Experimental Study on the Damage of Artificial Fracture Permeability in Coal during the Flow Back of Guar-Based Fracturing Fluid

Table 1

The main components of each group of fracturing fluids.

Group no.	Mass fraction of each additive
	Thickener	Cross-linker	Antiswelling agent	Breaker
1	Hydroxypropyl guar (0.1%)	The organic boron (0.4%)	The KCl (1.5%)	The ammonium persulfate (0.04%)
2	Hydroxypropyl guar (0.2%)
3	Hydroxypropyl guar (0.3%)
4	Hydroxypropyl guar (0.4%)