中性螯合体系对无机堵塞物的溶蚀机理及性能评价

Corrosion Mechanism and Performance Evaluation of Inorganic Blockage by Neutral Chelating System

屈鸣 侯吉瑞 吴伟鹏 王远征 肖立晓 赵宝顺 王恒

QU Ming HOU Jirui WUWeipeng WANG Yuanzheng XIAO Lixiao ZHAO Baoshun WANG Heng

碳酸盐岩油藏常规酸化技术在生产过程中易出现水锁、腐蚀管柱、井筒结垢等现象，导致储层受损，储层产 能降低。针对这一问题，以乙二胺四乙酸（EDTA）和聚丙烯酸（PAA）为主要成分，加入少量Na2SO3，经去离子水 融合过滤，120 ℃脱水研磨粉碎，500 ℃焙烧活化制得中性螯合体系，并对中性螯合体系的溶蚀性能进行评价。 结果表明，该体系对Ca2+无机堵塞物具有良好的溶蚀性，常温下24 h 内的溶蚀率可达95%；对N80 级钢材具有较 好的缓蚀性，在90 ℃下静置12 h 的腐蚀速率最大值为4.45 g/（m2·h）；对天然碳酸盐岩心的平均溶蚀率大于 70%。基于抑制金属离子二次沉淀、改善渗透率，中性螯合体系对油套管的腐蚀伤害较低，可清除地层内无机盐 垢，无需返排，不会对地层产生二次伤害，适用于清除含碳酸盐垢的油井。

Conventional acidizing techniques for carbonate reservoirs are prone to water lock，corrosion of tubular columns and wellbore scaling during production，resulting in reservoir damage and reduction of reservoir capacity. Aiming at this problem，the neutral chelating system was made by adding a small amount of Na2SO3 with ethylenediaminetetraacetic acid （EDTA） and polyacrylic acid（PAA）as the main components，fused and filtered by deionized water，ground and crushed by dehydration at 120 ℃ ，and activated by roasting at 500 ℃ . The dissolution and corrosion performance of the neutral chelating system was evaluated. The results showed that the system had good corrosion resistance to Ca2+ inorganic clogs，with the corrosion rate reaching 95% within 24 h at room temperature. It had good corrosion inhibition to N80 grade steel，with the maximum corrosion rate of 4.45 g/（m2·h）at 90 ℃ after 12 h standing. The average corrosion rate of natural carbonate cores was more than 70%. Based on the inhibition of secondary precipitation of metal ions and improvement of permeability，the neutral chelating system had low corrosion damage to oil casing and could remove inorganic salt scale in the formation without rejection，which would not cause secondary damage to the formation and was suitable for scaling removal of oil wells with mainly carbonate scale.

10.19346/j.cnki.1000-4092.2023.02.005