Page 236 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

220 Gas Wettability of Reservoir Rock Surfaces with Porous Media

6.3.2.1.2 Optimization With Centrifuging and Dilatometer
Methods
A certain amount of bentonite powder was added in a centrifuge tube using
an appropriate scale. Kerosene was then added in measured quantities, along
with an antiswelling agent and injected with water (three parallel samples
were prepared for each experiment), and was stirred to completely wet the
clay. Bubbles were discharged and preswelling was processed for 2 hours at
60 C. After 3B5 minutes of being centrifuged, the volume of bentonite in ker-

osene V 0 , the volume in antiswelling agent solution V 1, and the volume in
injected water V 2 were measured, respectively. The antiswelling rate was then
calculated as:
V 2 2 V 1
B 1 5 3 100
V 2 2 V 0
In the formula:

B 1 : antiswelling rate of antiswelling agent.
V 0 : volume of clay in kerosene.
V 1 : volume of clay in antiswelling agent solution.
V 2 : volume of clay in injected water.
This method was used to set industry standards in the oil and gas sector, and
is referred to as SY/T 5971-94 Evaluation Method of Clay Stabilizer for Water
Injection. The antiswelling rate of each sample was measured using the centri-
fuge method and a dilatometer, respectively, as shown in Table 6.12.
Table 6.12 shows that except for Polygnlactomannas, the antiswelling perfor-
mance of cationic polymer A in the side chain of quaternary ammonium
groups is obviously better than that of other kinds of products.

Table 6.12 Performance Evaluation Results of Several Antiswelling
Agents
Sample Antiswelling Rate (%)
Centrifugation Dilatometer
Method
A 93 90
FSJ-03 90 82
GD-09 92 83
Triethanolamine methyl chloride 89 83
(M-I company product)
Polygnlactomannas(Rhone-Ponlene 93 91
company product)
Chlorovinyl formamide (Ciba company 85 83
product)