达西定律

Darcy’s law
•formulated by the French hydrologist Henry•Darcy
•based on the results of experiments on the flow of water through beds of sand.
•widely used in petroleum engineering and geology, describing the permeability.
Darcy’s law can be written as
•In theory, permeability is one of rock’s properties and its value is determined by the rock itself, having nothing to do with the fluid used in labs. This theoretical permeability is called absolute permeability.
•But in fact because Darcy’s law is only valid when there is no chemical reaction between the fluid and rock and when only one fluid phase completely fills the pores, the value of permeability we get using a liquid as the fluid is always a variable value. The permeability is measured in the lab using an inert gas.
•Inert gas
•
refers to the atmospheric pressure.
•kelinkenberg effect
•克林肯伯格效应亦称滑脱效应，系指气体在岩石孔道中渗流特性不同于液体。

液体通过孔道时，孔道中心的液体分子比靠近孔道壁表面的分子流速要高，越靠近孔道壁表面，分子流速越低。

而气体则不然，靠近孔道壁表面的气体分子与孔道中心气体分子的流速几乎没有什么差别，这种特性称为滑脱效应
The end Thank you。