Hot polymer injection for improving heavy oil recovery

Abstract

A method for retrieving heavy oil from a reservoir is provided. In the method, an injection well traversing a subsurface into a reservoir containing a heavy oil is treated via introducing a hot aqueous-based fluid into the reservoir through the injection well. The hot aqueous-based polymer solution may be heated to a temperature above the injection well prior to injecting it into the injection well. The method further includes recovery of a heavy oil mixture from a production well of the reservoir.

What is claimed: 
     
         1 . A method for retrieving heavy oil from a reservoir, the method comprising:
 providing an injection well traversing a subsurface into the reservoir containing a heavy oil;   introducing a hot aqueous-based fluid into the reservoir via the injection well,
 wherein the hot aqueous aqueous-based fluid comprises a polymer and an aqueous carrier fluid; and 
   retrieving the heavy oil from a production well of the reservoir.   
     
     
         2 . The method of  claim 1 , wherein the hot aqueous aqueous-based fluid comprises the polymer in a concentration in a range of from about 0.001 wt% to 5.0 wt.% based on a total weight of the aqueous-based fluid. 
     
     
         3 . The method of  claim 1 , wherein the polymer is selected from a group consisting of partially hydrolyzed polyacrylamides, copolymers of acrylamide and acrylate, copolymers of acrylamide tertiary butyl sulfonate (ATBS) and acrylamides, copolymers of acrylamide, acrylic acid and ATBS, Xanthan gum, scleroglucan, and combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein the polymer comprises a copolymerized of an acrylamide and ATBS. 
     
     
         5 . The polymer of  claim 4 , wherein the polymer comprises ATBS in a range of 25 mol % to 99 mol % based on the acrylamide. 
     
     
         6 . The polymer of  claim 4 , wherein the polymer has a molecular weight in a range of 5 million Daltons (Da) and 30 million Da. 
     
     
         7 . The method of  claim 1 , wherein a temperature of the hot aqueous-based fluid is higher than that of the reservoir but lower than a boiling point of water at a prevailing reservoir pressure. 
     
     
         8 . The method of  claim 1 , wherein a temperature of the hot aqueous aqueous-based fluid is in a range from about 10° C. to 100° C. above reservoir temperature. 
     
     
         9 . The method of  claim 1 , wherein the hot aqueous-based fluid decreases a viscosity of the heavy oil to 10% to 80% of an original value of a viscosity of heavy oil. 
     
     
         10 . The method of  claim 1 , wherein the hot aqueous-based fluid decreases a mobility ratio of the reservoir to a range of 0.1 to 2.