稠油热采管BG90H钢在不同条件下的腐蚀行为

通过干空气和湿空气以及在H_2S和CO_2共存条件下腐蚀试验模拟油田现场稠油热采的过程,研究了稠油热采管BG90H钢在不同条件下的腐蚀行为。结果表明:BG90H钢在干空气中的均匀腐蚀速率小于在湿空气中的均匀腐蚀速率,在湿空气中材料出现局部腐蚀(点蚀);湿空气中水蒸气含量大,在金属材料表面结露、均匀成膜,且供氧充分,使BG90H钢的吸氧腐蚀速率显著上升,由于完整液膜下试样表面腐蚀原电池数量的显著增多,材料点蚀程度显著增强。在CO_2和H_2S共存腐蚀条件下,腐蚀速率在120℃出现最大值,此时金属表面上生成一层疏松的、多孔且较厚的腐蚀产物膜;当温度在100~120℃及大于180℃时,局部腐蚀较为严重,但在150~180℃时,局部腐蚀轻微;腐蚀过程由CO_2/H_2S联合交替控制。

Corrosion Behavior of BG90H Heavy Oil Thermal Recovery Tube under Different Corrosion Conditions

By simulating the process of heavy oil thermal recovery with dry air corrosion,wet air corrosion and corrosion in H2S and CO2 concomitant environment,the corrosion behavior of thermal recovery of heavy oil tube of BG90H steel was investigated.The results show that the uniform corrosion rate of BG90H steel in dry air was less than that in wet air,and the localized corrosion (pitting corrosion) appeared obviously in humid air.Wet air is rich in water vapor which leads to dew formation and uniform film on the surface of metal material.And with enough oxygen,a significant increase of oxygen absorption corrosion on BG90H steel was obviously observed.Since the increasr of the number of corrosion cells on the surface beneath the complete liquid membrane,the pitting corrosion was evidently worsening.In the H2S and CO2 concomitant environment,the maximum corrosion rate appeared at 120 ℃ and the corrosion product film was loose,porous and thick.The localized corrosion was more serious at the temperatures of 100-120 ℃ and higher than 180 ℃,but slight at 150-180 ℃.The corrosion process was controlled alternatively by CO2 and H2S.