Relative Permeability

Brief

Relative Permeability is the ratio of the effective permeability to base oil permeability measured at connate water saturation.

$k_{ro} = k_o/k_{oS_{wc}}$

$k_{rw} = k_w/k_{oS_{wc}}$

where

$k_{ro} =$ Oil relative permeability, fraction

$k_{rw} =$ Water relative permeability, fraction

$k_o =$ Effective water permeability, mD

$k_w =$ Effective water permeability, mD

$k_{oS_{wc}} =$ Effective oil permeability at irreducible oil saturation, mD

$S_{wc} =$ Connate water saturation, fraction

Related definitions

Effective permeability - oil, water, gas phase permeability when more than one phase is present. Depends on fluids saturations.

Absolute permeability - permeability of the core sample when saturated with one liquid. Independent of fluid. Dependent on pore throat sizes.

Example

Determine the Mobility Ratio using the following data:
Core is at 70% water and 30% oil saturation. Water phase permeability is 248 mD, oil phase permeability is 50 mD. Water viscosity is 1 cP, oil viscosity is 3 cP.

$M = \frac{248/1}{50/3} =15$

In this case the mobility of water is 15 times higher than the mobility of water.

See Also

• Mobility Ratio
• HCPV
• STOIIP
• VRR
• Pattern
• Block
• Mature Water Flood Analysis