Page 252 - A Practical Companion to Reservoir Stimulation

PRACTICAL COMPANION TO RESERVOIR STIMULATION

G = Elastic shear modulus, psi, bar Pr = Constant outer reservoir pressure, psi, bar
G,, = Gas cumulative production, SCF, m3 Ph = Hydrostatic pressure head, psi, Pa

h = Reservoir thickness, ft, m Pi = Initial reservoir pressure, psi, bar
h,! = Downward fracture height, ft, m Piw = Bottomhole injection pressure, psi, bar
h/ = Fracture height, ft, m = Standard pressure, psi, bar
PSC
= Permeable (net) height, ft, m = Bottomhole flowing pressure, psi, bar
41 Pwf
h,, = Upward fracture height, ft, m Plhr = Pressure on extension of semilogarithmic
H = Tubing vertical depth, ft, m -. straight line at r = 1 hr
k = Permeability, md PI '= Productivity index, bbl/d/psi, MSCF/d/psi, rn'/d/
bar
k/ = Fracture permeability, md
9 = Flow rate, STB/d (oil), MSCF/d (gas), m3/d
kH = Horizontal permeability, md (Ch. 19)
= Flow rate above bubblepoint, bbl/d, m3/d
k, = Damaged permeability, md
= Injection rate, bbl/d, BPM, d/d, m3/s
k,, = Vertical permeability, md (Ch. 19)
= Maximum injection rate, BPM, m3/s
K = Bulk modulus, psi
= Injection rate, MMSCF/d, m3/s
K' = Consistency coefficient in power law fluids, lbf-
secn'/ft2 = Dimensionless cumulative production
= Acid bank radius, ft, m
KIC = Critical stress intensity factor, psi/in.'R,
= Reservoir radius, ft, m
bar/m 1/2
4, = Perforation channel length, ft, m = Drainage radius, ft, m

L = Tubing length, ft, m = Ratio of permeability to fracture height
L = Horizontal well length, ft, m = Perforation radius, in., m
m = Slope on semilogarithmic straight line, = Well radius, ft, m
psi/cycle (oil), psi'/cycle (gas), or = Effective well radius, ft, m
psi'/cp/cycle (gas)
MI, = Mass of proppant, lb, kg = Dimensionless effective well radius
= Diverter cake resistance (Q. 15-1)
n = Number of moles (Ch. 1)
n' = Power law exponent = Rod load, Ibf, Nt
N,, = Oil cumulative production, bbl, mR S = Skin effect, dimensionless
= Skin due to partial penetration and slant
Npf, = Peclet number
= Temporary skin due to diverter cake
N,,,,! = Number of perforations
= Fracture face skin effect, dimensionless
NR(> = Reynolds number
NR~ = Reynolds number, dimensionless = Skin due to perforations

P = pressure, psi, bar = Gas saturation, fraction
P = Average reservoir pressure, psi, bar = Oil saturation, fraction
Ph = Bubblepoint pressure, psi, bar (Ch. 8) = Water saturation, fraction
p~ = Dimensionless pressure t = Time, hr

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