Page 53 - Formulas and Calculations for Petroleum Engineering

46 Formulas and calculations for petroleum engineering

1.105 Pore throat sorting

Input(s)
Q 3 : Capillary pressure at 75% saturation (psi)
Q 1 : Capillary pressure at 25% saturation (psi)

Output(s)
PTS: Pore Throat Sorting (fraction)

Formula(s)

0:5
Q 3
PTS ¼
Q
1
Reference: Dandekar, A. Y. 2006. Petroleum Reservoir Rock and Fluid Properties. Boca Raton, FL: CRC Press Taylor &
Francis Group, Chapter: 8, Page: 176.

1.106 Pore volume occupied by injection of gas and water

Input(s)
W INJ : Cumulative Water Injected (STB)
B w : Water Formation Volume Factor (bbl/STB)
G INJ : Cumulative Gas Injected (SCF)
B GINJ : Injected Gas Formation Volume Factor (bbl/SCF)

Output(s)

V t : Total Volume (bbl)

Formula(s)

V ¼ W B +G B
t INJ w INJ GINJ
Reference: Ahmed, T., McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 4,
Page: 302.

1.107 Pore volume through squared method in tight gas reservoirs
Input(s)

m g, avg : Average Gas Viscosity (cP)
z avg : Compressibility Factor (dimensionless)
q i : Initial Gas Rate (MSCF/day)
m gi : Initial Gas Viscosity (cP)
c ti : Initial Total Compressibility (1/psi)
P i : Initial Pressure (psi)
P wf : Bottom-hole Flowing Pressure (psi)
–1
D i : Decline Rate (day )
T: Temperature (°R)