Stimulation Techniques of Coalbed Methane Reservoirs

Table 3

Advantages and disadvantages of different stimulation techniques.

Classification	Stimulation technique	Advantages	Disadvantage
Thermal stimulation	Cryogenic liquid nitrogen	(1) Pollution-free; (2) Water saving	(1) High cost; (2) Cracks closed quickly; (3) Immature technology
	Microwave heating	(1) Water saving; (2) Reusable	(1) Immature technology; (2) Unsuitable for CMM extraction
Mechanical stimulation	Hydraulic fracturing	(1) Good performance; (2) Low cost; (3) Short duration; (4) Mature technology	(1) Wasting water; (2) Induced earthquake; (3) Environmental pollution
	Hydraulic slotting
	Hydraulic punching
	High-voltage electric fracturing	(1) Short duration; (2) Pollution-free; (3) Reusable	(1) High cost; (2) Immature technology
	Deep-hole blasting	(1) Low cost; (2) Short duration; (3) Mature technology	(1) Collapse; (2) Uncontrollable fracture direction; (3) Small range
	Liquid CO2 phase-change fracturing	(1) Controllable blasting pressure; (3) Reducing greenhouse gas; (2) Pollution-free; (3) Water saving	(1) Collapse; (2) Uncontrollable fracture direction; (3) Small range
	Underground CMM extraction under mining-induced stress-relieved seams	(1) Good performance; (2) Mature technology; (3) Low risk for CMM extraction	(1) Unsuitable for single coal seam; (2) Long duration
Chemical stimulation	Acidification reconstruction	—	(1) Environmental pollution; (2) Clay swelling
	Microbial stimulation	—	(1) Long duration; (2) Uncontrollable influence range; (3) Low stimulation effectiveness
	CO2-ECBM	(1) Good performance; (2) Reducing greenhouse gas; (3) Pollution-free; (4) Water saving	(1) Matrix swelling; (2) Long duration
	N2-ECBM	(1) Good performance; (2) Pollution-free; (3) Water saving	(1) Short break-through time; (2) Long duration