Page 58 - Reservoir Formation Damage

42 Reservoir Formation Damage

Conclusions

As presented in this section,

1. Swelling of clayey porous rocks is controlled by absorption of
water by a water-exposed-surface hindered diffusion process.
2. The characteristics of the swelling clayey formation, such as mois-
ture content, volume, and permeability, vary at rates proportional
to the water absorption rate and their values relative to their ter-
minal values that would be attained at the saturation limit.
3. The rate laws of different properties allow for cross-correlation
between these properties.

Civan's (1999) model provides insight into the mechanism of the clay
swelling process and a proper means of interpreting and correlating the
swelling-dependent characteristics of clayey formations.

Graphical Representation of Clay Content

The distribution of clays can be conveniently depicted by ternary line
diagrams such as given in Figure 2-27 by Lynn and Nasr-El-Din (1998).

ILLITE / MONTMOMLLONITE

30 20 10
KAOLINITE M 10 W M TO m (0 st Si CHLORITE
10
Figure 2-27. A ternary clay distribution chart (Reprinted from Journal of
Petroleum Science and Engineering, Vol. 21, Lynn, J. D., and Nasr-El-Din,
H. A., "Evaluation of Formation Damage due to Frac Stimulation of Saudi Ara-
bian Clastic Reservoir," pp. 179-201, ©1998; reprinted with permission from
Elsevier Science).