Made available in DSpace on 2014-12-17T14:07:20Z (GMT). No. of bitstreams: 1 EricaNMGP.pdf: 6433422 bytes, checksum: bf4255596957765009ee816c080d6b9a (MD5) Previous issue date: 2007-04-23 / The development of activities in the oil and gas sector has been promoting the search for materials more adequate to oilwell cementing operation. In the state of Rio Grande do Norte, the cement sheath integrity tend to fail during steam injection operation which is necessary to increase oil recovery in reservoir with heavy oil. Geopolymer is a material that can be used as alternative cement. It has been used in manufacturing of fireproof compounds, construction of structures and for controlling of toxic or radioactive waste. Latex is widely used in Portland cement slurries and its characteristic is the increase of compressive strength of cement slurries. Sodium Tetraborate is used in dental cement as a retarder. The addition of this additive aim to improve the geopolymeric slurries properties for oilwell cementing operation. The slurries studied are constituted of metakaolinite, potassium silicate, potassium hydroxide, non-ionic latex and sodium tetraborate. The properties evaluated were: viscosity, compressive strength, thickening time, density, fluid loss control, at ambient temperature (27 ?C) and at cement specification temperature. The tests were carried out in accordance to the practical recommendations of the norm API RP 10B. The slurries with sodium tetraborate did not change either their rheological properties or their mechanical properties or their density in relation the slurry with no additive. The increase of the concentration of sodium tetraborate increased the water loss at both temperatures studied. The best result obtained with the addition of sodium tetraborate was thickening time, which was tripled. The addition of latex in the slurries studied diminished their rheological properties and their density, however, at ambient temperature, it increased their compressive strength and it functioned as an accelerator. The increase of latex concentration increased the presence of water and then diminished the density of the slurries and increased the water loss. From the results obtained, it was concluded that sodium tetraborate and non-ionic latex are promising additives for geopolymer slurries to be used in oilwell cementing operation / O desenvolvimento das atividades do setor petr?leo e g?s tem promovido a busca de materiais mais adequados para cimenta??o de po?os de petr?leo. No estado do RN, a integridade da bainha cimentante tende a ser prejudicada durante a inje??o de vapor, procedimento necess?rio para aumentar a recupera??o do petr?leo em reservat?rios com ?leo de alta viscosidade. O geopol?mero ? um material que pode ser utilizado como cimento alternativo, uma vez que vem sendo empregado na produ??o de componentes resistentes ao fogo, na constru??o de estruturas, e para o controle de res?duos t?xicos ou radioativos. O l?tex ? extensamente usado em pastas de cimento Portland e tem como caracter?stica o aumento significativo da resist?ncia ? compress?o das pastas. O tetraborato de s?dio ? usado em cimentos odontol?gicos como retardador de pega em resinas. A adi??o deste aditivo tem a finalidade de melhorar a propriedades das pastas geopolim?ricas para cimenta??o de po?os de petr?leo. As pastas estudadas s?o constitu?das de metacaulim, silicato de pot?ssio, hidr?xido de pot?ssio, l?tex n?o i?nico e tetraborato de s?dio. As propriedades avaliadas foram: viscosidade, resist?ncia mec?nica, tempo de espessamento, densidade e controle de filtrado, na temperatura ambiente (27?C) e de especifica??o de cimento. Os testes foram realizados seguindo as recomenda??es pr?ticas da norma API RP 10B. As pastas aditivadas com tetraborato de s?dio n?o modificaram as propriedades reol?gicas em rela??o a pasta sem aditivo, assim como n?o modificaram as propriedades mec?nicas e a densidade das pastas. O aumento da concentra??o de tetraborato de s?dio aumentou o volume de filtrado das pastas nas duas temperaturas estudadas. A propriedade que o tetraborato de s?dio obteve o melhor desempenho foi em rela??o ao tempo de pega, onde a adi??o do aditivo conseguiu triplicar o tempo de espessamento das pastas. Com rela??o ?s pastas aditivadas com l?tex observou-se que a adi??o desse aditivo diminuiu as propriedades reol?gicas e a densidade do sistema. Na temperatura ambiente, o aditivo funcionou como acelerador de pega e aumentou a resist?ncia mec?nica das pastas. A presen?a de ?gua reduziu a densidade das pastas e aumentou o volume de filtrado a medida que aumentou a concentra??o do aditivo. A partir dos resultados obtidos concluiu-se que o tetraborato de s?dio e o l?tex n?o i?nico s?o aditivos promissores para pastas geopolim?ricas para cimenta??o de po?os de petr?leo

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)