Page 171 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

Effect of Gas Wettability on the Surface Properties CHAPTER 4 155

4. All artificial columns were cut into shorter rock columns (length: 7 cm,
diameter: 2.54 cm) and two core slices (thickness: 1.5 cm, diame-
ter:2.54 cm). Then, every four short core columns and two correspond-
ing core slices were regarded as one sample group, which was washed
with an organic solvent for 24 hours. Finally, it was placed in a vacuum

oven to dry at 80 C;
5. At the same time, a group of core columns and core slices were placed
into gas-wetting alteration water solutions of different concentrations
(0%, 3%, 6% and 9%), and underwent vacuuming and saturation treat-
ment over 24 hours until there were no bubbles. The solutions were
aged for 24 hours, and then sealed and dried for application.

4.4.1.2 EVALUATION OF BUBBLE CAPTURE METHOD OF GAS
WETTABILITY OF CORES
Cores treated with gas-wetting alteration agent solutions of different concen-
trations possess various gas wettabilities. The surface of porous media has wet-
ted capillary action [25], and the gas wettability of treated cores is evaluated
using the bubble capture method as displayed in Fig. 4.20.
Two pieces of dry core slices were taken out from a group of samples that
were treated with gas-wetting alteration agent solution. They were placed in
water and kerosene, respectively, and the gas wettability of the rock sample
surfaces was evaluated using the bubble capture method. The four core col-
umns of this group of samples were retained to conduct unidirectional and
reverse direction imbibition experiments of gas/water and gas/oil systems.

FIGURE 4.20
Evaluation of gas wettability of core surfaces (bubble capture method).