X65 钢在CO2/油/水环境中的腐蚀特性试验

1. 长江大学石油工程学院;2. 中国石油大学(华东)储运与建筑工程学院

原油;集输管道;CO2 腐蚀;X65 钢;产物膜

Test on the corrosion behavior of X65 steel in the simulated CO2/oil/water environment
CHENG Yuanpeng1,2, BAI Yu1, ZHENG Dukui1, LI Zili2

1. College of Petroleum Engineering, Yangtze University;2. College of Pipeline and Civil Engineering, China University of Petroleum (East China)

crude oil, gathering pipeline, CO2 corrosion, X65 steel, corrosion scale

备注

为了更深入地了解实际集输管道中的CO2 腐蚀特性,通过高温高压动态腐蚀反应釜模拟油田集输管道的腐蚀环境,使用腐蚀失重、电子扫描显微镜、X 射线衍射及能谱分析等方法对X65 钢在CO2 /油/水环境中的腐蚀特性进行研究。结果 表明:当原油含水体积分数较低(40%~50%)时,原油的浸润作用使X65 钢表面发生均匀腐蚀,由于原油吸附的不均匀性引起局部点蚀;当原油含水体积分数为70%~80%时,原油对X65 钢表面的屏障作用减弱,生成的产物膜厚而疏松、局部脱落引发台地腐蚀;当原油含水体积分数为90%时,台地腐蚀进一步加剧,其破坏区域扩大,X65 钢腐蚀严重。原油的存在可改变腐蚀产物晶体颗粒大小、堆垛方式、产物膜结构及化学成分,从而起到一定的缓蚀作用,随着腐蚀环境中原油量的减少,其缓蚀作用逐渐减弱。(图5表4,参[24]

In order to deeply understand the corrosion behavior of CO2 in actual gathering pipelines, the corrosion environment of oilfield gathering pipeline was simulated using high temperature and high pressure dynamic corrosion reactor, and the corrosion behavior of X65 steel in CO2/oil/ water environment was investigated by means of mass loss method, scanning electron microscope, X-ray diffraction and energy spectroscopy analysis. It is shown that when the water cut of crude oil is lower (40%-50%), uniform corrosion occurs on the surface of X65 steel due to the sweating action of crude oil, but local pitting corrosion appears due to the inhomogeneous adsorption of crude oil. When the water cut is in the range of 70%-80%, the barrier effect of crude oil on the surface of X65 steel is weakened, the corrosion scales are thick and loose and partial loss of the corrosion products leads to mesa corrosion. When the water cut is up to 90%, the mesa corrosion is aggravated further, the damage area is enlarged and X65 steel is corroded seriously. The existence of crude oil can change crystal size, piling pattern, and structure and chemical composition of corrosion scale, so as to play a certain role in corrosion inhibition. With the decrease of crude oil in the corrosion environment, its corrosion inhibition effect gets weak gradually. (5 Figures, 4 Tables, 24 References)