Polymer microsphere for injection profile modification and preparation method thereof

The invention belongs to a chemical agent in the technical field of oilfield oil recovery, and particularly relates to a polymer microsphere for injection profile modification and a preparation method thereof. The polymer microsphere for injection profile modification is prepared from a water phase substance and an oil phase substance according to a certain mass ratio, and has the advantages of water swelling, small particle size, favorable salt resistance and high dispersion speed. A water solution of the polymer microsphere prepared by water injection is not swollen after being injected into the stratum for a certain time, and the polymer microsphere starts to be swollen along with the rise of temperature and mineralization degree, thus solving the problem of influencing the deep injection profile modification effect due to the fact that the polymer microsphere for injection profile modification is easy to accumulate in advance at a pore throat and the subsequent polymer microsphere is difficult to keep on