K气田集输管道焊缝腐蚀失效研究  

Corrosion of CO_2 on Internal Gas Gathering and Transportation Pipelines in K Gas Field

作　　者：殷名学 姜放 张维臣 李天雷 蒲旭辉[2] 刘世平[2] 肖普朝[2] 

机构地区：[1]中国石油集团工程设计有限责任公司西南分公司,四川成都610017 [2]中国石油西南油气田公司川西北气矿,四川江油621709

出　　处：《天然气与石油》2011年第4期73-76,97-98,共4页Natural Gas and Oil

基　　金：中国石油天然气集团公司重点工程资助项目(S2002-62D)

摘　　要：K气田天然气中主要腐蚀介质为CO2和气田水中的氯离子。采用碳钢管道进行气田内部集输,使用1年左右碳钢管道发生了严重腐蚀。通过腐蚀调查和对典型管道腐蚀样品剖析检查,对腐蚀产物进行检测分析,采用了电化学测量方法测量在腐蚀环境中焊缝不同区域金属的腐蚀电位。分析结果表明:在发生腐蚀的阶段没有发现地层水参与腐蚀的证据,CO2是导致气田内部集输碳钢管道腐蚀失效的主要腐蚀介质;由于化学成分和微观结构的差异,焊逢与钢管母材金属在湿流体介质中形成了电位差,导致气田碳钢管道焊接区域发生严重腐蚀。焊接材料和焊接工艺对碳钢管道的CO2腐蚀有重要影响,对于含腐蚀性流体的气田,在进行内部集输工程建设设计和施工时,应开展焊接焊头抗腐蚀性评价试验研究。Main corrosive media in natural gas from Kela 2 Gas Field are CO2 and chloride ion in gas field water.Serious corrosion occurs in carbon steel pipelines in gathering and transportation system of the gas field after about one year of operation.Test and analyzed are corrosion products through investigation of typical pipeline corrosion,corrosion inspection and sampling and adopted is electrochemical measurement method to measure the corrosion potential of weld metal in different positions under corrosive environment.Analysis results show that no corrosion results from formation water and CO2 is the main corrosive medium in gas field carbon steel pipelines.Due to diversity of chemical compositions and microcosmic structures,electric potential differential forms between welding line and base metal of steel pipeline exposed to wet fluid medium,which leads to serious corrosion in welding areas of carbon steel pipelines.It is believed that welding materials and welding procedures have significant effects on CO2 corrosion in carbon steel pipelines and corrosion resistant evaluation test and study shall be conducted on welding materials during engineering design and construction of internal gathering and transportation system in corrosive gas fields.

关 键 词：CO2腐蚀 失效管道剖析 腐蚀产物分析 焊接工艺 电极电位 

分 类 号：TE973.3[石油与天然气工程—石油机械设备]