中原油田二氧化碳驱油井油管断裂分析

The pipe fracture analysis of carbon dioxide flooding well in Zhongyuan Oilfield

二氧化碳驱是中原油田提高采收率的一种主要技术。在现场实施先导试验的过程中,尽管电化学腐蚀速率控制指标优于行业标准,但还是出现了油管断裂造成的管柱损坏问题。通过现场工况条件、油管成分和力学性能等数据分析,结合油管断口的宏观形貌、微观形貌的观察分析,确定了油管断裂的原因为“复杂应力+腐蚀+疲劳”,是材料、应力、腐蚀环境三方面因素协同作用的脆性断裂。从材料、应力和腐蚀环境三个方面制定了防止油管断裂的对策。

Carbon dioxide flooding well is one of the main technologies for enhancing recovery efficiency in Zhongyuan Oilfield. During the pilot test on site, the electrochemical corrosion rate control index is better than industry standard, however, there is the problem of tubular pile damages caused by pipe fracture. Through the analysis of field working condition, pipeline composition, mechanical properties, macroscopic and microscopic morphology of pipe fracture, it was confirmed that the cause results from complex stress, corrosion and fatigue, which is called as brittle rupture created under the combined effect of material, stress and corrosion environment. Preventive measures were adopted accordingly.