Made available in DSpace on 2014-12-17T14:08:43Z (GMT). No. of bitstreams: 1 TiagoPC_DISSERT.pdf: 1471839 bytes, checksum: 916c40a19572e874803d077f6852a370 (MD5) Previous issue date: 2010-09-18 / In Brazilian Northeast there are reservoirs with heavy oil, which use steam flooding as a recovery method. This process allows to reduce oil viscosity, increasing its mobility and consequently its oil recovery. Steam injection is a thermal method and can occurs in continues or cyclic form. Cyclic steam stimulation (CSS) can be repeated several times. Each cycle consisting of three stages: steam injection, soaking time and production phase. CSS becomes less efficient with an increase of number of cycles. Thus, this work aims to study the influence of compositional models in cyclic steam injection and the effects of some parameters, such like: flow injection, steam quality and temperature of steam injected, analyzing the influence of pseudocomponents numbers on oil rate, cumulative oil, oil recovery and simulation time. In the situations analyzed was compared the model of fluid of three phases and three components known as Blackoil . Simulations were done using commercial software (CMG), it was analyzed a homogeneous reservoir with characteristics similar to those found in Brazilian Northeast. It was observed that an increase of components number, increase the time spent in simulation. As for analyzed parameters, it appears that the steam rate, and steam quality has influence on cumulative oil and oil recovery. The number of components did not a lot influenced on oil recovery, however it has influenced on gas production / No Nordeste brasileiro existem reservat?rios de ?leos pesados, nos quais se utiliza a inje??o de vapor como m?todo de recupera??o. Este processo permite diminuir a viscosidade do ?leo, aumentando a sua mobilidade e melhorando o volume de ?leo a ser recuperado. A inje??o de vapor ? um m?todo t?rmico e ocorre na forma cont?nua ou c?clica. A inje??o c?clica de vapor pode ser repetida diversas vezes. Cada ciclo consiste de tr?s etapas distintas: a fase de inje??o, fase de fechamento (soaking) e fase de produ??o. A inje??o c?clica se torna menos eficiente ? medida que o n?mero de ciclos aumenta. Neste sentido, este trabalho visa estudar a influ?ncia de modelos composicionais na inje??o c?clica de vapor e os efeitos de alguns par?metros, tais como: vaz?o de inje??o, qualidade do vapor e temperatura do vapor injetado; analisando a influ?ncia do n?mero de pseudocomponentes, no que diz respeito ? vaz?o de ?leo, produ??o acumulada de ?leo, fator de recupera??o e tempo de simula??o. Nas situa??es analisadas foi comparado o modelo de fluido de tr?s fases e tr?s componentes conhecido como Black-oil . Foram realizadas simula??es, utilizando um simulador comercial a partir de um modelo de reservat?rio homog?neo com caracter?sticas similares ?s encontradas no Nordeste brasileiro. Observou-se que quanto maior o n?mero de componentes, maior ? o tempo gasto na simula??o. J? para os par?metros analisados, verifica-se que a vaz?o de inje??o de vapor e a qualidade do vapor influenciam na produ??o acumulada de ?leo e no fator de recupera??o. O n?mero de componentes n?o exerceu muita influ?ncia na produ??o acumulada, nem no fator de recupera??o de ?leo, por?m foi significativa na produ??o de g?s do sistema

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-21T00:17:08Z No. of bitstreams: 1 FelipeDaSilvaPereiraAlbuquerqueOliveira_DISSERT.pdf: 6576373 bytes, checksum: b11e6d9b4401f339a1102a38b4351fa4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-03T22:40:49Z (GMT) No. of bitstreams: 1 FelipeDaSilvaPereiraAlbuquerqueOliveira_DISSERT.pdf: 6576373 bytes, checksum: b11e6d9b4401f339a1102a38b4351fa4 (MD5) / Made available in DSpace on 2017-03-03T22:40:49Z (GMT). No. of bitstreams: 1 FelipeDaSilvaPereiraAlbuquerqueOliveira_DISSERT.pdf: 6576373 bytes, checksum: b11e6d9b4401f339a1102a38b4351fa4 (MD5) Previous issue date: 2016-09-12 / Em campos de ?leo pesado onde se utilize a inje??o c?clica de vapor, uma das tarefas mais recorrentes, demoradas e importantes ? a defini??o do cronograma de estimula??o com vapor para as centenas de po?os produtores. A capacidade de gera??o de vapor ? usualmente limitada e ainda mais reduzida pelas recorrentes manuten??es dos geradores. Esse agendamento at? poderia ser feito a partir de um modelo num?rico, mas al?m de exigir a disponibilidade de infraestrutura computacional, s? ? vi?vel caso o tempo n?o seja um fator cr?tico nessa defini??o. A indisponibilidade de tempo para rodar as simula??es necess?rias para a otimiza??o ? normalmente um empecilho, haja vista que a tarefa deve ser recorrentemente realizada conforme as premissas evoluem no tempo. Por isso, a op??o mais comum ? aproveitar a experi?ncia do engenheiro e do ge?logo de reservat?rios em uma an?lise subjetiva dos par?metros de reservat?rio e hist?rico de produ??o, muitas vezes levando em considera??o um estudo feito para um po?o representativo daquele campo ou de uma ?rea do campo. Esse m?todo tem se mostrado eficaz, embora consuma razo?vel quantidade de tempo para an?lise das op??es e conte com a intui??o do profissional encarregado da tarefa. Muitas s?o as refer?ncias acad?micas sobre modelos anal?ticos para representar o processo de inje??o c?clica de vapor e, de posse desses modelos, foram publicadas tentativas de us?-los para maximizar os resultados da estimula??o de determinado po?o. Entretanto, abordaram o problema restrito de uma estimula??o em particular, sem que o problema da defini??o de qual po?o estimular a cada momento de disponibilidade do recurso cr?tico, que ? a capacidade instalada de gera??o de vapor. Esta disserta??o prop?e, portanto, uma nova metodologia sobre como combinar a simplicidade dos diversos modelos anal?ticos dispon?veis na literatura com a grande capacidade computacional moderna para realizar uma an?lise probabil?stica do melhor retorno econ?mico para a capacidade instalada de gera??o de vapor, podendo servir de base, inclusive, na an?lise de viabilidade econ?mica para aquisi??o de maior capacidade ou para mobilizar geradores entre campos ou entre ?reas de um mesmo campo. S?o tratados os aspectos te?ricos dos modelos anal?ticos incluindo as limita??es inerentes a alguns deles bem como em quais circunst?ncias a aplica??o teria mais confiabilidade al?m de poss?veis adapta??es que mitigariam algumas das preocupa??es sobre a aplicabilidade desses modelos. Ao inv?s de definir uma combina??o de modelo e estrat?gia que seja conveniente para todos os cen?rios de utiliza??o poss?vel, trata-se de uma sugest?o de metodologia a fim de alcan?ar melhores resultados, cabendo a quem for us?-la definir quais s?o as particularidades do caso concreto e buscar modelos e estrat?gias que convierem. Por fim, ganhos potenciais ficam claros com a compara??o dos resultados obtidos pelo m?todo com a op??o subjetiva mais intuitiva de injetar nos po?os seguindo uma ordem trivial com cotas fixas para um caso te?rico padr?o atrav?s da simula??o num?rica, para qual ser? utilizado o simulador STARS? da CMG para simula??o t?rmica. / Heavy oil fields that produce through cyclic steam stimulation often demands one very recurrent, time consuming and important task during its lifetime: stimulation scheduling along the hundreds of the existing wells. Installed steam generation capacity is usually lower than the demand and is diminished even more by maintenance stoppages. This scheduling could be defined using numerical simulation, but beyond demanding a computational infrastructure, the time needed to complete the task is usually much greater than the time available. Computational infrastructure is not usually an issue but time availability in order to run the numerous simulations necessary to complete the optimization task, as it is commonly recurrent as circumstances change as time passes. Therefore, the most common option has been to make use of the skills and experience the reservoir engineer and geoscientists gathered during their careers. Using historical production data and reservoir parameters in a subjective analysis, taking into account local experiences extrapolated to the adjacent area or even to the whole field, the reservoir team defines which order the stimulation should be done. That method has shown to be effective, but it takes time to be done and depends on the professional intuition. Many academic references describe analytical models that tries to represent the cyclic steam stimulation and using those models, some attempts were made in order to maximize the results of the stimulation of each well, regardless the of the critical resource usage optimization. This research proposes an unseen methodology versing about how to combine the simplicity of the numerous analytical models available and the amazing modern computational power in order to complete a probabilistic analysis of the optimum financial return that could be reached with the installed steam generation facilities. It can also be used to sustain decisions regarding either investing in capacity enlargement or transfer between fields or production areas. Analytical models theoretical aspects are discussed, including application limitations and in which circumstances one can have better confidence using them as well as which adaptations can be done to diminish lacks of fitting. Instead of defining a model and strategy combination that would fit every scenario, it is more likely a suggestion of a methodology that aims better results. Therefore, it is up to the evaluator to recognize which the characteristics of the real case are and choose a model and a strategy that better complies with the case. Finally, potential gains become clear as results from the methodology are compared with those obtained from an intuitive approach for a standard case through numerical simulation using Computer Modelling Group?s thermal simulator STARS?.

Made available in DSpace on 2014-12-17T15:01:22Z (GMT). No. of bitstreams: 1 GertrudesOQ.pdf: 1545154 bytes, checksum: 8733f5db29d9ddd6780de7e34160f375 (MD5) Previous issue date: 2005-12-16 / Thermal methods made heavy oil production possible in fields where primary recovery failed. Throughout the years steam injection became one of the most important alternatives to increase heavy oil recovery. There are many types of steam injection, and one of them is the cyclic steam injection, which has been used with success in several countries, including Brazil. The process involves three phases: firstly, steam is injected, inside of the producing well; secondly, the well is closed (soak period); and finally, the well is put back into production. These steps constitute one cycle. The cycle is repeated several times until economical production limit is reached. Usually, independent of reservoir type, as the number of cycles increases the cyclic injection turns less efficient. This work aims to analyze rock and reservoir property influence in the cyclic steam injection. The objective was to study the ideal number of cycles and, consequently, process optimization. Simulations were realized using the STARS simulator from the CMG group based in a proposed reservoir model. It was observed that the reservoir thickness was the most important parameter in the process performance, whilst soaking time influence was not significant / Os m?todos t?rmicos viabilizaram a produ??o de ?leo pesado em campos considerados n?o comerciais pelos m?todos convencionais de recupera??o. A inje??o de vapor, em particular, veio a se consagrar ao longo dos anos e ? hoje uma das principais alternativas economicamente vi?vel para o aumento da recupera??o dos ?leos pesados. Dentre as ramifica??es da inje??o de vapor existentes a inje??o c?clica tem sido utilizada com sucesso em escalas comerciais em v?rios pa?ses, incluindo o Brasil. O processo envolve tr?s fases: a primeira ? a inje??o de vapor na qual o vapor ? injetado, dentro do po?o produtor, por um per?odo espec?fico de tempo; em seguida, o po?o ? fechado por um curto per?odo de tempo ( soak period ); e finalmente, o po?o ? recolocado em produ??o durante meses a anos. Esse processo constitui um ciclo. O ciclo ? repetido um n?mero de vezes at? que o limite econ?mico na produ??o seja alcan?ado. Independente do tipo de reservat?rio, a inje??o c?clica geralmente se torna menos eficiente ? propor??o que o n?mero de ciclos aumenta. Este trabalho visa analisar a influ?ncia de algumas propriedades de rocha e reservat?rio na inje??o c?clica de vapor a fim de estudar o n?mero ideal de ciclos e, conseq?entemente, otimizar o processo. Foram realizadas simula??es, utilizando o simulador STARS do grupo CMG, a partir de um modelo de reservat?rio proposto. Observou-se que o efeito da espessura do reservat?rio foi o par?metro que mais influenciou no desempenho do processo, enquanto que para o tempo de soaking essa influ?ncia n?o foi significativa

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-18T20:55:14Z No. of bitstreams: 1 WendellRossineMedeirosDeSouza_TESE.pdf: 7150800 bytes, checksum: 939215abfa16589e581080cb1d3e85f5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-24T23:17:21Z (GMT) No. of bitstreams: 1 WendellRossineMedeirosDeSouza_TESE.pdf: 7150800 bytes, checksum: 939215abfa16589e581080cb1d3e85f5 (MD5) / Made available in DSpace on 2017-10-24T23:17:22Z (GMT). No. of bitstreams: 1 WendellRossineMedeirosDeSouza_TESE.pdf: 7150800 bytes, checksum: 939215abfa16589e581080cb1d3e85f5 (MD5) Previous issue date: 2017-05-30 / A exposi??o dos po?os de petr?leo a condi??es extremas os tem levado a in?meros problemas de integridade, mesmo quando projetados adequadamente. O uso de t?cnicas de recupera??o, tal como a inje??o c?clica de vapor, submete os materiais a varia??es de temperatura severas reduzindo a vida ?til do po?o; ainda, podendo levar ? falha do revestimento met?lico e da bainha de cimento. A perda da integridade da bainha de cimento pode acarretar no vazamento dos fluidos presentes na forma??o e, em alguns casos, ocasionando significantes preju?zos ambientais e econ?micos. No caso de po?os sujeitos ? inje??o c?clica de vapor, a resist?ncia, a flexibilidade e as propriedades t?rmicas t?m sido apontadas como chave do problema. Neste trabalho, as an?lises termomec?nicas foram realizadas utilizando o m?todo dos elementos finitos em modo transiente. O revestimento met?lico, a bainha de cimento e a forma??o foram modelados utilizando-se um modelo 2D axissim?trico com elementos quadril?teros de 8 n?s. Foi analisado o comportamento mec?nico de bainha de cimento, sendo tr?s formula??es de pastas estudadas: pasta de refer?ncia e mais duas aditivadas com l?tex em concentra??es de 125 e 250 ml/kg de cimento. A influ?ncia da espessura da bainha de cimento e a taxa de aquecimento foram observadas como tamb?m seis diferentes valores de coeficientes de expans?o t?rmica para pasta de cimento. Foram analisados gradientes de temperaturas distintos de 150 oC, 200 oC, 250 oC, 300 oC e 350 oC, t?picas temperaturas encontradas no processo de inje??o de vapor, bem como em meio a forma??es com v?rios n?veis de rigidez. O estudo evidenciou que um dos problemas da integridade da bainha de cimento devido a inje??o de vapor est? associado a fase de aquecimento do po?o e localizado na regi?o da bainha pr?ximo ? forma??o. Foi constatado que vincular o emprego da formula??o mais flex?vel e expansiva a uma aplica??o do gradiente de temperatura de modo mais lento, pode prevenir o surgimento de danos na bainha de cimento evitando manobras de recimenta??o. Tal procedimento se mostrou eficaz para meios rochosos mais r?gidos bem como para temperaturas alvo mais elevadas. / Exposure of oil wells to extreme conditions has led to numerous integrity issues, even when designed properly. The use of recovery techniques, such as the cyclic steam injection, submits the materials to severe temperature variations, reducing the oil well lifespan; and may lead to failure of the steel casing and cement sheath. The loss of integrity of the cement sheath may lead to leakage of the fluids present in the formation and, in some cases, causing significant environmental and economic damages. In the case of wells subjected to the cyclic steam injection, resistance, flexibility and thermal properties have been identified as the key to the problem. In the present work, thermomechanical analyzes were performed using the finite element method in transient mode. The steel casing, the cement sheath and the formation were modeled using an axisymmetric 2D model with 8-node quadrilateral elements. The mechanical behavior of the cement sheath was analyzed, being three formulations of pastes studied: reference paste and two other paste with latex additives in concentrations of 125 and 250 ml / kg of cement. The influence of the cement sheath thickness and the heating rate were observed as well as six different coefficient values of thermal expansion for cement paste. It was analyzed the temperature gradients of 150 oC, 200 oC, 250 oC, 300 oC and 350 oC, typical temperatures encountered during the steam injection process, as well as between formations with various levels of rigidity. The study revealed that one of the problems of cement sheath integrity due to steam injection is associated with the heating phase of the well and located in the region of the sheath near the formation. It has been found that linking the use of the more flexible and expansive formulation to an extending temperature gradient period application may prevent damage to the cement sheath by avoiding recementing maneuvers. Such a procedure proved to be effective for more rigid rock media as well as for higher target temperatures.

Made available in DSpace on 2014-12-17T14:07:00Z (GMT). No. of bitstreams: 1 MariaDMP_pre_textuais_ate_cap_3.pdf: 1552357 bytes, checksum: 286c69a88a6d2c4ec8689ee9514da8ec (MD5) Previous issue date: 2008-10-28 / Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductile, with emphasis on Portland cement systems with latex addition. Recent research efforts have presented geopolymeric systems as alternatives. These cementing systems are based on alkaline activation of amorphous aluminosilicates such as metakaolin or fly ash and display advantageous properties such as high compressive strength, fast setting and thermal stability. Basic geopolymeric formulations can be found in the literature, which meet basic oil industry specifications such as rheology, compressive strength and thickening time. In this work, new geopolymeric formulations were developed, based on metakaolin, potassium silicate, potassium hydroxide, silica fume and mineral fiber, using the state of the art in chemical composition, mixture modeling and additivation to optimize the most relevant properties for oil well cementing. Starting from molar ratios considered ideal in the literature (SiO2/Al2O3 = 3.8 e K2O/Al2O3 = 1.0), a study of dry mixtures was performed,based on the compressive packing model, resulting in an optimal volume of 6% for the added solid material. This material (silica fume and mineral fiber) works both as an additional silica source (in the case of silica fume) and as mechanical reinforcement, especially in the case of mineral fiber, which incremented the tensile strength. The first triaxial mechanical study of this class of materials was performed. For comparison, a mechanical study of conventional latex-based cementing systems was also carried out. Regardless of differences in the failure mode (brittle for geopolymers, ductile for latex-based systems), the superior uniaxial compressive strength (37 MPa for the geopolymeric slurry P5 versus 18 MPa for the conventional slurry P2), similar triaxial behavior (friction angle 21? for P5 and P2) and lower stifness (in the elastic region 5.1 GPa for P5 versus 6.8 GPa for P2) of the geopolymeric systems allowed them to withstand a similar amount of mechanical energy (155 kJ/m3 for P5 versus 208 kJ/m3 for P2), noting that geopolymers work in the elastic regime, without the microcracking present in the case of latex-based systems. Therefore, the geopolymers studied on this work must be designed for application in the elastic region to avoid brittle failure. Finally, the tensile strength of geopolymers is originally poor (1.3 MPa for the geopolymeric slurry P3) due to its brittle structure. However, after additivation with mineral fiber, the tensile strength became equivalent to that of latex-based systems (2.3 MPa for P5 and 2.1 MPa for P2). The technical viability of conventional and proposed formulations was evaluated for the whole well life, including stresses due to cyclic steam injection. This analysis was performed using finite element-based simulation software. It was verified that conventional slurries are viable up to 204?F (400?C) and geopolymeric slurries are viable above 500?F (260?C) / Po?os sujeitos ? inje??o c?clica de vapor apresentam importantes desafios para desenvolvimento de pastas de cimenta??o, devido principalmente aos esfor?os de tra??o causados pelos gradientes t?rmicos durante a sua vida ?til. Falhas em cimenta??es que empregaram pastas convencionais de elevada resist?ncia ? compress?o levaram ao emprego de pastas mais flex?veis e/ou d?cteis, com destaque para as pastas de cimento Portland com adi??o de l?tex. Recentes pesquisas t?m apresentado pastas geopolim?ricas como alternativa. Estas pastas cimentantes s?o baseadas na ativa??o alcalina de aluminosilicatos amorfos como o metacaulim ou a cinza volante e possuem propriedades vantajosas como alta resist?ncia ? compress?o, r?pido endurecimento e estabilidade t?rmica. Encontram-se na literatura formula??es geopolim?ricas b?sicas que atendem ?s especifica??es da ind?stria de petr?leo, incluindo reologia, resist?ncia ? compress?o e tempo de espessamento. Neste trabalho, desenvolveu-se novas formula??es geopolim?ricas ? base de metacaulim, silicato de pot?ssio, hidr?xido de pot?ssio, micross?lica e fibra mineral, utilizando o estado da arte em composi??o qu?mica, modelagem de misturas e aditiva??o para otimizar as propriedades relevantes para a cimenta??o de po?os. Partindo de raz?es molares consideradas ideais na literatura (SiO2/Al2O3 = 3,8 e K2O/Al2O3 = 1,0), realizou-se um estudo de misturas secas baseado no modelo do empacotamento compress?vel, obtendo-se um volume ?timo de 6% para o material s?lido adicional. Este material (micross?lica e fibra mineral) serve tanto como fonte de s?lica adicional (no caso da micross?lica) quanto refor?o mec?nico, principalmente no caso da fibra mineral, a qual incrementou a resist?ncia ? tra??o. Realizou-se o primeiro estudo mec?nico triaxial desta classe de pastas. Para efeito de compara??o, tamb?m foi realizado um estudo mec?nico de pastas convencionais ? base de l?tex. Apesar de diferen?as no modo de ruptura (fr?gil no caso dos geopol?meros, d?ctil no caso das pastas com l?tex), a superior resist?ncia compressiva uniaxial (37 MPa para a pasta geopolim?rica P5 versus 18 MPa para a pasta convencional P2), comportamento triaxial similar (?ngulo de atrito 21? para P5 e P2) e menor rigidez (na regi?o el?stica 5,1 GPa para P5 versus 6,8 GPa para P2) das pastas geopolim?ricas permitiu uma capacidade de absor??o de energia (155 kJ/m3 para P5 versus 208 kJ/m3 para P2) compar?vel entre as duas, sendo que os geopol?meros atuam no regime el?stico, sem a microfissura??o presente nas pastas com l?tex. Assim, os geopol?meros estudados neste trabalho devem ser dimensionados para aplica??es no regime el?stico para evitar fraturas fr?geis. Finalmente, a resist?ncia ? tra??o do geopol?mero ? originalmente pobre (1,3 MPa para a pasta geopolim?rica P3) devido ? sua estrutura fr?gil. Entretanto, ap?s a aditiva??o desse sistema com fibra mineral, a resist?ncia ? tra??o do mesmo tornou-se equivalente (2,3 MPa para P5 e 2,1 MPa para P2) ? das pastas com l?tex. A viabilidade t?cnica das formula??es convencionais e geopolim?ricas foi avaliada durante toda a vida ?til do po?o, incluindo os esfor?os devidos ? inje??o c?clica de vapor. Esta an?lise foi feita utilizando um software de simula??o ? base de elementos finitos. Verificou-se que as pastas convencionais s?o vi?veis at? a temperatura de 204?C (400?F) e as geopolim?ricas acima de 260?C (500?F)