Compositions containing a buffer and a peroxide or peracid useful for treating wells

Abstract

Compositions containing a peroxide or peracid and an organic acid salt buffer are disclosed. The compositions are useful for removing polymers from oil and gas wells, while simultaneously dissolving encountered calcium carbonate deposits.

1 - 17 . (canceled)  
   
   
       18 . A well treatment composition comprising: 
 water;    a buffer; and    hydrogen peroxide or a per-acid.    
   
   
       19 . The composition of  claim 18 , further comprising an iron-control agent, a surface tension reducer, a dispersant, a corrosion inhibitor, or a clay stabilizer.  
   
   
       20 . The composition of  claim 18 , wherein the composition has a pH of about 3 to about 5.  
   
   
       21 . The composition of  claim 18 , wherein the buffer comprises acetic acid and an acetate salt.  
   
   
       22 . The composition of  claim 21 , wherein the acetate salt is sodium acetate, potassium acetate, or ammonium acetate.  
   
   
       23 . The composition of  claim 18 , wherein the buffer comprises formic acid and a formate salt.  
   
   
       24 . The composition of  claim 23 , wherein the formate salt is sodium formate, potassium formate, or ammonium formate.  
   
   
       25 . The composition of  claim 18 , wherein the buffer comprises citric acid and a citrate salt.  
   
   
       26 . The composition of  claim 25 , wherein the citrate salt is sodium citrate, potassium citrate, or ammonium citrate.  
   
   
       27 . The composition of  claim 18 , wherein the per-acid is peroxyacetic acid.  
   
   
       28 . The composition of  claim 18 , wherein the concentration of hydrogen peroxide is about 1 weight percent to about 6 weight percent.  
   
   
       29 . The composition of  claim 18 , wherein the concentration of per-acid is about 1 weight percent to about 15 weight percent.  
   
   
       30 . The composition of  claim 18 , further comprising a peroxidase enzyme.  
   
   
       31 . The composition of  claim 18 , further comprising a phosphate salt or a phosphonate salt.