Method of sealing wells by squeezing sealant

Abstract

A method for sealing a well includes: placing an obstruction in a bore of an inner tubular string disposed in a wellbore; forming an opening through a wall of the inner tubular string above the obstruction; mixing a resin and a hardener to form a sealant; and squeezing the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and an outer tubular string, thereby repairing a cement sheath present in the annulus.

1 . A method for sealing a well, comprising:
 placing an obstruction in a bore of an inner tubular string disposed in a wellbore;   forming an opening through a wall of the inner tubular string above the obstruction;   mixing a resin and a hardener to form a sealant; and   squeezing the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and an outer tubular string, thereby repairing a cement sheath present in the annulus.   
     
     
         2 . The method of  claim 1 , wherein:
 the annulus is an inner annulus,   the opening is also formed through a wall of the outer tubular string, and   the sealant is also squeezed into an outer annulus, thereby repairing a cement sheath present in the outer annulus.   
     
     
         3 . The method of  claim 1 , wherein the inner and outer tubular strings are both casing strings. 
     
     
         4 . The method of  claim 1 , further comprising squeezing at least a portion of the sealant into a formation into which the inner tubular sting extends. 
     
     
         5 . The method of  claim 1 , further comprising squeezing at least a portion of the sealant into a formation into which the outer tubular sting extends. 
     
     
         6 . The method of  claim 1 , wherein the squeezing of the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and an outer tubular string comprises;
 pumping the sealant through a tubular extending into the inner tubular string and having a fluid volume; and   thereafter pumping a quantity of chaser fluid into the tubular having at least the volume of the tubular.   
     
     
         7 . The method of  claim 1 , wherein:
 the sealant is squeezed into the bore through coiled tubing, and   the method further comprises:
 lowering the coiled tubing and a bottom hole assembly (BHA) through the bore; and 
 forming the obstruction by setting a squeeze packer of the BHA against an inner surface of the inner tubular string. 
   
     
     
         8 . The method of  claim 1 , wherein:
 the wellbore is a subsea wellbore,   the method further comprises, prior to placing the obstruction:
 severing an upper portion of a production tubing string disposed in the wellbore from a lower portion thereof; and 
 removing the upper portion of the production tubing string from the wellbore. 
   
     
     
         9 . The method of  claim 1 , wherein:
 the resin is bisphenol F epoxide,   the hardener is selected from a group consisting of tetraethylenepentamine for a low temperature well and diethyltoluenediamine for a high temperature well, and the resin is premixed with a diluent selected from a group consisting of alkyl glycidyl ether and benzyl alcohol, and   a weighting material having a specific gravity of at least 2 is mixed with the resin and the hardener.   
     
     
         10 . A method for sealing a well, comprising:
 placing an obstruction in a bore of an inner tubular string disposed in a wellbore;   forming an opening through a wall of the inner tubular string above the obstruction;   mixing a resin and a hardener to form a sealant; and   squeezing the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and the wellbore, thereby repairing a cement sheath present in the annulus.   
     
     
         11 . The method of  claim 10 , wherein:
 the annulus is an inner annulus,   the opening is also formed through a wall of an outer tubular string, and   the sealant is also squeezed into an outer annulus, thereby repairing a cement sheath present in the outer annulus.   
     
     
         12 . The method of  claim 10 , wherein the inner tubular string is a casing string. 
     
     
         13 . The method of  claim 10 , wherein:
 the sealant is squeezed into the bore through coiled tubing, and   the method further comprises:
 lowering the coiled tubing and a bottom hole assembly (BHA) through the bore; and 
 setting a squeeze packer of the BHA against an inner surface of the inner tubular string. 
   
     
     
         14 . The method of  claim 10 , wherein:
 the wellbore is a subsea wellbore,   the method further comprises, prior to placing the obstruction:
 severing an upper portion of a production tubing string disposed in the wellbore from a lower portion thereof; and 
 removing the upper portion of the production tubing string from the wellbore. 
   
     
     
         15 . The method of  claim 1 , wherein:
 the resin is bisphenol F epoxide,   the hardener is selected from a group consisting of tetraethylenepentamine for a low temperature well and diethyltoluenediamine for a high temperature well, and   the resin is premixed with a diluent selected from a group consisting of alkyl glycidyl ether and benzyl alcohol.   
     
     
         16 . The method of  claim 10 , wherein the density of the sealant corresponds to the density of fluid present in the well. 
     
     
         17 . The method of  claim 10 , wherein a viscosity of the sealant is between 50-2,000 cp. 
     
     
         18 . The method of  claim 10 , wherein:
 the resin is premixed with a bonding agent, and   the bonding agent is silane.   
     
     
         19 . A method of infiltrating openings in a cement liner on the exterior of a subsurface tubular, comprising:
 preparing a sealant comprising:
 an epoxide resin, 
 a hardener selected from a group consisting of tetraethylenepentamine for a low temperature well and diethyltoluenediamine for a high temperature well, wherein; 
   extending a conduit inwardly of the subsurface tubular to a location therein having at least one opening extending through the wall thereof, the opening located above an obstruction in the tubular and extending through the tubular in a location where a cement is present on the exterior of the tubular; and   pumping the sealant through the conduit and through the at least one opening in the wall of the tubular, and thence into openings in the cement.   
     
     
         20 . The method of  claim 19 , further comprising an obstruction between the conduit and the wall of the tubular in a location above the openings in the wall of the tubular before pumping the sealant.