Abstract:

Polytetrafluoroethylene Teflon inertia reactor is used,(under the conditions of 25℃ and 45℃,the 20g/L ratio of solid to liquid),to study the reaction between kaolin and NaOH and Na^₂CO^₃alkaline flooding agents with different concentration,the duration of reaction is 0～600h,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 120h 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% Na^₂CO^₃.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.

Key words: kaolin, permeability, alkaline loss, silicon and aluminum ion concentrations, alkaline-rock reactions, formation damage