Nonequilibrium effects in the filtration of viscoelastic liquids

Abstract

An experimental investigation was made of nonequilibrium effects with the filtration of viscoelastic petroleums and polymer solutions. A scheme is proposed to explain the effects obtained. A comparison between theoretical dependences and experimental data confirms the proposed scheme of the phenomenon. The filtration of viscoelastic liquids has recently attracted considerable attention. The interest in it is connected with the discovery of well-expressed elastic properties in several high-viscosity petroleums, as well as with the need to explain the laws governing the movement of solutions and polymer melts in a porous medium, with application to industrial chemical equipment and to the injection of polymer solutions into oil-bearing strata with the aim of increasing the yield of petroleum. Among articles devoted to the filtration of viscoelastic liquids, there should be mentioned the fundamental investigation of Marshall and Metzner [1], me theoretical article of Wissler [2], and me review of Savins [3]. Specifically, it is shown in [1] that, as a result of elastic effects, the filtration resistance in a steady-state flow rises in accordance with the relationship 1+A(ΤV/r)² where V is the filtration rate; r is the mean pore radius; Τ is the relaxation time; A is a constant on the order of magnitude of 10. In [1] this increase in the resistance is explained qualitatively by the action of specific, for elastic liquids, normal stresses in contracting and then expanding pore channels. A corresponding calculation (for a flat channel and a determined nonlinear model of a viscoelastic liquid) was made in [2] using the method of perturbation theory.