Page 224 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 217

4.29 Flow coefficient during drawdown

Input(s)
p wf : Wellbore Flowing Pressure (psi)
P i : Average Pressure (psi)
Δp skin : Pressure Drop Due to Skin (psi)

Output(s)

E: Flow Coeffcient (fraction)

Formula(s)

P p Δp
i wf skin
E ¼
P p
i wf
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 1,
Page: 64.

4.30 Flow rate through orifice

Input(s)
Cd: Dimensionless Flow Factor (dimensionless)
ρ 1 : Initial Density (ppg)
ρ 2 : Final Density (ppg)
P 1 : Initial Pressure (psi)
P 2 : Final Pressure (psi)
γ: Adiabatic Constant (dimensionless)
2
S o : Output Cross Section (ft )
2
S 1 : Input Cross Section (ft )
Output(s)
3
w: Flow Rate (ft /s)

Formula(s)

γ 1 !
0 ! 1 0:5

P 1 γ P 2 γ
2 1
ρ
B C
B 1 γ 1 P 1 C
B C
2 o 2 ! 2 ! C
w ¼ Cd ρ S B
B S o P 2 γ C
1
@ A
S P
1 1
Reference: Bird, R.B., Stewart, W.E. and Lightfoot, E.N. (2002). Transport Phenomena (Second Ed.). John Wiley & Sons,
Chapter: 15, Page: 472.
4.31 Flow through fracture in response to pressure gradient
Input(s)
μ: Fluid Viscosity (cP)
L: Length (ft)