研究了一种适合砂岩地层深部酸化的以“酯+氟盐”自生得到的氢氟酸为主体酸的缓速酸液体系。自生HF的酸度特性曲线表明该缓速酸具有较强的缓冲性。不同甲酸甲酯/氟盐摩尔配比下的溶蚀实验确定了最佳甲酸甲酯/氟盐摩尔配比为2∶1，且在该比例下，通过调配盐酸的浓度配制出一种水解酯潜在缓速土酸：3%自生HF+10%盐酸。该潜在酸对选取的5号岩粉的溶蚀率由70℃时的20%增加到100℃时的33%，对7号岩粉的初始反应速率仅为常规土酸的一半，具有较好的温控溶蚀能力及缓速性能；对3种不同钻井液体系的溶蚀率均大于33%，对黏土矿物的溶蚀率均高于20%，具有解除钻井液及黏土矿物堵塞地层的能力；经潜在酸酸化后的岩心II的渗透率恢复为之前的4.01倍，达到常规土酸效果的2倍，具有良好的深部穿透的能力。%To resolve the problem of the high reaction rate and the short operating distance of mud acid, a kind of retarded acidizing lfuid, which is a kind of acid self-generated by ester and villiaumite, is studied in the article. Acidity characteristic curve of self-generated HF demonstrates that, the potential retarded acid based on hydrolytic ester presents better buffering effect. Dissolution experiment at different ratios of ester and villiaumite concludes that the best ratio of ester and villiaumite is 2∶1, and 3%self-generated HF acid with 10%hydrochloric acid is devised under the 2∶1 ratio of ester and villiaumite through many experiments. The dissolution rate of the acid system increases from 20%at 70℃to 33%at 100℃with NO.5 core, and its initial reaction rate is half of conventional mud acid with NO. 7 core at 80℃. It presents better temperature control capability and better dissolution inhibition capacity. It presents more than 33%dissolution rate to three kinds of mud lfuid and presents more than 20%dissolution rate to clay minerals, and presents stronger dissolution capability to slurry and clay mineral. The permeability of Core II that is acidized by potential acid is 4.01 times as large as before, which is 2 times effect of mud acid, and the potential acid presents better deep penetration capacity.
展开▼
