Chapter 4
100
80
60
40
20
θ 0 1 2 3
10 10 10 10
1:1 stoichiometry
IOO ppm naphthenate
CoTAB
Q
Amine oxide
Betaine
Additive (ppm)
Figure 4.13 Water-wet fraction of kaolinite with 100 ppm naphthenate adding
CaTAB, betaine 13 or amine oxide DO at pH 8.3
Among three surfactants, the optimal dosages are as follows: CsTAB <
amine oxide DO < betaine 13. The sensitivity of overdosage has the opposite
direction: CsTAB > amine oxide DO > betaine 13. Smalleroptimal dosage is better
for wettability change. Based on this criterion, CsTAB is the best. Lower sensitivity
of overdosage is better. Otherwise water-wet fraction of kaolinite will decrease
very fast if it is overdosed. If the exact concentration of naphthenate is unknown,
amine oxide DO is better than the other two because it has intermediate optimal
dosage and overdosage sensitivity.
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