Page 63 - Formulas and Calculations for Petroleum Engineering

56 Formulas and calculations for petroleum engineering

Output(s)

S: Saturation (fraction)
kog: Oil Relative Permeability Ratio (fraction)

Formula(s)

S o
S ¼
1 S
wi
2 2
ð 1 SÞ 1 S
kog ¼ krg
S 4
Reference: Ahmed, T. & McKinney, P.D. Advanced reservoir Engineering, Gulf Publishing House, Burlington, MA, 2015.

1.128 Total compressibility

Input(s)
c g : Compressibility of gas (/psi)
c o : Compressibility of oil (/psi)
c w : Compressibility of water (/psi)
c f : Compressibility of formation (/psi)
S g : Saturation of gas (fraction)
S o : Saturation of oil (fraction)
S w : Saturation of water (fraction)

Output(s)
c t : Total Compressibility (/psi)

Formula(s)

c ¼ c S + c S + c S + c f
g
o
o
g
w
w
t
Reference: Petrowiki.org.
1.129 Total pore volume compressibility
Input(s)
P i : Initial Pressure (psi)
P: Pressure (psi)
(PV) i : Pore Volume at Initial Reservoir Pressure (bbl)
(PV) p : Pore Volume at Pressure P (bbl)

Output(s)

c f : Cumulative Pore Volume (Formation or Rock) Compressibility (1/psi)