Page 190 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

174 Gas Wettability of Reservoir Rock Surfaces with Porous Media

(A) (B)

(C)
FIGURE 5.9
Front shape of oil-displacing-gas in capillaries having different gas wettability. (A) Nongas-wetting (concavity, θ oil 5 49.40 degrees),
(B) nongas-wetting (concavity, θ oil 5 56.83 degrees), (C) nongas-wetting (concavity, θ oil 5 69.84 degrees).

wettability of the slide surface is characteristic of the gas wettability of the
inner wall surfaces of capillaries, treated with gas-wetting alteration agent solu-
tion of same concentration. Under quasistatic conditions (oil-displacing-gas
speed is 0.3 mL/h), an oil-displacing-gas micro experiment was conducted on
single-straight capillaries with different gas wettability. During the experiment,
air is taken as the gas phase, and neutral kerosene dyed with a little
Sudan Red is taken as the oil phase. During the displacing process, the front
shape of oil-displacing-gas is captured, and the angle of the displacing front is
measured.

5.1.4.2 EXPERIMENT RESULT AND DISCUSSION
The result of gas wettability of quartz slides treated with gas-wetting alteration
agent solutions of different concentrations measured using bubble capture
method is as shown in Fig. 5.10.

It can be seen from Fig. 5.10 that as the concentration of the gas-wetting
alteration agent solution increases, gas wettability of the slide surface
increases gradually, and the gas contact angle θ gas reduces slowly. For glass
slides and capillaries made of the same material, the evaluation result of gas
wettability of quartz slide surface by bubble capture method is characteristic
of the gas wettability of the inner wall surface of straight capillaries treated