Made available in DSpace on 2014-12-17T14:08:56Z (GMT). No. of bitstreams: 1 LuannaCMP_DISSERT.pdf: 3195149 bytes, checksum: 9c2b834c5beeb3439f6a0d1955159637 (MD5) Previous issue date: 2013-09-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Although there are a wide variety of additives that act in fresh state, to adjust the properties of cement, there is also a search by additions that improve the tenacity of the cement in the hardened state. This, in turn, can often be increased by inserting fibers, which act on the deflection of microcracks. This study aimed to use a microfiber glass wool (silica-based) as an additive reinforcing the cement matrix, improving the rupture tenacity, in order to prevent the propagation of microcracks in the cement sheath commonly found in oil wells submitted to high temperatures. The fibers were added at different concentrations, 2 to 5% (BWOC) and varied average sizes, grinding for 90 s, 180 s, 300 s, 600 s. The cement slurries were made with a density of 1,90 g/ cm3 (15,6 lb/gal), using Portland cement CPP- Special Class as the hydraulic binder and 40% silica flour. The characterization of the fiber was made by scanning electron microscopy (SEM), particle size by sieving, X-ray fluorescence (XRF), X-ray diffraction (XRD) and thermogravimetry (TG / DTG). Were performed technological tests set by the API (American Petroleum Institute) by rheology, stability, free water, compressive strength, as well as testing rupture energy, elastic modulus and permeability. The characterization results showed good thermal stability of the microfiber glass wool for application in oil wells submitted to steam injection and, also, that from the particle size data, it was possible to suggest that microfibers milled up to 300 s, are ideal to act as reinforcement to the cement slurries. The rheological parameters, there was committal of plastic viscosity when larger lengths were inserted of microfiber (F90). The values obtained by free water and stability were presented according to API. The mechanical properties, the incorporation of microfiber to the cement slurries gave better rupture tenacity, as compared to reference cement slurries. The values of compressive strength, elastic modulus and permeability have been maintained with respect to the reference cement slurries. Thus, cement slurries reinforced with microfiber glass wool can ensure good application for cementing oil wells submitted to steam injection, which requires control of microcracks, due to the thermal gradients / Embora exista uma grande variedade de aditivos que atuam no estado fresco, para ajuste das propriedades do cimento, existe tamb?m uma busca por adi??es que melhorem a tenacidade do cimento no estado endurecido. Esta, por sua vez, pode comumente ser aumentada pela inser??o de fibras, as quais agem na deflex?o de microtrincas. Este trabalho tem como objetivo utilizar microfibras de l? de vidro (? base de s?lica) como aditivo de refor?o ? matriz ciment?cia, melhorando a tenacidade ? ruptura, a fim de evitar a propaga??o de microfissuras na bainha cimentante comumente encontradas em po?os de petr?leo submetidos a altas temperaturas. As fibras foram adicionadas em diferentes teores, de 2 a 5% (BWOC), e variados tamanhos m?dios, obtidos variando o tempo de moagem de 90 s, 180 s, 300 s e 600 s. As pastas foram formuladas com densidade de 1,90 g/ cm3 (15,6 lb/gal), utilizando o cimento Portland CPP-Classe Especial como aglomerante hidr?ulico e 40% de s?lica flour. A caracteriza??o da fibra foi feita por microscopia eletr?nica de varredura (MEV), granulometria por peneiramento, fluoresc?ncia de raios X (FRX), difra??o de raios X (DRX) e termogravimetria (TG/DTG). Foram realizados ensaios tecnol?gicos padronizados pela API (American Petroleum Institute) de reologia, estabilidade, ?gua livre, resist?ncia ? compress?o, bem como testes de energia de ruptura, m?dulo de elasticidade e permeabilidade. Os resultados da caracteriza??o mostraram boa estabilidade t?rmica da microfibra de l? de vidro para aplica??o em po?os submetidos ? inje??o de vapor. A partir dos dados de granulometria, foi poss?vel verificar que microfibras mo?das at? 300 s s?o ideais para agirem como refor?o ? pasta de cimento. Dos par?metros reol?gicos, houve o comprometimento da viscosidade pl?stica quando foram inseridos comprimentos maiores de microfibra (F90). Os valores obtidos de ?gua livre e estabilidade se apresentaram conformes ? norma API. Das propriedades mec?nicas, a incorpora??o de microfibra ? pasta de cimento conferiu melhor tenacidade ? ruptura, comparada a pasta de refer?ncia. Os valores obtidos de resist?ncia ? compress?o, m?dulo de elasticidade e permeabilidade foram mantidos com rela??o ? pasta padr?o. Desse modo, pastas ciment?cias refor?adas com microfibra de l? de vidro podem garantir boas aplica??es em cimenta??o de po?os de petr?leo sujeitas ? inje??o de vapor, que exija o controle de microfissuras em virtude do gradiente de temperatura

Made available in DSpace on 2014-12-17T14:08:56Z (GMT). No. of bitstreams: 1 LornnaLAG_DISSERT.pdf: 2131175 bytes, checksum: 63e4a76183bcbcfcae20c296d8b0364d (MD5) Previous issue date: 2014-01-31 / Cementing operation is one of the most important stages in the oil well drilling processes and has main function to form hydraulic seal between the various permeable zones traversed by the well. However, several problems may occur with the cement sheath, either during primary cementing or during the well production period. Cements low resistance can cause fissures in the cement sheath and compromise the mechanical integrity of the annular, resulting in contamination of groundwater and producing zones. Several researches show that biomass ash, in particular, those generated by the sugarcane industry have pozzolanic activity and can be added in the composition of the cementing slurries in diverse applications, providing improvements in mechanical properties, revenue and cement durability. Due to the importance of a low cost additive that increases the mechanical properties in a well cementing operations, this study aimed to potentiate the use of sugarcane bagasse ash as pozzolanic material, evaluate the mechanisms of action of this one on cement pastes properties and apply this material in systems slurries aimed to cementing a well with 800 m depth and geothermal gradient of 1.7 ?F/100 ft, as much primary cementing operations as squeeze. To do this, the ash beneficiation methods were realized through the processes of grinding, sifting and reburning (calcination) and then characterization by X-ray fluorescence, XRD, TG / DTG, specific surface area, particle size distribution by laser diffraction and mass specific. Moreover, the ash pozzolanic activity added to the cement at concentrations of 0%, 20% and 40% BWOC was evaluated by pozzolanic activity index with lime and with Portland cement. The evaluation of the pozzolanic activity by XRD, TG / DTG and compressive strength confirmed the ash reactivity and indicated that the addition of 20% in the composition of cement slurries produces improvement 34% in the mechanical properties of the slurry cured. Cement slurries properties evaluated by rheological measurements, fluid loss, free fluid, slurry sedimentation, thickening time and sonic strength (UCA) were satisfactory and showed the viability of using the sugarcane ash in cement slurries composition for well cementing / A opera??o de cimenta??o ? uma das etapas mais importantes no processo de perfura??o de po?os de petr?leo e tem a fun??o primordial de promover a veda??o hidr?ulica entre as diversas zonas perme?veis atravessadas pelo po?o. No entanto, v?rios problemas podem ocorrer com a bainha de cimento, seja durante a cimenta??o prim?ria ou no decorrer do per?odo produtivo do po?o. Cimentos de baixa resist?ncia podem causar trincas na bainha de cimento e comprometer a integridade mec?nica do anular, resultando em contamina??o de len??is fre?ticos e zonas produtoras. V?rias pesquisas comprovam que cinzas de biomassa, em particular, as geradas pela ind?stria sucroalcooleira apresentam atividade pozol?nica e podem ser adicionadas na composi??o das pastas cimentantes em diversas aplica??es, proporcionando benef?cios nas propriedades mec?nicas, no rendimento e na durabilidade do cimento. Dada a import?ncia de um aditivo de baixo custo e que aumenta as propriedades mec?nicas em uma opera??o de cimenta??o de po?os, este trabalho objetivou potencializar o uso da cinza de biomassa da cana-de-a??car (CBCC) como material pozol?nico, avaliar os mecanismos de atua??o desta nas propriedades de pastas de cimento e aplicar este material em sistemas de pastas destinadas ? cimenta??o de um po?o com 800 m de profundidade e gradiente geot?rmico de 1,7 ?F/100 p?s, tanto para as opera??es de cimenta??o prim?ria quanto corretiva (squeeze). Para isso, foram realizados m?todos de beneficiamento da cinza atrav?s dos processos de moagem, peneiramento e requeima (calcina??o) e, em seguida, a caracteriza??o por fluoresc?ncia de raios-X, DRX, TG/DTG, superf?cie espec?fica, granulometria a laser e massa espec?fica. Al?m disso, a atividade pozol?nica da cinza, adicionada ao cimento nas concentra??es de 0% (pasta padr?o), 20% e 40% BWOC, foi avaliada pelo ?ndice da atividade pozol?nica com a cal e com o cimento Portland. A avalia??o da atividade pozol?nica atrav?s das an?lises de DRX, TG/DTG e resist?ncia ? compress?o comprovaram a reatividade do material e indicaram que a adi??o de 20% de cinza na composi??o das pastas produz melhorias em at? 34% das propriedades mec?nicas da pasta endurecida. As propriedades das pastas avaliadas atrav?s dos ensaios de propriedades reol?gicas, perda de filtrado, ?gua livre, estabilidade, tempo de espessamento e resist?ncia ? compress?o (UCA) mostraram-se satisfat?rias e indicaram a viabilidade da utiliza??o da cinza na composi??o das pastas de cimento para po?os de petr?leo

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-14T19:53:37Z No. of bitstreams: 1 LechWalesaOliveiraSoares_DISSERT.pdf: 2473726 bytes, checksum: d7a80c7eeaba135cb9b0bb6355b7a8c2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-15T23:04:07Z (GMT) No. of bitstreams: 1 LechWalesaOliveiraSoares_DISSERT.pdf: 2473726 bytes, checksum: d7a80c7eeaba135cb9b0bb6355b7a8c2 (MD5) / Made available in DSpace on 2016-06-15T23:04:07Z (GMT). No. of bitstreams: 1 LechWalesaOliveiraSoares_DISSERT.pdf: 2473726 bytes, checksum: d7a80c7eeaba135cb9b0bb6355b7a8c2 (MD5) Previous issue date: 2015-04-10 / A cimenta??o de po?os de petr?leo tem como fun??o b?sica promover a estabilidade mec?nica e selar hidraulicamente o po?o impedindo a comunica??o entre os diferentes tipos de fluidos. Materiais pozol?nicos s?o adicionados ao cimento, pois reagem com o hidr?xido de c?lcio formando silicatos e aluminatos de c?lcio hidratado, melhorando a estabilidade qu?mica dos produtos das fases hidratadas. A utiliza??o da cinza da casca de arroz, um rejeito da agroind?stria, na substitui??o parcial ou em adi??o ao cimento ? uma alternativa sustent?vel, na qual ? poss?vel reduzir os ?ndices de emiss?o de CO2 no processo de fabrica??o do cimento. Nesse trabalho foi avaliada a atividade pozol?nica da cinza da casca de arroz (RHA e WRHA) em pastas de cimento para po?os de petr?leo em adi??es de 10% e 20% com rela??o ? massa de cimento (BWOC). As pastas foram curadas por 28 dias a 38?C. As cinzas foram caracterizadas pelas t?cnicas de Microscopia Eletr?nica de Varredura (MEV), Infravermelho com Transformada de Fourier (FTIR), Energia Dispersiva de Raios X (EDX) e ?rea superficial (BET). A atividade pozol?nica foi avaliada pelas t?cnicas de An?lise Termogravim?trica (TGA), Difra??o de Raios X (DRX) e Resist?ncia ? Compress?o. Os resultados de TGA demonstraram que a adi??o da WRHA promoveu uma redu??o de aproximadamente 73% da fase Portlandita com rela??o ? pasta padr?o. A partir dos resultados de DRX foi poss?vel se evidenciou a redu??o da intensidade dos picos de Portlandita. Com base nos resultados apresentados podemos concluir que a cinza da casca do arroz reagiu quimicamente com a Portlandita produzindo C-S-H confirmando seu efeito como agente pozol?nico. / Pozzolanic materials such as rice husk ash are widely used to substitute part of cement, because they react with calcium hydroxide (CH) producing calcium silicate hydrate (C-S-H), which aggregate better physical, chemical and mechanical properties to the cement slurry. The usage of rice husk biomass ash from agribusiness in addition to or partially replacing cement is a noble purpose and a good way of sustainable development which currently is an obsession around the world. The ashes utilized in this study were characterized by: scanning electron microscopy technique (SEM), Fourier transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and BET method. The pozzolanic activity of RHA and WRHA in cement slurries was evaluated by: thermal-gravimetric technique and derivative thermogravimetry (TGA/DTG), X-ray diffraction (XRD) and Compressive Strength. The slurries formulated with additions of 10% and 20% of RHA and WRHA were cured for 28 days at 58 ?C. The results of thermal analysis demonstrated that a 20% WRHA addition caused a reduction of approximately 73% of Portlandite (calcium hydroxide ? CH) phase related to standard slurry (STD). The XRD scans also demonstrated the reduction of the Portlandite peaks? intensity for each slurry compared with STD slurry. The RHA and WRHA react chemically with Portlandite producing calcium silicate hydrate (C-S-H), confirming their effect as a pozzolanic agent. The WRHA presented the best results as a pozzolanic material.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-17T19:32:33Z No. of bitstreams: 1 JoseEdenilsonOliveiraReges_TESE.pdf: 5841325 bytes, checksum: 2ead9ffcd013a5ed21850074ab97c30f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-18T00:04:04Z (GMT) No. of bitstreams: 1 JoseEdenilsonOliveiraReges_TESE.pdf: 5841325 bytes, checksum: 2ead9ffcd013a5ed21850074ab97c30f (MD5) / Made available in DSpace on 2017-03-18T00:04:04Z (GMT). No. of bitstreams: 1 JoseEdenilsonOliveiraReges_TESE.pdf: 5841325 bytes, checksum: 2ead9ffcd013a5ed21850074ab97c30f (MD5) Previous issue date: 2016-11-18 / Esta Tese ? uma contribui??o ao desenvolvimento de sensores de vaz?o na ind?stria de petr?leo e g?s. O objetivo geral do trabalho ? apresentar uma metodologia para medir as vaz?es em po?os injetores de ?gua multizonas a partir de perfis de temperatura do fluido e estimar a incerteza da medi??o. Inicialmente, foi apresentada a equa??o cl?ssica de Ramey descrevendo a temperatura do fluido como uma fun??o da vaz?o ao longo do po?o. Ent?o, foram descritos tr?s m?todos de c?lculo das vaz?es a partir do perfil de temperatura e o sensor de vaz?o foi modelado computacionalmente. Em seguida, foram calculadas as vaz?es em quatro po?os injetores multizonas, localizados no Rio Grande do Norte, a partir de perfis de temperatura medidos experimentalmente. As vaz?es calculadas foram comparadas ?s vaz?es medidas no campo. Os resultados preliminares obtidos nos Po?os 1 e 2 foram satisfat?rios. Nestes po?os, os erros m?ximos observados foram de 28,55% (Po?o 1) e 15,72% (Po?o 2). Entretanto, desvios significativos entre as vaz?es calculadas e medidas foram encontrados nos Po?os 3 e 4. Nestes po?os, os erros m?ximos observados foram de 536,84% (Po?o 3) e 335,54% (Po?o 4). Utilizando a expans?o em S?rie de Taylor da equa??o exponencial de Ramey, foi obtida uma fun??o expl?cita, linear, entre a vaz?o ao longo do po?o e a temperatura do fluido, sendo realizada uma an?lise quantitativa da incerteza de medi??o. A partir desta an?lise, foi observado que, devido ? baixa resolu??o nas medi??es de temperatura, a incerteza de medi??o expandida pode atingir cerca de 155,04% da vaz?o calculada. Foi ent?o apresentado um m?todo de c?lculo estoc?stico das vaz?es a partir das distribui??es de probabilidade das temperaturas medidas, atrav?s da Simula??o de Monte Carlo. As novas vaz?es calculadas apresentaram erros m?ximos de 3,67% (Po?o 1), 14,45% (Po?o 2), 14,62% (Po?o 3) e 22,29% (Po?o 4). Logo, a abordagem probabil?stica permitiu que as vaz?es injetadas fossem satisfatoriamente estimadas mesmo nos casos em que a resolu??o do sensor de temperatura era inadequada ? detec??o de pequenas varia??es na temperatura do fluido. Portanto, a metodologia de c?lculo das vaz?es injetadas a partir do perfil de temperatura do fluido foi validada com sucesso. / This thesis is a contribution to the development of flow sensors in oil and gas industry. The main objective of this work is presenting a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, the classical Ramey equation describing the fluid temperature as a function of flow was presented. Then, three methods to calculate the flow rates from temperature profile were described and the flow sensor was computationally modeled. Next, the flow rates into four multiple-zone injection-wells, located in Rio Grande do Norte, were calculated from temperature profiles experimentally measured. The calculated flow rates were compared to the measured flow rates. The preliminary results, obtained from Wells 1 and 2, were satisfactory. In these wells, the maximum errors were equals to 28,55% (Well 1) and 15,72% (Well 2). However, significant deviations between the calculated and the measured flow rates were found at Wells 3 and 4. In these wells, the maximum errors were equals to 536,84% (Well 3) and 335,54% (Well 4). The Ramey equation was expanded in Taylor Series and linearized to obtain an explicit, linear, function between the flow and the fluid temperature. Then, a quantitative uncertainty analysis was performed. From this analysis, it was observed, due the temperature sensor resolution, the expanded measurement uncertainty may achieve about 155,04% of the calculated flow rate. Then, the injected flow rates were stochastically recalculated from the probability distributions of the measured temperatures, through a Monte Carlo simulation. The new calculated flow rates presented maximum errors of 3,67% (Well 1), 14,45% (Well 2), 14,62% (Well 3) and 22,29% (Well 4). This probabilistic approach allowed injected flow rates to be estimated even in the cases where the temperature sensor resolution was inadequate to detection of small variations into the fluid temperature. Therefore, the methodology to calculate the injected flow rates from the fluid temperature profile was successfully validated.

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)

Made available in DSpace on 2015-03-03T15:28:31Z (GMT). No. of bitstreams: 1 JoaoBC_DISSERT_partes_autorizadas.pdf: 252147 bytes, checksum: e830f27faffa86c9087da28e43e699fd (MD5) Previous issue date: 2010-05-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / We considered prediction techniques based on models of accelerated failure time with random e ects for correlated survival data. Besides the bayesian approach through empirical Bayes estimator, we also discussed about the use of a classical predictor, the Empirical Best Linear Unbiased Predictor (EBLUP). In order to illustrate the use of these predictors, we considered applications on a real data set coming from the oil industry. More speci - cally, the data set involves the mean time between failure of petroleum-well equipments of the Bacia Potiguar. The goal of this study is to predict the risk/probability of failure in order to help a preventive maintenance program. The results show that both methods are suitable to predict future failures, providing good decisions in relation to employment and economy of resources for preventive maintenance. / Consideramos t?cnicas de predi??o baseadas em modelos de tempo de falha acelerado com efeito aleat?rio para dados de sobreviv?ncia correlacionados. Al?m do enfoque bayesiano atrav?s do Estimador de Bayes Emp?rico, tamb?m discutimos sobre o uso de um m?todo cl?ssico, o Melhor Preditor Linear N?o Viciado Emp?rico (EBLUP), nessa classe de modelos. Para ilustrar a utilidade desses m?todos, fazemos aplica??es a um conjunto de dados reais envolvendo tempos entre falhas de equipamentos de po?os de petr?leo da Bacia Potiguar. Neste contexto, o objetivo ? predizer os riscos/probabilidades de falha com a finalidade de subsidiar programas de manuten??o preventiva. Os resultados obtidos mostram que ambos os m?todos s?o adequados para prever falhas futuras, proporcionando boas decis?es em rela??o ao emprego e economia de recursos para manuten??o preventiva