| 摘要 |
The present invention relates to a method for the enhanced recovery of oil from an underground formation, in which a viscoelastic aqueous fluid comprising at least one viscosifying zwitterionic surfactant is injected into the said formation and the said fluid is conducted through this formation in order to displace the oil from the formation and to recover it via a different point from that where the viscoelastic aqueous fluid was introduced, characterized in that the said fluid exhibits an amount of a base sufficient to bring its pH to a value of greater than 10, preferably of between approximately 11 and 13. |
