Page 172 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

156 Gas Wettability of Reservoir Rock Surfaces with Porous Media

Gas contact angle in water Gas contact angle in water
100 Gas contact angle in kerosene 120 Gas contact angle in kerosene
90 100
80
Gas contact angle (°) 60 C 8740 =9wt% Gas contact angle (°) 80 C 8740 =6wt%
70
50
60
40
40
30
20
20
10
0 0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 5 10 15 20 25 30 35 40
Time (s) Time (s)
140 140 =0wt%
Gas contact angle (°) 100 Gas contact angle in water Gas contact angle (°) 100 Gas contact angle in water C 8740
120
120
80
80
60
60
Gas contact angle in kerosene
Gas contact angle in kerosene
40
40
20
0 C 8740 =3wt% 20 0
0 100 200 300 400 500 600 700 800 900 0 100 200 300 400 500 600 700 800 900 10001100
Time (s) Time (s)
FIGURE 4.21
Evaluation of gas wettability of core pieces.
Gas wettability of the rock slices treated by gas-wetting alteration agent solu-
tion of different concentrations was evaluated using the bubble capture
method. The result is displayed in Fig. 4.21.
从图4.21可知:
From Fig. 4.21, it can be seen that:

1. The initial gas contact angle in water or oil (gas contact angle at 0 sec-
ond) reduces as the concentration of gas-wetting alteration agent
increases. The initial contact angle of dry core slice treated by gas-
wetting alteration agents of 9% concentration is the smallest
(θ gas water 5 75 degrees, θ gas oil 5 90 degrees).
2. For the core slice treated by gas-wetting alteration agents of the same
concentration, the initial contact angle of gas in water is smaller than
that of gas in oil.
3. While gas contact angles on the surface of blank rock samples are rela-
tively stable, the contact angles of bubbles on the surface of other rocks
gradually reduce until they vanish. The greater the concentration of gas-
wetting alteration agent, the faster the bubbles disappear. Fig. 4.22 dis-
plays an example of changes in gas contact angles.
The greater the concentration of gas-wetting alteration agents of cationic fluorocar-
bon polymers, the lower the surface energy of treated rocks, and the stronger the
hydrophobic aerophily [26 28] of the surface, which is the same as in the experi-
mental result. The greater the concentration of gas-wetting alteration agent, the