Page 334 - Petrophysics 2E

PROBLEMS 303

TABLE 48
Sample No. Permeability Porosity F V& (%) Rt Ohm-m

127.0000 0.151 29.58 4.46 31
237.0000 0.171 24.40 4.17 38
3.1600 0.098 74.68 7.32 19
17 .GO00 0.113 47.17 5.33 27
1.6200 0.093 87.53 8.14 12
0.2280 0.075 128.32 9.62 9
2.7600 0.098 78.41 7.68 18
0.0248 0.040 312.41 12.5 3

5. Table 4B shows values of permeability, porosity, formation resistivity
factor, shale (clay) fraction, and resistivity R,, of eight zones of
a shaley (clayey) formation. The resistivity of shale is 4 ohm-m and
the formation water resistivity is 0.1 ohm-m.

(a) Estimate the water saturation in each zone using (1) the
generalized shale relationship, and (2) Hilchie’s approximate
shale relationship, and compare the results.
(b) Determine the tortuosity factor and correlate with the shale
fraction. Explain.
6. The following data are obtained from a Texas Gulf Coast well:

Zone A Zone B

Porosity, % 28.40 25.2
Water resistivity, ohm-m 0.06 0.06
True resistivity, ohm-m 1.8 1 .o

(a) Calculate water saturation in Zones A and B.
(b) Which zone is more likely to be producible?

7. Core analysis and well logging yielded the following data for a
limestone formation: @ = 0.15, Rt = 25 ohm-m, Rw = 0.lOohm-m,
and n = 2.75. Determine the water saturation.
8. A shaly (clayey) sandstone interval has the following characteristics:

Rw = 0.02 ohm-m m = 2.0 GR = 40 API units

Rw = 3.0 ohm-m a = 1.0 GR,h = 76 API units
Rw = 10.0 ohm-m I$ = 17.9 G&, = 20 API units