延长气田新型缓蚀剂现场应用效果评价

Evaluation on field application effect of novel corrosion inhibitor in Yanchang gas field

为提高气井腐蚀防护效果,现场验证了一种新型缓蚀剂的缓蚀效果。选择4口实验井,优选加注方式、注入点及计算合适加注量,分别采用挂片失重分析、SEM、EDS及XRD等评价手段分析缓蚀剂的现场应用效果和缓蚀原理。结果表明,加注缓蚀剂后,不同材质实验井的缓蚀效率大都在80%以上,加注缓蚀剂对20^(#)钢的缓蚀性能与N80的接近,挂片表面均覆盖了一层较为致密、鳞次状明显的腐蚀产物且分布均匀,均优于对16Mn的缓蚀性能,缓蚀剂对实验井的选择性不明显;20^(#)钢与N80钢腐蚀产物中O元素以及Cl元素含量明显减少;16Mn钢腐蚀产物中O元素含量较高,存在明显的堆积现象,局部腐蚀较多,但蚀坑直径较小;腐蚀产物中垢样含量升高,腐蚀产物含量降低,表明缓蚀剂起到了较好的缓蚀效果。

In order to improve the corrosion protection effect of gas well,a novel corrosion inhibitor is verified on the spot.Four experimental wells are selected to optimize the injection modes and points,and calculate the appropriate injection volume.Hanger weight loss analysis,SEM,EDS and XRD are utilized to analyze the field application effect and corrosion inhibition principle.It is shown from the results that the corrosion inhibition efficiencies of experimental well with different materials are more than 80%after the injection of the novel corrosion inhibitor.The corrosion inhibition performance of the novel corrosion inhibitor to 20#steel is close to that to N80 steel,and the surface of the hangers is covered with a layer of compact and scale-like corrosion products.The corrosion inhibitor has no obvious selectivity to experimental wells.The contents of O element and Cl element in the corrosion products of 20^(#)steel and N80 steel are obviously reduced,while the content of O element in the corrosion products of 16 Mn steel is higher,there is obvious accumulation phenomenon,more local corrosion,but smaller corrosion pit diameter.Scale content in corrosion products increases,corrosion products content decreases,indicating the inhibitor has played a good corrosion inhibition effect.