1Cr钢在含CO_(2)井筒环境中的腐蚀行为与耐蚀性

Corrosion Behavior and Corrosion Resistance of 1Cr Steel in CO_(2)-Containing Wellbore Environment

通过动态腐蚀试验,对比研究了两种套管钢(1Cr和N80)在不同温度地层水中的腐蚀行为。采用扫描电子显微镜(SEM)、能谱仪(EDS)和激光共聚焦显微镜(CLSM)对不同条件下套管钢的腐蚀特征进行了详细的表征。结果显示:在中温较低CO_(2)分压下(50℃,0.30 MPa),与1Cr钢比,N80钢的腐蚀速率大且点蚀程度严重;在较高温(100、114℃)较高CO_(2)分压(0.63、0.73 MPa)下,1Cr钢的腐蚀速率约为N80钢的3倍,呈现出严重的台地状腐蚀,N80钢则由于成膜优势,平均腐蚀速率较低,基体无明显点蚀特征。产物膜的组成及理化特性对套管钢的腐蚀行为产生了重要影响。1Cr钢在井筒浅部环境中具有优越性能;然而,在井筒深部不推荐使用该钢材,需要谨慎选择适当的材料。

The corrosion behavior of two types of casing steel(1Cr and N80)in formation water at different temperatures was compared and studied through dynamic corrosion tests.The corrosion features under different conditions were characterized in detail using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and confocal laser microscopy(CLSM).The results show that at medium temperature and low CO_(2) partial pressure(50℃,0.30 MPa),N80 steel had a higher corrosion rate and more severe pitting corrosion compared with 1Cr steel.At higher temperatures(100,114℃)and CO_(2) partial pressures(0.63,0.73 MPa),the corrosion rate of 1Cr steel was about three times that of N80 steel,showing severe mesa corrosion,while the lower average corrosion rate of N80 steel was low due to its film-forming advantage,and the substrate had no obvious pitting characteristics.The composition and physicochemical properties of the product film have a significant impact on the corrosion behavior of casing steel.1Cr steel exhibits superior performance under the environment of shallow wellbore.However,it is not recommended to use this steel in the deep wellbore,and appropriate materials need to be carefully selected.