塔河油田某井P110S油管腐蚀断脱原因分析

Analysis of the Corrosion and Fracture of P110S Tubing in a Well of Tahe Oilfield

为了研究塔河油田抗硫油管的腐蚀现状和腐蚀原因,并对油管采取腐蚀防护措施提供合理化建议,通过宏观形貌观察、理化性能检测、金相组织分析、扫描电镜观察和能谱分析等方法,并结合现场工况,对某井P110S油管腐蚀失效原因进行综合分析。结果表明:该油管的化学成分、力学性能及金相组织均符合标准API SPEC 5CT-2011的要求,高含CO_(2)、Cl^(-)、H_(2)O的腐蚀环境是引起油管内壁局部腐蚀、导致油管内壁严重减薄发生断脱的主要原因,且随着井深的增加,油管所处的温度也在升高,油管的腐蚀程度也趋于严重.

In order to study the corrosion status and reasons of the sulfur-resistant tubings in Tahe oilfield and provide reasonable suggestions for tubing corrosion protection,the causes of corrosion failure of P110S tubing in a well were comprehensively analyzed by means of macro-mor-phological observation,physical and chemical property testing,metallographic structure analysis,scanning electron microscope observation and energy spectrum analysis based on field conditions.Results showed that the tubing’s chemical composition,mechanical properties and metallo-graphic structure met API SPEC 5CT-2011 requirements,and a corrosion environment with high contents of CO_(2),Cl^(-)and H_(2)O was the main reason for the local corrosion of the inner wall of the tubing,which subsequently led to a serious thinning and fracture of the inner wall of the tub-ing.With the increase of the well depth,the service temperature of the tubing increased,and the corrosion degree of the tubing increased as well.