CO_2和H_2S在井下环境中共存时对油管钢的腐蚀

Coexistence of CO_2 and H_2S Corroding Tubing under Down Hole Environment

阐述了石油天然气中CO2和H2S共同存在时对油管钢联合腐蚀的危害性,分析了CO2和H2S腐蚀的研究方向与发展趋势。重点从理论上探讨了CO2和H2S共存时对油气管材的腐蚀机理及其影响因素,初步发现:当H2S和CO2共同存在时,其机理可能是CO2在液相中与钢先发生作用生成FeCO3,H2S在液相中与FeCO3反应生成了更为稳定的FexSy,在液相中,FexSy吸附层对离子的迁移起到了部分的阻拦作用。CO2和H2S腐蚀影响因素主要包括温度、压力、流速三类,油套管腐蚀的热点将集中在CO2和H2S共存时对油管钢联合腐蚀。

The harmfulness of coexistence of CO_2 and H_2S in oil and nature gas jointly corroding tubular goods is expounded.The research direction and contemporary trends of corrosion by CO_2 and H_2S are analyzed.The mechanism of this coexistence corroding tubular goods and its influenced factors are emphatically discussed in theory.It is tentatively found that when H_2S coexists with CO_2,the mechanism is likely that in liquid phase,first CO_2 acts on steel to generate FeCO_3;then H_2S acts on FeCO_3 to generate even more stable FeXSY;the FeXSY absorbed layer play a partial obstructed part in the migration of ions.The influenced factors of corrosion by CO_2 and H_2S mainly include three types,temperature,pressure and velocity.The central issue of tubular goods corrosion will focus on the combined corrosion of this coexistence.