Pore/fracture structure and gas permeability alterations induced by ultrasound treatment in coal and its application to enhanced coalbed methane recovery

Ultrasonic treatment is a highly potential method for reservoir permeability modification in enhanced coalbed methane recovery. Quantitative evaluations of ultrasonic induced changes in structure and permeability in coal are of great interest for potential field applications of ultrasound technology. In this study the scanning electron microscope (SEM) and low-temperature liquid nitrogen (LTLN) were used to examine the ultrasound induced...