Migration Resistance Of Polymer Solution In Porous Media Force Influencing Factor

In the context of polymer drive,which is one of the leading technologies for recovery enhancement,scanning electron microscopy(SEM),dynamic light scattering,hysteresis and percolation simulation experiments are used to investigate the factors influencing the transport resistance of polymer solutions in porous media,starting from the relationship between the characteristic parameters of polymer molecular structure and its retention and transport in porous media.The results of scanning electron microscopy(SEM)and dynamic light scattering tests show that the polymer mesh structure in water becomes more compact and the hydrodynamic radius increases significantly with increasing polymer concentration;the apparent viscosity and relaxation time,which characterize the macroscopic rheology of polymer solutions,have a direct positive correlation with the polymer hydrodynamic radius.Polymer retention and transport experiments were carried out using nucleopore membranes,glass bead porous media and quartz sand porous media,and the pore aggregation ratio Rtp was used as a characterization parameter for the relative size of polymer hydrodynamic radius and pore throat radius.In nucleopore membranes with simple pore structure,the filterability of polymer solutions is mainly determined by their hydrodynamic radii;the larger the hydrodynamic radius of the polymer(the smaller the Rtp),the lower the filtration rate.In glass bead porous media with simple pore throat structure and negligible adsorption retention,the trapping retention of polymer increases monotonically with decreasing Rtp.In quartz sand porous media with complex pore throat structure,the polymer retention has the same characteristics as the glass bead model-monotonically decreasing with Rtp.Accordingly,it can be determined that the dominant polymer retention in porous media is trapping retention.The glass bead model and the quartz sand model were used to simulate the transport of polymer solutions in porous media.The experimental results show that the drag coefficient and residual drag coefficient of the polymer in the porous media model increase with decreasing pore aggregation ratio Rtp(increasing polymer hydrodynamic radius).The difference in retention in the two media is very small,It can be determined that this is mainly due to the increased pore throat plugging by the increased polymer trapping retention with increasing hydrodynamic radius.A comprehensive analysis of the experimental results in this thesis shows that the effect of increasing polymer hydrodynamic radius on the macroscopic rheology of the polymer solution as a continuous medium is manifested by enhanced viscosity and viscoelasticity;in the porous medium it is manifested by increased blockage of discrete polymer molecular clusters trapping retention at tiny throats,which is the key reason for the abnormally high transport resistance of the polymer solution in the porous medium.