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TitlePermeability profiles in granular aquifers using flowmeters in direct-push wells
AuthorParadis, D; Lefebvre, R; Morin, R H; Gloaguen, E
SourceGround Water vol. 49, no. 4, 2011 p. 534-547, https://doi.org/10.1111/j.1745-6584.2010.00761.x
Year2011
Alt SeriesEarth Sciences Sector, Contribution Series 20090447
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceQuebec
NTS21L/11
AreaSaint-Lambert
Lat/Long WENS-71.5000 -71.0000 46.7500 46.5000
Subjectshydrogeology; aquifers; groundwater; groundwater circulation; groundwater resources; groundwater regimes; permeability; hydraulic conductivity; hydraulic analyses; wells
Illustrationslocation maps; tables; plots
ProgramGroundwater Geoscience
AbstractNumerical hydrogeological models should ideally be based on the spatial distribution of hydraulic conductivity (K), a property rarely defined on the basis of sufficient data due to the lack of efficient characterization methods. Electromagnetic borehole flowmeter measurements during pumping in uncased wells can effectively provide a continuous vertical distribution of K in consolidated rocks. However, relatively few studies have used the flowmeter in screened wells penetrating unconsolidated aquifers, and tests conducted in gravel-packed wells have shown that flowmeter data may yield misleading results. This paper describes the practical application of flowmeter profiles in direct-push wells to measure K and delineate hydrofacies in heterogeneous unconsolidated aquifers having low-to-moderate K (10?6 to 10?4 m/s). The effect of direct-push well installation on K measurements in unconsolidated deposits is first assessed based on the previous work indicating that such installations minimize disturbance to the aquifer fabric. The installation and development of long-screen wells are then used in a case study validating K profiles from flowmeter tests at high-resolution intervals (15 cm) with K profiles derived from multilevel slug tests between packers at identical intervals. For 119 intervals tested in five different wells, the difference in log K values obtained from the two methods is consistently below 10%. Finally, a graphical approach to the interpretation of flowmeter profiles is proposed to delineate intervals corresponding to distinct hydrofacies, thus providing a method whereby both the scale and magnitude of K contrasts in heterogeneous unconsolidated aquifers may be represented.
GEOSCAN ID261788