A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test
| Autor: | Daniel Kahuda, Pavel Pech |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
lcsh:Hydraulic engineering
020209 energy Geography Planning and Development 0207 environmental engineering 02 engineering and technology pumping test Aquatic Science Biochemistry Intersection (Euclidean geometry) skin effect lcsh:Water supply for domestic and industrial purposes lcsh:TC1-978 groundwater 0202 electrical engineering electronic engineering information engineering 020701 environmental engineering Water Science and Technology lcsh:TD201-500 Partial differential equation Laplace transform Function (mathematics) Mechanics wellbore storage Line (geometry) Drawdown (hydrology) laplace transform Skin effect unsteady flow Geology Test data well rehabilitation |
| Zdroj: | Water, Vol 12, Iss 3, p 744 (2020) Water Volume 12 Issue 3 |
| ISSN: | 2073-4441 |
| Popis: | 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&ndash 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. |
| Databáze: | OpenAIRE |
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