Characteristics of rock breaking with particle jet impact in deep geothermal reservoir

Abstract

Particle jet impact can fracture the rock, which can be utilized to improve the rock breaking efficiency of deep hot dry rock. In order to further explore the rock breaking characteristics, the breaking mechanism of hot dry rock under the action of particle jet impact were analyzed based on the Smoothed Particle Hydrodynamics (SPH) method, considering the deep geothermal high temperature and high confining pressure. The results show that the tensile stress generated by particle impact is much larger than the tensile strength of rock, and the rebound effect constituted an important factor in the crater diameter determination. Both the impact depth and breaking volume increased with the increase in the jet inlet velocity. Both the impact depth and breaking volume increases with the increase in the diameter. When the particle concentration exceeded a critical value (3%), both the impact depth and breaking volume increased slowly. The confining pressure will hinder the efficiency of particle impact rock breaking. High temperature will generate larger impact depth and breaking volume. The research can provide theoretical supports and parameter guidance for the application of efficient deep hot dry rock breaking technology with particle impact.