Simulation of cryogenic fracturing of rock-like materials using material point method

Cryogenic fracturing is a relatively new technique used in gas and oil extraction. The material point method (MPM) combines the advantages of the Lagrangian and Eulerian methods and effectively solves problems involving fracture propagation and thermomechanical coupling. Hence, in this study, this method was applied to the simulation of cryogenic fracturing in rocks to reveal the mechanism of the process. First, the heat-conduction equation was discretized using the MPM. Subsequently, the thermomechanical-coupling problem was solved under the unified framework of the MPM. The discontinuous fields around the fracture were described, and fracture propagation was predicted using the phantom node method and interaction integral methods in the MPM. The results were then compared with finite-element simulation results to verify the feasibility of these methods. Finally, cryogenic fracturing simulations in the literature were examined, and the simulation results agreed well with the experimental results. Moreover, the distribution characteristics of thermal fractures were explained using the inhibitory interactions between fractures. The simulation results indicated that increasing the convective heat transfer coefficient results in a significant increase in the number of fractures.