Page 245 - Formulas and Calculations for Petroleum Engineering

238 Formulas and calculations for petroleum engineering

Formula(s)

h
p
b ¼
h
h
k
h
A ¼ sqrt
r w k v
h
B ¼
h +0:25 h p
1
h
h ¼
d
h +0:75 h
1 p

1 b h d 1 b A 1
s ¼ ln π + ln sqrt
p
b 2 b b +2 B 1
Reference: Horizontal Well Technology, Joshi, Page: 499.

4.75 Quantifying formation damage and improvement

Input(s)
p wf : Pressure of Wellflow (psi)
p: Pressure of Reservoir (psi)
s: Skin Factor (dimensionless)
r s : Radius of skin (ft)
r w : Radius of Wellbore (ft)
q: Flow Rate (STB/day)
k: Permeability of Formation (mD)
μ: Viscosity of Oil (cP)
B: Volume factor (RB/STB)
h: Thickness of reservoir (ft)

Output(s)

k s : Permeability of altered zone (mD)
r wa : Effective Radius of Wellbore (ft)
E: Flow Efficiency (fraction)

Formula(s)

k
k ¼
s s
1+
r s
ln
r w
r wa ¼ r 2:71828 s
w
s

p p 141:2 q B μ
wf
E ¼ k h
p p
wf
Reference: Pressure Transient Testing, Lee, Rollins & Spivey, Page: 43.