Page 182 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

166 Gas Wettability of Reservoir Rock Surfaces with Porous Media

reducing energy. At this time, the contact angle is 0 , θ , 90 , and cos θ . 0,
water-displacing-gas front is concave, the direction of water-displacing-gas is
upright. The capillary force is P c . 0 and is the power of water-displacing-gas.
On the contrary, when σ solid-gas , σ solid-water , solid/water interface displacing
solid/gas interface is a process of energy increase. At this time, contact angle is

90 , θ , 180 , and cos θ , 0, water-displacing-gas front is convex, direction of
water-displacing-gas is upright. The capillary force is P c , 0 and is the
resistance of water-displacing-gas.
5.1.1.2 EXPERIMENT

5.1.1.2.1 Experiment Material and Apparatus
Experiment materials: distilled water, fluorocarbon polymer gas-wetting alter-
ation agent, quartz slides, quartz capillary (φ 5 0:8mm, L 5 40 mm).
Experiment apparatus: The contact angle of liquid drops in air is measured
with JC2000D3 contact angle meter. Under quasistatic conditions, the experi-
ment equipment for water-displacing-gas in capillaries is as shown in Fig. 5.2.

5.1.1.2.2 Experiment Method
1. Fluorocarbon polymer gas-wetting alteration agent solutions with mass
concentration of 0%, 0.2% and 8%, respectively, were prepared.
2. A quartz slide and a capillary were soaked in gas-wetting alteration
agent solutions of same concentration. After being immersed for
4 hours, they were then taken out and dried, and kept as the experiment
sample group.
3. The contact angle of water (θ water ) was measured with sessile drop
method for the quartz slide treated by gas-wetting alteration agent solu-
tion of certain concentration, to evaluate gas wettability of the quartz
slide surface.

Industrial-grade camera

Stereo microscope
Data cable

Computer
Injector

Light
Peristaltic pump
Platform Graduated cylinder
FIGURE 5.2
Microscopic experiment equipment.