Page 353 - Petrophysics

CAPILLARY PRESSURE 32 1

0.7-
8 0.6-
F
8 0.5-
i?
5 0.4-

0.3-
0.2-

0.1-
o r , 1 1 1 1 1 1 ,
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
WATER SATURATION
Figwe 5.6. Typical behavior of dimensionless Jrfunction versus saturation for cores
from sandstone.

where: Kz = Kozeny constant.
L = length of the porous medium, cm.
Le = length of fluid path through the porous medium, cm.
p = pressure, g/cm2.
f~ = mean hydraulic radius, cm.
u = velocity, cm/s.
dyne x s
p =viscosity, = g/cm x s = Pa. s.
cm2

Rearranging:

(5.17)

where: A, = area of the rock surface.
d = mean pore diameter.

The mean hydraulic radius (rH) is defined as the surface area divided by
the porosity per cubic centimeter of sample. Substituting @/As for rH,
Darcy’s equation for the fluid velocity, and rearranging:

44) (5.18)
ml