Page 251 - A Practical Companion to Reservoir Stimulation

Nomenclature

U = Prats' relative capacity parameter (Ch. 11) = Total compressibility, psi-', bar-'
U = Ellipse axis, ft, m (Ch. 19) = Compressibility of water, psi-I, bar-I
a = Viscosity degradation coefficient = Wellbore storage, bbl/psi, m3/bar
A, = Fracture area, ft2, m2 = Chemical concentration, mole/lit (Ch. 13 and
A, = Cross-sectional area of longitudinal fracture, Ch. 18)
ft?, m' C,. = Compressibility control leakoff coefficient,
A, = Fracture area during pumping, ft?, m2 ft/min'/ z, m/s '/
A, = Cross-sectional area of transverse fracture, = Dimensionless wellbore storage constant
ft', m2 = Fracture storage coefficient
Ac = Acid capacity number = Diverter concentration, lb/gal, kg/m'
b = Ellipse axis, ft, m = Leakoff coefficient, ft/min'/2, m/s'/'

b., = Width of fracture face damage, ft, m = Proppant concentration per fracture area,
B = Formation volume factor, resbbl/STB, lb/ft2, kg/m2
resft'/SCF, resm'/m' = Viscosity control leakoff coefficient,

B,, = Oil formation volume factor, resbbl/STB, ft /rnin'/?, m/sl/
resm'/m' = Fluid loss coefficient through wall filter cake,
B,e = Gas formation volume factor, resft'/SCF, ft/min I' 2, m/s '/
resm'/m' = Diameter, in., m

C = Compressibility, psi-', bar-' = Proppant diameter, in., m
c, = Compressibility of fissures, psi-', bar' = Tubing diameter, ft, m
(Ch. 1)
= Molecular diffusion constant, cm% (Ch. 13)
cf = Concentration of proppant in fracture, ppg, = Effective acid diffusion coefficient, ft2/s,
kg/m' (Ch. 8)
m2/s
c, = Fracture compliance
= Young's Modulus, psi, bar
C,, = Compressibility of oil, psi-', bar-'
= Plane-strain modulus, psi, bar
c~, = Compressibility of rock, psi-', bar-'
= Fanning friction factor
CI' = Proppant concentration, ppg, kg/m' (Ch. 8)
= Geometric factor for fracture shape
c,, = Heat capacity, BTU/lb, J/kg (Ch. 3)
= Dimensionless fracture conductivity
c/, = Average proppant concentration, ppg, kg/m3
= Acceleration of gravity, ft/s', m/s?
c/, = Slurry concentration, ppga, kg/m'
= Fracturing gradient, psi/ft, Pa/m

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