高岭石与碱性驱替剂反应实验研究

EXPERIMENTAL STUDY ON THE REACTION BETWEEN KAOLINIT AND ALKALINE FLOODING AGENTS

用聚四氟乙烯塑料反应器在25℃和45℃下,以20g/L的固液比,研究了高岭石与不同浓度NaOH或Na2CO3的溶蚀反应,反应时间为0～600h,用分光光度法测定反应后液相中硅、铝元素质量浓度,根据反应前后碱浓度的变化,计算反应绝对碱耗量;测定5.0%NaOH驱替过程中,高岭石填砂管渗透率和注入压力的变化。实验结果表明:高岭石在碱溶液中,通过扫描电镜能发现有明显溶蚀痕迹,在溶蚀反应前120h,溶液中硅、铝元素明显增加;相同温度下,高岭石在1.2%NaOH溶液中比5.0%Na2CO3溶液中碱耗量高;在碱驱过程中,渗透率上下波动,稳定后渗透率小幅下降。

Polytetrafluoroethylene Teflon inertia reactor is used,(under the conditions of 25℃ and 45℃,the 20g/L ratio of solid to liquid),to study the reaction between kaolin and NaOH and Na2CO3 alkaline flooding agents with different concentration,the duration of reaction is 0～600h,according to silicon and aluminum standard curve,the spectrophotometry is done to concentration parameters of silicon and aluminium in liquid phase after reaction,based on the variation of alkaline concentration before and after reaction,the absolute alkaline loss is calculated under different conditions,the variation of kaolinit sand-filling pipe permeability and inflow pressure is measured during the process of 5%NaOH solution flooding.Experimental result indicates kaolin dissolves in alkaline solution,under the electronic scanning microscope,apparent dissolution can be observed,in the first 120h while dissolution reacting,the aluminum and silicon ion concentration increases remarkably.Under the condition of same temperature,kaolin will consume more alkaline in 1.2% NaOH than in 5% Na2CO3.During the process of alkaline flooding,permeability,after fluctuating,will tend to stability,after stability,the migration of the new minerals derived from alkaline dissolving kaolin results in the decrease of permeability in sand-filling pipe.