某油田使用的一条原油输送管线举升段短时间内多次发生泄漏, 经检查输送管泄漏部位腐蚀严重并伴有壁厚减薄。采用宏观分析、材质理化检验(包括化学成分分析、金相组织分析、力学性能分析)、电子显微分析、X射线衍射仪分析以及腐蚀模拟试验, 对发生泄漏失效的流体输送管进行分析。结果表明, 此流体输送管所输送的流体偏酸性并含有高矿化度的地层水, 由于管线跨越位置流体流速变化引发沉积结垢, 垢下的小阳极大阴极腐蚀原电池引发严重局部腐蚀, 并在固体颗粒物和砂砾的冲击下加速了管壁的腐蚀穿孔。

A crude oil pipeline used in an oilfield leaked many times in short time, serious corrosion and wall thickness decrease were observed near the leak position of the failed pipe. Failed pipe was checked and analyzed by macroscopic analysis, chemical composition test, metallurgical analysis, mechanical property test, SEM analysis, XRD analysis and corrosion simulation test. The results showed that the formation water mixed in the pipeline was acidic and contained high salinity. The flow rate of fluid changed in across position and resulted in scaling in pipeline, led to serious localized corrosion caused by small anode big cathode corrosion galvanic cell reaction under scaling, thus wall thickness decreased, at last pipeline leaked due to the impact of solid particles and grit.