Characterization of the Multiscale Evolution of Coal Pore Structure Under Liquid CO Phase Change Fracturing.

As a green and highly efficient coal seam penetration enhancement technology, liquid CO phase change fracturing (LCPCF) technology has a great deal of promise to advance gas extraction and CO geological storage. A series of investigations were conducted using low-temperature liquid N adsorption (LT-N) adsorption, CO adsorption, CT scanning, and mercury intrusion porosimetry (MIP) to elucidate further the effect of LCPCF on the coal's pore structure. These experiments aimed to characterize coal's internal pore structure parameters and investigate 3D pore structure changes before and after LCPCF treatment at varying fracturing displacements.

Numerical and experimental studies on dynamic gas emission characteristics of boreholes.

The gas emission rate of boreholes is one of the most important indices for coal and gas outburst prediction. In this work, instantaneous gas emission velocity and environmental effects on borehole gas emission were studied. Through theoretical analysis, the mechanism of crack propagation in the coal borehole was clarified, and the effect of soft and hard coal on gas desorption and gas emission.