用于集输管线的0.5Cr钢在模拟塔里木油田环境中的H_2S/CO_2腐蚀行为研究

Experimental study on corrosion behaviors of H_2S and CO_2 to 0.5 Cr steel used in gathering pipeline at simulated environment of Tarim Oilfield

运用腐蚀失重和四点弯曲实验,参照NACE0177-2005标准研究了用于集输管线的0.5Cr钢在模拟塔里木油田腐蚀环境中的H2S/CO2腐蚀行为。结果表明,0.5Cr钢在CO2腐蚀环境中具有极高的均匀腐蚀速率,H2S腐蚀性气体的存在显著降低了材料的均匀腐蚀速率。在CO2分压为2MPa、H2S分压为0.5MPa时,腐蚀速率仅为0.152 3mm/a,表现出良好的抗均匀腐蚀和局部腐蚀能力。在H2S和CO2共存的环境条件下,0.5Cr钢表面的腐蚀产物为FeS,未出现CO2腐蚀产物成分FeCO3。在该模拟条件下,H2S的腐蚀占主导作用。同时模拟油田工况条件的抗H2S应力腐蚀开裂实验表明,0.5Cr钢具有良好的抗H2S应力腐蚀开裂能力。

According to the NACE 0177-2005 standard,the corrosion behaviors of H2S and CO2 to 0.5Cr steel used in gathering pipeline at the simulated environment of Tarim Oilfield were studied with the mass loss and four-point bent test.The results showed that the 0.5Cr steel had very high uniform corrosion rate at CO2 corrosion environment,and the occurrence of H2S reduced the corrosion rate of 0.5Cr steel.The corrosion rate of 0.5Cr steel was only 0.152 3 mm per year,when the partial pressure of CO2 was 2 MPa and partial pressure of H2 S was 0.5 MPa. Under those conditions, 0.5Cr steel presented the superior uniform and local corrosion resistance. At the simulated CO2 and H2S coexistence environment, the corrosion product was FeS, and H2S electrochemical corrosion dominated the corrosion course of 0.5Cr steel. The test showed that 0. 5Cr steel had the favorable resistance to H2S stress corrosion cracking at the simulated environment.