Hydrate Decomposition Inhibitors by Phase Change Cooling Storage Based on an Electrostatic Spraying Method

The heat transfer of drilling fluid to hydrate reservoir is the main cause of reservoir hydrate decomposition and borehole wall instability. Impeding or retarding heat transfer from drilling fluid to hydrate reservoir is key to maintaining reservoir hydrate stability. In order to intelligently control the temperature of the drilling fluid in the wellbore, phase change microcapsules were prepared using an innovative method of electrostatic spraying and physical cross-linking with mixed alkane as the core material and sodium alginate as the shell material. This synthesis method can control the particle size of phase change microcapsules. The phase change microcapsules were characterized by SEM, optical microscopy, and particle size analyzer. The experimental results presented that the latent heat of melting of the phase change material is 158.04 J/g, and the latent heat of solidification is 161.63 J/g. In addition, the microcapsules also have excellent thermal stability, and the thermal conductivity coefficient is 0.384 W/(m·°C). The results of the hydrate decomposition experiment show that the phase change microcapsules can effectively delay the decomposition of hydrates. These results provide valuable insights into a better understanding of the rational development of high-performance hydrate decomposition inhibitors for drilling fluids and the construction of drilling fluid systems.