Method of increasing pH of high-density brines

Abstract

It has been discovered that carbonate powders and bicarbonate powders are useful to increase the pH and corrosion resistance of high-density brines, such as zinc bromide brines, without significantly reducing their densities. The carbonates and/or bicarbonates should be water-soluble and may be sodium, potassium, magnesium and/or ammonium carbonates and/or bicarbonates and the like. The carbonates and/or bicarbonates are easily added in powder or other finely divided solid form.

1 - 22 . (canceled)  
     
     
         23 . A method for increasing the corrosion resistance of a brine fluid comprising: 
 providing a brine comprising: 
 water;  
 at least one source of water-soluble zinc cations to form a brine with the water, where the density of the brine is at least 11 pounds/gal; and  
   adding a brine-soluble additive selected from the group consisting of water-soluble carbonates, water-soluble bicarbonates, and mixtures thereof where the additive is in the form of a powder and in an amount effective to increase the pH of the brine and at a controlled rate that forms no precipitate, to give a corrosion resistant brine fluid.    
     
     
         24 . The method of  claim 23  where the additive has a cation selected from the group consisting of sodium, potassium, magnesium, ammonium and mixtures thereof.  
     
     
         25 . The method of  claim 23  where the brine is not a saturated brine.  
     
     
         26 . The method of  claim 23  where the source of water-soluble zinc cations is at least one salt selected from the group consisting of chloride, bromide, acetate, and formate salts.  
     
     
         27 . The method of  claim 23  where the source of water-soluble zinc cations is selected from the group consisting of zinc chloride and zinc bromide.  
     
     
         28 . The method of  claim 23  where the additive is selected from the group consisting of sodium carbonate, sodium bicarbonate, and mixtures thereof.  
     
     
         29 . The method of  claim 23  where the additive is present in a mole ratio to the total amount of water-soluble cation ranging from about 0.05/1 to about 2.0/1.  
     
     
         30 . The method of  claim 23  where the additive is present in an amount from 0.1 to 10 wt. % based on the total amount of water-soluble cation.  
     
     
         31 . The method of  claim 23  where the additive powder ranges in size from about 5 to about 500 microns.  
     
     
         32 . The method of  claim 23  further comprising adding at least one non-emulsifier and at least one wetting agent.  
     
     
         33 . The method of  claim 23  where the corrosion resistant brine fluid has a plurality of different sources of water-soluble cations selected from the group consisting of two or three, 
 where in the case there are at least two different sources of water-soluble cations the true crystallization temperature (TCT) and the last crystal to dissolve (LCTD) temperature independently range between about −70 to about 20° F., and    where in the case there are at least three different sources of water-soluble cations the true crystallization temperature (TCT) and the last crystal to dissolve (LCTD) temperature independently range between about 80 to about 0° F.    
     
     
         34 . The method of  claim 33  where in the case there are two different sources of water-soluble cations, the sources are zinc bromide and calcium bromide, and in the case there are three different sources of water-soluble cations, the sources are zinc bromide, calcium chloride and calcium bromide.  
     
     
         35 . The method of  claim 23  further comprising pumping the brine fluid downhole in a hydrocarbon recovery operation.  
     
     
         36 . The method of  claim 35  further comprising contacting the brine fluid with iron-based metals or alloys and where a corrosion rate of the metals and alloys is reduced as compared with an identical brine fluid absent the additive.  
     
     
         37 . A method for increasing the corrosion resistance of a brine fluid comprising: 
 providing a brine comprising: 
 water;  
 at least one source of water-soluble zinc cations to form a brine with the water, where the density of the brine is at least 11 pounds/gal, and where the brine is not a saturated brine; and  
   adding a brine-soluble additive selected from the group consisting of water-soluble carbonates, water-soluble bicarbonates, and mixtures thereof where the additive is in the form of a powder and in an amount effective to increase the pH of the brine and at a controlled rate that forms no precipitate, to give a corrosion resistant brine fluid, and where the additive has a cation selected from the group consisting of sodium, potassium, magnesium, ammonium and mixtures thereof.    
     
     
         38 . The method of  claim 37  where the source of water-soluble zinc cations is at least one salt selected from the group consisting of chloride, bromide, acetate, and formate salts.  
     
     
         39 . The method of  claim 37  where the additive is selected from the group consisting of sodium carbonate, sodium bicarbonate, and mixtures thereof.  
     
     
         40 . The method of  claim 37  where the additive is present in a mole ratio to the total amount of water-soluble cation ranging from about 0.05/1 to about 2.0/1.  
     
     
         41 . The method of  claim 37  where the additive is present in an amount from 0.1 to 10 wt. % based on the total amount of water-soluble cation.  
     
     
         42 . The method of  claim 37  where the additive powder ranges in size from about 5 to about 500 microns.  
     
     
         43 . The method of  claim 37  further comprising adding at least one non-emulsifier and at least one wetting agent.