Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-08T20:49:48Z No. of bitstreams: 1 LisztYeltsinCoutinhoMadruga_DISSERT.pdf: 2271075 bytes, checksum: b618178f5d7788b3f44ca35a53e1646c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-11T21:22:52Z (GMT) No. of bitstreams: 1 LisztYeltsinCoutinhoMadruga_DISSERT.pdf: 2271075 bytes, checksum: b618178f5d7788b3f44ca35a53e1646c (MD5) / Made available in DSpace on 2016-07-11T21:22:52Z (GMT). No. of bitstreams: 1 LisztYeltsinCoutinhoMadruga_DISSERT.pdf: 2271075 bytes, checksum: b618178f5d7788b3f44ca35a53e1646c (MD5) Previous issue date: 2016-01-14 / Nas opera??es de perfura??o de po?os, s?o frequentes os problemas provocados pela contamina??o do fluido de perfura??o. A dissolu??o de ?ons provenientes das forma??es geol?gicas prejudica as propriedades reol?gicas e de filtra??o dos fluidos. Esses ?ons blindam as cargas dos pol?meros i?nicos, podendo levar a sua precipita??o. Neste trabalho foi realizado um estudo criterioso sobre a estabilidade das propriedades de solu??es aquosas e de fluidos de perfura??o aquosos na presen?a de pol?meros carboxilados e sulfatados, empregando a carboximetilcelulose e a kappa-carragenana como compostos modelo de pol?mero carboxilado e sulfatado, respectivamente. Os efeitos da for?a i?nica do meio aquoso contendo ?ons Na+, Mg2+ e Ca2+ sobre as propriedades reol?gicas das solu??es polim?ricas e dos fluidos de perfura??o foram avaliados variando a concentra??o dos sais, pH e temperatura. Foi observado que os fluidos com ?-carragenana sofreram menor influ?ncia frente ? contamina??o pelos ?ons em pH 9 a 10, mesmo em maiores concentra??es, por?m maior influ?ncia em pH >11. Os fluidos contendo carboximetilcelulose se mostraram mais sens?veis ? contamina??o, com redu??o brusca da viscosidade e aumento significativo do volume de filtrado, enquanto que os fluidos ? base do pol?mero sulfatado kappa-carragenana apresentaram evid?ncias de intera??o com c?tions com preserva??o das propriedades reol?gicas e maior estabilidade no volume de filtrado. / In the well drilling operations problems caused by contamination of the drilling fluid are common. The dissolution of ions from the geological formations affects the rheological and filtration properties of the fluids. These ions shield the charges of ionic polymers, leading to its precipitation. In this work was performed a detailed study on the stability of the properties of aqueous solutions and aqueous drilling fluids in the presence of sulphated and carboxylated polymers, using carboxymethylcellulose and kappa-carrageenan as polymer compounds carboxylated and sulfated model, respectively. The effects of ionic strength of the aqueous medium containing Na+, Mg2+ and Ca2+ on rheological properties of the polymer and drilling fluids solutions were evaluated by varying the concentration of salts, pH and temperature. It was observed that the fluids with ?-carrageenan suffered less influence against the contamination by the ions at pH 9 to 10, even at higher concentrations, but higher influence on pH> 11. The fluids containing carboxymethylcellulose were more sensitive to contamination, with rapid reduction in viscosity and significant increase of the filtrate volume, while the fluid based polymer sulfated kappa-carrageenan showed evidence of interaction with cations and preserve the rheological properties and improved stability the volume of filtrate.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-02T11:57:41Z No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-06T20:51:56Z (GMT) No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) / Made available in DSpace on 2017-02-06T20:51:56Z (GMT). No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) Previous issue date: 2016-07-21 / O estudo da degrada??o t?rmica de pol?meros ? essencial para se determinar a estabilidade da sua estrutura e depende do estado f?sico em que o pol?mero se encontra. Um estudo comparativo da estabilidade t?rmica da kappa carragenana (KC), poliacrilamida parcialmente hidrolisada (HPAM) e carboximetilcelulose (CMC) foi realizado na tentativa de se estabelecer uma correla??o entre as estruturas qu?micas, estabilidade desses pol?meros e suas energias de ativa??o no estado s?lido e em solu??o. A estabilidade t?rmica dos pol?meros no estado s?lido foi avaliada por termogravimetria/termogravimetria derivada e a energia de ativa??o foi calculada utilizando o m?todo integral de Broido. J? para os tr?s pol?meros em solu??o, foram realizadas medidas de viscosidade em fun??o do tempo nas temperaturas de 40, 60, 80 e 100?C, e tamb?m a 120?C apenas para a HPAM, e constru?do um modelo de decaimento exponencial da viscosidade espec?fica para determina??o da energia de ativa??o. Observou-se uma estabilidade similar dos pol?meros no estado s?lido e em solu??o, com valores de energias de ativa??o superiores no estado s?lido em fun??o do transporte de calor mais eficiente em solu??o. Os resultados obtidos condizem com as particularidades estruturais de cada pol?mero, sendo a HPAM o pol?mero com maior estabilidade e energia de ativa??o de 467,92 kJ mol-1 no estado s?lido e 79,4 kJ mol-1 em solu??o. Entre os pol?meros naturais a rigidez estrutural desempenhou um papel importante, onde a CMC com valores de energia de ativa??o de 293,3 e 55,1 kJ mol-1 no estado s?lido e em solu??o, respectivamente, foi mais est?vel que a KC com valores de 245,0 kJ mol-1 no estado s?lido e 35,8 kJ mol-1 em solu??o. E, por meio da rela??o entre as energias de ativa??o no estado s?lido e em solu??o, foi proposta a possibilidade de utiliza??o de um modelo matem?tico ?til para previs?o do comportamento de outros pol?meros em solu??o a partir da sua an?lise no estado s?lido. / The study of thermal degradation of polymers is essential to determine the stability of the structure and depends on the physical state where the polymer is. A comparative study of the thermal stability of kappa carrageenan (KC), partially hydrolyzed polyacrylamide (HPAM) and carboxymethylcellulose (CMC) was performed in an attempt to establish a correlation between the chemical structures, stability of these polymers and their activation energies in the solid state and solution. The thermal stability of the polymers in the solid state was evaluated by thermogravimetric analysis/derivative termogravimetric and the activation energy was calculated using the integral method Broido. As for the three solution polymers, viscosity measurements were made as a function of time at the temperatures 40, 60, 80 and 100 ?C, and also 120?C only for HPAM, and constructed an exponential decay model of the specific viscosity for determining the activation energy. We observed a similar stability of polymers in the solid state and in solution, with higher activation energies in the solid state due to the more efficient heat transport in solution. The results are consistent with the structural particularities of each polymer, being HPAM the polymer with greater stability and activation energy of 467.9 kJ mol-1 in the solid state and 79.4 kJ mol-1 in solution. Among the natural polymers structural rigidity played an important role, where the CMC with 293.35 activation energy values and 55.1 kJ mol-1 in the solid state and in solution, respectively, was more stable than KC with values of 245,0 kJ mol-1 in the solid state and 35.8 kJ mol-1 in solution. And, by the relationship between the activation energies in the solid state and in solution has been proposed the possibility of using a mathematical model for other useful polymers in solution behavior prediction from the analysis in the solid state.