Comportamento reológico e mecânico de pastas de cimento fabricado com nanotubos de carbono crescidos em clinquer para poços de petróleo

Abstract

The cementing quality directly affects the useful life and the efficiency of oil wells. Recent studies show that oil well isolation loss is related to the cement paste mechanical strength especially when tensile stresses are involved. Carbon nanotubes due their properties as exceptional tensile strength, modulus of elasticity, electrical and thermal conductivity are potential candidates for the reinforcing cement matrices. In this sense, this research analyzes the behavior of the cement pastes produced with carbon nanotubes grown directly onto the clinker particles for oil wells. Cement slurries with 0.1 and 0.3% of carbon nanotubes and 0.2% of sulfonated polynaphthalene dispersant have been produced and evaluated in the fresh and hardened state. The stability, the paste compressive and splitting tensile strength as well as its durability were the properties assessed in the hardened state. The test results have shown that carbon nanotubes at the ratio of 0.1% and 0.3% with respect to cement content did not alter the rheological behavior of cement paste with the use of the sulfonated polynaphthalene based dispersant. Significant gains of compressive strength at the age of 28 days and splitting tensile strength at the ages of 7 and 28 days were achieved. The study showed that the cement slurries with carbon nanotubes are a viable option to be used use in oil wells.