The rapid emergence of embedded devices and sensor networks that frequently exchange object-level images foretells an increasing reliance on object-level systems. Additionally, nearly all computing systems, including control systems, enterprise applications, scientific codes and dynamic libraries operate eventually at the object code level. Studying adaptivity and runtime composition issues in such systems is becoming an important focus of systems research. In this thesis, we describe an object-level framework that will manipulate an object module to instrument control functionality and adaptivity in order to realize complex compositional scenarios. Using function and parameter remapping capabilities, our framework transcends programming language and design boundaries, and enables applications to adapt dynamically during runtime. We introduce the capability to "restart" an application automatically, a feature we utilize to support adaptivity not only spatially, over the algorithm domain, but temporally as well. A high-level adaptive control language based on XML is presented that allows complex adaptive scenarios to be expressed concisely. Additionally, the construction of several adaptive scenarios using our framework is illustrated, along with several experiments in ``learning adaptivity`` using reinforcement learning techniques. / Master of Science

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La pyrolyse rapide est une des voies de conversion thermochimique qui permet la transformation de biomasse lignocellulosique en bio-huiles. Ces bio-huiles, différentes des coupes lourdes du pétrole ne peuvent pas être directement mélangés dans les procédés de valorisation. En effet, en raison de leur forte teneur en oxygène, les bio-huiles nécessitent une étape de pré-raffinage, telle que l’hydrotraitement, pour éliminer ces composants.L’objectif de ce travail est de comprendre la structure, la composition et la réactivité de la bio-huile grâce à la modélisation de données expérimentales. Pour comprendre leur structure et leur composition, des techniques de reconstruction moléculaire basées sur des données analytiques, ont été appliquées, générant un mélange synthétique, dont les propriétés correspondent à celles du mélange. Pour comprendre leur réactivité, l'hydrotraitement de molécules modèles a été étudié: gaïacol et furfural. Pour cela, un modèle déterministe et stochastique a été créé pour chacun d’eux. L’approche déterministe visait à récupérer une gamme de paramètres cinétiques, qui ont ensuite été affinés par l’approche stochastique créant un nouveau modèle. Cette approche a permis de générer un réseau de réactions en définissant et en utilisant un nombre limité de familles et règles des réactions. Finalement, le mélange synthétique a été utilisé dans la simulation stochastique de l’hydrotraitement de la bio-huile, étayée par la cinétique des molécules modèles.En conclusion, ce travail a permis de recréer la fraction légère de la bio-huile et de simuler leur l'hydrotraitement, via les paramètres cinétiques des composés modèles, qui prédisent de manière raisonnable les effluents de l'hydrotraitement de celles-ci, mais sont inadéquat pour le bio-huile / Fast pyrolysis is one of the thermochemical conversion routes that enable the transformation of solid lignocellulosic biomass into liquid bio-oils. These complex mixtures are different from oil fractions and cannot be directly integrated into existing petroleum upgrading facilities. Indeed, because of their high levels of oxygen compounds, bio-oils require a dedicated pre-refining step, such as hydrotreating, to remove these components.The aim of the present work is to understand the structure, composition and reactivity of bio-oil compounds through modeling of experimental data. To understand the structure and composition, molecular reconstruction techniques, based on analytical data, were applied generating a synthetic mixture, whose properties are consistent with the mixture properties. To understand the reactivity, the hydrotreating of two model molecules was studied: Guaiacol and Furfural. A deterministic and stochastic model were created for each compounds. The deterministic approach intended to retrieve a range of kinetic parameters, later on refined by the stochastic simulation approach into a new model. This approach generates an reaction network by defining and using a limited number of reaction classes and reaction rules. To consolidate the work, the synthetic mixture was used in the stochastic simulation of the hydrotreating of bio-oils, supported by the kinetics of the model compounds.In sum, the present work was able to recreate the light fraction of bio-oil and simulate the hydrotreating of bio-oils, via the kinetic parameters of model compounds, which can reasonably predict the effluents of the hydrotreating of these, but are unsuitable for bio-oil.Fast pyrolysis is one of the thermochemical conversion routes that enable the transformation of solid lignocellulosic biomass into liquid bio-oils. These complex mixtures are different from oil fractions and cannot be directly integrated into existing petroleum upgrading facilities. Indeed, because of their high levels of oxygen compounds, bio-oils require a dedicated pre-refining step, such as hydrotreating, to remove these components.The aim of the present work is to understand the structure, composition and reactivity of bio-oil compounds through modeling of experimental data. To understand the structure and composition, molecular reconstruction techniques, based on analytical data, were applied generating a synthetic mixture, whose properties are consistent with the mixture properties. To understand the reactivity, the hydrotreating of two model molecules was studied: Guaiacol and Furfural. A deterministic and stochastic model were created for each compounds. The deterministic approach intended to retrieve a range of kinetic parameters, later on refined by the stochastic simulation approach into a new model. This approach generates an reaction network by defining and using a limited number of reaction classes and reaction rules. To consolidate the work, the synthetic mixture was used in the stochastic simulation of the hydrotreating of bio-oils, supported by the kinetics of the model compounds.In sum, the present work was able to recreate the light fraction of bio-oil and simulate the hydrotreating of bio-oils, via the kinetic parameters of model compounds, which can reasonably predict the effluents of the hydrotreating of these, but are unsuitable for bio-oil

[pt] Em reservatórios de gás retrógrado com pressões inferiores à pressão de orvalho, a produtividade dos poços pode ser comprometida devido ao aparecimento e acúmulo da fase líquida nas suas imediações. Este fenômeno é conhecido como bloqueio por condensação retrógrada e está associado à uma série de desafios para compreendê-lo. Um deles é a determinação da permeabilidade relativa das fases líquida e gasosa, que comumente advém de curvas de permeabilidade obtidas a partir da extrapolação de poucos dados experimentais. Dessa forma, elas tendem a não representar fielmente efeitos importantes para o escoamento, comprometendo a precisão da modelagem do fluxo no meio poroso. A fim de investigar o efeito das curvas de permeabilidade relativa sobre a formação de bancos de condensado, foi desenvolvido um modelo composicional em escala de reservatório para o estudo do escoamento de gás e condensado. Com o modelo, o uso de curvas de permeabilidade relativa obtidas através de simulação do escoamento de gás retrógrado na escala de poros e de correlações propostas na literatura foi avaliado. Considera-se: sistema isotérmico, escoamento bifásico e incorporação dos efeitos de forças capilares por meio do modelo de permeabilidade relativa. Equações de balanço molar e consistência de volume formam um sistema não linear resolvido pelo método de Newton que fornece pressão e número de mols de cada componente, em todos os volumes de controle do modelo, a cada passo de tempo. Para o equilíbrio de fases, a equação de Peng & Robinson foi implementada com uma rotina de flash a pressão e temperaturas constantes. O modelo foi validado contra a solução analítica para sistema monofásico e por fim, o simulador obteve a evolução temporal das curvas de pressão e saturação em função da distância do poço, a fim de comparar o efeito dos diferentes modelos de curvas de permeabilidade relativa na predição do bloqueio por condensado. Os resultados foram obtidos variando-se a permeabilidade absoluta do meio e a vazão de gás imposta no poço, e o impacto desses parâmetros no acúmulo de condensado foi avaliado. / [en] In gas-condensate reservoirs with pressures below the dew pressure, the productivity of wells can be compromised due to the accumulation of liquid in their surroundings. This phenomenon is known as condensate blockage and there are many challenges to understanding the formation of condensate banks. One of them is the determination of the relative permeability of the liquid and gas phases, which commonly comes from permeability curves obtained from the extrapolation of few experimental data. Thus, they tend not to reliably represent important effects for the flow, compromising the precision of the flow modeling in the porous medium. In order to investigate the effect of relative permeability curves on the formation of condensate banks, a reservoir-scale compositional model was developed for the study of flow of gas and condensate. With the model, the use of relative permeability curves obtained by simulating the gas-condensate flow at the pore-scale and with correlations proposed in the literature was evaluated. It is considered: isothermal system, two-phase flow and incorporation of capillary force effects through the relative permeability model. Molar balance and volume consistency equations form a nonlinear system solved by Newton s method that provides pressure and number of moles of each component, in all control volumes of the model, at each time step. For the phase equilibrium, calculations of the Peng & Robinson equation was implemented in a constant pressure and temperature flash routine. The model was validated against the analytical solution for single-phase flow and, finally, the simulator obtained the temporal evolution of the pressure and saturation as a function of the distance from the well, in order to compare the effect of different models of relative permeability curves in the prediction of condensate blockage. The results were obtained by varying the absolute permeability of the medium and the gas flow imposed in the well, and the impact of these parameters on the accumulation of condensate was evaluated.

[pt] A formação e o acúmulo de condensado em reservatórios de gás retrógrado, especialmente na vizinhança de poços de produção, obstruem parcialmente o fluxo de gás e afetam negativamente a composição dos fluidos produzidos. Entretanto, a previsão de bloqueio por condensado é comumente imprecisa, visto que experimentos raramente reproduzem as condições extremas e composições complexas dos fluidos dos reservatórios, enquanto a maioria dos modelos em escala de poros simplificam demasiadamente os fenômenos físicos associados à transição de fases entre gás e condensado. Para corrigir essa lacuna, um modelo de rede de poros isotérmico composicional e totalmente implícito é apresentado. As redes de poros propostas consistem em estruturas tridimensionais de capilares constritos circulares. Modos de condensação e padrões de escoamento são atrubuídos aos capilares de acordo com a molhabilidade do meio, as saturações locais e a influência de forças viscosas e capilares. Nos nós da rede, pressão e conteúdo molar são determinados através da solução acoplada de equações de balanço molar e consistênc ia de volumes. Concomitantemente, um cálculo de flash à pressão e à temperatura constantes, baseado na equação de estado de Peng e Robinson, é realizado em cada nó, atualizando as saturações e composições das fases. Para a validação do modelo proposto, análises de escoamento foram executadas baseadas em experimentos de escoamento em testemunho reportados na literatura, usando composição dos fluidos e condições de escoamento correspondentes, e geometria do meio poroso aproximada. Curvas de permeabilidade relativa medidas nos experimentos e previstas pelo modelo mostraram boa concordância quantitativa, para dois valores de tensão interfacial e três valores de velocidade de escoamento de gás. Após a validação, o modelo foi usado para avaliar alteração de molhabilidade e injeção de gás como possíveis métodos de recuperação avançada para reservatórios de gás retrógrado. Os resultados exibiram tendências similares àquelas observadas em experimentos de escoamento em testemunhos, e condições ótimas para melhoramento do escoamento foram identificadas. / [en] Liquid dropout and accumulation in gas-condensate reservoirs, especially in the near wellbore region, hinder gas flow and affect negatively the produced fluid composition. Yet, condensate banking forecasting is commonly inaccurate, as experiments seldom reproduce reservoir extreme conditions and complex fluid composition, while most pore-scale models oversimplify the physical phenomena associated with phase transitions between gas and condensate. To address this gap, a fully implicit isothermal compositional pore-network model for gas and condensate flow is presented. The proposed pore-networks consist of 3D structures of constricted circular capillaries. Condensation modes and flow patterns are attributed to the capillaries according to the medium s wettability, local saturations and influence of viscous and capillary forces. At the network nodes, pressure and molar contents are determined via the coupled solution of molar balance and volume consistency equations. Concomitantly, a PT-flash based on the Peng-Robinson equation of state is performed for each node, updating the local phases saturations and compositions. For the proposed model validation, flow analyses were carried out based on coreflooding experiments reported in the literature, with matching fluid composition and flow conditions, and approximated pore-space geometry. Predicted and measured relative permeability curves showed good quantitative agreement, for two values of interfacial tension and three values of gas flow velocity. Following the validation, the model was used to evaluate wettability alteration and gas injection as prospect enhanced recovery methods for gas-condensate reservoirs. Results exhibited similar trends observed in coreflooding experiments and conditions for optimal flow enhancement were identified.