Field tracer experiment in a low permeability fractured medium: results from El Berrocal site

D’Alessandro, Marco; Mousty, F.; Bidoglio, G.; Guimerà, Jordi; Benet, I.; Sánchez-Vila, Xavier; Garcı́a-Gutiérrez, Miguel; Llano, Abel Yllera de

doi:10.1016/s0169-7722(96)00068-x

Cited by 18 publications

(7 citation statements)

References 3 publications

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“…Since longitudinal dispersivity is a one‐dimensional parameter, flow distance was chosen as an appropriate scale of measurement. For a laboratory experiment, flow distance was generally determined by measuring the length of the horizontally oriented core through which the tracer traveled (e.g., Schulze‐Makuch 1996); for a field tracer test, by determining the distance between the injection and the withdrawal well (e.g., D’Alessandro et al 1997); and for a computer simulation, by the horizontal flow distance between a ground water source and a sink. The scale for single‐well injection tests and packer tracer tests was obtained by determining the radius of influence, which was calculated from the volume of water introduced (i.e., discharge or injection rate multiplied by the time interval) by assuming cylindrical flow to the well screen or packed interval, respectively.…”

Section: Methodsmentioning

confidence: 99%

Longitudinal dispersivity data and implications for scaling behavior

2005

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Longitudinal dispersivity (alpha) data were compiled from 109 different authors for different types of geological media. The data were subdivided into different subsets. Dispersivity values for consolidated media were subdivided as basalts, granites, sandstones, and carbonate rocks, while unconsolidated sediments were subdivided into three reliability classes. The data sets provided here may provide ground water practitioners a preliminary guide to estimate dispersivity values at various scales and to guide and verify theories on scaling behavior. Based on the data set presented here, the relationship that empirically best described the dispersivity data in regard to scale of measurement was in the form of a power law. The scaling exponent for consolidated and unconsolidated geological media varied between 0.40 and 0.92, and 0.44 and 0.94, respectively. Higher reliability subsets of data for the unconsolidated sediments and more frequently tested rock formations indicate that the scaling exponent is at the lower end of the observed range, close to 0.5. No significant difference in scaling exponent was found among different media, and no clear evidence exists for the presence of an upper bound or asymptotic behavior on the relationship for any of the analyzed media.

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Section: Methodsmentioning

confidence: 99%

Longitudinal dispersivity data and implications for scaling behavior

2005

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“…Many in situ experiments using nonsorbing tracers have been performed in fractured rock [ Birgersson et al , 1992; D'Alessandro et al , 1997; Haggerty et al , 2001; Himmelsbach et al , 1998; Sawada et al , 2000; Karasaki et al , 2000]. Although in situ tests with nonsorbing tracers are important for characterizing transport properties of rock volumes, reliable quantification of retention properties generally requires sorbing tracers.…”

Section: Introductionmentioning

confidence: 99%

Sorbing tracer experiments in a crystalline rock fracture at Äspö (Sweden): 2. Transport model and effective parameter estimation

Cvetković

Cheng

Widestrand

et al. 2007

Water Resources Research

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[1] Transport and retention of sorbing tracers in a single, altered crystalline rock fracture on a 5 m scale is investigated. We evaluate the results of a comprehensive field study (referred to as Tracer Retention Understanding Experiments, first phase (TRUE-1)), at a 400 m depth of the Ä spö Hard Rock Laboratory (Sweden). A total of 16 breakthrough curves are analyzed, from three test configurations using six radioactive tracers with a broad range of sorption properties. A transport-retention model is proposed, and its applicability is assessed based on available data. We find that the conventional model with an asymptotic power law slope of À3/2 (one-dimensional diffusion into an unlimited rock matrix) is a reasonable approximation for the conditions of the TRUE-1 tests. Retention in the altered rock of the rim zone appears to be significantly stronger than implied by retention properties inferred from generic (unaltered) rock samples. The effective physical parameters which control retention (matrix porosity and retention aperture) are comparable for all three test configurations. The most plausible in situ (rim zone) porosity is in the range 1%-2%, which constrains the effective retention aperture to the range 0.2-0.7 mm. For all sorbing tracers the estimated in situ sorption coefficient appears to be larger by at least a factor of 10, compared to the value inferred from through-diffusion tests using unaltered rock samples.

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“…Depending on the scope of the study, conservative or reactive tracers are used. Conservative tracers do not interact with the surrounding geological material; they are inert [10][11][12][13][14]. The positron-emitting halide 18 F is widely used as conservative tracer in geochemical studies, but the chemical inertness of the tracers depends strongly on the boundary conditions and the studied substrate.…”

Section: Introduction 1motivationmentioning

confidence: 99%

Production and Processing of the Radionuclide 76Br

Franke,

Schöngart,

Mansel

2024

Instruments

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Four-dimensional visualization, i.e., three-dimensional space plus time, of fluid flow and its interactions in geological materials using positron emission tomography (PET) requires suitable radiotracers that exhibit the desired physicochemical interactions. 76Br is a likely candidate as a conservative tracer in these studies. [76Se]CoSe was produced and used as the target material for the production of 76Br via the (p,n) reaction at a Cyclone 18/9 cyclotron. 76Br was separated from the target by thermochromatographic distillation using a semi-automated system, combining a quartz glass apparatus with a synthesis module. 76Br was successfully produced at the cyclotron with a physical yield of 72 MBq/µAh (EOB). The total radiochemical yield of 76Br from the irradiated [76Se]CoSe target (EOS) was 68.6%. A total of 40 MBq–100 MBq n.c.a. 76Br were routinely prepared for PET experiments in 3 mL 20 mM Cl− solution. The spatial resolution of a PET scan with 76Br in geological materials was determined to be about 5 mm. The established procedure enables the routine investigation of hydrodynamics by PET techniques in geological materials that strongly sorb commonly used PET tracers such as 18F.

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Field tracer experiment in a low permeability fractured medium: results from El Berrocal site

Cited by 18 publications

References 3 publications

Longitudinal dispersivity data and implications for scaling behavior

Longitudinal dispersivity data and implications for scaling behavior

Sorbing tracer experiments in a crystalline rock fracture at Äspö (Sweden): 2. Transport model and effective parameter estimation

Production and Processing of the Radionuclide 76Br

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