Talk:Permeability (materials science)

Untitled
This doesn't tell enough about the oxygen of the rocks.
 * what do you mean by that; the chemistry of the aquifer material? In most cases aquifers (not sure about oil reservoirs) are considered inert and non-reactive --kris 16:13, 17 November 2005 (UTC)

Aquifers are anything but inert. Groundwater is in constant motion, driven by hydraulic gradients, density gradients, and temperature gradients. As the waters move, they encounter rocks with which they have not yet attained chemical equilibrium, and a vast array of chemical reactions take place, causing mineral corrosion in some cases, precipitation of minerals in others, and in-situ transformation of other minerals. The kinds of reactions depend on the rock composition and the water chemistry.

Article naming
Could I suggest moving this article to Permeability (hydrology)? Please post comments below. Mwtoews 16:45, 25 July 2006 (UTC)
 * 1) It is a property used by geologists, hydrologist ... hell, even geographers and engineers.
 * 2) It kind of implies this is a phenomena exclusive to rocks, when is false, and can be measured/applied in peat, landfills, etc.
 * 3) It would make it more in-line with related processes, such as Infiltration (hydrology)
 * 4) Consider the basic simple definitions:
 * 5) *Hydrology is the study of the flow of water through the earth.
 * 6) *Geology is the study of rocks, and the history of earth.

Okay, I did it: I moved this to Permeability (fluid). Now this article is in the same taste as Permeability (electromagnetism), as it is a physical measure of a material. It does not need to be taged to any specific discipline, and I hope everyone should be happy with this. Fluids can be water, air, oil, (liquid) cheese, etc., and the material can be rocks, sand, Cheerios, etc. People intrested in this article could be geologists, hydrologists, geographers, engineers, etc. +Mwtoews 06:28, 27 July 2006 (UTC)
 * I moved the article to Permeability (earth sciences). A lot of folks were linking here from articles about physiology and biology (and paint). --Steven J. Anderson (talk) 19:35, 22 December 2007 (UTC)
 * This should be Permeability (Materials science). Moved. My very best wishes (talk) 03:04, 10 May 2024 (UTC)

Exploitable Hydrocarbon Reservoir are well below 100mD
In the USA, we are economically exploiting hydrocarbon reservoirs with permeabilities 1/10 to 1/1000th less than 100 mD suggested here. This is an everyday occurance. One of the largest natural gas plays in the USA, The Barnett Shale, has reservoir permeabilities in the micro darcy range. (0.001 mD). These wells produce on average over 1/2 mmcf/d, with initial production rates often more than 3 to 5 Mcf/d.

One might argue however that these reservoirs require stimulatin to be economic, but I think the blanket statement that 100 mD is a minimum is rediculus. An Oil reservoir with 10 mD is easilly exploitable with just a little knowledge.

Also, fluid permeability is not just a function of consolidated rock media. Darcy's law was derived from flow through sand beds used to purify water in Paris, France.

Dallas 75205 19:17, 13 June 2007 (UTC)

Anisotropic permeability
There is a misleading statement; "The tensor is positive definite as the component of the flow parallel to the pressure drop is always in the same direction as the pressure drop". This is not always true; if the author means pressure gradient when using "pressure drop", this statement is only true when considering the principal directions as obtained from solving the eigenproblem. I suggest changing it to "The tensor is positive definite because the energy being expended (the inner product of fluid flow and pressure gradient) is always positive". Backwatering (talk) 12:18, 16 December 2020 (UTC)

I have created the change above, with a slight change, because the energy expended is the product of fluid flow and negative pressure gradient. — Preceding unsigned comment added by Backwatering (talk • contribs) 17:58, 26 December 2020 (UTC)