corrosion inhibitor

1. n. [Well Workover and Intervention]
A chemical additive used in acid treatments to protect iron and steel components in the wellbore and treating equipment from the corrosive treating fluid. Corrosion inhibitors generally are mixed with the treatment fluid and are formulated to be effective in protecting the metal components the fluid is likely to contact. This protection must remain effective under the anticipated pressure and temperature environment for the duration of the treatment.
2. n. [Enhanced Oil Recovery]
In matrix treatments, a chemical added to acid that adsorbs on the pipe surface to form a protective film. This decreases the destructive reaction of acid with metals. The inhibitor does not completely stop the corrosion reaction, but it eliminates more than 99% of the metal losses that would occur if the inhibitor were not present. The inhibitor has little or no effect on the reaction rate of acid with limestone, dolomite or acid-soluble minerals. Specific corrosion inhibitors are environmentally compatible, effective in hydrogen sulfide [H2S] environments, effective on high chrome steel, and effective on special steel alloys, such as coiled tubing. These inhibitors may be used at temperatures approaching 500oF [260oC].