Abstract: A composition and methods for use in oilfield waterflood systems are disclosed. The composition is comprised of a phosphonate, a copolymer, and a permanganate and is effective at inhibiting the corrosion of metallic systems in petroleum oilfields caused by chlorine dioxide. Methods of use of phosphonate and permanganate alone are also disclosed. Chlorine dioxide is used in oilfield waterflood systems to control sulfides and sulfate reducing bacteria. However, chlorine dioxide is highly corrovive to the metallic components in the processing equipment of an oilfield system. The most effective system currently used to inhibit corrosion caused by chlorine dioxide comprises chromates. However, chromates are highly toxic and their use throughout the country is becoming increasingly restricted.

Abstract: A composition and methods for use in oilfield waterflood systems are disclosed. The composition is comprised of a phosphonate, a copolymer, and a permanganate and is effective at inhibiting the corrosion of metallic systems in petroleum oilfields caused by chlorine dioxide. Methods of use of phosphonate and permanganate alone are also disclosed. Chlorine dioxide is used in oilfield waterflood systems to control sulfides and sulfate reducing bacteria. However, chlorine dioxide is highly corrosive to the metallic components in the processing equipment of an oilfield system. The most effective system currently used to inhibit corrosion caused by chlorine dioxide comprises chromates. However, chromates are highly toxic and their use throughout the country is becoming increasingly restricted.

Abstract: A method of inhibiting manganese deposition in open, recirculating aqueous systems is disclosed. A water soluble acrylic acid/allyl hydroxy propyl sulfonate ether copolymer having repeat units characterized by the structural formula: ##STR1## wherein M is a water soluble cation, the molar ratio x:y is from about 3:1 to about 6:1 and the number average molecular weight of the copolymer is from about 5,000 to about 10,000, preferrably with an organic phosphonate is added to the aqueous system. The organic phosphonate is preferably hydroxy ethylidene diphosphonic acid, diethylene triamine penta-(methylene phosphonic acid) or blends thereof. The copolymer or copolymer and phosphonic acid is effective in inhibiting the deposition of manganese in aqueous systems.

Abstract: Methods for removing iron oxide and other accumulated corrosion products from metal surfaces in contact with aqueous systems, such as cooling water systems, are disclosed. The method steps can be performed without requirement of system shutdown and without requirement of acidic conditions. The methods comprise contacting the corroded surface with an organic reductant/chelant and an inorganic reducing agent while the pH of the aqueous system is maintained within the substantially neutral range of about 6.5-7.5. Pyrogallol and methyl gallate may be used as the organic reductant/chelant.