Impact of the Coupled Effect of Viscous Fingering and Subsurface Heterogeneity on Solute Transport
Abstract
Solute transport in geological media is affected by several factors. Most studies focus on the effect of hydraulic conductivity heterogeneity on solute mixing. On the other hand, other factors such as the viscosity contrast between the solute plume and the ambient fluid plays an important role too. In fact, it affects fundamental transport characteristics such as degree of mixing, spatial moments of the solute plume and arrival times. Although both these mixing mechanisms (field heterogeneity and viscous instability) had been acknowledged and studied, more investigations are needed in order to better characterize the effect of the variation of both the degree of viscous fingering and the variance of the log hydraulic conductivity on solute transport. This work aims to explore the impact of field heterogeneity and viscosity contrast on the statistics and fate of a solute plume being transported through a 2D domain. We develop a high-resolution numerical simulation framework based on the spectral method to solve coupled flow and transport equations governing the transport dynamics of a tracer slug for a range of viscosity contrast and log-conductivity variance. We analyze the degree and rate of mixing, macro-scale dispersion coefficient, contour length of the plume and arrival times at a control plane to characterize spreading and mixing in the domain. We find that the interplay between viscous fingering, high-permeability channeling, and low-permeability stagnation at small scales create non-trivial features in the spreading and mixing characteristics that can be used for predictive modeling of contaminant transport at larger scales.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H51R1734B
- Keywords:
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- 1829 Groundwater hydrology;
- HYDROLOGY;
- 1835 Hydrogeophysics;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY;
- 1869 Stochastic hydrology;
- HYDROLOGY