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Encyclopedia > Permeability (fluid)

In the earth sciences, permeability (commonly symbolized as κ, or k) is a measure of the ability of a material (typically, a rock or unconsolidated material) to transmit fluids. It is of great importance in determining the flow characteristics of hydrocarbons in oil and gas reservoirs, and of groundwater in aquifers. Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. ... Sedimentary, volcanic, plutonic, metamorphic rock types of North America. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... Pumpjack pumping an oil well near Sarnia, Ontario Petroleum (from Greek petra – rock and elaion – oil or Latin oleum – oil ) or crude oil is a thick, dark brown or greenish liquid. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations. ... An aquifer is an underground layer of water-bearing permeable rock, or permeable mixtures of unconsolidated materials (gravel, sand, silt, or clay) (see also groundwater). ...


The intrinsic permeability of any porous material is: In physics and chemistry an intensive property of a system is a physical property of the system that does not depend on the system size or the amount of material in the system. ... Used in geology, building science and hydrogeology, the porosity of a porous medium (such as rock or sediment) is the proportion of the non-solid volume to the total volume of material, and is defined by the ratio: where Vp is the non-solid volume (pores and liquid) and Vm...

where

κI is the intrinsic permeability [L2]
C is a dimensionless constant that is related to the configuration of the flow-paths
d is the average, or effective pore diameter [L]

Permeability needs to be measured, either directly (using Darcy's law) or through estimation using empirically derived formulas. Diameter is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... Darcys Law is a phenomologically derived constitutive equation that describes the flow of a fluid through a porous medium (typically water through an aquifer). ... Estimation is the calculated approximation of a result which is usable even if input data may be incomplete, uncertain, or noisy. ... Empirical method is generally meant as the collection of a large amount of data on which to base a theory or derive a conclusion in science. ...


A common unit for permeability is the darcy, or more commonly the milli-darcy or md (1 darcy 10−12m²). Other units are cm² and the SI m2. Darcy is the unit of the permeability of fluids in rocks and is named after Henry Darcy. ... Cover of brochure The International System of Units. ...


Permeability is part of the proportionality constant in Darcy's law which relates discharge (flow rate) and fluid physical properties (e.g. viscosity), to a pressure gradient applied to the porous media. The proportionality constant specifically for the flow of water through a porous media is the hydraulic conductivity; permeability is a portion of this, and is a property of the porous media only, not the fluid. In naturally occurring materials, it ranges over many orders of magnitude (see table below for an example of this range). Darcys Law is a phenomologically derived constitutive equation that describes the flow of a fluid through a porous medium (typically water through an aquifer). ... The pitch drop experiment at the University of Queensland. ... written by AmerHydraulic conductivity, mathematically represented as , is a property of soil or rock, in the vadose zone or groundwater, that describes the ease with which water can move through pore spaces or fractures. ...


For a rock to be considered as an exploitable hydrocarbon reservoir, its permeability must be greater than approximately 100 md (depending on the nature of the hydrocarbon - gas reservoirs with lower permeabilities are still exploitable because of the lower viscosity of gas with respect to oil). Rocks with permeabilities significantly lower than 100 md can form efficient seals (see petroleum geology). Unconsolidated sands may have permeabilities of over 5000 md. The pitch drop experiment at the University of Queensland. ... Petroleum geology is a term used to refer to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). ...


Ranges of common intrinsic permeabilities

Relative Permeability Pervious Semi-Pervious Impervious
Unconsolidated Sand & Gravel Well Sorted Gravel Well Sorted Sand or Sand & Gravel Very Fine Sand, Silt, Loess, Loam
Unconsolidated Clay & Organic Peat Layered Clay Fat / Unweathered Clay
Consolidated Rocks Highly Fractured Rocks Oil Reservoir Rocks Fresh Sandstone Fresh Limestone, Dolomite Fresh Granite
κ (cm²) 0.001 0.0001 10−5 10−6 10−7 10−8 10−9 10−10 10−11 10−12 10−13 10−14 10−15
κ (milliDarcies) 10+8 10+7 10+6 10+5 10,000 1,000 100 10 1 0.1 0.01 0.001 0.0001

Source: modified from Bear, 1972 Patterns in the sand Sand is an example of a class of materials called granular matter. ... Gravel being unloaded from a barge Gravel is rock that is of a certain grain size range. ... Loess in Hungary has travelled by wind from Asia This article is about the geologic material, for the statistical technique see Loess curve. ... Loam is soil composed of a relatively even mixture of three mineral particle size groups: sand, silt, and clay. ... This article or section does not cite its references or sources. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of natural clays. ... Petroleum geology is a term used to refer to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). ... Red sandstone interior of Lower Antelope Canyon, Arizona, worn smooth due to erosion by flash flooding over millions of years Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. ... Limey shale overlaid by limestone. ... Dolomite crystals from Touissite, Morocco Dolomite is the name of both a carbonate rock and a mineral consisting of calcium magnesium carbonate (formula: CaMg(CO3)2) found in crystals. ... Quarrying granite for the Mormon Temple, Utah Territory. ...


See also

written by AmerHydraulic conductivity, mathematically represented as , is a property of soil or rock, in the vadose zone or groundwater, that describes the ease with which water can move through pore spaces or fractures. ... Hydrogeology (hydro- meaning water, and -geology meaning the study of rocks) is the part of hydrology that deals with the distribution and movement of groundwater in the soil and rocks of the Earths crust (commonly in aquifers). ... Petroleum geology is a term used to refer to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). ...

Reference

  • Bear, Jacob, 1972. Dynamics of Fluids in Porous Media, Dover. — ISBN 0-486-65675-6

 
 

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