In order to quantitatively describe the changes of adsorption retention pore volume and Inaccessible pore volume in polymer flooding process, and provide an important basis for the optimization of Bohai J oilfield polymer flooding project, the experimental that research on polymer flooding and test of polymer output concentration is carried out according to the similarity principle, referring to the characteristic parameters of Bohai J oilfield. The experimental results show that there is preferably linear relationship between polymer solution concentration and absorbance， under the same concentration of injection polymer solution, the adsorption retention pore volume and inaccessible pore volume increase with decrease of core permeability， for the cores of same permeability, the adsorption retention pore volume and inaccessible pore volume increase with the increase of polymer injection concentration. The adsorption retention pore volume is about 0.04~0.02 PV and the inaccessible pore volume is about 0.12~0.22 PV of Bohai J oilfield.

As an important curve to understand the law of water flooding, the relationship between water cut and displacement multiples plays an important guiding role in understanding the rules of oilfield flooding, tapping the remaining oil and the law of water cut. However, during the experiment, due to the small size of core and high viscosity of crude oil and water, the accurate experimental data can not be obtained during the dry recovery period, the low water cut period or the middle water cut period, and the abnormal curve appears. The paper creatively establishes mathematical relation between water cut and displacement multiple, and corrects three kinds of abnormal curves of water cut and displacement multiple obtained from water flooding experiments in some heavy oilfields of Bohai Sea. According to the corrected curve, the water flooded map of M5⁃2 oilfield is drown up,which guides the remaining oil tapping the potential of the field.