Well Repair Using Swellable Material in a Remedial Matrix

Abstract

A technique enables performance of remedial treatments to block unwanted fluid migration in a well. The remedial treatment involves formation of a slurry with a swellable material. The slurry, including the swellable material, is pumped downhole and is directed to a remediation site. When deposited at the remediation site, the slurry establishes a desired remediation treatment able to block unwanted migration of a downhole fluid.

1 . A method, comprising:
 forming a cement slurry with swellable particles;   pumping the cement slurry downhole into a wellbore; and   using the cement slurry in performing a remedial cementing to limit unwanted migration of a downhole fluid.   
     
     
         2 . The method as recited in  claim 1 , further comprising initially injecting an oil into the wellbore. 
     
     
         3 . The method as recited in  claim 1 , further comprising initially injecting an acid into the wellbore, followed by injection of an oil, before pumping the cement slurry downhole. 
     
     
         4 . The method as recited in  claim 1 , wherein using the cement slurry in performing a remedial cementing comprises shutting off unwanted annular fluid migration. 
     
     
         5 . The method as recited in  claim 1 , wherein using the cement slurry in performing a remedial cementing comprises shutting off unwanted migration of a gas. 
     
     
         6 . The method as recited in  claim 1 , further comprising activating the swellable particles. 
     
     
         7 . The method as recited in  claim 1 , further comprising activating the swellable particles with a hydrocarbon-based fluid. 
     
     
         8 . A method, comprising:
 forming a cement slurry that contains a swellable material;   squeezing an activating agent ahead of the cement slurry in a wellbore to perform a remediation treatment; and   activating the swellable material to limit unwanted migration of a downhole fluid at a remediation site.   
     
     
         9 . The method as recited in  claim 8 , further comprising delivering an acid downhole into the wellbore ahead of the activating agent. 
     
     
         10 . The method as recited in  claim 8 , wherein squeezing the activating agent comprises moving an oil ahead of the cement slurry. 
     
     
         11 . The method as recited in  claim 8 , wherein forming the cement slurry comprises forming the cement slurry with swellable particles. 
     
     
         12 . The method as recited in  claim 8 , wherein activating the swellable material comprises activating the swellable material with a hydrocarbon-based fluid. 
     
     
         13 . The method as recited in  claim 8 , wherein activating the swellable material comprises activating the swellable material at a location selected to prevent unwanted annular fluid migration. 
     
     
         14 . The method as recited in  claim 8 , wherein activating the swellable material comprises activating the swellable material at a location selected to prevent unwanted migration of a gas. 
     
     
         15 . A system for remedial cementing, comprising:
 a cement slurry containing a swellable material; and   an activating agent deployed ahead of the cement slurry in a wellbore at a remedial site.   
     
     
         16 . The system as recited in  claim 15 , further comprising an acid deployed ahead of the activating agent. 
     
     
         17 . The system as recited in  claim 15 , wherein the swellable material comprises swellable particles. 
     
     
         18 . The system as recited in  claim 15 , wherein the activating agent comprises oil. 
     
     
         19 . A method, comprising:
 positioning an activating agent at a remedial site in a wellbore; and   delivering a swellable material to the remedial site such that the swellable material swells upon interaction with the activating agent.   
     
     
         20 . The method as recited in  claim 19 , further comprising initially preparing the remedial site with a preparatory fluid. 
     
     
         21 . The method as recited in  claim 19 , further comprising initially preparing the remedial site with a mud acid. 
     
     
         22 . The method as recited in  claim 19 , wherein positioning an activating agent comprises positioning a hydrocarbon-based activating fluid at the remedial site. 
     
     
         23 . The method as recited in  claim 19 , further comprising placing the swellable material in a cement slurry.