A Note on the Value of Ammonia Treatment for Tank and Casing Annulus Corrosion by Hydrogen Sulfide

Four-year tests of the effectiveness of anhydrous ammonia injections into the vapor space of tanks storing sour crude oil indicate that previously unexposed steel is protected for four to eight months. After this time, however, corrosion of the steel exposed to vapors from hydrogen sulfide containing crude proceeds at about the same rate in tanks with ammonia injections as those without it. Ammonia injections appear to have little beneficial effect when injected into tanks in which the steel already has been exposed to sulfide vapors. Analogous results are predicted from injection of ammonia into the casing-tubing annular space of sulfide producing wells.