Page 39 - Formulas and Calculations for Petroleum Engineering

32 Formulas and calculations for petroleum engineering

Formula(s)
1 N ø G ø
p o p g
DN ¼
p
ð ø Þ + GOR ø
o g
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 5,
Page: 335.

1.70 Ineffective porosity
Input(s)

3
V dis : Volume of Completely Disconnected Pores (cm )
3
V b : Bulk Volume (cm )
Output(s)
Ø in : Ineffective Porosity (fraction)

Formula(s)
V dis
Ø ¼
in
V
b
Reference: Dandekar, A. Y. 2006. Petroleum Reservoir Rock and Fluid Properties. Boca Raton, FL: CRC Press Taylor &
Francis Group, Chapter: 3, Page: 15.

1.71 Initial gas cap

Input(s)
m: Ratio of Initial Gas Cap Gas Reservoir Volume to Initial Reservoir Oil Volume (bbl/bbl)
N: Original Oil in Place (STB)
B oi : Oil Formation Volume Factor (bbl/STB)
B gi : Initial Gas Formation Volume Factor (bbl/SCF)

Output(s)

G: Initial Gas Cap Gas (SCF)

Formula(s)
m N B oi
G ¼
B
gi

Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 4,
Page: 300.

1.72 Initial gas in place for water-drive gas reservoirs

Input(s)
G p : Cumulative Gas Production at Depletion Pressure (SCF)
B g : Gas Formation Volume Factor at Depletion Pressure (bbl/SCF)
W e : Cumulative Water Influx (bbl)
W p : Cumulative Water Production at Depletion Pressure (STB)
B w : Water Formation Volume Factor (bbl/STB)
B gi : Initial Gas Formation Volume Factor (bbl/SCF)