Microstructural Evolution of Oil Well Cements with Nanoadditive at Elevated Temperatures and Pressur

• 作 者: SiweiMa;ShihoKawashima;
• 机 构: Civil Engineering and Engineering Mechanics Department, Columbia University, 10027, USA
• 出 处: The 14th International Congress on the Chemistry of Cement (
• 发表日期: 2015年期

　　Microstructural characterization of Class A oil well cement slurries was performed through synchrotron x-ray diffraction technique, which allowed for real-time, in-situ measurements of x-ray diffraction patterns to be obtained.Phases of interest, including portlandite, ettringite, monosulfate, and jaffeite (crystalline form of calcium silicate hydrate), were monitored up to 8 hours.The effect of elevated temperatures (60, 85, and 150℃)and elevated pressure (~150 MPa), as well as the effect of nanomaterial addition were investigated.Rate of conversion of ettringite to monosulfate increased with increasing temperature.On the other hand, increase in pressure led to a decrease in the rate of this conversion, although it still accelerated rate ofportlandite formation.Also, a seeding effect by the nano-sized attapulgite clays was observed, where there was a clear acceleration in the rate of formation of portlandite and jaffeite.