Study on the Effect and Influencing Factors of Polymer Flooding Plugging Removal System in L Oilfield of Bohai Sea

Due to factors such as formation and injection technology, oil well clogging occurs in L oilfield of Bohai Sea, which seriously affects the normal production of oilfields. In order to relieve the blockage of oil well in L oilfield, this paper analyzes the blockage of oil well in L oilfield of Bohai Sea, and simulates the formation blockage by using the scale formed in the core of sand pipe filled with screen, and studies the effect of the blockage removal in L oilfield of Bohai Sea. The results show that the core permeability can be significantly reduced during polymer injection, and depolymerizer α can effectively remove polymer plugging. With the decrease of core permeability, the increase of depolymerizer slug size and injection speed, the plugging removal effect of depolymerizer α increases, and the recovery rate of core permeability can reach up to 44.2%. With the decrease of the amount of heavy components, the increase of the amount of organic solvent β and the increase of injection pressure, the plugging removal effect of organic solvent β increases, and the plugging removal rate can reach 75.00% ～ 97.67%. And the higher the injection pressures of the plugging remover, the better the plugging removal effect. This study is of great significance for the later development in L oilfield of Bohai Sea.