Abstract: An iron control agent capable of reducing ferric iron containing compounds to ferrous iron containing compounds in an acidic solution, such as one used for formation acidizing. The iron control agent comprises a combination of a sulfur dioxide, sulfurous acid, sulfite salts, bisulfite salts, or thiosulfate salts or mixtures thereof, with a source of copper ions and a source of iodine or iodine ions. The iron control agent may also include small amounts of an adjunct such as stannous chloride, 2-mercaptoethanol, and thioglycolic acid and its salts.

Abstract: A solubilized iron reducing additive for acid solutions and method for preparing such a solubilized iron reducing additive. The additive includes an iron reducing agent reactable with ferric ions to produce therefrom ferrous ions and a spent iron reducing compound. The spent iron reducing compound is incapable of reacting with ferric ions to produce ferrous ions. So that the reducing process may continue, a regenerating agent is mixed with the iron reducing agent, the regenerating agent being reactable with the spent iron reducing compound for regenerating the spent iron reducing compound back to the iron reducing agent state. Because it has been found that the iron reducing agent and regenerating agent readily fall out of suspension as precipitates after short periods of time after mixing, a solubility facilitator is admixed thereto for facilitating establishment of the solubilized additive for acid solutions.