Page 43 - Primer on Enhanced Oil Recovery
P. 43
34 Primer on Enhanced Oil Recovery
Figure 4.1 Wettability on a rock surface. (A) Oil-wet surface and (B) water-wet surface.
Figure 4.2 Capillary phenomena with wetting fluid drawn against the gravitational force.
about oil-wet rock. In the case b) water/rock interaction is stronger than oil/rock
interaction and we talk about water-wet rock. It is possible to measure an angle at
the point where water surface meets the rock surface. This is so named contact
angle. If the angle is higher than 90 then the rock is oil-wet. If the angle is below
90 then the rock is water-wet. When angle is around 90 we talk about neutral
wettability.
The next step on analysis of liquid/rock interaction is capillary phenomena (see
Fig. 4.2).
