Filter cake removal composition for drilling fluids and method of use thereof

Abstract

Disclosed is a filter cake removal composition, and method of use thereof, for use in a wellbore for controlled removal of a filter cake present in a target production zone. The filter cake removal composition includes hydrochloric acid and an organic acid. The filter cake removal composition, when a mixture of the hydrochloric acid and the organic acid is applied to the filter cake in the target production zone, is operable to dissolve the filter cake in the target production zone over an extended reaction time. The mixture includes the hydrochloric acid present in an amount of between about 0.1% and 5% by weight and the organic acid present in an amount of between about 0.1% and 10% by weight.

What is claimed is: 
     
         1 . A filter cake removal composition for use in a wellbore for controlled removal of a filter cake present in a target production zone, the filter cake removal composition comprising:
 hydrochloric acid; and   an organic acid,   wherein the filter cake removal composition, when a mixture of the hydrochloric acid and the organic acid is applied to the filter cake in the target production zone, is operable to dissolve the filter cake in the target production zone over an extended reaction time, and   wherein the mixture comprises the hydrochloric acid present in an amount of between about 0.1% and 5% by weight and the organic acid present in an amount of between about 0.1% and 10% by weight.   
     
     
         2 . The filter cake removal composition of  claim 1 , wherein the hydrochloric acid is present in an amount of about 1% by weight. 
     
     
         3 . The filter cake removal composition of  claim 1 , wherein the organic acid is selected from the group consisting of formic acid, lactic acid, and malonic acid. 
     
     
         4 . The filter cake removal composition of  claim 1 , wherein the organic acid comprises lactic acid present in an amount of about 4% by weight. 
     
     
         5 . The filter cake removal composition of  claim 1 , wherein the filter cake removal composition comprises the mixture of the hydrochloric acid present in an amount of about 1% by weight and the organic acid present in an amount of about 4% by weight. 
     
     
         6 . The filter cake removal composition of  claim 1 , wherein the mixture of the hydrochloric acid and the organic acid is applied to the filter cake in the target production zone in a single treatment for about 18 hours at about 250° F. 
     
     
         7 . A method for the controlled removal of a filter cake from a target production zone of a wellbore using a filter cake removal composition, the method comprising:
 delivering the filter cake removal composition to the target production zone,   wherein the delivering comprises applying the filter cake removal composition to the filter cake for an extended reaction time during which extended time the filter cake removal composition acts to dissolve the filter cake and after which extended time the filter cake removal composition acts to control fluid loss from the wellbore into the target production zone,   wherein the delivering comprises applying a mixture of hydrochloric acid and an organic acid to the filter cake in the target production zone, and   wherein the mixture comprises the hydrochloric acid present in an amount of between about 0.1% and 5% by weight and the organic acid present in an amount of between about 0.1% and 10% by weight.   
     
     
         8 . The method of  claim 7 , wherein the delivering further comprises applying the mixture to the filter cake in the target production zone, wherein the mixture comprises the hydrochloric acid present in an amount of about 1% by weight. 
     
     
         9 . The method of  claim 7 , wherein the delivering further comprises applying the mixture to the filter cake in the target production zone, wherein the mixture comprises the organic acid being selected from the group consisting of formic acid, lactic acid, and malonic acid. 
     
     
         10 . The method of  claim 7 , wherein the delivering further comprises applying the mixture to the filter cake in the target production zone, wherein the mixture comprises the organic acid present in an amount of about 4% by weight. 
     
     
         11 . The method of  claim 7 , wherein the delivering further comprises applying the mixture of the hydrochloric acid present in an amount of about 1% by weight and the organic acid present in an amount of about 4% by weight. 
     
     
         12 . The method of  claim 7 , wherein the delivering further comprises applying the mixture of the hydrochloric acid and the organic acid to the filter cake in the target production zone in a single treatment for about 18 hours at about 250° F.