Method for reducing adsorbance of polymers for displacement of reservoir oil in oil field

The invention relates to a method for reducing adsorbance of polymers for displacement of reservoir oil in an oil field. The method comprises the steps of injecting cetyl trimethyl ammonium bromide (CTAB) aqueous solution into an injection well to serve as a pre-slug, then injecting hydrophobic associated polymers for polymer flooding, and finally conducting water flooding. A sacrificial agent adopted is the cationic surface active agent CTAB. Due to the fact that CTAB contains cationic groups, strong adsorption can be generated between CTAB and electronegative reservoir minerals. Meanwhile, electrostatic exclution can be generated between CTAB and the cationic hydrophobic group of hydrophobic associated polymers so as to weaken the interaction between CTAB and polymers, and finally polymers are isolated from a reservoir stratum and adsorbance of polymers in the immediate vicinity of a wellbore is reduced. Furthermore, polymer using cost is reduced, the adopted sacrificial agent is well compatible with formation water and polymers, and the method can be widely applied to the oil displacing process relevant to oil field polymers to reduce adsorbance of polymers in the immediate vicinity of a wellbore.