Permeable zone and leak plugging using cross-linking composition comprising delay agent

Abstract

A method for plugging a permeable zone or leak in a subterranean formation comprises introducing into the formation a cross-linking composition which comprises (a) an aqueous liquid, (b) a pH buffer, (c) a cross-linkable organic polymer, (d) a cross-linking agent which comprises an organic titanate, an organic zirconate, or combinations thereof, and (e) a delay agent which is a hydroxyalkylaminocarboxylic acid. The method can be used over a wide range of pH conditions.

1 . A method for plugging a permeable zone or leak in a subterranean formation which comprises: (a) contacting with said zone or leak, a cross-linking composition comprising (a) an aqueous liquid, (b) a pH buffer, (c) a cross-linkable organic polymer, (d) a cross-linking agent which comprises an organic titanate, an organic zirconate, or combinations thereof, and (e) a delay agent which is a hydroxyalkylaminocarboxylic acid.  
   
   
       2 . The method of  claim 1  wherein the delay agent is bishydroxyethylglycine.  
   
   
       3 . The method of  claim 2  wherein the cross-linking agent is an organic zirconium complex selected from the group consisting of zirconium α-hydroxycarboxylic acid salt, zirconium polyol complexes, zirconium alkanol amine complexes, zirconium hydroxyalkylated alkylenediamine complexes, and combinations thereof.  
   
   
       4 . The method of  claim 2  wherein the cross-linking agent is an organic titanium complex selected from the group consisting of titanium α-hydroxycarboxylic acid salt, titanium polyol complexes, titanium alkanol amine complexes, and combinations thereof.  
   
   
       5 . A method for plugging a permeable zone or leak in a subterranean formation which comprises: 
 (a) preparing the base gel by mixing an aqueous liquid with a cross-linkable organic polymer;    (b) preparing a delayed cross-linking composition by mixing a cross-linking agent which comprises an organic titanate, an organic zirconate, or combinations thereof with a delay agent which is a hydroxyalkylaminocarboxylic acid; 
 wherein a pH buffer is added to the base gel, the delayed cross-linking composition or both;  
   (c) contacting the base gel with the delayed cross-linking composition;    (d) permitting the base gel and the cross-linking agent to react after a controllable amount of time to form a cross-linked aqueous gel; and    (e) introducing the cross-linked gel into the permeable zone or leak.    
   
   
       6 . The method of  claim 5  wherein the delay agent is bishydroxyethylglycine.  
   
   
       7 . The method of  claim 6  wherein the cross-linking agent is an organic zirconium complex selected from the group consisting of zirconium α-hydroxycarboxylic acid salt, zirconium polyol complexes, zirconium alkanol amine complexes, zirconium hydroxyalkylated alkylenediamine complexes, and combinations thereof.  
   
   
       8 . The method of  claim 6  wherein the cross-linking agent is an organic titanium complex selected from the group consisting of titanium α-hydroxycarboxylic acid salt, titanium polyol complexes, titanium alkanol amine complexes, and combinations thereof.  
   
   
       9 . A method for plugging a permeable zone or leak in a subterranean formation which comprises: 
 (a) preparing a base gel by mixing an aqueous liquid with a cross-linkable organic polymer and a delay agent which is a hydroxyalkylaminocarboxylic acid;    (b) contacting the base gel with a cross-linking agent which comprises an organic titanate, an organic zirconate, or combinations thereof;    wherein a pH buffer is admixed with the base gel, the cross-linking agent or both, prior to contacting;    (c) permitting the base gel and the cross-linking agent to react after a controllable amount of time to form a cross-linked aqueous gel; and    (d) introducing the cross-linked gel into the permeable zone or leak.    
   
   
       10 . The method of  claim 9  wherein the delay agent is bishydroxyethylglycine.  
   
   
       11 . The method of  claim 10  wherein the cross-linking agent is an organic zirconium complex selected from the group consisting of zirconium α-hydroxycarboxylic acid salt, zirconium polyol complexes, zirconium alkanol amine complexes, zirconium hydroxyalkylated alkylenediamine complexes, and combinations thereof.  
   
   
       12 . The method of  claim 10  wherein the cross-linking agent is an organic titanium complex selected from the group consisting of titanium α-hydroxycarboxylic acid salt, titanium polyol complexes, titanium alkanol amine complexes, and combinations thereof.  
   
   
       13 . A method for plugging a permeable zone or leak in a subterranean formation which comprises: 
 (a) preparing a base gel by mixing an aqueous liquid with a cross-linkable polymer;    (b) introducing the base gel into the permeable zone or leak;    (c) simultaneously with or sequentially after, introducing the base gel into the permeable zone or leak, introducing a cross-linking agent which comprises an organic titanate, an organic zirconate, or combinations thereof into permeable zone or leak;    wherein a pH buffer and a delay agent which is a hydroxyalkylaminocarboxylic acid are independently admixed with the base gel, the cross-linking agent or both prior to introduction of the base gel and the cross-linking agent into the permeable zone or leak; and    (d) permitting the base gel and the cross-linking agent to react after a controllable period of time to form a cross-linked aqueous gel to plug the permeable zone or leak.    
   
   
       14 . The method of  claim 13  wherein the delay agent is bishydroxyethylglycine.  
   
   
       15 . The method of  claim 14  wherein the cross-linking agent is an organic zirconium complex selected from the group consisting of zirconium α-hydroxycarboxylic acid salt, zirconium polyol complexes, zirconium alkanol amine complexes, zirconium hydroxyalkylated alkylenediamine complexes, and combinations thereof.  
   
   
       16 . The method of  claim 14  wherein the cross-linking agent is an organic titanium complex selected from the group consisting of titanium α-hydroxycarboxylic acid salt, titanium polyol complexes, titanium alkanol amine complexes, and combinations thereof.