Page 247 - Petrophysics 2E
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220 PETROPHYSICS: RESERVOIR ROCK PROPERTIES
Wyllie and Gardner proposed the following relation for FR based on the
complex capillary tube model shown in Figure 4.1 1 [8]:
z/'i
o2
FR = - (4.37)
Unfortunately, natural formations rarely have uniform pore geometry
shown in Figures 4.8-4.11. But it is evident from Equations 4.31-4.36
that the formation factor FR is a function of porosity and pore structure.
Equation 4.37 produces satisfactory results in carbonates and highly
cemented sands.
+L+
Figure 4.9. Actual flow path and tortuosity
Figure 4.10. Inclined capillary tube model of porous media [7].
Figure 4.11. Two-size capillary tube model ofporous media [8].
