Chapter 4
4.2.4. Effect of surfactant containing cationic groups
Cationic surfactants are used to change carbonate wettability via the
mechanism forming ion pairs with carboxylates l8l't1°l. The authors proposed that
carbonate surface can adsorb negatively-charged carboxylates and become
oil-wet. Cationic surfactants can form ion pairs with carboxylates in aqueous
solution and thereby displace carboxylates from carbonate surface to make
carbonate more water-wet.
Table 4.2 Betaine samples used in wettability test
|
Product No. |
Chemical name and Formula |
Activity |
|
3 |
Capryizcapramidopropyl Betaine C H /C H -CO-NH-(CH ) -N+(CH ) -CH -COO |
33% - 38% |
|
4 |
CoCo-Betaine C10H0c -N+(CHo)o-CHo-COO' |
31% |
|
5 |
Cocamidoprotyl Betaine in Isopropanol and Water |
43% |
|
10 |
Octyl Betaine C H -N+(CHo)o-CHo-COO' |
50% |
|
13 |
Caprylamidopropyl Betaine C H -CO-NH-(CHo)o-N+(CH )o-CH -Cθθ' 8 17 ` 2,3 ' 3'2 2 |
30% |
Similar method can be used to change the wettability of kaolinite. Cationic
surfactants can form ion pairs with anionic naphthenate and displace naphthenate
97