Miscible Flooding of Polymeric Solution in Porous Media of Double Porosity

摘要

With the aim of study possible mechanical trappingrnphenomena and adsorption in a double porosity medium wernperformed two types of experiments:rn1) A saline polymer solution which initially saturates a porousrnmedium is displaced with another polymer solution with arndifferent salt concentration (conductivity measurement). Inrnboth solutions the polymer used is scleroglucane.rn2) A flow of a saline solution into a polymer solutionrn(scleroglucane), which initially saturates the porous media ofrndouble porosity (conductivity measurement). At the samerntime, a flow of a polymer solution marked with a radioactiverntracer (gamma emitter) is performed and its displacement canrnbe followed externally to the medium. In both cases, therndispersion profile at the outlet and at each position along thernmedium are analyzed. The polymer solution rheology wasrncarefully controlled: it is a shear thinning fluid with n=0.6,rnwhile ensuring the absence of microgels in the solution.rnThe porous medium was prepared with an homogeneous poralrnsize distribution, with grains of 500 micrometers diameter andrnan internal porosity of 30 percent, obtained by grindingrnsintered glass beads. The experiments were performed withrnthe medium in vertical position.rnThe first results suggest that the saline solution explores all thernporal structure while it is possible that the macromolecules ofrnthe polymer solution cannot penetrate into the small pores.rnWith these experiments we expect to obtain information aboutrnthe presence of heterogeneities in the bed. However, thisrninformation was obtained only in those cases where we changernthe concentration of the polymer solutions. Finally, we canrnobserve a retention phenomenon, whose interpretation is stillrncontrovertible.