Research On Preparation And Profile Control Properties Of Large-scale Polymer Microspheres

As the long-term water injection and the in-layer and interlayer heterogeneity,the oil fields in our country are featured with low sweep efficiency and oil recovery when they enter inyo high or particularly high moisture period.Improving the sweep efficiency is an important method to enhance oil recovery.Firstly,according to the millimeter-scale characteristics of big channel in reservoirs and based on the synthesis theory of polymer microspheres,two kinds of large-scale polymer microspheres with different formula were prepared by dispersion polymerization.Secondly,via the characterization methods of polymer materials,the strcture and property of large-scale polymer microspheres.At last,using sand-packed model displacement experiment,the plugging and shunt properties of large-scale polymer microspheres were studied.The results show that polymer elastic microspheres have good sphericity and normal distribution of particle size.The temperature resistance is more than 90?,mineralization tolerance is more than 20000mg/L.It also has good elasticity,strength and stability.The swelling ratio under different conditions is between 1 and 4.The swelling ratio increases with the temperature and declines with the mineralization.Three-dimensional interpenetrating network of elastic microspheres are more flexibility,strength,temperature tolerance,salt resistance than single network elastic microspheres.The plugging behavior of the elastic microspheres shows that they have good capability of injection,injection pressure and resistance coefficient increased in a fluctuant way,and have high(residual)drag coefficient.And they can selectively plug the high permeable zone and improve the injection profile of non-homogeneous formation.After the profile control,permeability differential of the two pipes can be reduced from 6.91 to 1.62;the effect of adjusting reservoir diversion ability is significant.With the increase of concentration of microspheres,profile control balance time drop significantly,the efficiency of profile control is improved.