含Cr材质在CO_2腐蚀环境中的腐蚀分析

雅克拉凝析气田具有高压力、高产量、高流速、CO2含量高、水和H2S含量低的＂四高两低＂特征,腐蚀介质非常复杂。气田开发以来,井下管柱和集输管道出现了严重的腐蚀。通过对13Cr材质在现场不同CO2腐蚀环境中的试验研究,验证了13Cr材质在CO2含量低的腐蚀环境中发生腐蚀较轻,随着CO2含量增加,13Cr材质腐蚀程度增加。模拟井下和集输管道两种CO2腐蚀环境,采用高温高压釜装置对不同Cr含量材质的腐蚀行为进行了试验研究,采用扫描电镜（SEM）、能谱分析（EDS）和X射线衍射（XRD）等方法对试样表面腐蚀产物的形貌及成分进行了分析。分析结果表明,22Cr和316L抗腐蚀性能优于3Cr和13Cr,并提出了适合雅克拉凝析气田井下和集输管道腐蚀治理的方向。

Analysis of Corrosion Behavior of Cr Steel in CO_2 Corrosive Environment

The media in Yakela Gas Field is characterized by high pressure,high throughput,high velocity,high CO2,low water and low H2S,and is very complex.Ever since the development of the gas field,the well tubes and gathering pipelines have corroded seriously.The tests of 13Cr steel in environments with different CO2 concentrations showed that the corrosion was little in low-CO2 environment.The corrosion became increasingly serious with increase of CO2 in service environment.The corrosion behavior of steel with different percentages of Cr was studied in the testes of simulated CO2 corrosive environments of gas well and gathering pipeline system on a HT and HP autoclave unit.The forms and compositions of corrosion products on sample surface were analyzed by scanning electron microscope（SEM,energy dispersion spectrum（EDS） and X-ray dispersion（XRD）,etc.The results indicate that the corrosion resistance of 22Cr and 316L steels is superior over that of 3Cr and 13Cr steels.The corrosion control applicable for Yakela Gas Field is proposed.