Oliveira, Danielle do Nascimento Silva; http://lattes.cnpq.br/3787175810934081; OLIVEIRA, Danielle do Nascimento Silva.
Résumé:
Cementing wells is a routine activity in the oil industry, but requires care series
because it is a costly activity that, if not properly conducted, can cause extra
expenses as well as environmental damage. These wells, generally, feature high
temperatures and pressure, which can destabilize the cement paste causing cracks.
This study aims propose through the mixture design and response surface
methodology, a composite composition of cement Portland commercial and silica
flour (SF), that can replace efficiently, the special Portland cement for oil well, when it
is not available in some stage of cementation and there is the need for their
immediate use. Initially, the characterization of the raw materials they were made by
through the sieve analysis of the laser granulometry, chemical analysis, X-ray
diffraction and thermal analysis. Then, were made compositions for cements CP II E,
CP III and CP IV more addition of SF through by the mixture design methodology,
and subjected to the determination tests of resistance to compressive and thermal
analysis, with the purpose to determine optimum composition that most resembles
the features of the Portland cement Special for oil wells. From the results obtained
with the mixture design, they were selected the compositions constituted of CP III
and CP IV with the addition of SF, because they presented better results. These
compositions were subjected to tests of water absorption and resistance to attack by
sulphates. The cement that showed more stability against attack by of sulfate was
CP IV. The addition of the SF as replacement of the Portland cement, improved
properties of these pastes against attack and water absorption. This allowed to
conclude that the CP IV cement was more effective to replace the special portland
cement for oil well and that the addition of silica flour as replacement of the Portland
cement improves the properties of the cement pastes against attack and the water
absorption. In addition to providing the same thermal stability.