Page 200 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

184 Gas Wettability of Reservoir Rock Surfaces with Porous Media

(A) (B)

(C)
FIGURE 5.17
Effect of gas wettability on gas/oil percolation state. (A) Nongas-wettability, (B) neutral-gas-wettability, and (C) preferential-
gas-wettability.

oil presents convexity. There are gas films on side walls of pores, and observed
between side walls of pores in the displacing front.

5.2.3.3 EFFECT OF GAS WETTABILITY ON GAS/OIL DISTRIBUTION
AND RECOVERY
Nongas-wettability model: From Fig. 5.18A, it can be seen that in the entire
gas/oil/water distribution model, gas is surrounded by oil or oil films, and a
lot of it remains. Gas distribution in pores is more than that in channels. Most
of the gas is distributed continuously.

Neutral-gas-wettability model: From Fig. 5.18B, it can be seen that piston-type
oil-displacing gas is more complete and there is less residual gas. That is
island-like and distributed in pores and channels, but mainly in pores.
Preferential-gas-wettability model: From Fig. 5.18C, it can be seen that residual
gas is mainly distributed in pores or side walls of channels in clumps or film.

5.3 GAS WETTABILITY OF CORES
For single-straight capillaries and etched glass network models, gas wettability
is theoretically studied through ideal micro models. This section studies the
gas wettability of gas/liquid system with physically cemented artificial cores,
and further provides a theoretical basis for the efficient development of gas
reservoir and condensed gas reservoir.