Corrosion mechanism of gas-water mixed pipeline and its affecting factors

Corrosion product in the gas-water mixed pipeline in Weiyuan Gasfield is tested. Results show that the corrosion product is mainly FeS and FeS₂, and the Fe(OH)₂ and Fe₂O₃ generated from FeS when the corroded pipe section is exposed to air. Laboratory simulation test confirms that the corrosion is primarily caused by H₂S. The effects of such factors as temperature of formation water, ion type, content of H₂S, salinity and pH value, etc. on pipeline corrosion are investigated. It is concluded that temperature has the most significant effect on corrosion.