Made available in DSpace on 2014-12-17T14:06:52Z (GMT). No. of bitstreams: 1 FernandoAML.pdf: 704139 bytes, checksum: 56133b8802fd230583fd96ae8805d657 (MD5) Previous issue date: 2009-04-30 / Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ?F showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration / Muitos problemas relacionados ? perda do isolamento hidr?ulico em po?os de petr?leo, causando migra??o de g?s e contamina??o da zona produtora por migra??o de ?gua, t?m sido reportados. A perda do isolamento hidr?ulico ? conseq??ncia de trincas que por sua vez s?o conseq??ncias de uma cimenta??o mal feita, onde houve invas?o de g?s durante a pega da pasta gerando trincas tamb?m chamadas de microanulares que s?o os caminhos por onde a migra??o de g?s ocorre. Essas trincas tamb?m s?o ocasionadas pela fratura do cimento quando este n?o suporta as cargas t?rmicas e din?micas, as quais o cimento ? submetido durante sua vida. Em reservat?rios onde o ?leo encontrado ? bastante viscoso, opera??es de inje??o de vapor de ?gua s?o requeridas a fim de facilitar o escoamento do ?leo. Essa opera??o aumenta a temperatura da malha de po?os, fazendo com que o revestimento dilate e frature o cimento no anular, ocasionando a perda do isolamento hidr?ulico. Uma vez detectada falhas no isolamento hidr?ulico, opera??es de corre??o s?o requeridas o que acaba gerando custos, perda de tempo com a interven??o e lucro cessante. Como o setor de constru??o civil trabalha com cimento a muito mais tempo que o setor de petr?leo, ? comum lan?ar-se m?o de tecnologias e solu??es apresentadas na constru??o e aplicar com os devidos ajustes no ramo do petr?leo. Nesse contexto, a vermiculita, um argilomineral encontrado em abund?ncia no Brasil, tem sido aplicado, na sua forma expandida, na constru??o civil para confec??o de concretos leves, resistentes a fogo e com excelentes propriedades de isolamento t?rmico e ac?stico. J? tem sido reportado em revistas cient?ficas, estudos de sua adi??o em cimento portland com boas propriedades relacionadas ? cimenta??o de po?os de petr?leo. Dessa forma o presente trabalho objetivou estudar o comportamento reol?gico, tempo de pega e a resist?ncia a compress?o de pastas com vermiculita expandida e cimento portland classe especial em quatro composi??es diferentes, fazendo um comparativo com as propriedades existentes da pasta padr?o contendo apenas cimento portland e ?gua, em duas temperaturas, ambiente e aquecida. Os resultados mostraram que a resist?ncia ? compress?o dos corpos de prova diminuiu com o aumento da concentra??o de vermiculita, por?m ainda dentro da faixa permitida para cimenta??o de po?os de petr?leo. Os ensaios de consistometria indicaram que o tempo de pega para a pasta padr?o foi de 120 min, enquanto que para a pasta com 12% de vermiculita expandida foi de 98 min. Os ensaios de estabilidade e a avalia??o do comportamento reol?gico das pastas mostraram que a vermiculita expandida por absorver ?gua, aumenta a viscosidade da pasta, mesmo aumentando o fator ?gua-cimento. O ensaio de estabilidade realizado ? 133 ?F mostrou que n?o houve rebaixamento e nem sedimenta??o para a pasta com 12% de vermiculita expandida. Logo a adi??o de vermiculita expandida ? pasta cimentante favorece a cura r?pida e a baixa retra??o do volume da pasta durante a pega, importantes para evitar migra??o de g?s

Made available in DSpace on 2014-12-17T15:41:41Z (GMT). No. of bitstreams: 1 KeilaSA.pdf: 2159921 bytes, checksum: eaf4fb1bec7305fa007222908f6259ac (MD5) Previous issue date: 2008-02-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Chitosan derivatives were prepared by reductive alkylation using glutaraldehyde and 3-amino-1-propanol. The reducing agent used was the sodium borohydride. Tests of solubility, stability and viscosity were performed in order to evaluate these parameters effects in the reaction conditions (molar ratio of the reactants and presence of nitrogen in the reaction system). The molecular structure of commercial chitosan was determined by infrared (IR) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR). The intrinsic viscosity and average molecular weight of the chitosan were determined by viscosimetry in 0.3 M acetic acid aqueous solution 0.2 M sodium acetate at 25 ?C. The derivatives of chitosan soluble in aqueous acidic medium were characterized by 1H NMR. The rheological behavior of the chitosan and of the derivative of chitosan (sample QV), which presented the largest viscosity, were studied as a function of polymer concentration, temperature and ionic strength of the medium. The results of characterization of the commercial chitosan (the degree of deacetylation obtained equal 78.45 %) used in this work confirmed a sample of low molar weight (Mv = 3.57 x 104 g/mol) and low viscosity (intrinsic viscosity = 213.56 mL/g). The chemical modification of the chitosan resulted in derivatives with thickening action. The spectra of 1H NMR of the soluble derivatives in acid aqueous medium suggested the presence of hydrophobic groups grafted into chitosan in function of the chemical modification. The solubility of the derivatives of chitosan in 0.25 M acetic acid aqueous solution decreased with increase of the molar ratio of the glutaraldehyde and 3-amino-1-propanol in relation to the chitosan. The presence of nitrogen and larger amount of reducing agent in reaction system contributed to the increase of the solubility, the stability and the viscosity of the systems. The viscosity of the polymeric suspensions in function of the shear rate increased significantly with polymer concentration, suggesting the formation of strong intermolecular associations. The chitosan presented pseudoplastic behavior with the increase in polymer concentration at a low shear rate. The derivative QV presented pseudoplastic behavior at all concentrations used and in a large range of shear rate. The viscosity of chitosan in solution decreased with an increase of the temperature and with the presence of salt. However, there was an increase of the viscosity of the chitosan solution at higher temperature (65 ?C) and ionic strength of the medium which were promoted by hydrophobic associating of the acetamide groups. The solutions of the chitosan derivatives (sample QV) were significantly more viscous than chitosan solution and showed higher thermal stability in the presence of salt as a function of the hydrophobic groups grafted into chitosan backbone / Derivados de quitosana foram preparados atrav?s de alquila??o redutiva usando glutaralde?do e 3-amino-1-propanol. O agente redutor utilizado foi o boro hidreto de s?dio. Os efeitos das vari?veis reacionais (propor??es molares dos reagentes e nitrog?nio no meio reacional) nas caracter?sticas dos pol?meros em fun??o das mudan?as estruturais foram avaliados atrav?s de testes de solubilidade, estabilidade e viscosidade. A estrutura molecular da quitosana comercial foi determinada por espectroscopia de infravermelho (IV) e de resson?ncia magn?tica nuclear de hidrog?nio (RMN 1H). A viscosidade intr?nseca e a massa molar m?dia da quitosana foram determinadas por viscosimetria, em ?cido ac?tico 0,3 M acetato de s?dio 0,2 M, a 25 ?C. Os derivados de quitosana sol?veis em meio aquoso ?cido foram caracterizados por RMN 1H. O comportamento reol?gico da quitosana e do seu derivado (amostra QV), que apresentou maior viscosidade, foram estudados em fun??o da concentra??o de pol?mero, da temperatura e da for?a i?nica do meio. Os resultados da caracteriza??o da quitosana comercial utilizada neste trabalho demonstraram uma amostra de baixa massa molar (Mv = 3,57 x 104 g/mol) e de baixa viscosidade (viscosidade intr?nseca = 213,56 mL/g). O grau m?dio de desacetila??o foi 78,45 %. A modifica??o qu?mica da quitosana resultou em derivados com caracter?sticas viscosificantes. Os espectros de RMN 1H dos derivados sol?veis em meio aquoso ?cido mostraram a inser??o de grupos hidrof?bicos na estrutura da quitosana em fun??o da modifica??o qu?mica realizada. A solubilidade dos derivados de quitosana em solu??o aquosa de ?cido ac?tico 0,25 M diminuiu com o aumento da propor??o molar do glutaralde?do e 3-amino-1-propanol em rela??o ? quitosana. A presen?a de nitrog?nio e maior quantidade de agente redutor no meio reacional contribu?ram para o aumento da solubilidade, estabilidade e viscosidade dos sistemas polim?ricos. A viscosidade das dispers?es polim?ricas em fun??o da taxa de cisalhamento aumentou significativamente com a concentra??o de pol?mero, sugerindo a forma??o de fortes associa??es intermoleculares. A quitosana apresentou comportamento pseudopl?stico com o aumento da concentra??o de pol?mero em solu??o e a baixas taxas de cisalhamento, enquanto que o seu derivado, QV, apresentou comportamento pseudopl?stico em todas as concentra??es utilizadas e em uma larga faixa de taxa de cisalhamento. A viscosidade da solu??o de quitosana diminuiu com o aumento da temperatura e com a presen?a de sal. No entanto, houve um aumento da viscosidade da solu??o de quitosana ? temperatura mais alta (65 ?C) e em maior for?a i?nica, promovido por associa??es hidrof?bicas dos grupos acetamido. As solu??es do derivado QV foram significativamente mais viscosas do que as solu??es de quitosana e obtiveram maior estabilidade t?rmica em solu??o na presen?a de sal em fun??o dos grupos hidrof?bicos inseridos na estrutura da quitosana