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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Efeito da adi??o de cargas minerais leves na resist?ncia mec?nica de grautes para cimenta??o de po?os offshore

Cabral, Kleber Cavalcanti 22 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:09:13Z (GMT). No. of bitstreams: 1 KleberCC_TESE.pdf: 2548288 bytes, checksum: f214aa096a5ffb2a48cfa0e23356dfc4 (MD5) Previous issue date: 2011-07-22 / The preparation of cement slurries for offshore well cementing involves mixing all solid components to be added to the mixing water on the platform. The aim of this work was to study the formulation of pre-prepared dry mixtures, or grouts, for offshore oilwell cementing. The addition of mineral fillers in the strength of lightweight grouts applied for depths down to 400 m under water depths of 500 m was investigated. Lightweight materials and fine aggregates were selected. For the choice of starting materials, a study of the pozzolanic activity of low-cost fillers such as porcelain tile residue, microsilica and diatomaceous earth was carried out by X-ray diffraction and mechanical strength tests. Hardened grouts containing porcelain tile residue and microsilica depicted high strength at early ages. Based on such preliminary investigation, a study of the mechanical strength of grouts with density 1.74 g/cm3 (14.5 lb/gal) cured initially at 27 ?C was performed using cement, microsilica, porcelain tile residue and an anti-foaming agent. The results showed that the mixture containing 7% of porcelain tile residue and 7% of microsilica was the one with the highest compressive strength after curing for 24 hours. This composition was chosen to be studied and adapted for offshore conditions based on testes performed at 4 ?C. The grout containing cement, 7% of porcelain tile residue, 7% of active silica and admixtures (CaCl2), anti-foaming and dispersant resulted satisfactory rheology and mechanical strength after curing for 24 hours of curing / A prepara??o de pastas de cimento para po?os offshore envolve a mistura de todos os componentes s?lidos da pasta e a prepara??o da ?gua de mistura feita na pr?pria plataforma. O objetivo desse trabalho ? apresentar um estudo de formula??o de misturas secas pr?preparadas, ou grautes, para a cimenta??o de po?os offshore. Foi avaliado o efeito da adi??o de cargas minerais leves na resist?ncia mec?nica de grautes para cimenta??o prim?ria inicial (at? 400 m) com l?minas d ?gua acima de 500 m. Foi realizada uma sele??o de materiais leves e finos, em substitui??o aos agregados utilizados nos grautes da constru??o civil. Para a escolha dos materiais de partida, primeiramente foi realizado um estudo da atividade pozol?nica de materiais de baixo custo, como res?duo cer?mico de porcelanato, s?lica ativa e diatomita, por meio de difratometria de raios X e resist?ncia mec?nica ? compress?o. Verificou-se que as misturas com adi??o de res?duo de porcelanato e s?lica ativa apresentaram maiores resist?ncias nas primeiras idades. Com isso, foi desenvolvido um estudo da resist?ncia mec?nica ? compress?o de grautes com massa espec?fica 1,74 g/cm3 (14,5 lb/gal), curadas, inicialmente, a 27?C e compostas por cimento, res?duo de porcelanato e s?lica ativa, aditivadas com anti-espumante. Os resultados revelaram que a mistura com 7% de res?duo de porcelanato e 7% de s?lica ativa foi a que apresentou a maior resist?ncia mec?nica ? compress?o em ensaio realizado com 24 horas de cura. Escolhida a composi??o a ser estudada, ela foi adaptada ?s condi??es de po?o offshore, cujos ensaios foram realizados a 4?C. A mistura composta por cimento, 7% de res?duo de porcelanato e 7% de s?lica ativa foi aditivada com acelerador de pega (CaCl2), anti-espumante e dispersante. Os ensaios revelaram que essa composi??o mostrou-se satisfat?ria quanto ? resist?ncia mec?nica ? compress?o com 24 horas de cura, reologia, tempo de pega e volume de ?gua livre

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