Method for subterranean petroleum recovery using a surfactant blend

A method for recovering petroleum from a subterranean formation, the method comprising injecting an aqueous solution into the subterranean formation to displace petroleum wherein the aqueous solution comprises:

• a. a nonionic surfactant of structure (I):
• where R1 is a linear or branched alkyl with from one to 23 carbons;
• R2 is selected from hydrogen and linear or branched alkyls with from one to 23 carbons provided that the total number of carbons in the combination of R1 and R2 is in a range of 7 to 23;
• (AO) is selected from a group consisting of CH(CH3)CH2O and CH(CH2CH3)CH2O;
• m is a number from zero to 10;
• n is a number from 5 to 30;
• and G is selected from a group consisting of hydrogen, chlorine, alkyl groups with one to four carbons, and COR′ where R′ is an alkyl with from one to four carbons;
• and
• b. an anionic surfactant of structure (II):
• where R3 and R4 are each independently selected from a group consisting of hydrogen and linear and branched alkyl groups with one to 16 carbons;
• and M is selected from sodium, potassium, lithium and ammonium.