Methods of recovering oil from rock formations

Abstract

A method of recovering oil from a formation includes providing carbonated water in a lower zone of the formation, releasing carbon dioxide gas from the carbonated water to produce released carbon dioxide gas, causing the released carbon dioxide gas to contact oil in an upper zone of the formation to increase a mobility of the oil, and recovering the oil from the formation.

What is claimed is: 
     
         1 . A method of recovering oil from a formation, the method comprising:
 providing carbonated water in a lower zone of the formation;   releasing carbon dioxide gas from the carbonated water to produce released carbon dioxide gas;   causing the released carbon dioxide gas to contact oil in an upper zone of the formation to increase a mobility of the oil; and   recovering the oil from the formation.   
     
     
         2 . The method of  claim 1 , further comprising delivering water to the formation. 
     
     
         3 . The method of  claim 2 , further comprising mixing the carbonated water with the water in the formation. 
     
     
         4 . The method of  claim 1 , further comprising delivering the carbonated water to the formation through lateral openings. 
     
     
         5 . The method of  claim 1 , further comprising causing the released carbon dioxide gas to flow from the lower zone of the formation to the upper zone of the formation. 
     
     
         6 . The method of  claim 1 , wherein increasing a mobility of the oil comprises transferring energy from the released carbon dioxide gas to the oil. 
     
     
         7 . The method of  claim 1 , further comprising increasing the mobility of the oil by up to about 40%. 
     
     
         8 . The method of  claim 1 , further comprising increasing a sweep efficiency of the formation by up to about 40%. 
     
     
         9 . The method of  claim 1 , further comprising flowing the carbonated water laterally across the formation. 
     
     
         10 . The method of  claim 1 , further comprising installing one or more downhole heaters within the formation. 
     
     
         11 . The method of  claim 10 , further comprising activating at least one of the one or more downhole heaters to generate heat within the formation. 
     
     
         12 . The method of  claim 11 , further comprising increasing a temperature of the carbonated water from a reference temperature. 
     
     
         13 . The method of  claim 11 , wherein the carbonated water absorbs the heat to cause the carbon dioxide gas to be released from the carbonated water. 
     
     
         14 . The method of  claim 10 , further comprising installing the one or more downhole heaters in one or more wellbores within the formation. 
     
     
         15 . The method of  claim 10 , further comprising activating the at least one of the one or more downhole heaters while the carbonated water is being provided in the formation. 
     
     
         16 . The method of  claim 10 , wherein the one or more heaters comprise low-carbon-intensity heaters. 
     
     
         17 . The method of  claim 1 , wherein the method comprises a water flooding phase, a carbonated water flooding phase, a heating phase, and a recovery phase. 
     
     
         18 . The method of  claim 1 , wherein recovering the oil from the formation comprises producing the oil from a production tube within the wellbore. 
     
     
         19 . The method of  claim 18 , wherein the production tube is spaced apart from an injection point for introducing the carbonated water into the formation. 
     
     
         20 . The method of  claim 1 , further comprising increasing an amount of oil recovered from the formation with respect to a reference amount that corresponds to a method in which oil is recovered from the formation without utilizing the released carbon dioxide gas.