Calcium chloride brine is incompatible with formation or injection brines containing CO<sub>3<sup>2-</sup></sub>, HCO<sub>3<sup>-</sup></sub>, or SO<sub>4<sup>2-</sup></sub>. Consequently, scale inhibitor must be used or a suitable (normally higher concentration and more costly) substitution of KCl or NH<sub>4</sub>Cl brines will suffice. Another alternative is to displace the noncompatible water with a slug of KCl or NH<sub>4</sub>Cl and follow this with CaCl<sub>2</sub>. | Calcium chloride brine is incompatible with formation or injection brines containing CO<sub>3<sup>2-</sup></sub>, HCO<sub>3<sup>-</sup></sub>, or SO<sub>4<sup>2-</sup></sub>. Consequently, scale inhibitor must be used or a suitable (normally higher concentration and more costly) substitution of KCl or NH<sub>4</sub>Cl brines will suffice. Another alternative is to displace the noncompatible water with a slug of KCl or NH<sub>4</sub>Cl and follow this with CaCl<sub>2</sub>. |