دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

a weak organic acid that serves as a chelating agent for iron (slows iron hydroxide formation).

iron hydroxide gel (a precipitate after acid spends).

valence state +3 iron in solution. A very common catalyst in oil field emulsion and sludge formation. Precipitates at iron hydroxide when the pH exceeds 1.8 to 2.2 (depending on sour conditions).

valence state +2 iron in solution. In oil field operations, most solution iron is ferrous until oxygen is encountered. Precipitates at iron hydroxide when the pH exceeds 7 or when oxidized to ferric by contact with oxygen.

a brown, gelatinous precipitate that comes out of a spent acid solution when the acid spends completely or when the Ferrous Iron (+2) in solution at pH > 1.8 oxidizes to Ferric iron (+3).

n: a chemical used with an acid in well treatment to inhibit the precipitation of insoluble iron hydroxides, which form when the acid contacts scales or iron salts and oxides, such as are found in corrosion products on casing.