Page 249 - Formulas and Calculations for Petroleum Engineering

242 Formulas and calculations for petroleum engineering

Formula(s)

k r s
s ¼ 1 ln
k r
s w
Reference: Fundamental Principles of Reservoir Engineering, Towler, Page: 62.

4.84 Skin factor by Hawkins method
Input(s)

k: Permeability of Reservoir (mD)
k s : Permeability of Skin Zone Near Wellbore (mD)
r w : Radius of Wellbore (ft)
r s : Radius of Skin Zone (ft)

Output(s)

S: Skin Factor (dimensionless)

Formula(s)

k r s
S ¼ 1 ln
k r
s w
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 37.

4.85 Skin factor due to partial penetration
Input(s)

h t : Total Formation Thickness (ft)
rw: Radius of Wellbore (ft)
k v : Vertical Permeability (mD)
k h : Horizontal Permeability (mD)
h p : Height of Perforated interval (ft)
h a : Height (ft)
h pd : Dimensionless Perforated Thickness (fraction)
h: Thickness of reservoir (ft)

Output(s)

r d : Permeability of altered zone (mD)
A: Dimensionless Constant A (dimensionless)
B: Dimensionless Constant B (dimensionless)
s p : Skin Factor from partial penetration (dimensionless)

Formula(s)

0:5
rw k v
r ¼
d
h k
t h