Page 23 - Formulas and Calculations for Petroleum Engineering

16 Formulas and calculations for petroleum engineering

1.31 Effective wellbore radius of a horizontal well—van der Vlis et al. method

Input(s)
h: Pay Zone Thickness (ft)
r w : Wellbore Radius (ft)
a: Slant Angle (degrees)

Output(s)
L: Length of Slant Wellbore (ft)
r w : Effective Wellbore Radius (ft)

Formula(s)

h
L ¼
cos aðÞ
i h
L h r w L
*
r ¼ 0:454 sin 360
w
4 h
Reference: Joshi, S. D. 1991, Horizontal Well Technology. Tulsa, Oklahoma: PennWell Publishing Company. Chapter: 3,
Page: 96.

1.32 Effective wellbore radius of a well in presence of uniform-flux fractures
Input(s)

x f : Fracture Half Length (ft)
e: Logarithmic Constant ¼ 2.718 (dimensionless)

Output(s)
r w : Effective Wellbore Radius (ft)

Formula(s)

x f
r ¼
w
e
Reference: Joshi, S. D. 1991, Horizontal Well Technology. Tulsa, Oklahoma: PennWell Publishing Company. Chapter: 5,
Page: 135.

1.33 Effective wellbore radius to calculate slant well productivity—van der Vlis et al.

Input(s)

h: Pay Zone Thickness (ft)
r w : Wellbore Radius (ft)
a: Slant Angle (degrees)

Output(s)

L: Length of Slant Wellbore (ft)
r w : Effective Wellbore Radius (ft)