输油管道垢下腐蚀的电化学行为  

Electrochemical Behavior of Under-Deposit Corrosion of Oil Pipelines

作　　者：冉文燊 郑民君 王果 赵静 亢福 RAN Wenshen;ZHENG Minjun;WANG Guo;ZHAO Jing;KANG Fu(China Special Equipment Inspection&Research Institute,Beijing 100029,China;Surface Engineering Department of Yingmai Oil and Gas Production Management Zone of Tarim Oilfield,Korla 841000;China Special Inspection Pipeline Engineering(Beijing)Co.,Ltd.,Beijing 100013,China)

机构地区：[1]中国特种设备检测研究院,北京100029 [2]塔里木油田英买采油气管理区地面工程部,库尔勒841000 [3]中特检管道工程(北京)有限公司,北京100013

出　　处：《腐蚀与防护》2024年第4期33-38,共6页Corrosion & Protection

摘　　要：针对CO_(2)驱油气田的CaCO_(3)垢下腐蚀问题,用电化学试验、图像表征和腐蚀产物分析等方法研究了垢层厚度对输油管道用Q235b钢腐蚀行为的影响。结果表明:垢层对试样的腐蚀影响主要分为三个阶段:(1)垢层促进腐蚀性介质扩散,加剧基体腐蚀,导致基体蚀坑尺寸和最大蚀坑深度增大,开路电位迅速负向偏移;(2)垢层起到一定的物理屏蔽作用,蚀坑尺寸和最大蚀坑深度减小,蚀坑数量增多,开路电位基本保持不变;(3)垢层起到有效的物理屏蔽作用,垢层内外的氧浓差腐蚀导致蚀坑数量显著增多,开路电位缓慢负向偏移。垢层主要影响试样的阴极反应过程,随着垢层厚度继续增加,试样腐蚀加剧,腐蚀电流密度增大。Regarding the corrosion problem under CaCO_(3)scale in CO_(2)driven oil and gas fields,the influence of scale layer thickness on the corrosion behavior of Q235b steel used in oil pipelines was studied by electrochemical testing,image characterization,and corrosion product analysis methods.The results show that the corrosion effect of the scale layer on the sample could be mainly divided into three stages.(1)The scale layer promoted the diffusion of corrosive media,intensified substrate corrosion,and led to an increase in the size and maximum depth of substrate corrosion pits,manifested by a rapid negative shift in the open circuit potential.(2)The scale layer played a certain physical shielding role,reducing the size and maximum depth of corrosion pits,increasing the number of corrosion pits,manifested as the open circuit potential remaining basically unchanged.(3)The scale layer played an effective physical shielding role,and the oxygen concentration difference corrosion inside and outside the scale layer led to a significant increase in the number of corrosion pits,manifested as a slow negative shift in the open circuit potential.The scale layer mainly affected the cathodic reaction process of the sample.As the thickness of the scale layer increased,the corrosion of the sample intensified,manifested by an increase in corrosion current density.

关 键 词：输油管道 CO_(2)驱 CaCO_(3)垢 腐蚀演化 电化学 

分 类 号：TG174[金属学及工艺—金属表面处理]