Page 202 - Petrophysics 2E

PERMEABILITY-POROSITY RELATIONSHIPS 175

TABU 3.10
PETROPHYSICAL PROPERTIES OF A HETEROGENEOUS RESERVOIR (AFTER REF. 60)

~~
Cementing Carbonates Clay
Core # Material % % @,% k,md F ‘I:
1 Si03 5.1 3 17 90 23.3 6
2 Clay and carbonate 6.1 9 14.7 7 51 7
3 Si02 and carbonate 21.9 6 6.7 4 67 15
4 Si02 and clay 7.2 4 17.6 220 16.6 6
5 Si02 2.3 1 26.3 1920 8.6 4
6 Si02 0.7 0.2 25.6 4400 9.4 4
10 Si02 1.9 2 13.9 145 33 7
11 Si02 and clay 4.9 4 18.6 25 22.9 5
12 Si02 2.8 2 18.8 410 18.6 5
13 Carbon, clay, Si02 7 4 16.1 3 42 6
14 Clay and carbonate 8 7 15 9 41 7
15 Carbonate and clay 12.1 1 22.1 200 13.1 5
16 Carbonate and clay 14.1 2 20.6 36 16.6 5
17 Si02 5.2 4 30.7 70 8.4 3
20 Si02 and carbonate 9 1 16.4 330 21.1 6
22 Si02, carbon, clay 6.8 0.4 18.8 98 19.3 5
23 Si02 and clay 1.1 0.2 24.8 1560 10.8 4
25 Clay 7.7 6 19.1 36 17.2 5
28 Clay 3.8 5 29.8 1180 8.4 3
31 Clay 0 2 27.1 3200 11.7 4
32 Si02 and carbonate 1.4 1 28.2 2100 10.9 4
33 Clay and Si02 - - 19.4 8 24 5
34 Si02 and clay 1.2 7 19.7 18 20.8 5
35 Clay 2.2 3 31.5 2200 6.9 3
36 Clay and Si02 3.9 7 19.3 19 24.4 5
37 Clay and Si03 0 4 27.3 88 12.4 4
38 Carbon, clay, Si02 21.2 5 25.1 370 11.6 4
39 Carbonate - - 15 115 37.3 7
40 Si02 and carbonate 6.1 1 18.4 130 19 5

The arithmetic mean can also be estimated graphically from a plot of
the frequency and cumulative frequency (%) versus porosity, as long as
the histogram is relatively symmetrical, as is the case in most porosity
distributions.

Figure 3.50 is a porosity histogram and distribution (cumulative
frequency) curve for the porosity data shown in Table 3.1 1. It is evident
from this figure that the porosity histogram is not symmetrical. This lack