Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-02T22:22:37Z No. of bitstreams: 1 RicardoFernandesDosSantos_DISSERT.pdf: 2252907 bytes, checksum: 88d413ff116d989401aa91ccaae14ee7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T00:42:27Z (GMT) No. of bitstreams: 1 RicardoFernandesDosSantos_DISSERT.pdf: 2252907 bytes, checksum: 88d413ff116d989401aa91ccaae14ee7 (MD5) / Made available in DSpace on 2015-12-09T00:42:27Z (GMT). No. of bitstreams: 1 RicardoFernandesDosSantos_DISSERT.pdf: 2252907 bytes, checksum: 88d413ff116d989401aa91ccaae14ee7 (MD5) Previous issue date: 2014-10-30 / A melhoria no desempenho de aglomerantes hidr?ulicos, a base de cimento Portland, consiste na sele??o e aplica??o criteriosa de materiais que promovam uma maior durabilidade e redu??o de custos com manuten??o. Existe uma grande variedade de aditivos qu?micos utilizados em pastas de cimento Portland para cimenta??o de po?os petrol?feros. Estes s?o projetados para se trabalhar em temperaturas abaixo de 0 ? C (em zonas congeladas da terra) a 300 ? C (na recupera??o t?rmica e po?os geot?rmicos); faixas de press?o pr?ximas a ambiente (em po?os rasos) at? mais de 200 MPa (em po?os profundos). Sendo assim, os aditivos tornam poss?vel a adequa??o das pastas de cimento para aplica??o em diversas condi??es. Dentre os materiais utilizados, em pastas de cimento Portland, para po?os petrol?feros, os de escala nanom?trica v?m sendo aplicados com bons resultados. A nanoss?lica, constitu?da por uma dispers?o de part?culas de SiO2, em escala nanom?trica, quando utilizada em sistemas de cimento melhora as caracter?sticas pl?sticas e mec?nicas do material endurecido. Essa dispers?o ? comercialmente utilizada como material de preenchimento, modificador de propriedades reol?gicas e/ou em recupera??o de processos da constru??o civil. Tamb?m ? usada em muitas formula??es de produtos, como tintas, pl?sticos, borrachas sint?ticas, adesivos, selantes ou materiais isolantes. Com base no exposto, este trabalho tem como objetivo avaliar a atua??o da nanos?lica como, aditivo estendedor, e melhorar o desempenho de pastas de cimento submetidas a baixas temperaturas (5?C ? 3?C), para aplica??o em fases iniciais de po?os petrol?feros mar?timos. Foram formuladas pastas de cimento, com densidades 11,12 e 13 ppg, e concentra??es de 0; 0,5;1,0 e 1,5 % . As pastas foram submetidas a baixas temperaturas (5?C ? 3?C) e, sua avalia??o, realizada atrav?s da ensaios reol?gicos, estabilidade, ?gua livre e resist?ncia ? compress?o, de acordo com os procedimentos estabelecidos pela API SPEC 10A. Tamb?m foram realizados ensaios de caracteriza??o t?rmica (TG/DTA) e cristalogr?fica (DRX). O uso da nanoss?lica promoveu redu??o de 30% do volume de ?gua livre e aumentou o valor da resist?ncia ? compress?o em 54,2 %, em rela??o ? pasta padr?o. Desta forma, a nanoss?lica se apresentou como um material promissor para aplica??o em pastas de cimento utilizadas em fases iniciais de po?os petrol?feros com baixas temperaturas. / The improved performance of hydraulic binders, the base of Portland cement, consists in the careful selection and application of materials that promote greater durability and reduced maintenance costs There is a wide variety of chemical additives used in Portland cement slurries for cementing oil wells. These are designed to work in temperatures below 0 ? C (frozen areas of land) to 300 ? C (thermal recovery wells and geothermal); pressure ranges near ambient pressure (in shallow wells) to greater than 200 MPa (in deep wells). Thus, additives make possible the adaptation of the cement slurries for application under various conditions. Among the materials used in Portland cement slurry, for oil wells, the materials with nanometer scale have been applied with good results. The nanoss?lica, formed by a dispersion of SiO2 particles, in the nanometer scale, when used in cement systems improves the plastic characteristics and mechanical properties of the hardened material. This dispersion is used commercially as filler material, modifier of rheological properties and / or in recovery processes construction. It is also used in many product formulations such as paints, plastics, synthetic rubbers, adhesives, sealants and insulating materials Based on the above, this study aims to evaluate the performance of nanoss?lica as extender additive and improver of the performance of cement slurries subjected to low temperatures (5 ? C ? 3 ? C) for application to early stages of marine oil wells. Cement slurries were formulated, with densities 11.0;12.0 and 13.0 ppg, and concentrations of 0; 0.5, 1.0 and 1.5%. The cement slurries were subjected to cold temperatures (5 ? C ? 3 ? C), and its evaluation performed by tests rheological stability, free water and compressive strength in accordance with the procedures set by API SPEC 10A. Thermal characterization tests (TG / DTA) and crystallographic (XRD) were also performed. The use of nanoss?lica promoted reduction of 30% of the volume of free water and increased compression resistance value of 54.2% with respect to the default cement slurry. Therefore, nanoss?lica presented as a promising material for use in cement slurries used in the early stages of low-temperature oil wells