【作者】 侯彬；

【导师】 魏无际； 周永璋；

【作者基本信息】 南京工业大学 ， 材料学， 2003， 硕士

【摘要】 在钻井工程中，钻具腐蚀是普遍存在的问题，并随着钻井向高速、深井方向发展而日趋严重，又由于钻具的不断提价而变得尤为突出。近年来，江苏油田承钻了位于洪泽、淮阴一带的盐井，使用饱和盐水钻井液。该钻井液中Cl^-含量高，同时富含K⁺、Ca²⁺、SO₄^2-等离子，电导率大；另外其中还含有多种成分复杂的添加剂，又因井内温度较高（80℃～90℃），钻井液内含溶解氧，因此对钻具的腐蚀更是尤为严重。 本文首先通过对钻杆腐蚀产物进行EDS分析从而推断腐蚀机理，结果表明：腐蚀产物主要成分是Fe₂O₃，饱和盐水钻井液对钻杆的腐蚀主要是氧的去极化作用所致，其电化学反应为：阳极过程：Fe-2e→Fe²⁺，阴极过程：O₂+2H₂O+4e→4OH^-，即：2Fe+3/2O₂+H₂O→2FeOOH→Fe₂O₃+H₂O。 动电位扫描极化曲线法进行缓蚀剂的室内筛选实验结果表明：氧化型缓蚀剂中含氮化合物A提高G105钢在饱和盐水中的孔蚀电位作用较明显；沉淀型缓蚀剂中含硅化合物B作用也较明显；吸附型缓蚀剂中只有有机胺C的作用较明显。然后，将含氮化合物A、含硅化合物B和有机胺C进行正交复配，筛选出效果较好的复合缓蚀剂（1％A+0.5％B+0.5％C）。 室内动态模拟实验结果表明：在温度为80℃、连续通氧（2L/h）、转速为2000r/min条件下，该复合缓蚀剂的室内缓蚀率达到95％以上，明显高于单组分缓蚀剂；运用腐蚀试验环法进行现场评价试验，结果表明：该复合缓蚀剂和饱和盐水钻井液配伍性良好，现场缓蚀率达到90％左右，效果明显。 最后，本文运用X-射线光电子能谱（XPS）对G105钢在饱和盐水中的钝化膜进行了初步研究，结果表明：G105钢在空白饱和盐水中形成的钝化膜的主要组成元素为Fe、C和O，而且钝化膜为两种铁的氧化物γ-FeOOH、FeO结构；G105钢在含有复合缓蚀剂的饱和盐水中的钝化膜除了含有Fe、C和O三种元素，还有N和Si，这说明复合缓蚀剂参与了钝化膜的形成，复合缓蚀剂的加入使钝化膜中γ-FeOOH的含量增高，从而提高了钝化膜的抗点蚀能力。更多还原

【Abstract】 In well-drilling projects, the corrosion of drill pipe is ubiquitous phenomena; moreover, it becomes more serious along with the development of deep wells and high-speed wells and it becomes more urgent because of rise in price of drill pipe in recent years. Lately, Jiangsu oil field drills lots of salt wells locating in Hongze and Huaiyin, saturated saltwater drilling fluids is used, the concentration of Cl- is very high; various additives are added into the drilling fluids; the conductance of drilling fluids is high; the temperature of wells is high(80℃~90℃ );Dissolved oxygen exists in it; so, the corrosion of drill pipe is more serious.In this work, by the method of EDS analysis of drill pipe corrosion production, we can conclude that the corrosion of drill pipe is mainly caused by the depolarization of dissolved oxygen; anode process: Fe-2e→Fe2+, cathode process: O2+2H2O+4e→ 4OH-, the whole process: 2Fe+3/2O2+H2O→2FeOOH→Fe2O3+H2O.Potentiodynamic polarization test results show: nitrogen containing compound A can apparently enhance G105 steel’s pitting potential in saturated saltwater among oxidation-type corrosion inhibitors; so does silicon containing compound B among deposition-type inhibitors; organic amine C also works a lot among adsorption-type inhibitors; then, by the method of orthogonal experiments we picked out composite inhibitor: 1%A+0.5%B +0.5%C.Laboratory dynamic simulation test results show: the inhibition efficiency of composite inhibitor is above 95%, which is superior to single inhibitors; Spot evaluation test, which was carried out by the method of corrosion test ring, results show: composite inhibitor is consistent to saturated saltwater drilling fluids, its inhibition efficiency is about 90%.X-ray photoelectron spectroscopy (XPS) was used to study the composition of G105 steel passive film formed in saturated saltwater. Results show that the major elements in the passive film are Fe, C and O; and that there are two oxides of iron( gamma -FeOOH, FeO) in the film. After adding composite inhibitor, the content of gamma-FeOOH in the film is increased, so, the ability of resistance of Cl- pitting corrosion is enhanced.更多还原