Borehole geophysical techniques to define stratigraphy, alteration and aquifers in basalt

Helm-Clark, C. M.; Rodgers, David W.; Smith, Richard P.

doi:10.1016/j.jappgeo.2003.06.003

Cited by 43 publications

(44 citation statements)

References 48 publications

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“…-Next, after collection of the diffusion samplers, profiles of temperature, conductivity, dissolved oxygen, pH and redox potential were established by a multiparameter probe (KLL-Q SEBA) before pumping. The temperature and conductivity may provide a good indication of the flow horizons and fractured zones (Mania et al, 1998;Helm-Clark et al, 2004). -Finally, a low-flow purging technique was applied; the pump was lowered into the well and the samples were taken every 5 m, once stability was attained.…”

Section: Methodsmentioning

confidence: 99%

Investigation of a chalk aquifer: advantages and limits of diffusion samplers and low-flow sampling techniques

Barrez¹,

Mania²,

Mansy³

et al. 2007

Hydrological Sciences Journal

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In order to estimate the vertical contaminant distributions in a chalk aquifer, two sampling techniques are used in the piezometers. The first is passive multi-level sampling, using dialysis membrane diffusion samplers. The second is the low-flow purging technique. Geochemical groundwater zones are also established by profiles of temperature, conductivity, dissolved oxygen, pH and redox potential. These sampling techniques enhance three-dimensional visualization of the chemical and physical parameters in the chalk aquifer. Except for the cases where there are large variations in the concentrations, these two methods provide approximately the same results. But these techniques should not be applied with the same aim. Dialysis membrane diffusion samplers preserve the weak chemical variations of an aquifer, but lead to mistakes in determining iron concentrations. Conversely, the lowflow rate technique preserves the iron concentration, but the depth resolution is weaker (on a scale much greater than 1 m) because pumping produces a mix of flow horizons.Key words chalk aquifer; groundwater sampling; dialysis membrane; hydrochemical stratification; low-flow sampling Investigations d'un aquifère de craie: avantages et limites des techniques d'échantillonnage bas débit et à base de cellules de dialyseRésumé Pour estimer les distributions verticales des contaminants dans un aquifère de craie, deux techniques d'échantillonnage en piézomètres sont utilisées. La première est un échantillonnage multiniveau passif, qui utilise les membranes de dialyse. La deuxième est la technique de purge bas débit. Les zonations hydro-géochimiques sont aussi établies par des profils de température, conductivité, oxygène dissous, pH et potentiel rédox. Ces techniques d'échantillonnage permettent d'améliorer la visualisation tri-dimensionnelle des paramètres chimiques et physiques de l'aquifère de craie. A l'exception des cas où de fortes variations de concentration existent, ces deux méthodes fournissent des résultats sensiblement équivalents. Mais ces techniques ne devraient pas être utilisées avec les mêmes objectifs. L'échantillonnage par dialyse permet de décrire les faibles variations chimiques d'un aquifère, mais conduit à des erreurs de mesure pour la concentration du fer. Inversement, la technique bas débit permet une mesure représentative du fer, mais le pompage provoque un mélange des horizons d'écoulement si bien que la précision des mesures suivant la profondeur est plus faible (à l'échelle de quelques mètres).

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Section: Methodsmentioning

confidence: 99%

Investigation of a chalk aquifer: advantages and limits of diffusion samplers and low-flow sampling techniques

Barrez¹,

Mania²,

Mansy³

et al. 2007

Hydrological Sciences Journal

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“…There are certainly viable means to explain the lower than average hydraulic conductivities observed for some wells in the study area. Mechanisms for lowering hydraulic conductivity include fine-grained sediment infiltration into fissures, a process that can be observed today on the surface of the Arco Rift at Dick's Fissure and has been documented in core from Well BG-77-1 (Helm-Clark, Rodgers, and Smith 2004). It also has been observed that some wells with low transmissivity effects have been completed with screened intervals placed against fine-grained sediments and cinders, both of which can clog screens.…”

Section: C-6mentioning

confidence: 97%

“…A lone dike will have no contrast on gravity, surface magnetic and aeromagnetic surveys, but it could be distinguished by the right combination of wireline logs. Assuming that a borehole intersected more than 2 m of a dike-the average minimum required to avoid resistivity inversion effects-the dike could be distinguished by a combination of resistivity ratios, high magnetic susceptibility due to lack of oxidized or glassy contacts (Helm-Clark, Rodgers, and Smith 2004), very low sonic travel time, high neutron flux, low gamma-gamma flux and no increase or decrease in the caliper log. The first two logging results are necessary and without them, the rest are not sufficient to identify a dike.…”

Section: C-4mentioning

confidence: 99%

“…Unfortunately, resistivity, velocity, and magnetic susceptibility are seldom collected in boreholes on the eastern Snake River Plain. Resistivity and sonic logs require the presence of water or a drilling fluid in the borehole but most INL boreholes are drilled using air rotary and usually do not penetrate into the aquifer more than ~30 m. Magnetic susceptibility is rarely used on the eastern Snake River Plain due to unfamiliarity and the difficulty of interpreting its results in basalt (Helm-Clark, Rodgers, and Smith 2004). So, while it is not really true that a buried dike lacks geophysical contrast, it is rare that the suite of data needed to identify a dike is collected.…”

Section: C-4mentioning

confidence: 99%

“…Juxtaposing screens and fine-grained materials may further compromise transmissivity, especially since well development is uncommon in the highly transmissive basalts of the INL. The presence of abundant fine-grained sediment in interflow zones, in discrete sedimentary interbeds b and in infiltrated fractures (Helm-Clark, Rodgers, and Smith 2004) are other conditions that can lower hydraulic conductivity.…”

Section: C-6mentioning

confidence: 99%

See 2 more Smart Citations

Development Report on the Idaho National Laboratory Sitewide Three-Dimensional Aquifer Model

Wood¹,

Helm-Clark²,

Huang³

et al. 2007

Self Cite

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A sub-regional scale, three-dimensional flow model of the Snake River Plain Aquifer was developed to support remediation decisions for Waste Area Group 10, Operable Unit 10-08 at the Idaho National Laboratory (INL) Site. This model has been calibrated primarily to water levels and secondarily to groundwater velocities interpreted from stable isotope disequilibrium studies and the movement of anthropogenic contaminants in the aquifer from facilities at the INL. The three-dimensional flow model described in this report is one step in the process of constructing a fully three-dimensional groundwater flow and contaminant transport model as prescribed in the Idaho National Engineering and Environmental Laboratory Operable Unit 10-08 Sitewide Groundwater Model Work Plan.An updated three-dimensional hydrogeologic conceptual model is presented along with the geologic basis for the conceptual model. Sediment-dominated three-dimensional volumes were used to represent the geology and constrain groundwater flow as part of the conceptual model. Hydrological, geochemical, and geological data were summarized and evaluated to infer aquifer behavior. A primary observation from development and evaluation of the conceptual model was that relative to flow on a regional scale, the aquifer can be treated with steady-state conditions. Boundary conditions developed for the three-dimensional flow model are presented along with inverse simulations that estimate parameterization of hydraulic conductivity. Inverse simulations were performed using the pilot-point method to estimate permeability distributions. Thermal modeling at the regional aquifer scale and at the sub-regional scale using the inverted permeabilities is presented to corroborate the results of the flow model.The results from the flow model show good agreement with simulated and observed water levels almost always within 1 meter. Simulated velocities show generally good agreement with some discrepancies in an interpreted low-velocity region near the toe of the Arco Hills. This discrepancy persisted in each of the aquifer bottom thickness scenarios that were simulated precluding decisions on which aquifer bottom thickness to use in transport simulations. When joint-calibration was performed using both water levels and velocities assigned as calibration targets, the discrepancy was prevented. This result highlighted the need to consider multiple calibration objectives and not rely solely on calibration to water levels.

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Analysis of hydrodynamic and hydrochemical behaviour of an aquifer using dialysis cells

Barrez

Mania²

2009

Hydrogeol J

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Borehole geophysical techniques to define stratigraphy, alteration and aquifers in basalt

Cited by 43 publications

References 48 publications

Investigation of a chalk aquifer: advantages and limits of diffusion samplers and low-flow sampling techniques

Investigation of a chalk aquifer: advantages and limits of diffusion samplers and low-flow sampling techniques

Development Report on the Idaho National Laboratory Sitewide Three-Dimensional Aquifer Model

Analysis of hydrodynamic and hydrochemical behaviour of an aquifer using dialysis cells

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