Study On The Preparation And Performance Of Composite Aluminum Gel

Gel plugging agent is the most commonly used chemical plugging reagents for water plugging and profile control,which has the characteristics of low cost and strong plugging ability.However,the most widely used polyacrylamide crosslinked gel blocking agent has a higher raw material viscosity,which is difficult to meet the needs of site construction.In view of this,this paper found that aluminum gel is cheap,easy to inject,no pollution to the environment,it is worth studying for oil field plugging agent.In this paper,²⁷Al NMR nuclear magnetic method and Al-Ferron time-wise complex colorimetric method are used to determine the hydrolysis form of aluminum,and the gel forming mechanism of aluminum gel is clarified.Using the selected polyaluminum and urea as basic raw materials,the influence of polyaluminum chloride base degree,temperature and salinity on the gelling properties of aluminum gel is investigated.On this basis,gelation time,gelation strength and long-term stability are used as evaluation indicators,and the formulations of polyaluminum chloride at different temperatures are preferred.The experimental results found that the aluminum gel system has high gel strength and good stability at 70°C-90°C.However,the honeycomb shape of the system is obvious and the elasticity is poor.In order to improve the aluminum gel honeycomb morphology and poor elasticity and other shortcomings,cationic polymer and chromium acetate are added to the gel forming solution.The resulting composite gel system not only improves the viscoelasticity of the aluminum gel,but also further increases the gel strength.After investigating the influence of temperature,salinity and other factors on the properties of the composite gel,the formulation of the composite gel is optimized and its dynamic properties are evaluated.The evaluation shows that the optimum temperature of the composite gel is 70℃-90℃.At this temperature,the dehydration rate of the composite gel in 150 days is about 3%,and the stability is good.The viscosity of the gel-forming liquid is 32 m Pa·s,the plugging breakthrough pressure is 6.4MPa·m^-1,and the injection and plugging properties are good.