Page 546 - Petrophysics

PETROPHYSICAL. PROPERTIES 513

SOLUTION

Using Equation 8.18, the fracture intensity index is:

1/Rxo - 1/Rt 1/9.7 - 1/95
-
FII = - = 0.15
1/R,f - 1/Rw 1/0.17 - l/O.l9
The distance to the nearest fault is estimated from the correlation
corresponding to the upthrown block and can now be estimated using
Equation 8.16:

1
~LLJ =
4.2 x 10-2FI12 - 2.43 x
1
dLU = = 1,lOOft
4.2 x lop2 (0.15)2 - 2.43 x

The distance to the fault can be directly estimated using Figure 8.13. For
the FII value of 15%, the distance is approximately 1 100 ft.

EXAMPLE

Resistivity survey in a well yielded the following data: wellbore
corrected mud filtrate resistivity = 0.165 ohm-m, water resistivity =
0.18 ohm-m, invaded zone resistivity = 12 ohm-m, and deep formation

6000
c
c
c.
LL
9 5000
Q
0
f
cn 4Ooo
-
r
3
m
LL
Q 3000
5
r
0
Q
0 2000
S
B
4- fn
is
lo00
0
0 5 10 15 20 25 30
Fracture Intensity Index (FFI) xlOz
Figure 8.13. Fault proximity index (FPI) as a function of fracture intensity index
(FIIj in Austin chalk [25J