A property of a porous medium quantifying its ability to transmit fluids under a pressure gradient that depends only on pore geometry and connectivity, independent of fluid viscosity and density; commonly measured in darcys or square meters.

Principle

Arises from pore-scale geometry and connectivity: larger, well-connected pores and throats yield higher intrinsic permeability; it is the medium parameter in Darcy's law separated from fluid properties.

Demonstration

Laboratory constant-head or falling-head permeability tests on a sandstone core produce a permeability k (m^2); converting to hydraulic conductivity requires multiplying by fluid density and gravity and dividing by viscosity.

Misapplication

Using hydraulic conductivity values as if they were intrinsic permeability without correcting for fluid viscosity and density, or treating permeability as isotropic and scale-invariant when it often displays anisotropy and scale dependence.

Consequence

Correct use of intrinsic permeability permits prediction of volumetric fluxes under given pressure gradients for any fluid once fluid properties are specified; it underpins upscaling of flow models and informs reservoir and aquifer performance.

Reversal

Hydraulic conductivity emphasizes the combined effect of medium and fluid (k scaled by ρg/μ); for the same medium, conductivity will vary with fluid type or temperature while intrinsic permeability does not.

Boundary

Refers to the porous matrix property at the continuum scale; excludes effects dominated by single fractures unless fracture aperture networks are represented in the bulk medium and recognizes that measured permeability depends on sample scale and heterogeneity.

Semantic Tension

Often confused with hydraulic conductivity or transmissivity; intrinsic permeability is a pure medium property, whereas hydraulic conductivity couples medium and fluid and transmissivity integrates conductivity over thickness.

Synthesis

Intrinsic permeability is the pore-geometry-determined capacity of a porous medium to conduct fluids under pressure gradients; it is the fluid-independent coefficient that, when combined with fluid viscosity and density, yields hydraulic conductivity and flow rates via Darcy's law.