Klinkenberg (or slip) effect

The Klinkenberg effect is a gas flow phenomenon and occurs if the mean free path is of the same magnitude as the pore diameter. Gas then no longer “sticks” to the walls of the pore channels but slips along them. The mean free path of Brownian motion depends on pressure, temperature and the type of gas. It decreases with increasing pressure. According to Klinkenberg (1941) the apparent permeability (falsified by the slip effect) ka is a function of the true permeability k0, the mean, absolute gas pressure within the specimen p and a the Klinkenberg factor bk:

ka = k0*(1 + bk/p)

Plotting ka vs. 1/p gives bk as the gradient of the regression line of the individual data points and k0 as the intersection point of this regression line with the ordinate at 1/p = 0 bar-1. The Klinkenberg effect increases with decreasing permeability, decreasing gas pressure and decreasing gas viscosity. For practical considerations it can be assumed that the Klinkenberg effect plays an important role for k < 0.1µm2. In case of sandstone and dolomite the Klinkenberg factor bk can be assumed to follow the empirical relation:

bk = 4.84*10-3ka-0.35 (Häfner et al. 2009).



21.02.2018 10:12

AAPG ACE 2018 in Salt Lake City (19.-23.05.2018)

Gesteinslabor will present brandnew results from the frontline of research at one of the key events for petroleum geologists.

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21.02.2018 08:45

TSK 2018 in in Jena (21.-23.03.2018)

Gesteinslabor will take part at the distinguished conference dealing with tectonics, structural geology and crystalline rocks.

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31.01.2018 12:06

Spring meeting 2018 in Celle

Following a well established tradition, also in 2018 DGMK and ÖGEW will host their annual conference in the Congress Union Celle.

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