Experiment Study of Microwave Power and Moisture Content's Effect on Fracture Development in Coal Sample


Jinxin Huang, Curtin University; Guang Xu, Curtin University; Ping Chang, Curtin University; Guozhong Hu, China University of Mining and Technology

Abstract: As hydraulic fracturing is forbidden in some countries due to its accompanying environmental pollutions, microwave fracturing was proposed as a substitute technology to enhance coal seam permeability.  Its mechanism includes: on the one hand, thermal stress caused by non-uniform microwave heating leads to fracture development in coal body, which increases coal seam permeability for gas; on the other hand, moisture within the coal body that hinders gas desorption and diffusion is removed during this process.  To study the effect of moisture content on fracture development under microwave irradiation, high resolution photographs were taken before and after microwave treatment.  These photographs were then binarized and skeletonized.  Based on the processed photographs, the total area were calculated using ImageJ.  The results showed that coal samples with 0% and 25% water saturation have more variation in fracture development as compared to that of samples with 50%, 75% and 100% water saturation.  This study can be very useful in gas drainage and gas control in coal mines.