Page 242 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 235

Output(s)

h d : Dimensionless Payzone Thickness (dimensionless)
b: Penetration Ratio (dimensionless)
Gb: Function for penetration ratio (dimensionless)
s p : Skin due to partial penetration (dimensionless)

Formula(s)

h p
h ¼
d
h
0:5
h kh
b ¼
rw kv
2 3
Gb ¼ 2:948 7:363 b +11:45 b 4:675 b

1
s ¼ 1 ln h ðÞ Gbð Þ
p d
b
Reference: Horizontal Well Technology, Joshi, Page: 493.

4.71 Pseudo-skin factor due to partial penetration
(Yeh and Reynolds correlation)
Input(s)

h p : Perforation Interval (ft)
h: Total pay thickness (ft)
C d : Location of open interval from graphical co-relation by Yeh and Ronald (dimensionless)
k v : Horizontal Permeability (mD)
k h : Vertical Permeability (mD)
r w : Wellbore Dia (ft)

Output(s)
b: Penetration ratio (dimensionless)
C 1 : Location of open interval from graphical co-relation by Yeh and Ronald (dimensionless)
h d : Dimensionless payzone thickness (dimensionless)
h {wd} : Effective Wellbore depth (ft)
s p : Skin due to partial penetration (dimensionless)

Formula(s)

h
p
b ¼
h

h k h
C ¼ sqrt
1
r k
w v
h ¼ 0:481 + 1:01 b 0:838 b 2
d