Polyester dendritic polymer as well as preparation method and application thereof

The invention discloses a polyester dendritic polymer as well as a preparation method and application thereof. The polyester dendritic polymer is obtained by polymerizing hydroxyl-terminated dendritic polyester and an alkenyl monomer, the hydroxyl-terminated dendritic polyester is obtained by carrying out esterification reaction on a compound containing more than two hydroxyl-terminated groups and carboxylic acid containing more than two hydroxyl-terminated groups; or the hydroxyl-terminated dendritic polyester is obtained by carrying out transesterification on a compound containing more than two hydroxyl-terminated groups and carboxylic ester containing more than two hydroxyl-terminated groups. The polyester dendritic polymer disclosed by the invention has excellent plugging and filtrate reducer performance, can effectively reduce the permeability of a mud cake while remarkably reducing the filtrate loss, can effectively plug microcracks of a well wall, and has dual effects of plugging and filtrate loss redu