摘要
镍基合金718是一种高酸性油气井中常用的金属材料,但对其应力腐蚀开裂敏感性及其影响因素的研究较少。利用高温高压反应釜进行应力腐蚀开裂模拟试验,结合扫描电子显微镜(SEM)和能谱仪(EDS)等分析手段研究了温度对718镍基合金在高含H_2S/CO_2环境下应力腐蚀行为的影响。结果表明:在CO_2分压3.5 MPa、H_2S分压3.5 MPa、Cl^-含量150 000 mg/L的模拟环境下,镍基合金718在150,175,205℃下均未发现点蚀和裂纹,应力腐蚀开裂敏感性较低;但随温度升高,镍基合金718的C环应力腐蚀试样表面的钝化膜出现明显的硫化和颗粒状的腐蚀产物,并逐步团聚形成点蚀源。
718 nickel-based alloy as one of metal materials of downhole tools and equipment is commonly used in high acid oil and gas wells. However, stress corrosion cracking sensitivity and impact factors have not been widely researched. In this paper, with simulating the stress cor- rosion cracking test by high temperature and high pressure reactor, the effect of temperature on the stress corrosion behaviors of 718 alloy in H2S/CO2-containing environment was studied by scanning electron microscopy (SEM) and X-ray energy spectmum analysis (EDS). Results showed that under the simulating environment of 3.5 MPa C02 partial pressure, 3.5 MPa H2S partial pressure and 150 000 mg/L Cl- concentration, no obvious corrosion pits or cracks were observed on the surface of 718 alloy at 150, 175, 505℃, presenting that the stress corrosion cracking sensitivity of alloy was low. However, with the increase of temperature, the passivating film on the surface of the C-ring stress corrosion specimen of 718 alloy showed obvious sulfidation, and some granular corrosion products existed, which gradually agglomerated to form a pitting corrosion source.
作者
张奎林
张瑞
马兰荣
李大朋
路民旭
ZHANG Kui-lin1, ZHANG Rui2, MA Lan-rong2, LI Da-peng3, LU Min-xu3(1. Ministry of Science and Technology, China Petroleum & Chemical Corporation, Beijing 100728, China; 2. Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China; 3. Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, Chin)
出处
《材料保护》
CAS
CSCD
北大核心
2018年第4期35-38,共4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)
中国石化科技部攻关项目"Φ178×Ф127(Φ114)mm双防旋转尾管悬挂器的研制"(P14113)联合资助