Hydrodynamic Adsorption of Cationic Polymer in Porous Media

Core flood experiments were carried out using unconsolidated SiC sand-packs at different injection rates under isothermal conditions. The thickness of adsorbed polymer layers could be calculated from the residual resistance factors measured in core flood experiments. The results show that adsorption of cationic polymers in porous media is affected mainly by electrostatic attraction and hydrodynamic forces. At low polymer injection rates, polymer adsorption is dominated by electrostatic forces, while it is dominated by hydrodynamic forces at higher polymer injection rates. The adsorbed layer thickness increases linearly from 290 to 1 510 nm with polymer injection rates. The adsorbed layer thickness is also affected by the brine injection rate in back-flush: high brine injection rate can increase the adsorption. Therefore, the adsorption of polymers can be improved using higher rates in squeezing both polymer and back-flush brine solutions, and so the water control efficiency.