摘要
现有酸液体系以液体盐酸为主剂,在存放、运输和使用过程中存在设备成本高、安全风险大、酸岩反应速率快、高腐蚀、高污染的问题.基于一种无毒的有机酸酐得到一种耐高温且环保的固体自生酸SGA,其在180℃下的最高生酸浓度和生酸时间分别为17.10％盐酸当量和120 min.通过添加其他助剂进行复配得到一种耐超高温固体自生酸体系,并系统研究其性能.优选的自生酸体系为30％固体酸+3％～5％缓蚀剂+0.5％铁离子稳定剂+0.5％助排剂+0.6％胶凝剂.180℃下,高压动态平均腐蚀速率仅为78.36 g/(m2·h),远低于标准值[80 g/(m2·h)];残酸表面张力较低且无生物毒性;酸岩反应速率为-1.49×10-4 mol/(s·cm2),远远小于常规酸液体系的反应速率.该耐超高温固体自生酸具有生酸浓度高、耐高温、低腐蚀、缓速效果好的优点,适用于180℃以上深层、超深层碳酸盐岩储层的酸化改造.
Abstract
The existing acid system,which mainly takes liquid hydrochloric acid as main agent,has the problems such as high equipment cost,high risk,fast reaction rate between acid and rock,high corrosion and high pollution during the storage,transportation and usage processes.SGA,a high-temperature resistant and environmentally friendly solid self-generated acid,is obtained on the basis of a kind of non-toxic organic anhydride,and its maximum acid concentration and acid generation time at 180℃ are 17.10％hydrochloric acid equivalent and 120 min,respectively.An ultra-high temperature resistant solid autogenous acid system is obtained by adding other additives for compounding SGA,and its performance is systematically studied.The preferred autogenous acid system contains 30％solid acid,3％-5％corrosion inhibitor,0.5％iron ion stabilizer,0.5％co-discharging agent,and 0.6％gelling agent.Under 180℃,the high-pressure dynamic average corrosion rate is only 78.36 g/(m2·h),much lower than the standard value[80g/(m2·h)].The residual acid has a low surface tension and no biotoxicity.The acid-rock reaction rate is-1.49×10-4 mol/(s·cm2),which is much smaller than that of conventional acid-liquid system.This ultra-high temperature resistant solid autogenous acid system has the advantages such as high acid concentration,high temperature resistance,low corrosion,and good retardation effect,and it is suitable for acidizing and reforming deep or ultra-deep carbonate reservoirs above 180℃.
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