Mechanism of drilling rate improvement using high-pressure liquid nitrogen jet

HUANG Zhongwei,WU Xiaoguang,LI Ran,ZHANG Shikun,YANG Ruiyue

Table 1 Mechanical properties of the rock samples.

Type Young’s modulus/GPa Poisson’s ratio Linear thermal expansion coefficient/10-6 K-1 Shale 28.3 0.27 6.7 Granite 34.1 0.23 7.3 Sandstone 9.5 0.12 8.6