牙哈YH301井油管腐蚀失效研究

通过理化性能检测评价和采用扫描电镜微观分析方法,对YH301天然气井油管公螺纹根部产生的腐蚀穿孔、公螺纹根部外表面产生的周向环状腐蚀沟槽和油管内外表面产生浅白色结垢层进行分析研究.结果表明,该油管的材质符合API相关标准;腐蚀穿孔首先是点状机械损伤,而后是由外向里引起的严重的局部腐蚀;周向环状腐蚀沟槽是接箍处缝隙腐蚀引起的;油管内的严重结垢是腐蚀穿孔后环空液进入油管内与气相中CO2作用所形成的;油管外表面的结垢是管内部分气相窜入管外与环空液作用所形成的;管体产生的腐蚀产物主要是FeCO2和Fe3O4.

Study on Corrosion Failure for Gas Well YH301

It has been studied that the corrosion perforation from the end of screw threads on the surface of the tubing, annularity corrosion slots at the end of screw threads and the layers of white solid sediments on the inner and outer surface of tubing have been found while repairing the gas well YH301 by physical and chemical inspection and means of SEM. The result shows that the material properties of this oil tube conform to API standard, the corrosion perforation initiated at dot mechanical damage where corroded locally from the outer to the inner; circumferential annularity corrosion slots came from crevice corrosion of couples; heavy solid sediments on the in ner surface of three oil tubes owe to aggradations of the reaction product of protective liquid entering the tube after perforation with COe in gas phase in the oil tubes. The corrosion product is mainly made of FeCO2 and Fe3O4.