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

Table 3

Data analysis of pure methane flowrate in borehole.

Zone	Borehole	Distance from the antireflection borehole	Average pure methane flowrate	Increment
Zone 0	Average	/	0.002673 m^3/min	/
Zone 1	#1	8 m	0.005758 m^3/min	2.15times
	#2	4 m	0.01011 m^3/min	3.78 times
	#3	2 m	0.01769 m^3/min	6.62times
Zone 2	#1	8 m	0.00992 m^3/min	3.71times
	#2	4 m	0.01256 m^3/min	4.70times
	#3	2 m	0.01505 m^3/min	5.63times