CO2和微量H2S共存环境中套管防腐优选研究  

Corrosion Behavior of Casing Steel with Different Materials in CO2 and H2S Environment

作　　者：谢涛 张晓诚 林海 窦蓬 孙连坡 闫伟[2] XIE Tao;ZHANG Xiao-cheng;LIN Hai;DOU Peng;SUN Lian-po;YAN Wei(State Key Laboratory Offshore Oil Exploitation,Tianjin Branch of CNOOC China Limited,Tianjin 300459,China;China University of Petroleum,Beijing 102249,China)

机构地区：[1]中海石油(中国)有限公司天津分公司&海洋石油高效开发国家重点实验室,天津300459 [2]中国石油大学(北京),北京102249

出　　处：《装备环境工程》2021年第1期57-63,共7页Equipment Environmental Engineering

基　　金：国家重大专项“渤海油田高效开发示范工程”(2016ZX05058-002)。

摘　　要：目的研究不同材质套管在CO2和微量H2S共存环境中的腐蚀特征。方法采用高温高压腐蚀仪,以渤海某油田实际采出水样为腐蚀介质进行模拟实验,利用扫描电镜,能谱仪(EDAX)分析不同管材在不同腐蚀条件下腐蚀试样表面腐蚀产物的形貌和组分特征,对比分析不同钢材在对应腐蚀环境下的腐蚀速率,并建立长期腐蚀速率预测模型。结果单独CO2(分压为0.1 MPa)腐蚀环境中,N80材质在50℃条件下发现有局部腐蚀,其他材质表现为均匀腐蚀。CO2(分压为0.1 MPa)和微量H2S(分压为0.0006 MPa)共存条件下,碳钢和低Cr钢腐蚀差异小,为均匀腐蚀。微量H2S的加入改善了腐蚀环境,13Cr钢表面腐蚀程度较小,几乎不腐蚀。单独CO2与CO2/H2S共存的腐蚀速率相比,腐蚀速率降低60%以上。随着测试时间的增加,几种材质的腐蚀速率按照幂函数形式递减,N80、1Cr、3Cr材质的长期腐蚀速率分别为0.023、0.19、0.13 mm/a。结论微量H2S对CO2腐蚀具有明显的抑制作用,3Cr-N80套管、线重69.983 kg/m以上能够满足腐蚀后套管强度要求。To study the corrosion characteristics of different casing materials in the coexistence environment of CO2 and H2S.The simulated experiment is carried out using high temperature and high pressure corrosion instrument and taking actual produced water samples from an oilfield of the Bohai sea as corrosion medium.The morphology and composition of corrosion products on the surface of corrosion specimens in different corrosion environment are analyzed by scanning electron microscopy(SEM)and energy dispersive X-ray spectroscopy(EDAX).The corrosion rates of different steels in the corrosive environment are measured,and a long-term corrosion rate prediction model is established.The results show that N80 has local corrosion in single CO2 environment(partial pressure is 0.1 MPa)when the temperature is 50℃,and the others present uniform corrosion.The difference of surface corrosion between carbon steel and low Cr steel is small in the coexistence environment of CO2(partial pressure is 0.1 MPa)and H2S(partial pressure is 0.0006 MPa),with both of them presenting uniform corrosion.Trace H2S has improved the corrosion environment,leading less surface corrosion to 13 Cr steel,which is almost no corrosion;Compared with corrosion rate between environments of single CO2 and CO2/H2S,the corrosion rate was reduced more than 60%.With the increase of testing time,the corrosion rate of several materials decreases in the form of power function.The long-term corrosion rates of N80,1 Cr and 3 Cr materials are 0.023 mm/a,0.19 mm/a and 0.13 mm/a respectively.Trace H2S has obvious inhibition effect on CO2 corrosion.3 Cr-N80 casing with over 69.983 kg/m can meet the requirements of casing strength after corrosion.

关 键 词：CO2 H2S 套管钢 腐蚀机理 腐蚀速率 

分 类 号：TG174.2[金属学及工艺—金属表面处理]