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

Flow Behavior through Porous Media and Displacement Performance of a SILICA/PAM Nanohybrid: Experimental and Numerical Simulation Study

“…For the HPAM solution, the RF gradually increases with the increase in shear rate, while the RRF slightly decreases and tends to balance. It has been previously reported that the increase in the injection rate of the polymer solution (shear rate) produces the elastic deformation of the polymer molecules by hydrodynamic forces, leading to an increase in the effective viscosity and the RF . In contrast, the increase in the injection rate of the chase water causes a reduction in the RRF due to the scouring of the retained polymer molecules in the porous media.…”

“…IPV and adsorption were calculated from eqs and . The shear rate (γ̇) in porous media was calculated from eqs and . , Finally, the effective viscosity of the polymer solution in porous media was determined from eq I P V = 1 − normalP V s e c o n d .25em p o l y m e r s .25em s l u g @ C C normalo = 0.5 a d s o r p t i o n = normalP V f i r s t .25em p o l y m e r .25em s l u g @ C C normalo = 0.5 − normalP V s e c …”

“… 64 , 65 Finally, the effective viscosity of the polymer solution in porous media was determined from eq 7 . 66 where C is the polymer concentration in the effluent, C o is the initial polymer concentration, Q is the flow rate (cm 3 /min), A is the surface flow area of the porous media (cm 2 ), ϕ is porosity (fraction), K is the absolute permeability (cm 2 ), R p is the porous radius (cm), α is the formation shape factor which is assumed 1 (dimensionless) for the sandstone plugs, μ eff is the effective viscosity of polymer (cP), and μ w is the viscosity of water (cP).…”

“…64,65 Finally, the effective viscosity of the polymer solution in porous media was determined from eq 7. 66…”

Effect of viscoelasticity on displacement processes in porous media

“…Although it is meanwhile a consolidated hypothesis that the improvements of the sweep efficiency by viscoelastic polymer flooding can be attributed to the elastic properties of such fluids, the underlying fundamental mechanisms remain obscure Urbissinova et al [29]; Clarke et al [30]; Rock et al [31]. Various displacement mechanisms were proposed in the literature including a strip-off of oil films attached to pore walls caused by an apparent slip length Beaumont et al [32]; Wei et al [33], reducing the effective permeability of porous media by polymer retention Ekanem et al [34]; Zhu et al [35], mobilization of oil entrapments by an apparent shear-thickening effect as a consequence of purely elastic instability Clarke et al [23]; Mitchell et al [24]; Xie et al [36]; Clarke et al [30]; Kawale et al [37]; Browne and Datta [38], as well as breakup, and pulling effects originating from normal stress differences that remove oil from dead ends Zhang et al [7]; Lima et al [39]; Wang et al [40]; Fan et al [41]. However, displacement processes in natural porous media might be affected by some if not by all the listed mechanisms, yet it remains an open question which mechanism prevails to (re-) mobilize capillary entrapments.…”