Page 87 - Reservoir Formation Damage

70 Reservoir Formation Damage

water wetting
Oil droplets
the rock

Negatively charged
clay particles Positively charged
asphaltenes
Negatively charged
silica grain

Figure 4-2. Mechanism of wettability alteration by asphaltene adsorption
(Leontaritis et al., ©1992 SPE; reprinted by permission of the Society of
Petroleum Engineers).

1

C, = 250 mg/L
0.9
2nd 25 mL fraction of effluent analysed
0.8
0.7
0.6
W R 0.5 Prudhoe Bay 95 Asphaltenes
0.4
0.3 •
0.2
Wyoming "95 Asphaltenes
0.1 •

Adsorption (mg/g)
Figure 4-3. Variation of the wettability index by asphaltene adsorption in
Berea sandstone (Van et al., ©1997 SPE; reprinted by permission of the
Society of Petroleum Engineers).