1. n. [Enhanced Oil Recovery]
A corrosion by-product [FeS2] formed when hydrogen sulfide [H2S] contacts the iron [Fe] present in steel. Ferrous sulfide is a black crystalline material at bottomhole conditions. However, when it contacts air at surface, it will be converted into iron oxide, which is a red-brown compound. Ferrous sulfide is also called iron sulfide.
Alternate Form: iron oxide
See: hydrogen sulfide
