Page 244 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 237

k v : Horizontal permeability (mD)
k h : Vertical permeability (mD)
r w : Wellbore dia (ft)

Output(s)

b: Penetration ratio (dimensionless)
A: Constant for calc (dimensionless)
B: Constant for calc (dimensionless)
h d : Dimensionless payzone thickness (dimensionless)
s p : Skin due to partial penetration (dimensionless)

Formula(s)

h
p
b ¼
h

h k h
A ¼ sqrt
r k
w v
h
B ¼
h +0:25 h
1 p
h
h ¼
d
h +0:75 h p
1
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: 498.

4.74 Pseudo-skin factor due to perforations
Input(s)

h p : Perforation interval (ft)
h: Total pay thickness (ft)
h 1 : Distance from top of reservoir to top of open interval (ft)
k v : Horizontal permeability (mD)
k h : Vertical permeability (mD)
r w : Wellbore dia (ft)

Output(s)

b: Penetration ratio (dimensionless)
A: Constant for calc (dimensionless)
B: Constant for calc (dimensionless)
h d : Dimensionless payzone thickness (dimensionless)
s p : Skin due to partial penetration (dimensionless)