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The permeability of a medium is related to the porosity, but also to the shapes of the pores in the medium and their level of connectedness. [2] Fluid flows can also be influenced in different lithological settings by brittle deformation of rocks in fault zones ; the mechanisms by which this occurs are the subject of fault zone hydrogeology . [ 3 ]
At the microscopic and macroscopic levels, porous media can be classified. At the microscopic scale, the structure is represented statistically by the distribution of pore sizes, the degree of pore interconnection and orientation, the proportion of dead pores, etc. [4] The macroscopic technique makes use of bulk properties that have been averaged at scales far bigger than pore size.
Micro CT of porous medium: Pores of the porous medium shown as purple color and impermeable porous matrix shown as green-yellow color. Pore structure is a common term employed to characterize the porosity, pore size, pore size distribution, and pore morphology (such as pore shape, surface roughness, and tortuosity of pore channels) of a porous medium.
Connected porosity is more easily measured through the volume of gas or liquid that can flow into the rock, whereas fluids cannot access unconnected pores. Porosity is the ratio of pore volume to its total volume. Porosity is controlled by: rock type, pore distribution, cementation, diagenetic history and composition. Porosity is not controlled ...
This is a very important mechanism in biology where fluids inside a blood vessel need to be regulated and controlled. Permeation can occur through most materials including metals, ceramics and polymers. However, the permeability of metals is much lower than that of ceramics and polymers due to their crystal structure and porosity.
The porosity is a measure of the total pore space in the soil. This is defined as a fraction of volume often given in percent. The amount of porosity in a soil depends on the minerals that make up the soil and on the amount of sorting occurring within the soil structure.
Permeability (earth sciences), a measure of the ability of a material (such as rocks) to transmit fluids Relative permeability, in multiphase flow in porous media; Permeability (foundry sand), a test of the venting characteristics of a rammed foundry sand; Hydraulic conductivity, the permeability of soil for water
In case of its absence, which is common in most cases, an estimate for permeability can be derived from empirical relationships with other measurements such as porosity, NMR and sonic logging. Darcy's law [10] is applied in the laboratory to measure the core plug permeability with an inert gas or liquid (i.e. that does not react with the rock). [6]