Symbol	Description	Unit
C	Acid concentration (HBF4 or HF)	mol/m3
CD	Dimensionless acid concentration	—
Cf (x,t)	Acid concentration in the fracture	mol/m3
CHF	HF concentration	mol/m3
Cmj	Concentration of mineral category j	mol/m3
Cmj ,0	Initial concentration of mineral category j	mol/m3
CPA	HBF4 concentration	mol/m3
C 0	Initial acid concentration	mol/m3
CL	Leak-off coefficient	m/√min
CL,i	Leak-off coefficient for cell i	m/√min
CL,total	Overall leak-off coefficient	m/√min
Da	Damköhler number (leak-off zone)	—
Da f	Damköhler number (fracture)	—
fgel(CHF,t)	Gel cleanup factor	—
H	Fracture height	m
k	Permeability	mD
k0	Initial permeability	mD
kavg	Average permeability of leak-off zone	mD
khyd	HBF4 hydrolysis rate constant	s−1
kj	Reaction rate constant for mineral j	mol/(m2·s·(mol/m3))
L	Fracture length	m
Lf	Leak-off depth	m
Mj	Molar mass of mineral j	kg/mol
N	Number of fracture cells	—
M	Number of leak-off depth cells	—
Nac	Acid capacity number	—
ΔP	Pressure difference across fracture wall	Pa
RPA	HBF4 hydrolysis rate to HF	mol/(m3·s)
Rr,HF	HF consumption rate by mineral reactions	mol/(m3·s)
Sj	Specific surface area of mineral j	m2/m3
t	Time	s or min
tD	Dimensionless time	—
u	Acid flow velocity within fracture	m/s
uD	Dimensionless velocity	—
ula	Leak-off velocity	m/s
w	Fracture width	m
x	Coordinate along fracture direction	m
xD	Dimensionless distance (fracture direction)	—
y	Coordinate along leak-off depth direction	m
yD	Dimensionless distance (leak-off direction)	—
α	Cementation exponent	—
Δxi	Length of fracture cell i	m
Δy	Leak-off depth cell length	m
ε	Convergence tolerance	—
ϕ	Porosity	—
ϕ 0	Initial porosity	—
μ	Fluid viscosity	Pa·s
νj	Stoichiometric coefficient for mineral j	—
ρj	Density of mineral j	kg/m3