Page 248 - Formulas and Calculations for Petroleum Engineering

Production engineering formulas and calculations Chapter 4 241

2
k: Specific Heat Ratio (dimensionless) A: Cross Sectional Area of Choke (in. )
γ g : Gas Specific Gravity related to Air (dimensionless)
T u : Upstream Temperature (R)
C d : Choke Discharge Coefficient (dimensionless)

Output(s)
q sc : Gas Flow Rate (Mscf/D)

Formula(s)

0 1
2 k +1
! ! ! 0:5

k P d k P d k
q * A
d
sc ¼ 1248 C A P @
u
ð k 1Þ γ T P P
g u u u
Reference: Boyun, G., William, C., & Ali Ghalambor, G. (2007). Petroleum Production Engineering: A Computer-Assisted
Approach, Page: 5/61.
4.82 Single-phase liquid flow through choke
Input(s)

C d : Upstream Pressure at Choke (psi)
2
A: Choke Area (ft )
2
g c : Unit Conversion Factor (Constant ¼ 32.17) (lb ft/ lbf s )
2
ΔP: Pressure Drop (lbf/ft )
3
ρ: Fluid Densty (lbm/ft )
Output(s)
3
q: Flow Rate (ft /s)

Formula(s)

0:5

ΔP
q ¼ C A 2 * g c* ρ
d
Reference: Boyun, G., William, C., & Ali Ghalambor, G. (2007). Petroleum Production Engineering: A Computer-Assisted
Approach, Page: 5.

4.83 Skin factor

Input(s)
k s : Permeability of damaged zone (mD)
r s : Radius of damaged zone (ft)
r w : Radius of wellbore (ft)
k: Permeability (mD)

Output(s)

s: Skin (dimensionless)