escoamentos óleo viscoso-gás em golfadas e estratificado ondulado em um duto horizontal em escala laboratorial. Para aprimorar os resultados desta metodologia, dados experimentais foram usados conjuntamente com um procedimento de otimização e uma versão simplificada do Modelos de Dois-Fluidos 1D para criar duas novas expressões para o fator de atrito interfacial, as quais mostraram maior eficiência que correlações padrão da literatura. O efeito da introdução da pressão dinâmica, difusão axial de quantidade de movimento e tensão interfacial dinâmica no Modelo de Dois-Fluidos 1D foi analisado. Resultados de gradiente de pressão e de fração volumétrica de líquido (histogramas, valores médios e perfis transientes) foram comparados com dados experimentais. Observou-se, com o auxílio de análises de boa-colocação, que a pressão dinâmica e as novas expressões para o fator de atrito interfacial fornecem resultados satisfatórios. / [en] The current depletion of traditional oil fields is increasing the demand for the production and transport of unconventional oils, which might possess a high dynamic viscosity. In this context, the study of the simultaneous flow of gas and viscous oils in pipelines is of paramount importance for the Oil and Gas industry. One-dimensional numerical simulations play a key role in such studies, especially the ones based on the 1D Two-Fluid Model, whose numerical solution in fine meshes consists in the Regime Capturing Methodology. The purpose of this work is to use this approach for reproducing the experimental data of isothermal slug and stratified wavy viscous oil-gas flows in a horizontal laboratory-scale pipe. For improving the results of the methodology, experimental data were used together with an optimization procedure and a simplified version of the 1D Two-Fluid Model for successfully creating two new expressions for the interfacial friction factor, which showed better efficiency than standard literature correlations. The effect of introducing a dynamic pressure, axial momentum diffusion and dynamic interfacial shear in the 1D Two-Fluid Model was examined. Results of pressure gradient and liquid holdup (histograms, mean values and transient profiles) were compared against experimental data. It was seen, with the aid of well-posedness analyses, that the dynamic pressure and the new expressions for the interfacial shear stress provided satisfactory results.