Page 549 - Petrophysics

5 16 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

Figure 8.14. Unit model with two dominantpore radii. The systemspossess different
petrophysical properties such as porosity and permeability.

individual flow rates through each system, the systems having different
petrophysical properties such as porosity and permeability.

qt = ql + q2 (8.21)

Using Darcy’s law (for qt) and Poiseuille’s (for ql and q2), we have:

(8.22)

The total area for the system is:

(8.23)

Also, we know from Chapter 3 that:

2
r, = ~ (8.24)
SVP

Substituting Equation 8.23 in 8.22 and Equation 8.24 in the resulting
equation gives:

(8.25a)