油田用双金属机械复合管失效原因分析与对策

Failure Analysis and Measures of Bimetallic Mechanical Composite Pipefor Oil Field

目的分析研究双金属机械复合管的失效原因,并提出改进措施。方法对比说明双金属机械复合管几种常见的典型制造方法及其优缺点,介绍应用中典型传统焊接工艺焊接的环焊缝腐蚀剌漏或穿孔、环焊缝开裂、内衬塌陷或鼓包以及爆管等常见的失效形式,利用现场应用的失效实例、统计数据和室内检测结果,分析这些失效类型的原因,并提出针对性建议或措施。结果双金属机械复合管几种典型的制造方法各有优缺点,但其产品的内衬与基管的结合力均较小。造成其管材失效的主要原因有高压、高温、含CO_(2)/Cl^(-)腐蚀介质、封焊结构、焊接工艺、外防腐层施工、应力腐蚀或电偶腐蚀等。根据现场应用实践,提出并应用了管端堆焊结构、环焊缝用镍基合金焊材、增加内衬厚度和小管径等防止失效的建议或措施,取得很好的防护效果。结论造成此类管材失效的因素有腐蚀、封焊结构、焊接、外防腐施工及应力腐蚀或电偶腐蚀等,可采取堆焊结构、镍基合金焊材、厚衬层和小管径等措施。

The paper aims to study the failure cause of bimetallic mechanical composite pipe and put forward improvement measures.A brief comparison of several typical and common manufacturing methods and their advantages and disadvantages are introduced,and the failure types of the pipes welded by the typical traditional welding process such as girth weld corrosion leakage or pitting,girth weld cracking,lining collapse or bulge,and pipe bursts,are introduced.Using oilfield application failure examples,statistical data and test results,the causes of these failure types are analyzed,and targeted recommendations or measures are put forward.The results show that several typical manufacturing methods of bimetal mechanical composite pipes have their own advantages and disadvantages,but the bonding force between the inner lining and the base pipe of the product is relatively small.The main reasons for the failure of this type of pipe are high pressure and high temperature,CO_(2)/Cl^(-) corrosive medium,the sealing structure and welding process,external anti-corrosion layer construction,stress corrosion or galvanic corrosion,etc.According to the field application practice,suggestions or measures to prevent failures such as pipe end surfacing structure,nickel-based alloy welding material for girth weld,increase of lining thickness and small pipe diameter,etc.have been put forward and applied,and a good protective effect has been achieved.