Influencing factors for effective establishment of residual resistance factor of polymer solution in porous media

Exploring the influencing factors of establishing the residual resistance factor (RRF) of polymer solution is helpful to analyze the realization of effective mobility control in polymer flooding process and achieve the purpose of enhanced oil recovery (EOR). The rheological properties, viscoelasticity, hydrodynamic size, adsorption capacity and other solution properties of partially hydrolysed polyacrylamide and hydrophobically modified partially hydrolysed polyacrylamide were tested. The seepage law experiments under different displacement rates are carried out to study the ways and influencing factors of establishing the residual resistance factor of different types of polymer solutions. The results show that the dynamic adsorption retention of polymer HMPAM in 2000md rock core is 4 ~ 6 times that of polymer HPAM. The dynamic retention decreases with the increase of displacement speed. When the displacement rate of polymer solution increases from 0.1 mL·min −1 to 10 mL·min −1 , the residual resistance factor of polymer HMPAM decreases from 364.9 to 7.5, and the residual resistance factor of polymer HPAM decreases from 25.4 to 2.9. The greater the displacement rate, the more unfavorable it is for the polymer solution to establish a higher residual resistance factor. For polymers with different properties, structural polymers have stronger properties than linear polymers at low flow rate, so the structural polymers have higher residual resistance factor. Under the condition of high flow rate, the adsorption retention is reduced due to the scouring of aqueous solution. The linear polymer establishes the seepage resistance through high effective viscosity by increasing the elastic viscosity. The structural polymer still has a high residual resistance factor due to its large hydrodynamic size, so the corresponding seepage resistance can be established by relying on the residual resistance.