砂岩储层酸化自转向酸研究与应用

ResearchandApplicationofSelf-DivertingMudAcidinSandstoneReserviorAcidizing

王世彬 王浩儒 郭建春 赖杰

WANG Shibin ，WANG Haoru，GUO Jianchun ，LAI Jie

利用一种长链甜菜碱表面活性剂在酸液中的聚集形态变化，形成了以土酸为主体酸的自转向酸体系：15%HCl+3% HF+ 4% 转向剂+ 1% 缓蚀剂+ 0.5% 铁离子稳定剂。该体系在酸化改造过程中不需要大量钙镁离子的“交联”作用，仅依靠自身聚集形态随酸浓度的变化即可增黏，胶束平均水合直径最大可达330.5 nm，酸液黏度最大 可达180 mPa·s，能有效实现砂泥岩储层暂堵转向酸化的目的。体系缓速性能出色，酸岩反应20min后，含转向剂的土酸酸液溶蚀率仅为13% ，并且具有良好的耐高温流变性，在90℃下剪切90min后的黏度依然保持在60mPa·s 以上。自转向酸残酸凝胶与地层原油接触120 min后，酸液黏度降至10mPa·s 左右，能加快残酸返排。现场试验表明，自转向土酸酸液体系在砂岩储层增产效果明显。图6 参12

Based on the morphological change of surfactant aggregates in acid，self-diverting mud acid was formed and evaluated，which included15% HCl ，3% HF，4% diverting agent，1% corrosion inhibitor and 0.5% iron ion stabilizer. The system did not require a lot of calcium and magnesium ions in the acidification process to increase the acid viscosity and could only rely on their own aggregation morphology changes ，which effectively achieved the purpose of solution acid temporary diverting in sand and shale reservoirs. The system exhibited a maximum viscosity of 180 mPa·s and a maximum hydrodynamic diameter of 330.5 nm in average of micelle aggregate. This system had a good performance on reaction retardation ，indicated by only 13% dissolution rate after 20min in the acid-rock reaction. The system could endure high temperature ，which viscosity remained more than 60mPa·s after shearing 90min at 90℃. In addition ，this acid system had a good rheological behavior at high temperature and could degrade quickly with a viscosity of 10mPa·s when contacted with crude oil after 120 min. Field tests showed that acidification using self-diverting mud acid achieved remarkable effect.