Incorporação de aditivos minerais comerciais e produzidos por moagem otimizada nas diferentes escalas de tamanho e natureza em pastas visando aplicação na cimentação de poços de petróleo

Abstract

The benefit of using ultrafine and nanometer size particles in the synthesis of materials has been demonstrated in various industries (ceramics, chemistry, among others); however, relatively little is known about the influence of particle size of mineral additives on the performance of pastes for oil well cementing applications. This work aims at the incorporation of quartz, ultrafine quartz, silica fume, nano-silica, metakaolin and ultrafine metakaolin on petroleum well cementing pastes with 2.5% cement replacement. Ultrafine mineral additives, quartz and metakaolin, were obtained in the laboratory by means of high energy grinding, whereas the other additives were commercial. Fresh and hardened properties of the pastes were assessed, as well as their physical properties, besides hydration studies. It was observed that ultrafine (with the exception of QZ2) and nanometer size additions increased the compressive strength at early ages, besides refining the porous structure, modifying the quantity and types of hydration products. The ultrafine metakaolin presented similar behavior to that of silica fume, in spite of the effect of the dispersant (HMPNa) in the early hydration times. Nevertheless, nanossílica demonstrated to be more reactive that all other mineral additions.