Iron is present in nature in the form of its oxides, or in combination with silicon or sulfur. The soluble iron content of surface waters rarely exceeds 1 mg/L, while ground waters often contain higher concentrations. The National Secondary Drinking Water Standard for iron is 0.3 mg/L, as iron concentrations in excess of 0.3 mg/L impart a foul taste and cause staining. High concentrations in surface waters can indicate the presence of industrial effluents or runoff.
Iron contamination in oil field brines are typically a result of corrosion processes of iron-containing metallic components and equipment. Accumulation of insoluble iron salts in a brine completion fluid can result in substantial formation damage and can significantly affect the productivity of an oil well. Quantifying total iron in brine is critical.
The Ferric Thiocyanate Method (Iron in Brine)
References: D. F. Boltz and J. A. Howell, eds., Colorimetric Determination of Nonmetals, 2nd. ed., Vol. 8, p. 304 (1978). Carpenter, J.F. “A New Field Method for Determining the Levels of Iron Contamination in Oilfield Completion Brine”, SPE International Symposium (2004).
The Iron in Brine test employs the ferric thiocyanate chemistry. In an acidic solution, hydrogen peroxide oxidizes ferrous iron. The resulting ferric iron reacts with ammonium thiocyanate forming a red-orange colored thiocyanate complex, in direct proportion to the iron concentration. Results, expressed in mg/L, can be converted to mg/kg by dividing by the density of the brine.
Kit comes in a plastic case and contains everything needed to perform 30 tests (except distilled water): Refill, Low and High Range Comparators, Acidifier Solution, Activator Solution, 50 mL sample cup with cap, 1.0 mL syringes, and instructions.
Range: 0-100 & 100-1000 mg/L
MDL: 5 mg/L
Method: Ferric Thiocyanate (Iron in brine)
WARNING! This product can expose you to chemicals including methanol, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.