Investigation of the Ultrasonic Stimulation Performance on Permeability Enhancement in Coal Seam: Field Tests and In Situ Permeability Evaluation

Table 2

Data analysis of gas flowrate in borehole.

Zone	Borehole	Distance from the antireflection borehole	Average gas flowrate	Increment
Zone 0	Average	/	0.041 m^3/min	/
Zone 1	#1	8 m	0.0492 m^3/min	20%
	#2	4 m	0.0791 m^3/min	93%
	#3	2 m	0.0829 m^3/min	102%
Zone 2	#1	8 m	0.0757 m^3/min	85%
	#2	4 m	0.0836 m^3/min	104%
	#3	2 m	0.0843 m^3/min	106%