多元酸酸化技术在注水井中的应用

APPLICATION OF POLYHYDRIC ACID ACIDIFICATION TECHNOLOGY IN WATER INJECTION WELLS

针对塔里木油田注水井堵塞及欠注因素,使用盐酸混合多元酸酸化体系,新型缓速多元酸酸化体系作为主体酸,并使用主体酸与盐酸混合获得前置酸(土酸),确定了适合岩性段的储层特点的酸性液体体系,考察了不同影响因素下储层及注水井酸化情况。实验结果表明,多元酸缓速性能较强,溶蚀率符合酸化溶蚀规定,完整保留储层胶结物;0.25%~0.35%多氢酸酸化注水井溶蚀最好;该多元酸具有良好的二次抑制性能,实际应用工程中能够获得显著增注效果。

The causes of water injection well blockage and under-injection factors as well as the acidification technology were deeply analyzed.Therefore,the application of polyhydric acid acidification technology in water injection wells was proposed and studied.A new slow polyhydric acid acidification system(the main acid)using the mixture of hydrochloric acid and polyhydric acid was applied for acidification.Thus,the pre acid(earth acid)was obtained by mixing the main acid and hydrochloric acid.The acidic liquid system suitable for the lithological section reservoir was finally determined.The acidification of the reservoir and the water injection well under different influencing factors was also cearfully investigated.The experimental results show that the polyhydroacid has a strong retarding performance,and the dissolution rate meets acidification corrosion regulations,the reservoir cements are completely retained.The best dissolution in water injection wells is the acidification of polyhydric acid with a concentration range of 0.25%to 0.35%.The polyhydric acid also has good secondary inhibition performance and can obtain significant increased injection effect in direct application,