Page 268 - Petrophysics 2E
P. 268
FORMATION RESISTMTY FACTOR 24 1
100
a9
4
.- 5
v)
2
0
n
10
1 10 100
Porosity Correlating Factor, F(dG)'.I
Figure 4.27. Correlation ofporosity with thegeometric mean grain diameter and the
formation factor [19J
Figure 4.26 can be expressed as:
2.75
(4.60)
k = 2.53 x lo5 ( FR2:Lc2)
For a uniform grain-size distribution system, the standard deviation 02
k = 2.53 X lo5 (z) (4.61)
is zero and Equation 4.60 becomes:
2.75
A correlation of porosity with respect to the formation resistivity and
geometric mean grain diameter, as shown in Figure 4.27, was developed
in the same study:
@=(&) (4.62)
where the porosity, @, is expressed as a percentage. The straight line in
Figure 4.27 can be expressed as follows:
51
@= (4.63)
(FR $&) 0'50
