页岩气井内涂层油管穿孔失效原因分析

李虹杰; 黄洪发; 苗超; 朱文旭; 宋宇; 黄红兵; 唐楠; 贺建峰

doi:10.3969/j.issn.1007-3426.2026.03.013

页岩气井内涂层油管穿孔失效原因分析

Cause analysis of perforation failure of internally coated tube in a shale gas well

摘要

摘要:
目的以四川某页岩气井为例，厘清内涂层油管穿孔失效的原因。
方法通过宏观形貌分析、理化性能测试、腐蚀产物分析、涂层微观形貌分析等方法对失效内涂层油管进行失效分析。
结果失效内涂层油管由外向内被腐蚀导致穿孔，气流由外向内冲刷涂层内表面，导致涂层脱落；内涂层油管基体材料的组织、化学成分、屈服强度和抗拉强度均符合标准要求，伸长率略低于标准要求；腐蚀产物分析表明内涂层油管发生CO₂腐蚀导致失效。
结论内涂层油管外壁发生CO₂腐蚀，Cl⁻促进局部腐蚀坑的发展，气举冲刷导致内涂层脱落失效。

Abstract:
Objective This study aims to clarify the causes of the perforation failure of internally coated tube in a shale gas well in Sichuan Province.
Method Failure analysis was carried out in the failure internally coated tube by macroscopic morphology analysis, physical and chemical property testing, corrosion product analysis, and microscopic morphology analysis of the coating.
Result Corrosion of the failed internally coated tube occurred from the outside inward, leading to perforation. The gas flow scoured the inner surface of the coating from the outside inward, resulting in coating detachment. The microstructure, chemical composition, yield strength, and tensile strength of the base material of the tubing met the standard requirements, while the elongation was slightly below the specified value. Corrosion product analysis indicated that the failure was caused by CO₂ corrosion.
Conclusion CO₂ corrosion occurred on the outer wall of the internally coated tube, and Cl^- promoted the development of localized corrosion pits. Additionally, gas lift scouring led to the detachment of the internal coating, resulting in failure.

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