In order to solve the problems that the effectual time and effective features of polymer flooding in horizontal wells of oilfields developed directly after natural energy development are quite different from those of polymer flooding in high water-cut periods

a more efficient and convenient way to determine the effectual time of polymer flooding is proposed by production dynamic analysis

that is the change features of production capacity

water cut and submergence depth. Based on the effectual time

the production period after polymer injecting is divided into the induced effective period

the dominant effective period and the subsequent effective period

and the relation between the injected pore volume and the stage is established. Then

a study has been conducted to characterize the changes in injection pressure

injection capacity

oil production capacity and integrated water content at different injection pore volumes

and the purpose and main content of the on-site measures at each stage have been clarified. According to the reservoir conditions in the polymer flooding well area and the outstanding problems exposed during the polymer flooding process

the influence of these factors on the development effect of the polymer flooding well group is evaluated and the main factors affecting the development effect of the current polymer flooding well group is clarified. This research provides a reliable basis for the efficient management of the oilfield polymer flooding well group on-site

and clarifies the target well areas of the subsequent conversion well group.