RESEARCH AND APPLICATION OF FRACTURING FLUID SYSTEM WITH LOW CONCENTRATION

Jelly system of polymer fracturing fluid can cause reservoir damage, decreasing polymer concentration can eliminate the damage during fracturing operation, but the viscoelasticity of jelly system is reduced to cause proppant sedimantary decrease, therefore, it is important to research and optimize low concentration fracturing fluid system suited for solid-carrying requirements. By means of test methods, the thickener, cross linking agent and gel breaker of low concentration fracturing fluid were researched, and its temperature resistancy, anti-sheafing performance, rheological behavior, solid-carrying behavior, gel breaker performance, low damage behavior, anti -expansion performance and filtration performance were evaluated.Test results showed low fracturing fluid concentration was half of conventional fracturing fluid concentration, it could meet solid-carrying requirements in fracturing operation, temperature resistance and anti-sheafing performance were higher than cleaning fracturing fluid and conventional polymer fracturing fluid, the level of residue in bottom hole decreased obviously after gelout, and reservoir damage degree was decreased. It is a perfect environmental protection low damage fracturing fluid.