Page 139 - Petrophysics 2E

1 12 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

where d,, is in cm. 1/8 mm = 0.0125 cm.

6
SVgr = = 480cm-'
(0.0125)

-
Q3 - (0.2)3 = 0.0125
(1 - $)Z (1 - 0.2)2
Now, using the Kozeny equation, 3.19, the permeability can be
estimated:

1
(0.0125) = 2.71 x 10-'cm or 2750 mD.
= ( Z(0.0125)2)

The Carman-Kozeny equation can also be used to estimate the
permeability:

1
(0.0125) = 1.085 x cm or 1100 mD.
= ( S(0.0125)2)

Changing the constant from 2 to 5 yields a 40% change in the value of k.

CONCEPT OF FLOW UNITS

Petroleum geologists, engineers, and hydrologists have long
recognized the need of defining quasi geological/engineering units to
shape the description of reservoir zones as storage containers and
reservoir conduits for fluid flow. Several authors have various definitions
of flow units, which are resultant of the depositional environment and
diagenitic process. Bear defined the hydraulic (pore geometrical) unit as
the representative elementary volume of the total reservoir rock within
which the geological and petrophysical properties of the rock volume are
the same [20]. Ebanks defined hydraulic flow units as a mappable portion
of the reservoir within which the geological and petrophysical properties
that affect the flow of fluid are consistent and predictably different from
the properties of other reservoir rock volume [2 11. Hear et al. defined