LAUSR

Abstract Based on the requirements of low hydration heat and maximum temperature of cement slurry used in deep-water natural gas hydrate formation, a novel cement slurry containing phase change micro-encapsulated thermal control material was prepared and investigated. Firstly, a novel phase change micro-encapsulated thermal control material (Micro-P1) was synthesized and studied. It was found that the Micro-P1 have spherical structure and the particle diameter is 2.664 μm, the phase change properties, thermal conductivity, mechanical properties and hydrophilicity of Micro-P1 were significantly improved by nano-SiO2. Secondly, the Micro-P1 was introduced into cement slurry, and the controlling effects of Micro-P1 on the heat development of cement slurry was investigated. Moreover, the innovation of this study is that based on the established heat transfer decomposition model of hydrate, the influences of different cement slurry on the stability of hydrate were quantitatively calculated. The results show that the maximum temperature was reduced by 9.3 °C, the hydration heat of 24 and 48 h was reduced by 26.9 and 12.78%. Especially, the quantitative calculation shows that when the decomposition interface moves distance is 0.30 m, the required time was increased by 30.6%, in other words, the stability of hydrate was obviously improved.