Page 40 - Reservoir Formation Damage

24 Reservoir Formation Damage

Mohan and Fogler (1997) conclude that crystalline swelling occurs at
high concentrations below the critical salt concentration and osmotic
swelling occurs at low concentrations above the critical salt concentra-
tions. Mohan and Fogler (1997) measured the interplanar spacing as an
indication of swelling of montmorillonite in various salt solutions. Thus,
according to Figures 2-13 and 2-14 given by Mohan and Fogler (1997),
the crystalline and osmotic swelling regions can be distinguished by a
sudden jump or discontinuity in the value of the interplanar spacing which
occurs at the critical salt concentration.

200.0-
o Swy-1 - Norrish
• Stevens - This Work
g> 150.0- D Swy-2- This Work
"o
<J 100.0 Crystalline Swelling
CB
Osmotic Swelling
J5
& 50.0- Critical Salt
Concentration
0.0
10

Figure 2-13. Swelling of montmorillonite in sodium chloride brine (after
Mohan, K. K., and Fogler, H. S., ©1997; reprinted by permission of the AlChE,
©1997 AlChE. All rights reserved).

100.0 -

'<, 80.0 -
O)
£
a 60.0 H
(A
l_
(0 40.0 -
c
S- 20.0 H

0.0
0.5 1 1.5 3.5

Figure 2-14. Swelling of montmorillonite in various brine (after Mohan,
K. K., and Fogler, H. S., ©1997; reprinted by permission of the AlChE, ©1997
AlChE. All rights reserved).