Aqueous solution and method for use thereof

Abstract

Aqueous compositions contain hydrochloric acid at a concentration between 8 wt % and 28 wt % inclusive. The amino acid; hydrochloric acid mole ratio may be between 0.2 and 1.5. Sufficient water is present to dissolve the hydrochloric acid and the amino acid. Such compositions have utility as retarders for acid compositions employed in the stimulation of subterranean formations. Slowing the reaction between the acid and formation helps maximize formation permeability and productivity.

1 . An aqueous treatment fluid composition, comprising:
 (i) hydrochloric acid at a concentration between 8 wt % and 28 wt %, inclusive; and   (ii) at least one amino acid,   wherein the amino acid:hydrochloric acid molar ratio is between 0.2 and 1.5, and sufficient water is present to dissolve the hydrochloric acid and the amino acid and   wherein the amino acid comprises alanine, asparagines, aspartic acid, cysteine, glutamic acid, histidine, leucine, lysine, methonine, proline, serine, threonine or valine or combinations thereof.   
     
     
         2 . The composition of  claim 1 , further comprising hydrofluoric acid at a concentration higher than or equal to 0.25 wt %. 
     
     
         3 . The composition of  claim 1 , wherein the composition exhibits an acid retardation factor higher than or equal to 15 at 20° C. 
     
     
         4 . The composition of  claim 1 , wherein the composition exhibits an acid retardation factor higher than or equal to 15 at 93° C. 
     
     
         5 - 17 . (canceled) 
     
     
         18 . A method for handling a composition, comprising:
 (i) providing an aqueous solution having an amount of hydrochloric acid exceeding 37 wt %;   (ii) adding an amino acid fixing agent to the solution, wherein the amount of fixing agent includes a molar ratio of fixing agent:hydrochloric acid between 0.2 and 1.5 inclusive;   (iii) placing the solution into an atmospherically pressured vessel; and   (iv) transporting the vessel to a service location over a public road, a railway or both.   
     
     
         19 . The method of  claim 18 , wherein the amino acid comprises alanine, asparagines, aspartic acid, cysteine, glutamic acid, histidine, leucine, lysine, methonine, proline, serine, threonine or valine or combinations thereof. 
     
     
         20 . The method of  claim 18 , wherein the solution is diluted with water at the service location. 
     
     
         21 . The method of  claim 18 , further comprising allowing the solution to reside in the vessel for at least one hour. 
     
     
         22 . The method of  claim 18 , wherein the vessel is equipped to allow an operator to perform a fluid utility operation with the solution. 
     
     
         23 . The method of  claim 22 , wherein the fluid utility operation comprises measuring a solution level in the vessel, removing a solution sample, measuring a pH of the solution, introducing additional materials to the solution, agitating the solution, or transferring the solution from the vessel to another container or a high-pressure pump or a combination thereof. 
     
     
         24 . The method of  claim 18 , wherein the high-pressure pump is used to place the solution in a subterranean well. 
     
     
         25 . The composition of  claim 1 , wherein the treatment fluid composition is injected by a pump into a formation at matrix rates, and contacting a wellbore of the formation. 
     
     
         26 . The composition of  claim 1 , wherein the composition is diluted with water at a service location.