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  • Non-monotonic permeability ...
    Chequer, L.; Russell, T.; Behr, A.; Genolet, L.; Kowollik, P.; Badalyan, A.; Zeinijahromi, A.; Bedrikovetsky, P.

    Journal of hydrology (Amsterdam), February 2018, 2018-02-00, Letnik: 557
    Journal Article

    Display omitted •Non-monotonic permeability variation during fines migration was observed.•Re-attachment of mobilised particles at high salinities is explained by DLVO theory.•The dependence of permeability on both attached and strained particle concentrations is assumed.•The model accounts for a delay in particle detachment during salinity alteration.•The derived model captures the observed effect of non-monotonic permeability. Permeability decline associated with the migration of natural reservoir fines impairs the well index of injection and production wells in aquifers and oilfields. In this study, we perform laboratory corefloods using aqueous solutions with different salinities in engineered rocks with different kaolinite content, yielding fines migration and permeability alteration. Unusual permeability growth has been observed at high salinities in rocks with low kaolinite concentrations. This has been attributed to permeability increase during particle detachment and re-attachment of already mobilised fines by electrostatic attraction to the rock in stagnant zones of the porous space. We refine the traditional model for fines migration by adding mathematical expressions for the particle re-attachment rate, particle detachment with delay relative to salinity decrease, and the attached-concentration-dependency of permeability. A one-dimensional flow problem that accounts for those three effects allows for an exact analytical solution. The modified model captures the observed effect of permeability increase at high water salinities in rocks with low kaolinite concentrations. The developed model matches the coreflooding data with high accuracy, and the obtained model coefficients vary within their usual intervals.