Non-damaging bimodal stimulation composition and method of use thereof

Abstract

A method and apparatus for a bimodal stimulation composition for removal of thickness of a filter cake while minimizing fluid loss is provided. The bimodal stimulation composition includes water, a salt, an acid, and a viscoelastic surfactant.

That which is claimed is: 
     
         1 . A method for the controlled removal of a filter cake from a target production zone of a wellbore penetrating a subterranean formation of hydrocarbons using a bimodal stimulation composition, the method comprising the steps of:
 delivering the bimodal stimulation composition of  claim 1  to the target production zone such that the bimodal stimulation composition contacts the filter cake for an extended reaction time during which extended time the bimodal stimulation compositions acts to remove filter cake and after which extended time the bimodal stimulation composition acts to control fluid loss from the wellbore into the target production zone.   
     
     
         2 . The method of  claim 1  wherein the viscoelastic surfactant is present in an amount of between about 3 and 10% by volume. 
     
     
         3 . The method of  claim 1  wherein the acid is present in an amount of between about 1 and 10% by weight. 
     
     
         4 . The method of  claim 1  wherein the bimodal stimulation fluid is prepared by the steps of: preparing a brine such that the salt concentration of the bimodal stimulation fluid is between about 0.5 and 10% by weight; adding the acid such that the acid concentration of the bimodal stimulation fluid is between about 1 and 10% by weight; and adding the viscoelastic surfactant such that the viscoelastic surfactant concentration of the bimodal stimulation fluid is between about 3 and 10% by weight. 
     
     
         5 . The method of  claim 1  wherein the acid is selected from the group consisting of weak acids, dilute strong acids, and combinations of the same. 
     
     
         6 . The method of  claim 1  wherein the acid is selected from the group consisting of formic acid, acetic acid, citric acid, or lactic acid. 
     
     
         7 . The method of  claim 1  wherein the acid is selected from the group consisting of hydrochloric acid or hydrofluoric acid. 
     
     
         8 . The method of  claim 1  wherein an amount of acid is present in the bimodal stimulation composition such that the bimodal stimulation composition has a pH in a range of about 0 to 5. 
     
     
         9 . The method of  claim 1  wherein the brine is selected from a group consisting of a solution of sodium chloride, potassium chloride, ammonium chloride, calcium chloride, calcium bromide, zinc halide or a combination. 
     
     
         10 . The method of  claim 1  wherein an amount of brine is present in the bimodal stimulation composition such that the bimodal stimulation composition has an ionic concentration in a range of about 0.5% by weight to 10% by weight. 
     
     
         11 . A method for treating a target production zone of a hydrocarbon bearing reservoir, the method comprising the steps of:
 delivering a bimodal stimulation composition to the hydrocarbon bearing formation such that the bimodal stimulation composition contacts a filter cake or the hydrocarbon bearing formation; wherein the bimodal stimulation composition includes an acid, a viscoelastic surfactant, and a brine; and wherein contacting the filter cake or the formation with the bimodal stimulation composition results in at least one of the controlled removal of the filter cake or increased hydrocarbon production from the reservoir.   
     
     
         12 . The method of  claim 11  wherein the acid is selected from formic acid, lactic acid, citric acid, acetic acid, hydrochloric acid, or hydrofluoric acid, wherein the viscoelastic surfactant is selected from a zwitterionic or amphoteric compound, and wherein the brine is present in the bimodal stimulation composition such that the composition has an ionic concentration in a range of between about 0.5% by weight and about 10% by weight.