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A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test

Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic
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Water 2020, 12(3), 744; https://doi.org/10.3390/w12030744
Received: 16 January 2020 / Revised: 21 February 2020 / Accepted: 28 February 2020 / Published: 8 March 2020
(This article belongs to the Section Hydrology)
This study analyzes the unsteady groundwater flow to a real well (with wellbore storage and the skin effect) that fully penetrates the confined aquifer. The well is located within an infinite system, so the effect of boundaries is not considered. The Laplace-domain solution for a partial differential equation is used to describe the unsteady radial flow to a well. The real space solution is obtained by means of the numerical inversion of the Laplace transform using the Stehfest algorithm 368. When wellbore storage and the skin effect dominate pumping test data and testing is conducted for long enough, two semilogarithmic straight lines are normally obtained. The first straight line can be identified readily as the line of the maximum slope. The correlation of the dimensionless drawdown for the intersection time of this first straight line, with the log time axis as a function of the dimensionless wellbore storage and the skin factor, is shown. This paper presents a new method for evaluating the skin factor from the early portion of a pumping test. This method can be used to evaluate the skin factor when the well-known Cooper–Jacob semilogarithmic method cannot be used due to the second straight line not being achieved in the semilogarithmic graph drawdown vs. the log time. A field example is presented to evaluate the well rehabilitation in Veselí nad Lužnicí by means of the new correlation. View Full-Text
Keywords: groundwater; unsteady flow; pumping test; Laplace transform; well rehabilitation; wellbore storage; skin effect groundwater; unsteady flow; pumping test; Laplace transform; well rehabilitation; wellbore storage; skin effect
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MDPI and ACS Style

Kahuda, D.; Pech, P. A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test. Water 2020, 12, 744. https://doi.org/10.3390/w12030744

AMA Style

Kahuda D, Pech P. A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test. Water. 2020; 12(3):744. https://doi.org/10.3390/w12030744

Chicago/Turabian Style

Kahuda, Daniel, and Pavel Pech. 2020. "A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test" Water 12, no. 3: 744. https://doi.org/10.3390/w12030744

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