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利用高温高压釜模拟井下高温高压环境,通过气、液相失重法、表面轮廓分析和形貌观察评价和研究TP140高强度套管钢与PTFE、HP13Cr及其自身构成的缝隙在模拟地层水中的腐蚀敏感性及缝隙腐蚀特征;并借助动电位极化测试和电化学阻抗谱技术对比了不同结构缝隙在90℃模拟地层溶液中的电化学行为差异以揭示TP140钢在井下地层水环境中的缝隙腐蚀行为机制。结果表明:高强度套管钢TP140在井下地层水中具有较高的缝隙腐蚀敏感性;TP140所构成的3种结构缝隙在模拟地层水的液相中相比于气相呈现出更为严重的全面腐蚀损伤,其中TP140与HP13Cr构成的缝隙中腐蚀尤为严重,这归因于电偶促进作用的显著影响。
The high temperature and high pressure autoclave was used to simulate the underground high temperature and high pressure environment. The gas, the liquid phase loss, the surface profile analysis and the morphology observation were used to evaluate and study the corrosion of TP140 high strength casing steel, PTFE, HP13Cr and their own cracks in simulated formation water Sensitivity and crevice corrosion characteristics of the TP140 steel. The differences of electrochemical behavior between different structural gaps in 90 ℃ simulated formation solution were compared by potentiodynamic polarization and electrochemical impedance spectroscopy to reveal the crevice corrosion of TP140 steel in the downhole formation water environment Behavior mechanism. The results show that the high strength casing steel TP140 has high crevice corrosion sensitivity in the downhole formation water. The three kinds of structural slits formed by TP140 show more severe overall corrosion in the liquid phase of the simulated formation water than the gas phase The corrosion was particularly serious in the gap between TP140 and HP13Cr due to the significant effect of galvanic coupling.