Is permeability the same as porosity?

Is permeability the same as porosity?

More specifically, porosity of a rock is a measure of its ability to hold a fluid. Mathematically, it is the open space in a rock divided by the total rock volume (solid and space). Permeability is a measure of the ease of flow of a fluid through a porous solid.

What is the permeability of basalt?

Fresh basalts have an average permeability of 5.2 × 10~16cm2, but the presence of secondary minerals has a substantial effect upon the permeabilities of altered basalts.

What is permeability and porosity?

For groundwater to be able to get into a rock with good porosity it must also have good permeability. For a rock to be permeable and for water to move through it, the pore spaces between the grains in the rock must be connected. Permeability is therefore a measure of the ability of water to move through a rock.

What is the trend between porosity and permeability?

The porosity of the same material is the same, even if the particle size is different. But permeability is a different thing. It increases as particle size increases. By definition, permeability is a MEASURE OF EASE with which fluids will flow though a porous rock, soil or sediment.

What controls a material’s porosity?

Porosity is controlled by: rock type, pore distribution, cementation, diagenetic history and composition. Porosity is not controlled by grain size, as the volume of between-grain space is related only to the method of grain packing. Rocks normally decrease in porosity with age and depth of burial.

How do you calculate porosity and permeability?

To calculate the permeability of a porous material, use Darcy’s law equation:

1. Multiply together the fluid discharge rate, dynamic viscosity, and distance traveled.
2. Divide the result from Step one by the cross-sectional area of the material multiplied by the pressure difference on either side of the material.

Is basalt porous or nonporous?

Porous and permeable materials include soil (if not too clay rich), sand, sandstone, limestone, fractured igneous and metamorphic rock, vesicular basalt and scoria. Impermeable and/or non-porous materials include clay, shale, non-fractured igneous and metamorphic rocks.

Is basalt permeable or impermeable?

Basalts are the most productive aquifers of all volcanic rock types. The permeability of basaltic rocks is highly variable and depends largely on the following factors: the cooling rate of the basaltic lava flow, the number and character of interflow zones, and the thickness of the flow.

Is an Aquitard permeable?

Aquitards have very low permeability and do not transfer water well at all. In fact, in the ground they often act as a barrier to water flow and separate two aquifers.

Why is porosity and permeability important?

The porosity and permeability of rocks is important in determining which rocks will make a good reservoir. A rock that is both porous and permeable would make a good reservoir rock as it allows oil and gas to move up through the pores in the rock closer to the surface where it can be extracted.