Dual-Continuum Modeling of Contaminant Transport in Fractured Formations

Birkhölzer, Jens; Rouve, G.

doi:10.1007/978-94-010-9204-3_80

Cited by 7 publications

(13 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A variety of dual‐porosity (mobile‐immobile) approaches have been described in the literature, most of which with a focus on solute transport in fractured porous media. Respective models have been developed with simple first‐order transfer terms [e.g., Huyakorn et al , 1983a; Birkholzer and Rouve , 1994] or more complex higher‐order approaches, where local‐scale detailed descriptions of diffusive transport are employed in the immobile domain [e.g., Bibby , 1981; Huyakorn et al , 1983b, 1983c; Dykhuizen , 1990; Zimmerman et al , 1990, 1993; Birkholzer and Rouve , 1994]. Note that variations of dual‐porosity approaches have also been used to study solute‐transport problems in heterogeneous porous media bimodal permeability structures [e.g., Roth and Jury , 1993; Haggerty and Gorelick , 1995; Feehley et al , 2000; Flach et al , 2004].…”

Section: Introductionmentioning

confidence: 99%

Continuous time random walk analysis of solute transport in fractured porous media

Cortis

Birkhölzer

2008

Water Resources Research

View full text Add to dashboard Cite

[1] The objective of this work is to discuss solute transport phenomena in fractured porous media, where the macroscopic transport of contaminants in the highly permeable inter-connected fractures can be strongly affected by solute exchange with the porous rock matrix. We are interested in a wide range of rock types, with matrix hydraulic conductivities varying from almost impermeable (e.g., granites) to somewhat permeable (e.g., porous sandstones). In the first case, molecular diffusion is the only transport process causing the transfer of contaminants between the fractures and the matrix blocks. In the second case, additional solute transfer occurs as a result of a combination of advective and dispersive transport mechanisms, with considerable impact on the macroscopic transport behavior. We start our study by conducting numerical tracer experiments employing a discrete (microscopic) representation of fractures and matrix. Using the discrete simulations as a surrogate for the ''correct'' transport behavior, we then evaluate the accuracy of macroscopic (continuum) approaches in comparison with the discrete results. However, instead of using dual-continuum models, which are quite often used to account for this type of heterogeneity, we develop a macroscopic model based on the Continuous Time Random Walk (CTRW) framework, which characterizes the interaction between the fractured and porous rock domains by using a probability distribution function of residence times. A parametric study of how CTRW parameters evolve is presented, describing transport as a function of the hydraulic conductivity ratio between fractured and porous domains.

show abstract

Section: Introductionmentioning

confidence: 99%

Continuous time random walk analysis of solute transport in fractured porous media

Cortis

Birkhölzer

2008

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…The multi continuum approach requires a particular consideration of volume consistency, which is achieved by introducing relative reference volumes and . More details on the multi continuum modelling are given in References [5,6,8,9].…”

Section: Principle Of Multi Continuum Modellingmentioning

confidence: 99%

Sensitivities of flow and transport parameters in fractured porous media using automatic differentiation

Vogel

Vera-Bachmann

Hauschild

et al. 2005

Numerical Meth Engineering

View full text Add to dashboard Cite

SUMMARYThe hydraulic complexity of hardrock aquifers with, for example, fast fluid flow in fractures, storage effects in the rock matrix, high contrasts in permeability, and a high spatial variability of structures requires a high standard of experimental and numerical techniques. This paper focuses on the interpretation of tracer tests. The sensitivity of tracer breakthrough curves with respect to flow and transport parameters is analysed for different model types in order to identify the relevant flow and transport processes. This leads to a better understanding of the system behaviour and facilitates the interpretation of experimental results. The technique of automatic differentiation is used to evaluate the sensitivities. The main advantage of this technique is that the sensitivities are calculated without truncation error.

show abstract

“…Extensions of the classical dual-porosity concept have been developed to model solute transport in fractured porous media. Solute transport in the mobile domain is represented by an effective transport velocity and macrodispersivity, whereas solute diffusion between the immobile and mobile regions is approximated with first-order transfer terms [Huyakorn et al, 1983;Birkholzer and Rouve, 1994], higherorder transfer terms [Bibby, 1981;Dykhuizen, 1990;Zimmerman et al, 1990Zimmerman et al, , 1993Birkholzer and Rouve, 1994], multicontinuum models [Lichtner and Kang, 2007], linear Boltzmann transport equations [Benke and Painter, 2003;Painter and Cvetkovic, 2005], a distribution of transfer rates [Haggerty and Gorelick, 1995;Feehley et al, 2000;Flach et al, 2004;Berkowitz et al, 2008], or by using stochastic continua [Neuman, 1987;Birkholzer et al, 1999;Vesselinov et al, 2001;Ando et al, 2003;Neuman, 2005].…”

Section: Introductionmentioning

confidence: 99%

Upscaling solute transport in naturally fractured porous media with the continuous time random walk method

Geiger

Cortis

Birkhölzer

2010

Water Resources Research

View full text Add to dashboard Cite

[1] Solute transport in fractured porous media is typically "non-Fickian"; that is, it is characterized by early breakthrough and long tailing and by nonlinear growth of the Green function-centered second moment. This behavior is due to the effects of (1) multirate diffusion occurring between the highly permeable fracture network and the low-permeability rock matrix, (2) a wide range of advection rates in the fractures and, possibly, the matrix as well, and (3) a range of path lengths. As a consequence, prediction of solute transport processes at the macroscale represents a formidable challenge. Classical dual-porosity (or mobile-immobile) approaches in conjunction with an advection-dispersion equation and macroscopic dispersivity commonly fail to predict breakthrough of fractured porous media accurately. It was recently demonstrated that the continuous time random walk (CTRW) method can be used as a generalized upscaling approach. Here we extend this work and use results from high-resolution finite element-finite volume-based simulations of solute transport in an outcrop analogue of a naturally fractured reservoir to calibrate the CTRW method by extracting a distribution of retention times. This procedure allows us to predict breakthrough at other model locations accurately and to gain significant insight into the nature of the fracture-matrix interaction in naturally fractured porous reservoirs with geologically realistic fracture geometries.

show abstract

Dual-Continuum Modeling of Contaminant Transport in Fractured Formations

Cited by 7 publications

References 3 publications

Continuous time random walk analysis of solute transport in fractured porous media

Continuous time random walk analysis of solute transport in fractured porous media

Sensitivities of flow and transport parameters in fractured porous media using automatic differentiation

Upscaling solute transport in naturally fractured porous media with the continuous time random walk method

Contact Info

Product

Resources

About