摘要
目前就元素S对高酸性油气井中常用的金属材料镍基合金718腐蚀行为影响的研究较少。在模拟高温、高含H2S/CO2和高Cl-浓度的腐蚀环境中,通过高温高压腐蚀模拟试验,结合失重测量、扫描电子显微镜(SEM)和X射线能谱分析(EDS)等技术手段研究了元素S对镍基合金718腐蚀行为的影响。试验表明:在205℃,CO2分压3.5 MPa、H2S分压3.5 MPa、Cl-浓度200 g/L环境下,1 g/L元素S的加入加剧了镍基合金718的腐蚀,增加了应力腐蚀开裂的敏感性。点蚀主要源于Cl-参与的歧化反应,而均匀腐蚀是高温下的单质S直接或间接与金属发生反应导致的。开裂的成因是单质S的加入加速了点蚀坑的形成和发展,导致多个点蚀坑连通构成长条状的腐蚀坑,最终形成裂纹导致开裂。
At present,the influence of element S on the corrosion behavior of nickel-based alloy 718 that is commonly used in high acid oil and gas wells has not been widely researched.In this paper,a set of technical methods including high-temperature and high-pressure corrosion simulation test,weight loss measurement,scanning electron microscopy(SEM)and X-ray energy spectrum analysis(EDS)were implemented to study the influence of element S on the corrosion behavior of the nickel-based alloy 718.Results showed that the addition of 1 g/L element S exacerbated the corrosion of nickel-based alloy 718 and increased the sensitivity of stress corrosion cracking in high acidic environment of 3.5 MPa CO2 partial pressure,3.5 MPa H2S partial pressure and 200 g/L chloride ion concentration at 205℃.In addition,pitting corrosions were mainly caused by the disproportionation reaction of Cl-,while uniform corrosions were caused by the direct or indirect reactions of elemental S with metal at high temperature.Furthermore,the elemental S accelerated the formation and development of the pits,and then a plurality of pitting pits formed a long strip of corrosion pits,which eventually led to cracking.
作者
张瑞
李夯
阮臣良
路民旭
ZHANG Rui;LI Hang;RUAN Chen-liang;LU Min-xu(State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,Beijing 100101,China;Sinopec Research Institute of Petroleum Engineering,Beijing 100101,China;Institute of Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China)
出处
《材料保护》
CAS
CSCD
北大核心
2020年第3期61-65,77,共6页
Materials Protection
基金
国家科技重大专项“高压低渗油气藏固井完井技术”(2016ZX0521005)资助。
