Page 13 - Formulas and Calculations for Petroleum Engineering

6 Formulas and calculations for petroleum engineering

1.8 Capillary number

Input(s)
m w : Viscosity of Displacing Fluid (cP)
V: Characteristic Velocity (ft/D)
s ow : Surface or Interfacial Tension of Oil and Water Phases (dyn/cm)

Output(s)
N c : Capillary Number (dimensionless)

Formula(s)
m V
w
Nc ¼
s ow

Reference: Wikipedia.org.

1.9 Capillary pressure
Input(s)

s: Fluid interfacial Tension (dyn/cm)
y: Angle of Wettability (degree)
r: Radius of Capillary (cm)

Output(s)
P C : Capillary Pressure (dyn/cm)

Formula(s)

2 s cos yðÞ
P ¼
C
r
Reference: Wikipedia.org.

1.10 Characteristic time for linear diffusion in reservoirs

Input(s)
F: Porosity (fraction)
b f : Fluid Compressibility (1/psi)
b r : Rock Compressibility (1/psi)
m: Viscosity (cP)
l: Characteristic Length Scale of Diffusion (ft)
k: Permeability (mD)

Output(s)

τ: Time (s)