为研究H2S-CO2共存环境下H2S含量对Q245R钢腐蚀行为的影响机制,通过模拟某油气田现场工况,利用高温高压釜设备开展不同PH2S下Q245R钢在H2S-CO2环境中腐蚀性能试验,并采用金相显微镜、XRD、SEM和EDS等手段来分析Q245R钢的点蚀、腐蚀形貌和腐蚀产物组成等.结果表明:随着PH2S由0.001 MPa增至0.11 MPa,Q245R钢均匀腐蚀速率增幅达196%,均匀腐蚀速率最大值为0.892 1 mm/a;腐蚀主控因素由CO2腐蚀(PH2S =0.001~0.05 MPa)转变为H2S腐蚀(PH2S =0.11 MPa),主要腐蚀产物由FeCO3转变为FeS.由于腐蚀产物膜中的裂纹与孔洞等腐蚀微观通道的增加,以及反应溶液流动产生的腐蚀介质扩散,Q245R钢的腐蚀不断加剧.
In order to investigate the effect of H2S content on the corrosion behavior of Q245R steel in H2S-CO2coexistence environment,the corrosion performance test of Q245R steel was carried out in H2S-CO2 environment under different PH2S by using high temperature and high pressure autoclave through simulating the corrosive environment of the selected oil field.The pitting corrosion,corrosion morphology and corrosion product composition of Q245R steel were analyzed by means of metallographic microscope,XRD,SEM and EDS.The results show that the average corrosion rate of Q245R steel has increased by 196%with the increase of PH2S from 0.001 MPa to 0.11 MPa,and the maximum average corrosion rate is 0.892 1 mm/a.The main corrosion controlling factor changes from CO2 corrosion(PH2S= 0.001~0.05 MPa)to H2S corrosion(PH2S =0.11 MPa),and the corresponding main corrosion product changes from FeCO3 to FeS.Due to the increase of corrosion micro-channels such as cracks and holes in the corrosion product film and the diffusion of corrosive media generated by the flow of the reaction solution,the corrosion of Q245R steel is gradually enhanced.