Page 30 - Formulas and Calculations for Petroleum Engineering

Reservoir engineering formulas and calculations Chapter 1 23

Output(s)

p h : Disassociation Pressure (psi)

Formula(s)
( " #
2:50744 10 3 2 4 2
p ¼ 0:1450377 exp + F 1:214644 10 + 4:676111 10 F +0:0720122
h 3 m m
ð g +0:46852Þ
h
)
3:6625 10 4 2 3
T+ +F 5:44376ð Þ + F 3:89 10 + 29:9351Þ
ð
3 m m
ð g + 0:485054ÞÞ
ð
h
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 274.
1.50 Gas material balance equation
Input(s)

: Ratio of Pressure to Compressibility Factor at Initial Conditions (psi)
P i
z i
P SC : Pressure at Standard Conditions (psi)
T SC : Temperature at Standard Conditions (°R)
T: Current Temperature (°R)
3
V: Original Gas Volume (ft )
G p : Cumulative Gas Production (SCF)

Output(s)
P
z : Ratio of Pressure to Compressibility Factor at Current Conditions for P/z vs G p plot (psi)

Formula(s)

P P i P SC T
¼ G p
z z T V
i SC
Reference: Ahmed, T., McKinney, P.D.2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 3,
Page: 203.

1.51 Gas produced by gas expansion
Input(s)

A: Drainage Area (acres)
h: Thickness (ft)
Ø: Porosity (fraction)
S wi : Initial Water Saturation (fraction)
3
B g : Gas Formation Volume Factor (ft /SCF)
3
B gi : Initial Gas Formation Volume Factor (ft /SCF)

Output(s)

G p : Gas Produced (SCF)