渤海海上油田修井液腐蚀机理分析及防护

Corrosion Mechanism Analysis and Protection of Workover Fluid in Bohai Offshore Oilfield

渤海海上油田现场作业中采用不同类型的修井液,为了解不同类型地热水、修井液和压井液对管柱的腐蚀情况,实验评价了不同类型修井液在60℃时对N80钢的腐蚀情况。实验发现,渤海L油田常用的修井液对N80钢的腐蚀速率均较高,腐蚀速率均高于行标中要求的≤0.076 mm/a;HCOONa压井液腐蚀速率最高可达0.45 mm/a左右。针对渤海海上油田修井液的腐蚀现状,当井筒完整性保护工作液加量增加至4.0%以上时,可将所有类型修井液的腐蚀速率控制在0.076 mm/a以下,腐蚀防护效果明显。

Different types of workover fluids are used in the field work of Bohai offshore oilfield.In order to understand the corrosion of different types of geothermal water,workover fluid and killing fluid to the string,the corrosion of N80 steel by different types of workover fluid at 60℃are evaluated.It is found that the corrosion rate of N80 steel by workover fluid commonly used in Bohai L oilfield is higher than 0.076mm/a which is required in the standard,and the corrosion rate of HCOONa kill fluid is high up to about 0.45mm/a.According to the corrosion status of workover fluid in Bohai offshore oilfield,when the amount of workover fluid for wellbore integrity protection is increased to more than 4.0%,the corrosion rate of all types of workover fluids can be controlled below 0.076mm/a,showing a good corrosion protection effect.