常压页岩气油管断裂原因与防腐策略讨论

Discussion on Causes of Atmospheric Shale Gas Tubing Fracture and Anticorrosion Strategies

南川页岩气田2021年某井油管发生腐蚀断裂,给页岩气开采带来了较大的安全隐患。本文主要针对南川页岩气田某井油管断裂现象展开分析,通过对采出气、采出水和腐蚀产物等研究,发现硫酸盐还原菌是造成油管腐蚀穿孔的主要原因,CO_(2)的存在促进了点蚀的发展,同时,Cl^(-)起到催化与促进点蚀的作用,最终导致油管腐蚀穿孔甚至断裂。为了有效遏制油管穿孔现象,需对井筒加注缓释杀菌剂,并结合对油管涂敷内涂层,实现对油管腐蚀的有效控制。

The tubing of a certain well in the Nanchuan shale gas field was corroded and fractured in 2021,which brought great safety hazard to the production of shale gas.The phenomenon of tubing fracture by research on produced gas, produced water and corrosion products was manily analyzed.It was found that sulfate reducing bacteria was the main cause of tubing corrosion and perforation.The presence of CO_(2) promoted the development of pitting corrosion. Cl^(-) also played the role of catalysis and promotion of pitting corrosion, which eventually led to corrosion and perforation or even fracture of the tubing.In order to effectively curb the perforation of the tubing, it was necessary to inject a slow-release bactericide into the wellbore, and apply an internal anti-corrosion coating to the tubing to achieve effective control of tubing corrosion.