抗硫油管与镍铬合金钢材料的电偶腐蚀研究

Research on Galvanic Corrosion on Sulfur Resistant Oil Pipeline and Ni-Cr Alloy Material

在川东北高酸性天然气田开发过程中,部分气井使用了718镍铬合金井下工具,与在用的普通抗硫油管之间可能发生电偶腐蚀。为进一步了解川东北高酸性天然气田普遍使用的VM80SS抗硫油管与718镍铬合金井下工具材料间电偶腐蚀的影响程度,以罗家11H井完井油管管串结构为例,进行了电偶腐蚀评价试验研究。结果表明,在井下环境VM80SS油管和718镍铬合金井下工具材料间存在发生电偶腐蚀的条件和可能性,阳极(VM80SS)面积越小,腐蚀率越大。罗家11H井完井管串中没有出现VM80SS/718面积比(1的情况,因此完井管串组合结构中的电偶腐蚀影响并不十分严重。

In Sichuan northeast high sour gas field development,718 Ni-Cr alloy was used for downhole components in some gas wells,which may result in galvanic corrosion on the existing general sulfur resistant oil pipeline in service.Take the Luojia 11H completion well tubing structure for example,the galvanic corrosion is test,studied and evaluated in order to find out the effect of galvanic corrosion on VM80SS/718 Ni-Cr alloy couple.The results show that the possibility and conditions of galvanic corrosion on VM80SS/718 Ni-Cr alloy couple exist in downhole environments.The corrosion rate increases if the anode(VM80SS) area becomes smaller.In this completion well,ratio of VM80SS/718 area is not less than 1,so the effect of galvanic corrosion on this completion well tubing structure is not serious.