Simulation of Hydraulic Heterogeneity and Upscaling Permeability and Dispersivity in Sandy-Clay Formationsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 15 августа 2019 г.
Аннотация:Abstract Since 1963, radioactive waste has been injected in deep artesian aquifers
of Cretaceous terrigenous deposits in western Siberia. It is well known that geologic
heterogeneity strongly affects contaminant transport in unconsolidated formations.
To predict the long-term migration of this radioactive waste the effective hydraulic
and macrodispersion parameters are estimated by using a three-dimensional highresolution
hydraulic heterogeneity model. The heterogeneous model of the injection
area is developed by applying transition probability geostatistics. This model is used
to simulate local steady-state groundwater flow and advective transport, leading to
numerical estimates of effective hydraulic conductivity and macrodispersion parameters.
Mean seepage velocities and effective longitudinal macrodispersion are calculated
from observed breakthrough curves for a conservative tracer. Results show that
mean horizontal lengths exceed vertical lengths by a factor of more than 30. As a
result, vertical effective hydraulic conductivity is two orders of magnitude less than
the horizontal effective conductivity. Observed breakthrough curves exhibit long tails
and appear to be non-Fickian. Estimated effective longitudinal macrodispersivity in
the vertical direction is one order of magnitude less than that in the horizontal direction.
Under a Fickian framework, this implies that dispersion modeling for regional
transport simulations requires an anisotropic-media dispersion model. First online: 28 March 2015