Patent ID: 9315716
Filing Date: 2016-04-19
CPC Classification: C09K

Claim Text:
1. A method of tertiary mineral oil extraction, which is a method for surfactant flooding, comprising injecting a surfactant formulation through at least one injection bore into a mineral oil deposit, thereby lowering an interfacial tension between water and mineral oil, and removing crude oil from the deposit through at least one production bore, said surfactant mixture comprising at least the following surfactants: (A) from 50 to 99% by weight of at least one surfactant (A) of the general formula R (B) from 1 to 50% by weight of at least one cosurfactant (B), where the amounts stated are based in each case on the total amount of all surfactants in the mixture, wherein the cosurfactant (B) has the general formula R n is from 7 to 10, R R where p is 1 or 2, R R with the proviso that the amount of surfactants (A) and cosurfactants (B) together is at least 25% by weight based on the amount of all surfactants in the mixture; wherein the surfactants, the water, and the mineral oil form a microemulsion.