Detecting a hydraulic short circuit along a monitoring well with the recovery curve of a pumping test in a confined aquifer: method and example

1998 ◽  
Vol 35 (5) ◽  
pp. 790-800 ◽  
Author(s):  
Robert P Chapuis ◽  
Djaouida Chenaf
Keyword(s):  
Preferential Flow ◽  
Short Circuit ◽  
Pumping Test ◽  
Recovery Phase ◽  
New Method ◽  
Confined Aquifer ◽  
Initial Water ◽  
Recovery Curve ◽  
Monitoring Well ◽  
Aquifer Test

It is important to verify if a monitoring well was correctly sealed into the ground to avoid preferential flow between aquifer layers (hydraulic short circuit). Previous papers have shown how to check this by variable-head permeability tests interpreted with the velocity-graph method. This paper presents a new method to make this check with the recovery curve of an aquifer test. The theory of this new method is presented. When there is a hydraulic short circuit, the drawdowns and recoveries due to a pumping test in a confined aquifer do not yield unique values of transmissivity and storativity as they should theoretically. An example is provided, that of monitoring well E1 of the Pelican River aquifer test. The pumping phase was interpreted using the methods of Theis and Cooper-Jacob. The recovery phase was interpreted by two methods: (i) the usual graph of sprime versus log (t/tprime) gave transmissivity T and either the Jacob method or the U.S. Department of the Interior Ground Water Manual gave storativity S; and (ii) the method of (sp - sprime) versus log tprime gave both T and S. As a result, four values of T and S were obtained. They differed by 9% for T and by 186% for S. According to the proposed method there was a hydraulic short circuit close to the monitoring well: it gave an initial water level that differed from the real piezometric level by 40 cm. Drawdown and recovery values were corrected for reinterpretation. The new log-log and semilog graphs yielded identical T and S values, thus validating the diagnosis of a hydraulic short circuit and illustrating the detection method.Key words: monitoring well, pumping, recovery, quality control, transmissivity, storativity.

A Graphical Method for Storage Coefficient Determination from Quasi-Steady State Flow Data

1996 ◽  
Vol 27 (4) ◽  
pp. 247-254 ◽  
Author(s):  
Zekâi Şen
Keyword(s):  
Steady State ◽  
Graphical Method ◽  
Pumping Test ◽  
Quasi Steady State ◽  
Flow Data ◽  
Steady State Flow ◽  
Storage Coefficient ◽  
State Flow ◽  
Aquifer Test

A simple, approximate but practical graphical method is proposed for estimating the storage coefficient independently from the transmissivity value, provided that quasi-steady state flow data are available from a pumping test. In the past, quasi-steady state flow distance-drawdown data have been used for the determination of transmissivity only. The method is applicable to confined and leaky aquifers. The application of the method has been performed for various aquifer test data available in the groundwater literature. The results are within the practical limits of approximation compared with the unsteady state flow solutions.

scholarly journals A New Method of Early Short Circuit Detection

2014 ◽  
Vol 02 (04) ◽  
pp. 432-427 ◽  
Author(s):  
Feng Du ◽  
Weigang Chen ◽  
Yue Zhuo ◽  
Michael Anheuser
Keyword(s):  
Short Circuit ◽  
New Method

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

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 744
Author(s):  
Daniel Kahuda ◽  
Pavel Pech
Keyword(s):  
Skin Effect ◽  
Pumping Test ◽  
Real Space ◽  
New Method ◽  
Maximum Slope ◽  
Skin Factor ◽  
Wellbore Storage ◽  
Straight Line ◽  
Early Portion ◽  
Well Rehabilitation

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.

Does the duration of the magnetic storm recovery phase depend on the development rate in its main phase? 2. A new method

2016 ◽  
Vol 56 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
I. G. Lodkina ◽  
N. S. Nikolaeva ◽  
M. Yu. Yermolaev
Keyword(s):  
Magnetic Storm ◽  
Recovery Phase ◽  
Development Rate ◽  
Main Phase ◽  
New Method ◽  
Phase 2

scholarly journals RESEARCH ON SHORT-CIRCUIT IMPEDANCES OF NEW CONVERTER TRANSFORMER

2020 ◽  
Vol 38 (02) ◽  
Author(s):  
TRAN THANH NGOC
Keyword(s):  
Theoretical Analysis ◽  
Topological Structure ◽  
Short Circuit ◽  
Experimental Results ◽  
New Method ◽  
Mathematical Relationship ◽  
Hvdc System ◽  
Grid Side ◽  
Relationship Of ◽  
Circuit Impedance

The short-circuit impedance of converter transformers is one of the most important specifications in HVDC system. Compared with the traditional converter transformers, the new converter transformer has unique windings connection diagrams. Based on the topological structure of the new converter transformer, this paper proposes a new method to establish the mathematical relationship of short-circuit impedances and filters impedances under considering the valve side and grid side shortcircuit conditions. The analysis on short circuit at valve side and grid side shows that short-circuit impedances values are almost the same in both two conditions, so that the impedance of the new converter transformer is symmetrical. Finally, simulation and experimental results verify the correctness of the theoretical analysis.

scholarly journals On the application of storage coefficient determination by quasi-steady-state flow

2005 ◽  
Vol 36 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Mehmet E. Birpinar ◽  
Ayhan Gazioglu
Keyword(s):  
Steady State ◽  
Quasi Steady State ◽  
Confined Aquifer ◽  
Steady State Flow ◽  
Steady State Condition ◽  
Storage Coefficient ◽  
Unconfined Aquifers ◽  
Aquifer Test ◽  
Order Of Magnitude ◽  
Observation Wells

A simple analytical method has been used for estimating the storage coefficient provided that transmissivity of the aquifer is known at the quasi-steady-state condition in confined or unconfined aquifers. The application of the method has been performed for unconfined and confined aquifer test data in Chaj Doab, Pakistan with observation wells and compared with conventional methods in the groundwater flow literature dealing with pumping tests. The results from the methodology presented in this paper conform well in practice with the results obtained from the traditional methods on the basis of order of magnitude.

Non-Darcian effect on a variable-rate pumping test in a confined aquifer

2020 ◽  
Vol 28 (8) ◽  
pp. 2853-2863
Author(s):  
Yabing Li ◽  
Zhifang Zhou ◽  
Chao Zhuang ◽  
Yong Huang ◽  
Jinguo Wang
Keyword(s):  
Pumping Test ◽  
Variable Rate ◽  
Confined Aquifer

Effects of monitoring and pumping well pipe capacities during pumping tests in confined aquifers

2003 ◽  
Vol 40 (6) ◽  
pp. 1093-1103 ◽  
Author(s):  
Robert P Chapuis ◽  
Djaouida Chenaf
Keyword(s):  
Water Storage ◽  
Pumping Test ◽  
Unconfined Aquifer ◽  
Confined Aquifer ◽  
Pumping Tests ◽  
Constant Flow Rate ◽  
Pumping Wells ◽  
Confined Aquifers ◽  
Large Tank ◽  
Definition Of

This paper establishes how the water stored in the pipes of monitoring and pumping wells influences the drawdown curves of pumping tests in confined aquifers. Experimental and numerical results obtained with a physical model are first studied and then confirmed by field-test data. A large tank was used for fully controlled pumping tests. It contains a lower confined aquifer, an aquitard, and an upper unconfined aquifer. Pumping tests at a constant flow rate in the confined aquifer provided drawdowns that were analyzed for unsteady-state, steady-state, and recovery conditions. For a single monitoring well, the different interpretation methods provided similar values of transmissivity, T, and storativity, S. Drawdown curves gave much too high S values. These S values were equal to those resulting from water storage in the pipes of monitoring and pumping wells, according to the physical definition of storativity. The experimental T and S values were confirmed by two numerical analyses (finite elements) of the pumping test, one considering no water was stored in the pipes and the other considering stored water. Data of real pumping tests in confined aquifers confirmed that the S value calculated from drawdown curves can be influenced by water storage in monitoring and pumping wells for usual pipe diameters.Key words: pumping test, transmissivity, storativity, sandbox, in situ test, pipe capacity.

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