Preparation and evaluation of micro-encapsulated thermal control materials for oil well cement slurry

Abstract

Abstract In the process cementing of deep water, cement particles react with water to produce a lot of hydration heat, which can lead to decomposition of natural gas hydrate. We synthesized a kind of micro-capsule thermal control material with paraffin wax as the base material and calcium carbonate as the skeleton support material. At first, the chemical structure and chemical element composition of thermal control material were obtained by FTIR and EDS, respectively. Secondly, the phase change properties of MPCM-1 were measured by using DSC. As a result, it was shown that phase change temperature and phase change enthalpy of thermal control material is 31.11 °C and 88.59 J/g, respectively. Simultaneously, the thermal stability of IPCM-1 was obtained by using a synchronous thermal analyzer. Then, the micro-encapsulated thermal control material is introduced into the cement slurry system, and the hydration heat and maximum hydration temperature rise of the cement slurry were investigated by a self-made hydration heat test device. As a result, compared with cement slurry CB, the hydration heat released to the environment by cement slurry CS12.0% decreased by 44.16% (at 48 h), and the maximum hydration temperature of cement slurry CS12.0% is reduced by 25.4 °C. Besides, compared with cement slurry CB, the compressive strength of cement slurry CS12.0% increased by 5.9% (24 h) and 9.8% (48 h). The thermal control material was added into the cement slurry, and a low hydration heat cement slurry system was successfully prepared.