The effective conductivity of heterogeneous aquifers Kefu relates the mean flux to the mean head gradient in mean uniform (natural gradient) flow. While Kefu depends on the hydraulic conductivity K statistical moments (KG, the geometric mean and σY2, the logconductivity variance for a given structure model) it is not a local property for strongly nonuniform well flow. In hydraulic tomography, flow to a short well segment which is considered here, can be approximated by that toward a source in a three-dimensional heterogeneous medium. We investigate the equivalent conductivity Keq, which unlike Kefu, is a measurable property, directly related to the head H (or its mean) and the discharge. The dependence of Keq on K statistics and distance r from the source is determined for steady source flow in a formation of random stationary and statistically isotropic K. For the first time Keq is derived by numerical simulations for σY2≤ 4. The derivation of the transition of Keq from the local exact value for r/I < < 1 (I is the integral scale) to Kefu for r/I⪆1 is one of the main results of the study. Application to a synthetic example of hydraulic tomography to derive KG, σY2and I, from H measurements, demonstrates the promise of the method and calls for its further development and validation.

Equivalent and effective conductivities of heterogeneous aquifers for steady source flow, with illustration for hydraulic tomography / Bellin, Alberto; Fiori, Aldo; Dagan, Gedeon. - In: ADVANCES IN WATER RESOURCES. - ISSN 0309-1708. - ELETTRONICO. - 142:(2020), pp. 103632.1-103632.8. [10.1016/j.advwatres.2020.103632]

Equivalent and effective conductivities of heterogeneous aquifers for steady source flow, with illustration for hydraulic tomography

Bellin, Alberto;
2020-01-01

Abstract

The effective conductivity of heterogeneous aquifers Kefu relates the mean flux to the mean head gradient in mean uniform (natural gradient) flow. While Kefu depends on the hydraulic conductivity K statistical moments (KG, the geometric mean and σY2, the logconductivity variance for a given structure model) it is not a local property for strongly nonuniform well flow. In hydraulic tomography, flow to a short well segment which is considered here, can be approximated by that toward a source in a three-dimensional heterogeneous medium. We investigate the equivalent conductivity Keq, which unlike Kefu, is a measurable property, directly related to the head H (or its mean) and the discharge. The dependence of Keq on K statistics and distance r from the source is determined for steady source flow in a formation of random stationary and statistically isotropic K. For the first time Keq is derived by numerical simulations for σY2≤ 4. The derivation of the transition of Keq from the local exact value for r/I < < 1 (I is the integral scale) to Kefu for r/I⪆1 is one of the main results of the study. Application to a synthetic example of hydraulic tomography to derive KG, σY2and I, from H measurements, demonstrates the promise of the method and calls for its further development and validation.
2020
Bellin, Alberto; Fiori, Aldo; Dagan, Gedeon
Equivalent and effective conductivities of heterogeneous aquifers for steady source flow, with illustration for hydraulic tomography / Bellin, Alberto; Fiori, Aldo; Dagan, Gedeon. - In: ADVANCES IN WATER RESOURCES. - ISSN 0309-1708. - ELETTRONICO. - 142:(2020), pp. 103632.1-103632.8. [10.1016/j.advwatres.2020.103632]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/284105
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