Well stimulation

Abstract

Methods of conducting matrix acidizing in a well in a formation by simultaneously or alternatingly injecting an acid and a diverter into the formation through tubing. The acid is injected into the formation through a first tubing and the diverter is injected into the formation through a second tubing. The second tubing may extend within said first tubing and the formation may be a chalk formation.

1 . A method of conducting matrix acidizing in a well in a formation by simultaneously or alternatingly injecting an acid and a diverter into the formation through tubing, said acid being injected into the formation through a first tubing and said diverter being injected into the formation through a second tubing.  
   
   
       2 . A method according to  claim 1 , wherein before said acid and said diverter are injected alternatingly through the first and the second tubings respectively, the formation is pre-flushed by acid that is injected into the formation through said second tubing.  
   
   
       3 . A method of conducting matrix acidizing as defined in  claim 1 , wherein said diverter comprises benzoic acid diluted in methanol.  
   
   
       4 . A method of conducting matrix acidizing as defined in  claim 1 , wherein said formation is a chalk formation.  
   
   
       5 . A method of conducting matrix acidizing in a well in a formation by simultaneously or alternatingly injecting an acid and a diverter into the formation through tubing, said acid being injected into the formation through a first tubing and said diverter being injected into the formation through a second tubing, said second tubing extending within said first tubing.  
   
   
       6 . A method according to  claim 5 , wherein before said acid and said diverter are injected alternatingly through the first and the second tubings respectively, the formation is pre-flushed by acid that is injected into the formation through said second tubing.  
   
   
       7 . A method of conducting matrix acidizing as defined in  claim 5 , wherein said diverter comprises benzoic acid diluted in methanol.  
   
   
       8 . A method of conducting matrix acidizing as defined in  claim 4 , wherein said formation is a chalk formation.