江苏油田钻完井液对N80套管腐蚀研究

为查找中国石油化工股份有限公司江苏油田分公司油水井自由段套管腐蚀原因，开展了钻完井液对NS0套管腐蚀行为的实验研究。在分析江苏油田自由段所用套管的钢级、壁厚以及所处温度环境的基础上，实验评价了江苏油田常用钻完井液分别在40，50，60和70℃下，经过0．5，1，2，4和6个月对N80套管的腐蚀行为。研究结果表明：江苏油田常用钻完井液对N80套管的腐蚀行为以局部腐蚀为主，大多发生在饱和盐水钻完井液中；饱和盐水钻完井液的平均腐蚀速率大于淡水钻完井液中的腐蚀速率；目前常用淡水钻完井液中挂片平均腐蚀速率和最大腐蚀速率均在0．0502mm／a以下，表明淡水钻完井液对套管腐蚀的影响小。

Study of Corrosion of Drilling and Completion Fluids in Jiangsu Oilfield on N80 Steel Casing

The pilot study of corrosion behavior of drilling and completion fluids on NS0 easing was performed to find out the root corrosion causes of free casing of oil wells in Jiangsu Oil Field. On the basis of analysis of easing steel grade, thickness and service temperature in free section, the corrosion behaviors of drilling and completion fluids on NS0 casing were evaluated by the tests at 40, 50, 60 and 70 ℃ temperatures for 0.5, 1, 2, 3,4 and 6 months. The study results demonstrate that the corrosion of drilling and completion fluids on N80 casing in Jiangsu Oil Field is mainly local corrosion, which mostly occurs in saturated salty drilling and completion liquid. The average corrosion rate of saturated salty drilling and completion liquid is greater than that of clean water drilling and completion fluid. The average corrosion rate and maximum corrosion rate of test coupon in clean water drilling and completion fluid is lower than 0.0502 mm/a, which indicates that clean water drilling and completion fluid has little impact on the corrosion of casing.