Polymer-enhanced surfactant flooding for permeable carbonates

A process for recovering hydrocarbons in a carbonate reservoir, the process comprising the steps of:

• introducing a first saline solution into the carbonate reservoir having a temperature ranging from 90° C. to 110° C., wherein the first saline solution comprises water and salt and lacks a surfactant;
• recovering a first amount of hydrocarbon from the carbonate reservoir;
• introducing a second saline solution into the carbonate reservoir, wherein the second saline solution has a salt concentration in a range of 35,000-80,000 ppm, and comprises water, salt, a saline soluble betaine surfactant, and a saline soluble polymer containing xanthan gum without a pyruvylate group at a concentration ranging from 0.01 weight percent to 0.2 weight percent of the second saline solution;
• and
• recovering a second amount of hydrocarbon from the carbonate reservoir.