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TitrePermeability profiles in granular aquifers using flowmeters in direct-push wells
AuteurParadis, D; Lefebvre, R; Morin, R H; Gloaguen, E
SourceGround Water vol. 49, no. 4, 2011 p. 534-547,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20090447
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS-71.5000 -71.0000 46.7500 46.5000
Sujetsaquifères; eau souterraine; circulation des eaux souterraines; ressources en eau souterraine; régimes des eaux souterraines; perméabilité; conductivité hydraulique; analyses hydrauliques; puits; hydrogéologie
Illustrationslocation maps; tables; plots
ProgrammeGéoscience des eaux souterraines
Diffusé2010 09 28
Résumé(disponible en anglais seulement)
Numerical 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.