Page 193 - Formulas and Calculations for Petroleum Engineering

186 Formulas and calculations for petroleum engineering

Output(s)

P Dw : Dimensionless Pressure at the well face (dimensionless)
s: Skin Effect (dimensionless)

Formula(s)

kh P P ws
i
P Dw + s ¼
sc
0:4568v qBm

2 2 2 3
P 1hr P wf k
s ¼ 1:151 4 log 10 +0:0919 5
m ∅mc r 2
t w
Reference: Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum
Engineering, Stanford University, Page: (5.13).

3.24 Dimensionless pressure drop during pseudo-steady state flow for a fractured
vertical well in a square drainage area

Input(s)
t DA : Dimensionless Time (dimensionless)
C f : Shape Factor for a Fractured Vertical Well (dimensionless)
x e : Half the Side of Square Drainage Area (ft)
x f : Fracture Half Length (ft)

Output(s)

P D : Wellbore Dimensionless Pressure Drop (dimensionless)

Formula(s)

2
! !
x e 2:2458
P ¼ 2 p t DA +0:5 ln +0:5 ln +0:5 2:77
D
x C
f f
Reference: Joshi, S. D. 1991, Horizontal Well Technology. Tulsa, Oklahoma: PennWell Publishing Company. Chapter: 7,
Page: 211.

3.25 Dimensionless pressure drop during pseudo-steady state flow for a horizontal
well in a bounded reservoir
Input(s)

t DA : Dimensionless Time (dimensionless)
C Ah : Shape Factors for Horizontal Wells (dimensionless)
L: Length of Horizontal Well (ft)
A: Drainage Area (ft)

Output(s)

P D : Wellbore Dimensionless Pressure Drop (dimensionless)