Page 486 - Petrophysics

454 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

9

7-
-

5- Por or i t y = 1 5.8 %
K=250 d
P=3.09xlO'ft-'
3
3 4
0 1.0 2.0 3.0 4.0
q
AP
Figure 7.8. Evaluation of p and K.

it against qm/Apg, as shown in Figure 7.8 [37]. Equation 7.113 may be
written in the general form:
1
Yck = P&k + - (7.115a)
k
where Yck (atm-sec/cm2-cP) is given by:

(7.1 15b)

and the variable &k(g /crn2-sec-cP) is:

(7.1 1%)

The subscript ck stands for Cornell-Katz. Equation 7.115a plots as a
straight line, with slope b and intercept l/k. Such a plot can be used
to estimate the non-Darcy flow coefficient, as well as the permeability
of the sample. This apparent permeability must be corrected for the
Klinkenberg effect to obtain the absolute permeability as explained
in the Appendix especially at very low pressures. At high pressure,
the Klinkenberg effect is negligible. Figure 7.9 is a log-log plot of the
turbulence factor versus permeability, which can be used to estimate
p knowing k for any reservoir:

4.11 x 10''
= k4/3 (7.116a)