Patent ID: 6894008

Claim:
A corrosion resistant brine fluid made by the process comprising: providing a brine selected from the group consisting of packer fluids, completion fluids and workover fluids, the brine comprising: water; at least one source of water-soluble zinc cations to form a brine with the water; and an absence of a precipitate; and adding a brine-soluble additive selected from the group consisting of carbonates, bicarbonates, and mixtures thereof where the cation of the additive is selected from the group consisting of sodium, potassium, magnesium, ammonium and mixtures thereof, where the additive is in the form of a powder in an amount effective to increase the pH of the brine fluid and at a controlled rate that forms no precipitate; where the density of the brine is at least 11 pounds/gal, where the brine is not a saturated brine, and 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.