多氢酸对砂岩矿物的缓速性能分析

RETARD PERFORMANCE ANALYSIS OF MULTI-HYDRO ACID TO SANDSTONE MINERAL

迄今为止,砂岩酸化均采用含有HF的酸液体系。然而,HF与粘土矿物反应非常迅速,酸液大部分消耗在井筒附近,造成酸液穿透距离短,甚至还会产生二次沉淀,造成储层的永久性伤害。因此,对HF与砂岩酸化作用机理进行研究,优选酸液体系,降低酸与粘土矿物的反应速率,避免在施工中产生二次沉淀,改善酸化效果具有重要意义。文中以HF与砂岩主要成分铝硅酸盐的一、二次反应动力学为基础,进行了多氢酸酸液体系特性、多氢酸与砂岩矿物的溶蚀实验评价分析。分析研究表明,多氢酸酸液体系能长时间的维持HF处于低浓度状态;多氢酸与砂岩矿物的反应速率比较慢且产生二次沉淀的几率较小;对于高温砂岩储层和蒙脱石、高岭石与黑云母含量较高的储层推荐采用多氢酸进行酸化。

Up to now,acidization of sandstone reservoirs usually uses HF-based acid. However,HF acid reacts rapidly with clay mineral and the majority of acidizing fluids are consumed near the wellbore,which results the short acid penetration,the secondary precipitation damage and the perpetuity formation damage. So,the mechanism research on HF reaction with sandstone was carried out,the optimization of the acidizing fluid system,the reduction of the reaction rate on acid with clay,and the avoidance secondary deposition during treatment and so on,are important to improve the acid effect. Based on the primary reaction and the secondary reaction kinetics of HF and alumo silicate existent in sandstone,the characteristics of multi-hydro acid fluid system was analyzed and the denude test of multi-hydro acid with sandstone was evaluated. The results showed that the mulyi-hydro acid fluid system could maintain the HF in low concentration for a long time,the reaction rate of multi-hydro acid and sandstone was slow and the probability of the secondary precipitation was little. The multi-hydro acid was recommended to apply in the sandstones reservoir with high temperature and the high content of daunialite,kaolinite and biotite.