某油田地面集输管道用材腐蚀行为研究

Corrosion Behavior of Materials Used for Surface Gathering and Transportation Pipeline in an Oilfield

模拟油田现场腐蚀环境,利用高温高压实验设备辅以失重法研究了某油田地面集输管道正在使用中的管材20G钢、L245钢、5Cr钢、316L不锈钢和板材16Mn钢在不同温度和CO2分压下的腐蚀行为,并采用扫描电镜(SEM)、电子能谱(EDS)和X射线衍射(XRD)等方法对腐蚀产物的形貌及成分进行分析。结果表明:20G钢、L245钢、5Cr钢、16Mn钢和316L不锈钢均在温度一定的情况下,随CO2分压的增大,平均腐蚀速率先增大后减小;在CO2分压一定的情况下,平均腐蚀速率随温度的升高先增大后减小。在温度为80℃,CO2分压为0.5 MPa时,均达到最大平均腐蚀速率。20G钢、L245钢、5Cr钢和16Mn钢的腐蚀形貌为不均匀的全面腐蚀,腐蚀产物主要为FeCO3,316L不锈钢由于在腐蚀介质中发生钝化,腐蚀形貌为轻微的点蚀。

The corrosion behavior of 20G steel, L245 steel, 5Cr steel, 16Mn steel and 316L stainless steel in CO2 containing fluids at different temperatures and pressures was assessed by weight loss method via an autoclave, which aims to simulate the operating situation of the field. Then the morphology and composition of corrosion products were characterized by scanning electron microscopy(SEM), electronic energy spectrum(EDS) and X-ray diffraction(XRD). The results show that the average corrosion rate of 20G steel, L245 steel, 5Cr steel, 16Mn steel and 316L stainless steel increases first and then decreases with the increase of CO2 partial pressure at a given temperature, and with the increase of temperature by a given CO2 partial pressure respectively. The maximum average corrosion rate of the five materials emerged at 80 ℃ and 0.5 MPa of CO2 partial pressure. 20G steel, L245 steel, 5Cr steel and 16Mn steel were suffered from non-uniformly general corrosion with corrosion products composed mainly of FeCO3.Whilst 316L stainless steel was passivated with slight pitting corrosion in the corrosive medium.