【作者】 张强；

【导师】 杨文忠；

【作者基本信息】 南京工业大学 ， 应用化学， 2005， 硕士

【摘要】 本文综述了国内油田套管的现状、影响套损的因素，以及江苏油田套损的情况。通过极化曲线法研究了套管用N80钢腐蚀的电化学因素；采用慢应变拉伸（SSRT）技术研究了N80钢的应力腐蚀断裂（SCC）行为，并用扫描电镜（SEM）进行断口形貌分析，探讨SCC过程的微观机制；采用腐蚀疲劳试验研究了N80钢的腐蚀疲劳情况；采用光电子能谱研究了添加缓蚀剂前后N80钢的表面情况。试验结果表明： （1）几种气体对N80钢的腐蚀速率的影响大小顺序为： 硫化氢＞二氧化碳＞氧气＞氮气 （2）在不同气体饱和的情况下，温度和转速的变化对N80钢的腐蚀有一定的影响。一定转速下，N80钢的腐蚀速率在75℃左右温度范围内的腐蚀速率最大；一定温度下，1500rpm时N80钢的腐蚀速率最大。 （3）江苏油田水介质对N80钢的力学性能有一定的影响。N80钢在空气中断裂的断口为韧窝，表现出良好的韧性断裂；而在油田水中，韧性降低，屈服应力、最大承受应力均降低，力学性能等均下降，表现出部分沿晶断裂。 （4）N80钢的力学性能受应变速率和温度的共同作用和影响。 （5）N80钢试样在油田水中较空气中具有一定的SCC敏感性，且较低的应变速率有助于减轻N80的韧性损失，降低SCC的敏感性。 （6）添加缓蚀剂后使N80试样的韧性有明显的增加，断口裂纹缝隙明显减小，力学性能有了明显的提高。 （7）通过腐蚀疲劳试验，得出油田用水介质状态下条件疲劳极限S_0.1=326N／mm²。 （8）通过光电子能谱分析，缓蚀剂主要通过Zn、P、Ca等化合物在表面成膜，而未加缓蚀剂的腐蚀产物主要是铁的氧化产物。更多还原

【Abstract】 The actuality of casing failure of inland oilfield and the affecting factor of casing failure were reviewed in this paper, and the circumstantialities of casing failure of Jiangsu oilfield were also introduced. The electrochemical factors of N80 steel casing corrosion and the stress corrosion cracking （SCC） of N80 steel were studied by polarization curve and slow strain rate tension （SSRT） separately, and the fracture surface morphology was examined by scanning electron microscopy （SEM）, and the mechanism of SCC process was discussed. Moreover, corrosion fatigue properties of N80 steel was studied by corrosion fatigue experiment. Furthermore, the inhibition performance of corrosion inhibitor which was used in oilfield-water, was researched by X-ray photoemission spectroscopy （XPS）. The results showed:（1） The sequence of different gas accelerating corrosion rate of N80 steel in oilfield-water is:H₂S>CO₂>O₂>N₂（2） The temperature and rotating rate have effect on corrosion of N80 steel when the oilfield-water is saturated by different gas, and the corrosion rate of N80 steel arrives at the top at about 75 degree centigrade and 1500 rpm.（3） The oilfield-water of Jiangsu oilfield has distinct effect on mechanics property of N80 steel. N80 steel displays the fracture features of the dimple in air, which appears excellent ductile fracture. However, the ductility, yield stress and maximum bear stress decrease of N80 steel decreases in oilfield-water, which expressed partial intergranular fracture.（4） The mechanical property of N80 is affected by strain rate and temperature.（5） N80 steel has definite SCC sensibility in oilfield-water compared in air, but lower strain rate administer to relieving the ductility loss and the SCC sensibility of N80 steel.（6） The mechanical property of N80 steel has increased obviously after adding corrosion inhibitor, where the ductility of N80 steel increased, and crack fissure of fracture surface decrease.（7） Corrosion fatigue test shows that the state fatigue limit S_0.1 of N80 steel is 326N/mm² in oilfield-water.（8） XPS analysis shows the presence of Zn、P、Ca etc. on the surface of N80 steel after corrosion inhibitor is added, but the corrosion products are mainly ironic oxidation without corrosion inhibitor.更多还原