This type of permeability is the conductance of a porous medium for one fluid phase when the medium is saturated with more than one fluid. What is the name?

This type of permeability is the conductance of a porous medium for one fluid phase when the medium is saturated with more than one fluid. What is the name?

• A. Effective permeability
• B. Absolute permeability
• C. Relative permeability
• D. Intrinsic permeability

Answer: (A)

When more than one fluid is present in a porous medium, the actual ability of that medium to transmit a specific phase is reduced compared to when that phase flows alone. The quantity that describes this real conductance is the effective permeability for that phase. It combines the rock’s inherent ability to transmit fluid with the limiting effect of the other fluids, through the relation k_eff,i = k_absolute × kr,i,where kr,i is the relative permeability of that phase at the given saturations. For example, if the rock has an absolute permeability of 100 mD and the oil relative permeability is 0.4, the oil’s effective permeability is 40 mD, which is the value you’d use in Darcy’s law for the oil flow under those multi-phase conditions. Relative permeability, by comparison, is the fraction of the absolute permeability available to the phase; effective permeability is the actual conductance value resulting from that fraction.

When more than one fluid is present in a porous medium, the actual ability of that medium to transmit a specific phase is reduced compared to when that phase flows alone. The quantity that describes this real conductance is the effective permeability for that phase. It combines the rock’s inherent ability to transmit fluid with the limiting effect of the other fluids, through the relation k_eff,i = k_absolute × kr,i,where kr,i is the relative permeability of that phase at the given saturations. For example, if the rock has an absolute permeability of 100 mD and the oil relative permeability is 0.4, the oil’s effective permeability is 40 mD, which is the value you’d use in Darcy’s law for the oil flow under those multi-phase conditions. Relative permeability, by comparison, is the fraction of the absolute permeability available to the phase; effective permeability is the actual conductance value resulting from that fraction.