Water soluble surfactant mobility control agent in oil recovery

In a method of recovering oil from an oil containing subterranean formation penetrated by one or more injection wells and a production well and wherein an aqueous fluid is injected via said injection well, or wells, into said formation to displace said oil to said production well, the improvement comprising:

• employing in at least a portion of said aqueous fluid injected via said injection well, or wells, into said formation a water-soluble polymer having a molecular weight within the range of 10,000 to 10,000,000, said polymer being employed in a sufficient amount to thicken said portion of said aqueous fluid and provide improved efficiency in displacing said oil to said production well, said water-soluble copolymer being formed of synthetic polymers having stiff backbones wherein the main chain consists of ##STR3## wherein at least 20 percent by wt. of the OH groups have been replaced by:
• --O--(CH.sub.2 --CH.sub.2 --O).sub.y --CH.sub.2 --CH.sub.2 --CH.sub.2 SO.sub.3 Na
• where y is 2 to 10 and wherein R is alkyl having from about 1 to 30 carbon atoms, aryl having from about 6 to 24 carbon atoms or alkylaryl having from about 6 to 30 carbon atoms.