煤层气田采气平台20钢在高含水率高Cl~-土壤环境下的腐蚀行为研究  

Research on Corrosion Behavior of 20 Steel under High Moisture Content and High Cl-Soil Environment in Coalbed Methane Field Production Platform

作　　者：赵学芬 张琛逸 蔡少辉 邱正阳 ZHAO Xuefen;ZHANG Chenyi;CAI Shaohui;QIU Zhengyang(College of Petroleum and Natural Gas Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;China Petroleum Western Drilling Engineering Co.,Ltd.,Yumen Drilling Branch,Jiuquan 735000,Gansu,China;Sinopec Linfen Coalbed Methane Branch,Linfen 041000,Shanxi,China)

机构地区：[1]重庆科技大学石油与天然气工程学院,重庆401331 [2]中国石油集团西部钻探工程有限公司玉门钻井分公司,甘肃酒泉735000 [3]中国石化临汾煤层气分公司,山西临汾041000

出　　处：《焊管》2025年第1期16-21,34,共7页Welded Pipe and Tube

基　　金：中国石油化工股份有限公司临汾煤层气分公司研究项目“延川南煤层气田井场埋地管道外腐蚀与防护”(项目编号ML-19-0094)。

摘　　要：为了探究煤层气排水采气平台埋地管道在采出水渗入管道埋设土壤时的腐蚀行为,采用现场长期埋设20钢腐蚀试片,利用SEM、EDS和XRD等方法分析20钢腐蚀形貌和腐蚀产物组成,并结合长期土壤电化学阻抗谱和极化曲线研究其在实际土壤样本中的腐蚀行为。结果表明,埋设75 d后20钢试片发生全面腐蚀,并伴随点状腐蚀;电化学研究进一步揭示了20钢在埋设初期发生氧去极化腐蚀,腐蚀过程主要受氧扩散控制;随着大量Cl~-透过疏松的腐蚀产物膜形成点蚀核,腐蚀发展为活化和扩散混合控制。因此,采出水溢出渗入地层会使20管线钢在氧去极化和Cl~-的酸化催化作用下由全面腐蚀逐渐发展成为点蚀,最终将导致穿孔泄漏。In order to study the corrosion mechanism of the buried pipeline in soil suffering from produced water flooding in the coalbed methane drainage and production platform,corrosion coupons of 20 steel were installed in-site of buried pipeline in the long term,and the corrosion profile and corrosion production were analyzed by means of SEM,EDS and XRD,and then the corrosion behavior of 20 steel was studied by combining with its long-term soil electrochemical impedance spectroscopy and polarization curve test in soil samples with 20%water content in the laboratory.The results showed that 20 steel exhibited general corrosion with pitting corrosion characteristicsafter being buried for 75 days;long term electro-chemical research further revealed that 20 steel undergoes oxygen polarization corrosion due to during the initial burial stage,and the corrosion process is controlled by oxygen diffusion.As a large amount of Cl-ions penetrated through the loose corrosion product film and formed the pitting nuclei,the corrosion process was controlled by the activation and the diffusion.Therefore,produced water flooding made 20 steel developing into the pitting corrosion from the general corrosion in the influence of the oxygen polarization and Cl-autocatalytic acidification effect,thereby evolving into the perforation and leakage of the pipeline.

关 键 词：20钢 埋地管道 土壤腐蚀 点蚀 腐蚀产物膜 

分 类 号：TG172.4[金属学及工艺—金属表面处理]