En rapport avec la transition énergétique, d’importantes capacités de stockage énergétique sont nécessaires pour intégrer la forte variation de la production énergétique au travers des centrales éoliennes et photovoltaïques. La transformation de l’énergie électrique en énergie chimique sous forme d’hydrogène est l’une des possibles techniques. La technologie de stockage de l’hydrogène souterrain, selon laquelle l’hydrogène est stocké dans les formations souterraines semblables au stockage du gaz naturel est actuellement un axe de recherche de plusieurs états européens. Par comparaison au stockage du gaz naturel dans les formations souterraines et qui est établie depuis de nombreuses années, l'hydrogène a montré des différences significatives dans son comportement hydrodynamique et biochimique. Ces aspects ont été étudiés dans la présente thèse en utilisant différentes approches analytiques et numériques / In the context of energy revolution large quantities of storage capacity are required for the integration of strongly fluctuating energy production from wind and solar power plants. The conversion of electrical energy into chemical energy in the form of hydrogen is one of the technical possibilities. The technology of underground hydrogen storage (UHS), where hydrogen is stored in subsurface formations similar to the storage of natural gas, is currently in the exploratory focus of several European countries. Compared to the storage of natural gas in subsurface formations, which is established since many years, hydrogen shown some significant differences in its hydrodynamic and bio-chemical behavior. These aspects were investigated in the present thesis by different analytical and numerical approaches

Orientador: Osvair Vidal Trevisan / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica, Instituto de Geociencias / Made available in DSpace on 2018-08-14T09:21:28Z (GMT). No. of bitstreams: 1 Laboissiere_Philipe_M.pdf: 2164531 bytes, checksum: 22b3c21ed4e8fe61df63d3f1a38fb70b (MD5) Previous issue date: 2009 / Resumo: Métodos térmicos de recuperação, especialmente injeção de vapor, estão à frente da maioria dos projetos de recuperação de óleo pesado em terra. A injeção contínua e, mais recentemente, a injeção de vapor auxiliada por drenagem gravitacional permitem aumentar a recuperação. A razão do volume de vapor injetado por volume de óleo recuperado é um parâmetro decisivo na economicidade de projetos de inundação por vapor. No presente trabalho, um estudo experimental e um numérico na célula linear e um estudo numérico na célula SAGD foram desenvolvidos para entender melhor como a injeção de nitrogênio combinado com vapor contribui ao mecanismo de recuperação e para a possível redução em volume do vapor injetado. O estudo experimental foi conduzido num aparato de laboratório constituído de uma célula linear para a injeção contínua de vapor. Os estudos foram conduzidos em escala de laboratório com óleo pesado da bacia do Espírito Santo. As experiências na célula linear consistiram em injetar vapor ou vapor combinado com nitrogênio para recuperação de óleo. Nas experiências, vapor superaquecido a 170 ° C foi injetado a vazões entre 5 e 4,5 ml/min (equivalente em água fria) e nitrogênio injetado a vazões entre 50 e 180 ml/min. As principais conclusões da investigação (derivadas de cinco experimentos executados com consistentes condições operacionais) são: 1) a injeção de nitrogênio combinado com vapor acelera o início e o pico de produção de petróleo em comparação com a injeção de vapor puro; 2) a melhoria da razão vapor/óleo mostra o efeito benéfico da injeção de nitrogênio em substituição a uma fração substancial de vapor; 3) os volumes recuperados e as análises dos remanescentes apontam fatores de recuperação superiores a 45%. Pelos estudos numéricos, os resultados da modelagem da célula linear mostram frentes de vapor com comportamentos de acordo com os observados experimentalmente. No entanto, uma investigação mais aprofundada sobre o papel dos principais parâmetros utilizados para o ajuste de histórico é necessário. Os resultados simulados do SAGD - Wind Down mostram que 84% da produção do SAGD convencional podem ser recuperados com a metade de volume de vapor injetado, indicando uma redução da razão vapor/óleo de 42%. / Abstract: Thermal recovery methods, especially steam injection, are at the forefront of most onshore projects of heavy oil. The continuous injection and, recently, the steam assisted gravity drainage yield high recoveries. The ratio of the volume of steam injected per volume of produced oil is a decisive parameter in the success of steam flood projects. In the present work, an experimental and a numerical study were developed in the linear cell and a numerical study in the SAGD cell to better understand how the injection of nitrogen combined with steam contributes to the recovery mechanism, and to the possible reduction in volume of the injected steam. The experiment runs were conducted in a linear cell built for the continuous injection of steam. The studies were conducted at the lab scale using heavy oil originated from the Espírito Santo basin. The experiments in the linear cell consisted of continuously injecting steam or steam combined with nitrogen to recover oil. In the experiments, superheated steam at 170 ° C was injected at flow rates between 5 and 4,5 ml/min (cold-water equivalent) and nitrogen injected at rates between 50 and 180 ml/min. The main findings of the research (derived from five runs with consistent operating conditions) are as follows: 1) the injection of nitrogen combined with steam accelerates the start and peak of oil production compared to steam injection alone; 2) the improvement of steam oil ratio shows the beneficial effect of nitrogen injection in substitution to a substantial fraction of steam; 3) results indicates recovery factors exceeding 45%. On the numerical studies, the results from modelling of the linear cell show steam front behaviors in agreement to those observed experimentally. However, further investigation on the role of main parameters used for the history matching is necessary. The simulated results of SAGD - Wind Down shows that 84% of the production of conventional SAGD can be recovered with half of the volume of steam injected, indicating a reduction of steam oil ratio of 42%. / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

Orientador: Denis José Schiozer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-26T04:26:34Z (GMT). No. of bitstreams: 1 Ferreira_CarlaJanaina_D.pdf: 10505037 bytes, checksum: df3394746ff67486b69af759c8682915 (MD5) Previous issue date: 2014 / Resumo: A produção de hidrocarbonetos é um negócio que envolve muitos riscos. As incertezas inerentes à produção estão relacionadas às incertezas no estado físico do reservatório e variáveis externas. A incerteza do reservatório pode ser reduzida conforme dados de produção e dinâmicos são adquiridos. A sísmica 4D (S4D) tem sido utilizada na indústria de petróleo, pois a integração de informação geofísica e de engenharia aumenta a capacidade preditiva da simulação de reservatórios. Entretanto, há questões técnicas que devem ser avaliadas antes de se iniciar um projeto de S4D. Vários estudos geofísicos usam o conceito de chance de sucesso para identificar os casos favoráveis onde são avaliados o levantamento sísmico e a magnitude das mudanças sísmicas. Porém, do ponto de vista de engenharia é importante avaliar o impacto da nova informação na operação do campo e o consequente benefício financeiro. A estimativa da chance de sucesso de um projeto de S4D é um desafio. Portanto, este trabalho apresenta uma metodologia que estima a chance de sucesso sob a perspectiva da engenharia de reservatórios. A metodologia foi desenvolvida em três fases. A primeira fase mostra que o erro de saturação de água pode ser utilizado para medir a melhora no entendimento da movimentação de fluidos no reservatório devido à aquisição da S4D. Além disso, mostra que o momento em que a sísmica 4D é adquirida impacta no valor da informação. Na segunda fase a metodologia para determinar o melhor momento para a aquisição da S4D é apresentada. O melhor momento é determinado avaliando o tempo para a chegada de água nos poços e as curvas de erro de saturação. Por fim, a metodologia para a estimativa da chance de sucesso é apresentada. A metodologia é um processo iterativo simples. A metodologia é composta por seis etapas, no qual algumas são bem estabelecidas na literatura. A tese incorpora a data que aquisição da sísmica 4D no processo e avalia a chance de sucesso por meio da variação do beneficio econômico ocasionado pelas incertezas do reservatório. A metodologia foi aplicada para um caso sintético para ilustrar o procedimento do cálculo do valor da informação e da probabilidade de sucesso / Abstract: Production of hydrocarbons is a high-risk business. The uncertainties inherent to production are related to the uncertainties in the physical state of the reservoir and external variables. Reservoir uncertainty can be reduced as new production and dynamic data become available. 4D seismic technology has been used in the petroleum industry because the integration of geophysics and engineering information increases the predictive capability of reservoir simulations. However, there are technical issues to be addressed before starting a 4D seismic project. Several geophysical studies use the chance of success concept to identify the favorable cases; evaluating the seismic survey and the magnitude of seismic changes. From the engineering point of view, it is important to evaluate the impact of new information on field operations and the consequent monetary benefit. The estimation of 4D seismic data chance of success before its acquisition is a challenge. Therefore, the thesis presents a methodology to estimate the chance of success of a 4D seismic project from the reservoir engineering perspective. The methodology was developed in three phases. The first phase shows that water saturation error can measure the improvement on the fluid behavior understanding due to 4D seismic data. Moreover, it shows that the time for 4D seismic data acquisition affects its value. The second phase presents the methodology to estimate the best time to acquire 4D seismic data. The best time estimation is determined by evaluating time for water breakthrough and the water saturation error curves. Finally, the chance of success methodology is presented. The methodology is simple and an iterative process. It is divided in six steps, in which some of them are well established in the literature. The thesis incorporates the date of 4D seismic data acquisition in the process and assesses the chance of success through the variation in the economic benefit caused by the reservoir uncertainties. The methodology was applied to a synthetic reservoir model, showing a procedure to estimate the expected value of information and the probability of success / Doutorado / Reservatórios e Gestão / Doutora em Ciências e Engenharia de Petróleo

[pt] A redução drástica no valor do barril de petróleo em decorrência do crescimento desacelerado das maiores economias do mundo e da queda no consumo está promovendo uma mudança no comportamento da Indústria de Petróleo, uma vez que a redução dos custos de produção associado ao aumento da produtividade é essencial para o setor. Além disso, os aspectos ambientais estão em evidencia devido ao aumento da temperatura global nos últimos anos. Sendo assim, o Método de Recuperação Avançado WAG (Water Alternating Gas) com injeção de dióxido de carbono (CO2) é capaz de aliar aumento de produção de óleo com redução da emissão de dióxido de carbono na atmosfera. Essa dissertação tem o objetivo de estudar o efeito do WAG-CO2 sobre o fator de recuperação e sequestro de dióxido de carbono em reservatório arenítico. Para isso, serão realizadas simulações numéricas de fluxo contínuo em modelos blackoil e composicional utilizando as ferramentas WinProp, Builder, IMEX e GEM, do pacote de simuladores da CMG (Computer Modelling Group). Sendo o IMEX usado para modelos black-oil e o GEM para composicional. O conhecimento das permeabilidades, fenômenos de histerese e tensão interfacial para a simulação numérica são fundamentais para definir o plano de desenvolvimento e as variáveis do processo, responsáveis pelo acréscimo do fator de recuperação e economicidade. Porém, o IMEX e o GEM não permitem que a tensão interfacial e histerese sejam estudos simultaneamente. O fator de recuperação das simulações considerando tensão interfacial foram, em média, 3 por cento maiores que para os casos com histerese, e 0,6 por cento superiores nas injeções iniciando com o gás. Além disso, o aumento no número de poços produtores e injetores melhorou o varrido do reservatório, porém, aspectos como pressão do reservatório, produção de gás e de água devem ser monitorados. / [en] The drastic reduction in the amount of oil as a result of slowed growth of the world s largest economies and the fall in consumption, is promoting a change in the behavior of the Petroleum Industry, since the reduction in production costs coupled with increased productivity is essential for the sector. Moreover, environmental aspects are evident due to the global temperature rise in recent years.Therefore the Advanced Recovery Method WAG (Water Alternating Gas) with carbon dioxide injection (CO2) is able to combine oil production increase with a reduction in carbon dioxide emissions in the atmosphere. This dissertation is intended to study the effect of WAG-CO2 on the recovery factor and carbon dioxide sequestration in sandstone reservoir. For this, numerical simulations streaming will be held in black-oil and compositional models using the WinProp tools, Builder, IMEX and GEM, the simulator package CMG (Computer Modelling Group). Being the IMEX used for black-oil models and the GEM to compositional. Knowledge of permeability, hysteresis phenomena and interfacial tension for the numerical simulation are essential to define the development plan and the process variables responsible for the increase in the recovery factor and economy. However, IMEX and GEM not allow the interfacial tension and hysteresis be studied simultaneously. The result of simulations for interfacial tension were, on average, greater than 3 percent for the cases with hysteresis, and 0.6 percent higher in injections with starting gas. Furthermore, the increase in number of producing and injection wells improved sweep of the reservoir, however, aspects such as reservoir pressure, gas production and water must be monitored.

In an effort to mitigate carbon dioxide (CO2) emissions in the atmosphere, the Southeast Offshore Storage Resource Assessment (SOSRA) project has for objective to identify geological targets for CO2 storage in two main areas: the eastern part of the Gulf of Mexico and the Atlantic Ocean subsurface. SOSRA's second objective is to estimate the geological targets' capacity to store up to 30 million metric tons of CO2 each year with an error margin of ±30%. As part of this project, the research presented here focuses on the outer continental shelf of North Carolina and its potential for the deployment of large-scale offshore carbon storage in the near future. To identify geological targets, workflow followed typical early oil and gas exploration protocols: collecting existing datasets, selecting the most applicable datasets for reservoir exploration, and interpreting datasets to build a comprehensive regional geological framework of the subsurface of the outer continental shelf. The geomodel obtained can then be used to conduct static volumetric calculations estimating the storage capacity of each identified target. Numerous uncertainties regarding the geomodel were attributed to the variable coverage and quality of the geological and geophysical data. To address these uncertainties and quantify their potential impact on the storage capacity estimations, dynamic volumetric calculations (reservoir simulations) were conducted. Results have shown that, in this area, both Upper and Lower Cretaceous Formations have the potential to store large amounts of CO2 (in the gigatons range). However, sensitivity analysis highlighted the need to collect more data to refine the geomodel and thereby reduce the uncertainties related to the presence, dimensions and characteristics of potential reservoirs and seals. Reducing these uncertainties could lead to more accurate storage capacity estimations. Adequate injection strategies could then be developed based on robust knowledge of this area, thus increasing the probability of success for carbon capture and storage (CCS) offshore projects in North Carolina's outer continental shelf. / Doctor of Philosophy / Since the industrial revolution, a significant increase in the anthropogenic emissions of greenhouse gases has been observed worldwide. The rise in concentration of these gases in the atmosphere, specifically carbon dioxide (CO₂), has been linked to an increase in the average temperature on Earth, what is commonly known as global warming. To mitigate the emission of anthropogenic CO₂ in the atmosphere and consequently limit its impact on Earth’s climate, Carbon Capture and Storage projects (CCS) have been developed on various scales. In this type of project, CO₂ is captured from an emitting source (e.g., power plants), then transported via pipelines and stored in deep geological formations. In the United States, onshore CCS projects have demonstrated the technical feasibility of such projects. However, controversies associated with public acceptance and mineral ownership make expansive onshore CCS project development complicated. For these reasons, the U.S. Department of Energy (DOE) has been investigating offshore locations for the deployment of large-scale CCS projects. Southeast Offshore Storage Resource Assessment (SOSRA) is a project sponsored by the U.S. DOE to assess the storage potential of the eastern part of the Gulf of Mexico and the Atlantic Ocean as a first step towards the development of large-scale offshore storage of CO₂. The state of North Carolina was identified as an adequate candidate for CO₂ offshore storage due to its location on the Atlantic coast and its elevated CO₂ emissions from the power plants on its coastal plains. However, as exploration conducted on the outer continental shelf of North Carolina has been minimal, published information regarding the subsurface of this area remains limited to this date. To ensure the safe, long-term storage of CO₂ in this area, an extensive study was needed to select suitable geological formations and determine the storage capacity of each identified target. The research described here aimed to identify such geological targets and estimate the CO₂ storage capacity of North Carolina’s outer continental shelf

Master of Science / Department of Geology / Matthew Totten / The Petersilie oil field in Ness County, Kansas produces out of the Mississippian System, a reservoir composed mainly of shallow water carbonates, at depths of around 4375 ft (1334 m). The lithology of the field ranges from limestone to dolomite, to interlaminated limestone-dolomite beds. Chert is commonly found throughout. Petersilie field lies to the west of the Central Kansas Uplift, and to the east of the Hugoton Embayment. The field saw much drilling activity in the 1960’s, when it reached a production peak of nearly 378,000 barrels of oil per year. Production declined swiftly after that until the late 1990’s, when waterflooding was successfully employed. In this study, a reservoir model was produced for the Mississippian as it occurs in Petersilie field using the Department of Energy’s EdBOAST reservoir modeling software, with the intent of providing a reference for future drilling activity in the Mississippian and determining reservoir characteristics that may have contributed to the effectiveness of waterflooding in this area. The reservoir model was checked by simulation with a companion reservoir simulator program, BOAST 98. Subsequent comparison of simulated and actual oil production curves demonstrates the reliability of well log and drill stem test data for the field and proves the reservoir model to be a good fit for the Mississippian in Petersilie. Production curve analysis of Petersilie indicates the field was an ideal candidate for waterflooding because it has a solution-gas drive mechanism. As the field approached depletion from primary recovery, oil saturations remained high. Petersilie also exhibits high porosity and good permeability. The BOAST software was found to be an effective and inexpensive means for understanding the Mississippian reservoir in central to south-central Kansas. It was determined that BOAST has potential for practical use by smaller independent oil companies targeting the Mississippian in Kansas.

The dynamic solution of multiphase flow through porous media is of special interest to several fields of science and engineering, such as petroleum, geology and geophysics, bio-medical, civil and environmental, chemical engineering and many other disciplines. A natural application is the modeling of the flow of two immiscible fluids (phases) in a reservoir. Others, that are broadly based and considered in this work include the hydrodynamic dispersion (as in reactive transport) of a solute or tracer chemical through a fluid phase. Reservoir properties like permeability and porosity greatly influence the flow of these phases. Often, these vary across several orders of magnitude and can be discontinuous functions. Furthermore, they are generally not known to a desired level of accuracy or detail and special inverse problems need to be solved in order to obtain their estimates. Based on the physics dominating a given sub-region of the porous medium, numerical solutions to such flow problems may require different discretization schemes or different governing equations in adjacent regions. The need to couple solutions to such schemes gives rise to challenging domain decomposition problems. Finally, on an application level, present day environment concerns have resulted in a widespread increase in CO₂capture and storage experiments across the globe. This presents a huge modeling challenge for the future. This research work is divided into sections that aim to study various inter-connected problems that are of significance in sub-surface porous media applications. The first section studies an application of mortar (as well as nonmortar, i.e., enhanced velocity) mixed finite element methods (MMFEM and EV-MFEM) to problems in porous media flow. The mortar spaces are first used to develop a multiscale approach for parabolic problems in porous media applications. The implementation of the mortar mixed method is presented for two-phase immiscible flow and some a priori error estimates are then derived for the case of slightly compressible single-phase Darcy flow. Following this, the problem of modeling flow coupled to reactive transport is studied. Applications of such problems include modeling bio-remediation of oil spills and other subsurface hazardous wastes, angiogenesis in the transition of tumors from a dormant to a malignant state, contaminant transport in groundwater flow and acid injection around well bores to increase the permeability of the surrounding rock. Several numerical results are presented that demonstrate the efficiency of the method when compared to traditional approaches. The section following this examines (non-mortar) enhanced velocity finite element methods for solving multiphase flow coupled to species transport on non-matching multiblock grids. The results from this section indicate that this is the recommended method of choice for such problems. Next, a mortar finite element method is formulated and implemented that extends the scope of the classical mortar mixed finite element method developed by Arbogast et al [12] for elliptic problems and Girault et al [62] for coupling different numerical discretization schemes. Some significant areas of application include the coupling of pore-scale network models with the classical continuum models for steady single-phase Darcy flow as well as the coupling of different numerical methods such as discontinuous Galerkin and mixed finite element methods in different sub-domains for the case of single phase flow [21, 109]. These hold promise for applications where a high level of detail and accuracy is desired in one part of the domain (often associated with very small length scales as in pore-scale network models) and a much lower level of detail at other parts of the domain (at much larger length scales). Examples include modeling of the flow around well bores or through faulted reservoirs. The next section presents a parallel stochastic approximation method [68, 76] applied to inverse modeling and gives several promising results that address the problem of uncertainty associated with the parameters governing multiphase flow partial differential equations. For example, medium properties such as absolute permeability and porosity greatly influence the flow behavior, but are rarely known to even a reasonable level of accuracy and are very often upscaled to large areas or volumes based on seismic measurements at discrete points. The results in this section show that by using a few measurements of the primary unknowns in multiphase flow such as fluid pressures and concentrations as well as well-log data, one can define an objective function of the medium properties to be determined, which is then minimized to determine the properties using (as in this case) a stochastic analog of Newton’s method. The last section is devoted to a significant and current application area. It presents a parallel and efficient iteratively coupled implicit pressure, explicit concentration formulation (IMPEC) [52–54] for non-isothermal compositional flow problems. The goal is to perform predictive modeling simulations for CO₂sequestration experiments. While the sections presented in this work cover a broad range of topics they are actually tied to each other and serve to achieve the unifying, ultimate goal of developing a complete and robust reservoir simulator. The major results of this work, particularly in the application of MMFEM and EV-MFEM to multiphysics couplings of multiphase flow and transport as well as in the modeling of EOS non-isothermal compositional flow applied to CO₂sequestration, suggest that multiblock/multimodel methods applied in a robust parallel computational framework is invaluable when attempting to solve problems as described in Chapter 7. As an example, one may consider a closed loop control system for managing oil production or CO₂sequestration experiments in huge formations (the “instrumented oil field”). Most of the computationally costly activity occurs around a few wells. Thus one has to be able to seamlessly connect the above components while running many forward simulations on parallel clusters in a multiblock and multimodel setting where most domains employ an isothermal single-phase flow model except a few around well bores that employ, say, a non-isothermal compositional model. Simultaneously, cheap and efficient stochastic methods as in Chapter 8, may be used to generate history matches of well and/or sensor-measured solution data, to arrive at better estimates of the medium properties on the fly. This is obviously beyond the scope of the current work but represents the over-arching goal of this research. / text

A large percentage of oil and gas reservoirs in the most productive regions such as the Middle East, South America, and Southeast Asia are naturally fractured reservoirs (NFR). The major difference between conventional reservoirs and naturally fractured reservoirs is the discontinuity in media in fractured reservoir due to tectonic activities. These discontinuities cause remarkable difficulties in describing the petrophysical structures and the flow of fluids in the fractured reservoirs. Predicting fluid flow behavior in naturally fractured reservoirs is a challenging area in petroleum engineering. Two classes of models used to describe flow and transport phenomena in fracture reservoirs are discrete and continuum (i.e. dual porosity) models. The discrete model is appealing from a modeling point of view, but the huge computational demand and burden of porting the fractures into the computational grid are its shortcomings. The affect of natural fractures on the permeability anisotropy can be determined by considering distribution and orientation of fractures. Representative fracture permeability, which is a crucial step in the reservoir simulation study, must be calculated based on fracture characteristics. The diagonal representation of permeability, which is customarily used in a dual porosity model, is valid only for the cases where fractures are parallel to one of the principal axes. This assumption cannot adequately describe flow characteristics where there is variation in fracture spacing, length, and orientation. To overcome this shortcoming, the principle of the full permeability tensor in the discrete fracture network can be incorporated into the dual porosity model. Hence, the dual porosity model can retain the real fracture system characteristics. This study was designed to develop a novel approach to integrate dual porosity model and full permeability tensor representation in fractures. A fully implicit, parallel, compositional chemical dual porosity simulator for modeling naturally fractured reservoirs has been developed. The model is capable of simulating large-scale chemical flooding processes. Accurate representation of the fluid exchange between the matrix and fracture and precise representation of the fracture system as an equivalent porous media are the key parameters in utilizing of dual porosity models. The matrix blocks are discretized into both rectangular rings and vertical layers to offer a better resolution of transient flow. The developed model was successfully verified against a chemical flooding simulator called UTCHEM. Results show excellent agreements for a variety of flooding processes. The developed dual porosity model has further been improved by implementing a full permeability tensor representation of fractures. The full permeability feature in the fracture system of a dual porosity model adequately captures the system directionality and heterogeneity. At the same time, the powerful dual porosity concept is inherited. The implementation has been verified by studying water and chemical flooding in cylindrical and spherical reservoirs. It has also been verified against ECLIPSE and FracMan commercial simulators. This study leads to a conclusion that the full permeability tensor representation is essential to accurately simulate fluid flow in heterogeneous and anisotropic fracture systems. / text

[pt] Reservatórios carbonáticos respondem por mais de 50 por cento da produção mundial de hidrocarbonetos. No Brasil, ganharam mais importância com o descobrimento do Pré-Sal, em 2006. A principal ferramenta de previsão e gerenciamento de reservatórios é a simulação numérica que, tradicionalmente, tem na compressibilidade do poro o único parâmetro geomecânico. Normalmente é adotado apenas um valor, mantido constante, deste parâmetro para todo o reservatório. Porém, a rocha-reservatório sofre deformações durante a explotação do campo, as quais induzem redução da porosidade e permeabilidade. Enquanto o primeiro efeito não é bem representado pela compressibilidade, o segundo não sofre qualquer alteração. Além disso, cada fácies tem um comportamento tensão versus deformação diferente. Por isso a importância de se fazer modelagens acopladas de fluxo e geomecânica em que cada tipo de rocha é representado individualmente. Visando essas análises integradas, mas sem aumento do custo computacional, utiliza-se o pseudoacoplamento, o que permite que esses modelos sejam usados de forma rotineira pelos engenheiros de reservatórios. Esse tipo de acoplamento atualiza a porosidade e a permeabilidade com base em tabelas que relacionam poropressão com multiplicadores de porosidade e permeabilidade. Visando uma boa representação do comportamento da rocha-reservatório, as tabelas de pseudoacoplamento são elaboradas com base em ensaios mecânicos laboratoriais realizados com amostras do próprio campo, representativas de cada fácies. São realizadas análises comparativas utilizando modelos homogêneos e heterogêneos, variando o tipo de representação da geomecânica, que pode ser através da compressibilidade ou do pseudoacoplamento. Conhecidos os efeitos geomecânicos da compactação, a etapa final desta metodologia consiste no estudo de um modelo que visa atenuá-los. / [en] Carbonate reservoirs are responsible for over 50 per cent of world hydrocarbon production. In Brazil, they started to gain more importance after the Pre-Salt discovery, in 2006. The main method to predict and manage reservoirs is numerical simulation in which, traditionally, the only geomechanical parameter is the rock compressibility. Usually it is adopted one single value for the whole model, which is kept constant. During exploitation, though, the reservoir-rock deforms, causing porosity and permeability reduction. While the first effect is not well predicted by rock compressibility, the second is simply kept constant. Besides that, each facies has its own stress-strain behavior. That is why it is so important to model the reservoir flow coupled to geomechanics representing each rock type in a single layer. With the aim of obtaining these integrated analyses, but without additional computational cost, the pseudo-coupling is used, which lets such models to be ran on day-by-day basis by reservoir engineers. This kind of coupling updates both porosity and permeability based on tables that correlate porepressure and porosity and permeability multipliers. In order to have the mechanical behavior of the reservoir-rock well represented, the pseudo-coupling tables are elaborated based on laboratory mechanical tests with samples from the same field to be modeled. In this way, each facies represented on the model has its own table that takes to reservoir simulation the geomechanical effects through porosity and permeability variation. Comparative analyses are done using homogeneous and heterogeneous models, varying the type of geomechanical representation, through rock compressibility or pseudo-coupling. Once known the compaction geomechanical effects, it is simulated a model that tries to attenuate them.

The injection of carbon dioxide (CO2) into saline formations for the purpose of limiting greenhouse gas emissions has been proposed as an alternative to the atmospheric venting of carbon dioxide. In the evaluation process for selecting a potential target saline formation for the disposal of carbon dioxide, flow characterisation of the disposed plume should be undertaken by reservoir simulation of the target formation. The movement of injected carbon dioxide in the saline formation is influenced by many factors including the physics of carbon dioxide at deep formation depths and pressure, physical interactions with formation rock and pore water and variations in the rock flow pathways through changes in formation heterogeneity. This thesis investigates the roles of physical interactions on the disposal of carbon dioxide and the ability to contain the injected gas through evaluation of trapping mechanisms such as dissolution of CO2 in formation water and residual gas trapping through the process of gas-water relative permeability hysteresis. Variable formation heterogeneity is evaluated for its impact on the migration of injected CO2 plume movement and the role of formation heterogeneity in impeding or accelerating the immobilisation of injected carbon dioxide. Multiple reservoir simulation studies were conducted to evaluate, initially, the role of different trapping mechanisms in immobilising the movement of injected carbon dioxide and subsequently, the role of variations in formation rock in the migration and trapping of and injected plume of carbon dioxide. The major simulation study shows that the selection process for identifying appropriate saline formations should not only consider their size and permeability but should also consider their degree of heterogeneity endemic to the formation. / A set of reservoir performance metrics were developed for the CO2 disposal projects. The metrics were applied to compare plume migration of injected CO2 (both vertically and laterally) and containment (through dissolution and residual phase trapping) in these studies. The findings demonstrate how formation heterogeneity has a significant impact on the subsurface behaviour of the carbon dioxide. Formation dip influences the rate of migration, with low formation dipping reservoirs having slower rates of vertical migration. Increasing the tortuousity of the migration flow path by either increasing the shale (non-reservoir) content or lengthening the shale baffles in the formation (corresponding to a gradual decrease in reservoir quality), can progressively inhibit the vertical flow of the plume whilst promoting its lateral flow. The increase in the tortuosity of the CO2 migration pathway delays the migration of CO2 and increases the residence time for the CO2 in the formation. Thus, formation heterogeneity impedes the onset of residual gas trapping through hysteresis effects. Ultimately less carbon dioxide is likely to collect under the seal in heterogeneous formations due to increased reservoir contact and long residence times, thereby reducing the risk of seepage to overlying formations. / Given sufficient permeability for economic injection of CO2, then low to mid net-to-gross heterogeneous saline formations with low formation dip and lengthy intra-bedded shales are desirable for selection for the geological disposal of CO2. Detailed reservoir characterisation of any potential geological disposal saline formations is required in order to accurately predict the range of outcomes in the long term flow characterisation of injected CO2 into those formations.