Page 269 - Formulas and Calculations for Petroleum Engineering

262 Formulas and calculations for petroleum engineering

5.8 Blowdown time in unsteady gas flow

Input(s)
3
V: Volume (ft )
C d : Valve Discharge Coefficient (dimensionless)
2
A v : Valve Area (in. )
g: Gas Specific Density (dimensionless)
z: Average Gas Compressibility (dimensionless)
T: Temperature (K)
P a : Initial Pressure (psi)
P b : Output Pressure (psi)
B: Constant

Output(s)

t: Interstitial Velocity2 (cm/s)

Formula(s)

B V g 0:5 P a
t ¼ ln
C A z T P
d v b
Reference: John M. Campbell, Gas Conditioning and Processing, Campbell Petroleum Series, Oklahoma, 1992, Vol. 2,
Page 29.

5.9 Boltzmann equation

Input(s)
C K : Boltzmann Constant, 1.38042 * 10 23 (J/K)
T a : Absolute Temperature (Kelvin)

Output(s)
E mp : Most Probable Energy (eV)

Formula(s)

E mp ¼ C T a
K

Reference: Bassiouni, Z., 1994, Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4.
Chapter 2, Page: 37.

5.10 Boussinesq approximation—Buoyancy

Input(s)
2
g: Acceleration due to Earth (m/s )
3
r 2 : Final Density (kg/m )
3
r 1 : Initial Density (kg/m )
r: Single Density (kg/m3)