Page 189 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

Effect of Gas Wettability on Capillaries CHAPTER 5 173

Concentration of Zonyl 8740 solution (%)
0 2 8 10 12
0
Parameter of gas wettability Zonyl 8740 –0.2 ζ gas-oil = –0.694)
–0.1

(θ = 46.01˚,
oil
–0.3

–0.4

–0.5
(θ oil = 53.15˚,
–0.6
= –0.435)
gas-oil
–0.7 ζ gas-oil = –0.600) ζ (θ oil = 64.23˚,
FIGURE 5.8
Evaluation of gas wettability of straight capillary wall surfaces (gas/oil).

the front shape of oil-displacing-gas is captured, and the angle of the displa-
cing front is measured.

5.1.3.2 EXPERIMENT RESULT AND DISCUSSION
The result of gas wettability of quartz slide surfaces treated with gas-wetting
alteration agent solutions of different concentrations was measured using the
sessile drop method, as shown in Fig. 5.8.
It can be seen from Fig. 5.8 that as the concentration of gas-wetting alteration
agent solution increases, gas wettability of the slide surface and gas wettability
parameter ζ gas-oil increase gradually.
The quasistatic oil-displacing-gas experiment is conducted on the inner wall
surface of capillaries having different gas wettability. The result is as shown in
Fig. 5.9. It can be seen from Fig. 5.9 that the advancing angles of oil-
displacing-gas θ oil are all smaller than 90 degrees in capillaries. The capillary
surface is oleophylic and gasphobic. As gas wettability increases, the curvature
of the displacing front decreases, while oleophilic effect is strengthened.

5.1.4 Gas-Displacing-Oil in Capillaries
5.1.4.1 EXPERIMENT
Gas-wetting alteration agent solutions of 0.1%, 2%, and 10% concentrations
were used to treat quartz slides and inner walls of quartz capillary, made of
the same material. After that, the gas wettability of the slide surface and inner
wall surface of capillary changes. Gas wettability of the slide surface having
different gas wettability is evaluated using sessile drop method in air. The gas