The Impact of DNAPL Source-Zone Architecture on Contaminant Mass Flux and Plume Evolution in Heterogeneous Porous Media

2013 ◽  
Author(s):  
Mark L. Brusseau
Keyword(s):  
Porous Media ◽  
Mass Flux ◽  
Heterogeneous Porous Media ◽  
Source Zone ◽  
The Impact ◽  
Contaminant Mass Flux

The impact of heterogeneous anisotropy of porous media on density-driven convection

2019 ◽  
Vol 30 (2) ◽  
pp. 956-976
Author(s):  
Qian Li ◽  
Weihua Cai ◽  
Xiaojing Tang ◽  
Yicheng Chen ◽  
Bingxi Li ◽  
...  
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Pseudospectral Method ◽  
Heterogeneous Porous Media ◽  
Saline Aquifers ◽  
Anisotropic Permeability ◽  
Content Type ◽  
Monotonic Trend ◽  
The Impact

Purpose The aim of this study is to numerically simulate the density-driven convection in heterogeneous porous media associated with anisotropic permeability field, which is important to the safe and stable long term CO2 storage in laminar saline aquifers. Design/methodology/approach The study uses compact finite difference and the pseudospectral method to solve Darcy’s law. Findings The presence of heterogeneous anisotropy may result in non-monotonic trend of the breakthrough time and quantity of CO2 dissolved in the porous medium, which are important to the CO2 underground storage. Originality/value The manuscript numerically study the convective phenomena of mixture contained CO2 and brine. The phenomena are important to the process of CO2 enhanced oil recovery. Interesting qualitative patterns and quantitative trends are revealed in the manuscript.

scholarly journals Mixing-scale dependent dispersion for transport in heterogeneous flows

2015 ◽  
Vol 777 ◽  
pp. 178-195 ◽  
Author(s):  
Marco Dentz ◽  
Felipe P. J. de Barros
Keyword(s):  
Porous Media ◽  
Velocity Fluctuation ◽  
Heterogeneous Porous Media ◽  
Coarse Grained ◽  
Dispersion Effect ◽  
Dispersion Coefficients ◽  
Velocity Fluctuations ◽  
Heterogeneous Flow ◽  
Scalar Dispersion ◽  
The Impact

Dispersion quantifies the impact of subscale velocity fluctuations on the effective movement of particles and the evolution of scalar distributions in heterogeneous flows. Which fluctuation scales are represented by dispersion, and the very meaning of dispersion, depends on the definition of the subscale, or the corresponding coarse-graining scale. We study here the dispersion effect due to velocity fluctuations that are sampled on the homogenization scale of the scalar distribution. This homogenization scale is identified with the mixing scale, the characteristic length below which the scalar is well mixed. It evolves in time as a result of local-scale dispersion and the deformation of material fluid elements in the heterogeneous flow. The fluctuation scales below the mixing scale are equally accessible to all scalar particles, and thus contribute to enhanced scalar dispersion and mixing. We focus here on transport in steady spatially heterogeneous flow fields such as porous media flows. The dispersion effect is measured by mixing-scale dependent dispersion coefficients, which are defined through a filtering operation based on the evolving mixing scale. This renders the coarse-grained velocity as a function of time, which evolves as velocity fluctuation scales are assimilated by the expanding scalar. We study the behaviour of the mixing-scale dependent dispersion coefficients for transport in a random shear flow and in heterogeneous porous media. Using a stochastic modelling framework, we derive explicit expressions for their time behaviour. The dispersion coefficients evolve as the mixing scale scans through the pertinent velocity fluctuation scales, which reflects the fundamental role of the interaction of scalar and velocity fluctuation scales in solute mixing and dispersion.

scholarly journals Impact of Low- or High-Permeability Inclusion on Free Convection in a Porous Medium

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Min Yan ◽  
Chunhui Lu ◽  
Jie Yang ◽  
Yifan Xie ◽  
Jian Luo
Keyword(s):  
Porous Media ◽  
Free Convection ◽  
Solute Transport ◽  
Large Scale ◽  
Effective Area ◽  
Source Zone ◽  
Sensitivity Analyses ◽  
Low Permeability ◽  
High Permeability ◽  
The Impact

Density-driven free convection in porous media is highly affected by large-scale heterogeneity, typical of which are low- or high-permeability inclusions imbedded in homogeneous porous media. In this research, we applied the modified Elder problem to investigate the impact of low- or high-permeability inclusions on the migration of a dense, unstable salt plume. Sensitivity analyses were conducted in terms of the permeability contrast, the effective area (the area of the inclusion beneath the source zone), and the distance of the inclusion from the source zone, all of which were found to play a significant role in controlling the total mass flux released from the source into the media. Results show that (1) a high-permeability inclusion has stronger effects than low-permeability inclusion, due to significantly unbalanced solute distributions caused by accelerated solute transport, (2) the inclusion with a larger effective area has more potential to influence free convection, (3) free convection is more sensitive to the low-/high-permeability inclusion vertically closer to the source zone, and (4) free convection is more susceptible to the low-permeability inclusion horizontally closer to the source zone. For high-permeability inclusions, the inclusion horizontally closer to the source zone influences the transport process more significantly at the early stage, and conversely, the inclusion far from the source zone has a later impact. The results obtained could offer significant implications for understanding unstable density-driven flow and solute transport in porous media with structured heterogeneity.

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