油管钢在酸性模拟环境下耐腐蚀性能研究

Research on the corrosion-resistant performance of tubing steel in the acid simulation environment

结合实际井况,对抗硫管材在不同温度、不同H2S分压下的耐腐蚀性能进行了分析研究。采用扫描电子显微镜、电子能谱仪以及X射线衍射仪分别对材料的腐蚀形貌、平均腐蚀速率、腐蚀产物成分进行对比分析。结果表明,材料的腐蚀速率随着温度的升高先降低后稍有增大,说明温度是影响腐蚀性能的关键因素,直接影响气体H2S/CO2在溶液中的溶解度,从而影响腐蚀状况;在低温时抗硫管并没有显示耐蚀的优势。形貌物相分析表明,抗硫管材在150℃时产物膜均匀,膜层对深层腐蚀有阻碍作用,局部腐蚀不明显,相对低合金管材表现出耐腐蚀优势。低合金管材相对抗硫管腐蚀程度严重,不适宜在试验环境下应用。

In light of realistic well conditions, the corrosion-resistant performance of sulphate-resistant tubular goods was analyzed and studied in different temperatures and different H2S partial pressures. The high-temperature and high-pressure soaking method, scanning electron microscope, electron spectrometer and x-ray diffractometer were adopted to make a comparative analysis of the material’s corrosion morphology, average corrosion rate and corrosion product components. The result showed that, with the temperature rise, the material’s corrosion rate first decreased and then increased slightly, indicating that temperature was the key factor to affect the corrosion performance and that it directly affected the solubility of H2S/CO2 in the solution and therefore affected the corrosion condition. In a low temperature, the sulphate-resistant tubing did not show its strength of corrosion resistance. The morphological facies analysis showed that the sulphate-resistant tubular goods had an even product scale in 150 ℃, the scale layer produced a barrier to deep-layer corrosion, the local corrosion was not remarkable and tubular goods of relative low-alloy showed their strength of corrosion resistance. Low-alloy tubular goods had a more serious corrosion in comparison with the sulphate-resistant tubing and therefore they were unsuitable for the test environment.