Page 196 - Gas Wettability of Reservoir Rock Surfaces with Porous Media
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180 Gas Wettability of Reservoir Rock Surfaces with Porous Media
tubes. The two are perpendicular with 72 nodes in total. There are guiding
grooves vertically and horizontally at the two ends of the model, which aid in
injecting fluids evenly. The diameter of the thicker capillary channel in the
center of the model is 0.2 mm, and the diameter of pores is 0.92 mm. The
diameter of the capillary channel with symmetrical structure on two sides is
0.12 mm, and the diameter of pores is 0.5 mm. Except the guiding groove, the
2
pore-throat area of the entire model is 32.36 mm .
5.2.1.2.2 Wettability Treatment of the Micromodel
The air in the micromodel was pumped off using a vacuum pump and satu-
rated with the fluorocarbon polymer gas-wetting alteration agent solution of
different concentrations. It was then put aside for 24 hours. The solution was
displaced by high-pressure air, before it was placed and dried in an oven at
80 C.
5.2.1.2.3 Measuring Wettability of the Micromodel
As the micromodel is a porous network media, gas wettability of pore-throat
surface of the etched glass model treated with gas-wetting alteration agent
solution of a certain concentration is characteristic of gas wettability of the
inner wall of the capillary, treated with solution of same concentration.
5.2.1.2.4 Displacement Experiment of Micromodel
First, the model was saturated with air before distilled water or neutral kero-
sene was slowly injected in the model at a speed of 0.3 mL/h with a peristaltic
pump, for water or oil displacing gas experiments. The distilled water was
dyed with methylene blue, and the neutral kerosene was dyed with Sudan red.
A microscope camera is attached through an optical microscope to study the
percolation characteristics of gas/water or gas/oil system in the model and dis-
tribution after displacement.
5.2.2 Gas Wettability of Gas/Water System With Etched
Glass Network Model
The study of microscope percolation mechanism of the two phases (gas/water)
in porous media is the theoretical foundation for developing water-displacing
reservoirs. Wettability is an important aspect of the physical property of the
porous media surface. It has a significant effect on microscopic percolation
mechanism of the two phases (gas/water) in porous media. However, at pres-
ent the microscopic percolation mechanism of the two phases (gas/water) is
primarily specific to developing oil reservoir. Studies on microscopic percola-
tion mechanism of water-displacing gas reservoirs are few, and the microscopic
percolation mechanism of the two phases (gas/water) study the porous struc-
ture and the effect of input speed on the percolation mechanism of the two
phases (gas/water) [6 8]. Therefore, the wettability of porous media is signifi-
cant in the study of the microscopic percolation mechanism of the two phases
(gas/water).