Interpretation of transient borehole flow metering data in a fissured granite formation

Székely, Ferenc; Galsa, Attila

doi:10.1016/j.jhydrol.2005.11.033

Cited by 9 publications

(9 citation statements)

References 12 publications

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“…The flow rate occurring in the probe is calculated from the travel time of the heat impulse from the emitter to the sensors; the water flow outside the flowmeter is excluded by deformable rubber disks used as packers. To ensure high accuracy in the measurement, we applied the repeated point‐by‐point method with a resolution of 1 m (Sze´kely and Galsa ).…”

Section: Methodsmentioning

confidence: 99%

Efficiency verification of a horizontal flow barrier via flowmeter tests and multilevel sampling

Mastrocicco

Sbarbati

Colombani

et al. 2012

Hydrological Processes

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The remediation strategy for an industrial site located in a coastal area involves a pump and treat system and a horizontal flow barrier (HFB) penetrating the main aquifer. To validate the groundwater flow conceptual model and to verify the efficiency of the remediation systems, we carried out piezometric measurements, slug tests, pumping tests, flowmeter tests and multilevel sampling. Flowmeter tests are used to infer vertical groundwater flow directions, and base exchange index is used to infer horizontal flow directions at a metric scale. The selected wells are located both upstream and downstream of the HFB. The installation of the HFB produced constraints to the groundwater flow. A stagnant zone of contaminated freshwater floating over the salt wedge in the upper portion of the aquifer is detected downstream of the HFB. This study confirms that the adopted remediation system is efficiently working in the area upstream of the HFB and even downstream in the bottom part of the aquifer. At the same time, it has also confirmed that hot spots are still present in stagnant zones located downstream of the HFB in the upper part of the aquifer, requiring a different approach to accomplish remediation targets. The integrated approach for flow quantification used in this study allows to discriminate the direction and the magnitude of groundwater fluxes near an HFB in a coastal aquifer

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Section: Methodsmentioning

confidence: 99%

Efficiency verification of a horizontal flow barrier via flowmeter tests and multilevel sampling

Mastrocicco

Sbarbati

Colombani

et al. 2012

Hydrological Processes

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“…To ensure high accuracy in the measurement, the repeated point-by-point method has been applied with a vertical resolution of 1 m (Székely and Galsa 2006).…”

Section: Flow Meter Testsmentioning

confidence: 99%

Performance of different assessment methods to evaluate contaminant sources and fate in a coastal aquifer

Sbarbati

Colombani

Mastrocicco

et al. 2015

Environ Sci Pollut Res

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The present study deals with the application of different monitoring techniques and numerical models to characterize coastal aquifers affected by multiple sources of contamination. Specifically, equivalent freshwater heads in 243 monitoring wells were used to reconstruct the piezometric map of the studied aquifer; flow meter tests were carried out to infer vertical groundwater fluxes at selected wells; deuterium and oxygen isotopes were used to identify the groundwater origin, and tritium was analyzed to estimate the residence time; compound-specific isotope analyses and microbial analyses were employed to track different sources of contamination and their degradation; numerical modelling was used to estimate and verify groundwater flow direction and magnitude throughout the aquifer. The comparison of the information level for each technique allowed determining which of the applied approaches showed the best results to locate the possible sources and better understanding of the fate of the contaminants. This study reports a detailed site characterization process and outcomes for a coastal industrial site, where a comprehensive conceptual model of pollution and seawater intrusion has been built using different assessment methods. Information and results from this study encourages combining different methods for the design and implementation of the monitoring activities in real-life coastal contaminated sites in order to develop an appropriate strategy for control and remediation of the contamination.

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“…The WT is able to use an analytical technique based on the numerical Laplace inversion (Hemker 1999) and also a numerical technique which is a finite difference method improved by Székely and Galsa (2006). The wellbore simulator of the WT software includes the evaluation of the following effects: laminar and/or turbulent well-loss with depth and/or time variant parameters of the well screen; turbulent axial friction loss; a non-uniform static level in the screened model layers; induced flow-controlled drawdown in observation wells; and wellbore storage.…”

Section: Analytical and Numerical Wt Softwarementioning

confidence: 99%

“…Automatic parameter calibration may be carried out by fitting the simulated drawdown, recovery, flow metering and overflow data to the measured ones. The software has been successfully applied to the evaluation of field tests conducted in sedimentary aquifers (Székely 1992(Székely , 2012Mukhopadhyay et al 1994), fissured granite (Székely 2013;Székely and Galsa 2006) and in volcanic aquifers (Székely et al 2015), as well. Table 2 shows the comparison of the VTZ and the WT models.…”

Section: Analytical and Numerical Wt Softwarementioning

confidence: 99%

Revision of archive recovery tests using analytical and numerical methods on thermal water wells in sandstone and fractured carbonate aquifers in the vicinity of Budapest, Hungary

et al. 2020

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This study offers a reinterpretation of archive aquifer tests, predominantly on the basis of recovery data, from an original datasheet of thermal water wells located in carbonate and sandstone aquifer units in the vicinity of Budapest, Hungary. The study compares the hydraulic conductivity (K) and specific storage (S s) values derived in the first instance from an aquifer test evaluation. This included an initial application of the classical analytical Cooper and Jacob method. Subsequently, the visual two-zone (VTZ) numerical method was applied, then third, a more complex model, namely, WT software. It was found that the simple analytical solution is not able to represent the field conditions accurately, while in the course of the application of the VTZ model, it proved possible to alter the various hydraulic parameters within reasonable limits to fit the field data. In the case of the VTZ model, the researcher is required to calculate the accuracy of the fitted model separately, while with the WT model, this is automatic, the software seeks out the best fit. In addition to VTZ parameters, the WT model can efficiently incorporate data on up to 500 model layers, water level, and pressure. The optimization of the parameters may be achieved by automatic calibration, improving the accuracy of the numerical results. Recovery tests for 12 wells were numerically simulated to obtain values for vertical and horizontal hydraulic conductivity and specific storage for Triassic and Eocene fractured carbonate and the Upper-Miocene-Pliocene granular sandstone aquifer units. When an analytical solution is applied, only average values could be obtained. The conclusion reached was that the results of the analytical solution can be improved by the use of numerical methods. These methods are able to incorporate basic information on well design, aquifer material and the hydrogeological environment in the course of the evaluation. The revision of the archive recovery data using numerical methods may assist in the quest for better data for numerical flow and transport simulations without the need to perform new tests. In addition, the methods employed here can explain cases in which the original analytical interpretations proved unable to yield reliable data and predictions.

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Interpretation of transient borehole flow metering data in a fissured granite formation

Cited by 9 publications

References 12 publications

Efficiency verification of a horizontal flow barrier via flowmeter tests and multilevel sampling

Efficiency verification of a horizontal flow barrier via flowmeter tests and multilevel sampling

Performance of different assessment methods to evaluate contaminant sources and fate in a coastal aquifer

Revision of archive recovery tests using analytical and numerical methods on thermal water wells in sandstone and fractured carbonate aquifers in the vicinity of Budapest, Hungary

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