scholarly journals Well Rehabilitation via the Ultrasonic Method and Evaluation of Its Effectiveness from the Pumping Test

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1250
Author(s):  
Daniel Kahuda ◽  
Pavel Pech ◽  
Václav Ficaj ◽  
Hana Pechová
Keyword(s):  
High Efficiency ◽  
Ultrasonic Method ◽  
Functional Condition ◽  
Pumping Test ◽  
Specific Yield ◽  
Prototype Development ◽  
Ultrasonic Technology ◽  
Skin Zone ◽  
Well Rehabilitation ◽  
Groundwater Reserves

The exploitation of groundwater reserves, especially for drinking purposes, is becoming increasingly important. This fact has created the need to maintain wells in the best possible functional condition. However, wells are subject to an ageing process during intensive use, which entails an increase in up-to-date resistances in the well itself and its immediate surroundings (the skin zone). This causes a decrease in the efficiency of the well (a decrease in the pumped quantity, a decrease in the specific yield, an increase of the drawdown in the well, and creation of the skin zone). The increased hydraulic gradient in the skin zone causes an increase in the inflow rate to the well, thereby inducing the movement of fine material towards the casing. This material can clog the well casing and injection ports, which is compounded by an increase in chemical and biological plugging of the skin zone. In cooperation with the company sonic technologies, GmbH. (Sailauf, Germany), an experimental ultrasonic technology-based well rehabilitation assembly was developed and successfully tested. This article describes the prototype development of the ultrasonic device, including its incorporation into the rehabilitation set and a demonstration of its pilot deployment in the MO-4 pumping well in Czech Republic with an evaluation of the rehabilitation effects using the authors’ software (Dtest_ULTRA). Based on visual inspection and the results of hydraulic and geophysical analysis, the high efficiency of the tested technology was demonstrated in virtually all monitored parameters, where an improvement in the range of 25–55% compared to the original condition was identified.

Drawdowns at the Free Water Table During Pumping Tests in Artesian and Semiartesian Aquifers

1980 ◽  
Vol 11 (3-4) ◽  
pp. 159-168 ◽  
Author(s):  
Henrik Kærgaard
Keyword(s):  
Water Table ◽  
Free Water ◽  
Pumping Test ◽  
Water Withdrawal ◽  
Specific Yield ◽  
Minor Role ◽  
Long Term Effects ◽  
Long Term Storage ◽  
Term Storage

In an earlier paper I have shown an example of how long term drawdowns can be used for the computation of long term storage in artesian and semiartesian areas. In most cases the long term storage is more or less equivalent to the specific yield at the water table; the storage mechanisms of consolidation playing a minor role in long term situations. The specific yield in artesian areas is a very important parameter in the prediction of long term effects of ground water withdrawal. Especially the stream depletion will often mainly be governed by draw-downs in upper nonpumped aquifers near the water table, and these drawdowns depend to a great extent on the specific yield at the water table. A determination of long term storage will often necessitate long term draw-down data, however, under certain circumstances a determination can be made on the basis of a pumping test of limited duration (3-5 weeks) provided drawdown observations at the water table can be made. In this paper some formulas dealing with water table drawdowns in different geohydrologic systems are reviewed, and two cases in which these formulas have been used in practice are presented.

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.

Measurement of Welding Residual Stress by Ultrasonic Technology

2015 ◽  
Vol 750 ◽  
pp. 206-213 ◽  
Author(s):  
Hu Chen ◽  
Jin Dan Zhu ◽  
Yan Xun Xiang
Keyword(s):  
Residual Stress ◽  
Ultrasonic Method ◽  
Ultrasonic Inspection ◽  
Welding Residual Stress ◽  
Ultrasonic Technology ◽  
Longitudinal Residual Stress ◽  
Measurement Results ◽  
Acoustic Elasticity ◽  
Good Repeatability ◽  
Acoustic Travel Time

An ultrasonic method was developed to measure the residual stress in a welded joint based on the modified acoustic-elasticity theory. Phase frequency analysis method was introduced by incombination with shear wave and longitudinal wave. The acoustic-elasticity parameters of joint material was derived by ultrasonic inspection during loading experiment. Transverse and longitudinal residual stress was determined by precisely measuring of short-distance acoustic travel time. The ultrasonic measurement results was confirmed by H&K theory and XRD methods with good repeatability and reliability.

scholarly journals Transient drawdown solution for a constant pumping test in finite two-zone confined aquifers

2012 ◽  
Vol 16 (2) ◽  
pp. 441-449 ◽  
Author(s):  
C.-T. Wang ◽  
H.-D. Yeh ◽  
C.-S. Tsai
Keyword(s):  
Large Time ◽  
Pumping Test ◽  
Residue Theorem ◽  
Optimization Scheme ◽  
Finite Radius ◽  
Infinite Extent ◽  
Confined Aquifers ◽  
Skin Zone ◽  
Finite Extent

Abstract. The drawdown solution has been widely used to analyze pumping test data for the determination of aquifer parameters when coupled with an optimization scheme. The solution can also be used to predict the drawdown due to pumping and design the dewatering system. The drawdown solution for flow toward a finite-radius well with a skin zone in a confined aquifer of infinite extent in radial direction had been developed before. To our best knowledge, the drawdown solution in confined aquifers of finite extent with a skin zone so far has never before been presented in the groundwater literature. This article presents a mathematical model for describing the drawdown distribution due to a constant-flux pumping from a finite-radius well with a skin zone in confined aquifers of finite extent. The analytical solution of the model is developed by applying the methods of Laplace transforms, Bromwich contour integral, and residue theorem. This solution can be used to investigate the effects of finite boundary and conductivity ratio on the drawdown distribution. In addition, the inverse relationship between Laplace- and time-domain variables is used to develop the large time solution which can reduce to the Thiem solution if there is no skin zone.

Ultrasonic Method for Monitoring Environmental Risks Associated with Precipitation

2013 ◽  
Vol 38 (1) ◽  
pp. 125-135 ◽  
Author(s):  
Tadeusz Gudra ◽  
Dariusz Banasiak ◽  
Krzysztof Herman ◽  
Krzysztof Opieliński
Keyword(s):  
Block Diagram ◽  
Ultrasonic Method ◽  
Measurement Precision ◽  
Environmental Risks ◽  
Operating Conditions ◽  
Snow Layer ◽  
Factors Affecting ◽  
Ultrasonic Technology ◽  
Actual Operation ◽  
Device Operation

Abstract This paper presents a solution that utilises ultrasonic technology to allow monitoring snow layer thickness or water level based on measurement from air. It describes the principle of operation of a measurement device using three methods of compensating for changing external factors affecting appliance’s precision. Block diagram of the device is also provided. In order to verify the proposed solutions, the research team tested the device in laboratory and operating conditions. The results obtained this way make it possible to select a configuration of device operation depending on the required measurement precision and limitations associated with installing the system for actual operation.

scholarly journals Transient drawdown solution for a constant pumping test in finite two-zone confined aquifers

2011 ◽  
Vol 8 (5) ◽  
pp. 9299-9321
Author(s):  
C.-T. Wang ◽  
H.-D. Yeh ◽  
C.-S. Tsai
Keyword(s):  
Large Time ◽  
Pumping Test ◽  
Optimization Scheme ◽  
Finite Radius ◽  
Aquifer Parameters ◽  
Infinite Extent ◽  
Confined Aquifers ◽  
Skin Zone ◽  
Finite Extent

Abstract. The drawdown solution has been widely used to analyze pumping test data for the determination of aquifer parameters when coupled with an optimization scheme. The solution can also be used to predict the drawdown due to pumping and design the dewatering system. The drawdown solution for flow toward a finite-radius well with a skin zone in a confined aquifer of infinite extent in radial direction had been developed before. To our best knowledge, the drawdown solution in confined aquifers of finite extent so far has never before been presented in the groundwater literature. This article presents a mathematical model for describing the drawdown distribution due to a constant-flux pumping from a finite-radius well with a skin zone in confined aquifers of finite extent. The analytical solution of the model is developed by applying the methods of Laplace transforms and Bromwich contour integral. This solution can be used to investigate the effects of finite boundary and conductivity ratio on the drawdown distribution. In addition, the inverse relationship between Laplace- and time-domain variables is used to develop the large time solution which can reduce to the Thiem solution if there is no skin zone.

Application of Ultrasonic Technology in the Enzyme Pretreatment of PLA Fabric

2013 ◽  
Vol 821-822 ◽  
pp. 378-381 ◽  
Author(s):  
Zhong Jun Fu ◽  
Hao Fei Huang ◽  
Lu Shan Yu ◽  
Yun Fei Sun
Keyword(s):  
Weight Loss ◽  
Ultrasonic Treatment ◽  
Loss Rate ◽  
Ultrasonic Method ◽  
Weight Loss Rate ◽  
Time Saving ◽  
Enzyme Pretreatment ◽  
Ultrasonic Technology ◽  
Fabric Weight

In this paper, compared with the traditional desizing process, the ultrasonic technology was applied to the pretreatment of PLA fabric combined with enzyme. The results showed that the fabric weight loss rate and the whiteness of the fabric increased 15% and 20% respectively after the ultrasonic treatment. Besides, the efficiency of the ultrasonic method also increased by 20% time saving.

scholarly journals Optimal estimation of unconfined aquifer parameters in uncertain environment based on fuzzy transformation method

2018 ◽  
Vol 19 (2) ◽  
pp. 444-450
Author(s):  
Atefeh Delnaz ◽  
Gholamreza Rakhshandehroo ◽  
Mohammad Reza Nikoo
Keyword(s):  
Test Data ◽  
Statistical Error ◽  
Optimal Estimation ◽  
Pumping Test ◽  
Transformation Method ◽  
Unconfined Aquifer ◽  
Uncertain Variable ◽  
Specific Yield ◽  
Pumping Rate ◽  
Fuzzy Transformation

Abstract In this paper, a fuzzy simulation–optimization model coupled with the genetic algorithm based on Boulton's equation is presented to estimate transmissibility (T), storage coefficient (S), specific yield (Sy) and leakage factor (Dt) of an unconfined aquifer. This model is capable of minimizing the deviation between observed and calculated drawdowns of pumping test data. To assess the applicability of the model, its results are compared with the graphically obtained solutions from Boulton's equation. To this end, real pumping test data obtained from an unconfined aquifer in Dayton, Ohio, are considered as the case problem to evaluate the efficacy of the model. In the fuzzy approach, pumping rate is considered as an uncertain variable. For evaluation of the model, several statistical error indices are utilized. Results show better matches for the model as evidenced by much smaller errors. As an example, mean absolute relative error for the proposed model and graphical Boulton's solution is 2.52% and 4.98%, respectively. It is concluded that the model is accurate and may replace the graphical Boulton's solution. T and Sy were found to be more sensitive to uncertainty in the pumping rate measurement, when compared with S and r/Dt.

Study of Ultraviolet Spectrophotometer for Rapid Analysis of Oil Content in the Oil-Contaminated Soil

2013 ◽  
Vol 864-867 ◽  
pp. 930-934 ◽  
Author(s):  
Li Hua Mao ◽  
Xue Mei Han
Keyword(s):  
Contaminated Soil ◽  
Room Temperature ◽  
Oil Content ◽  
High Efficiency ◽  
Extraction Efficiency ◽  
Detection Method ◽  
Ultrasonic Method ◽  
Rapid Analysis ◽  
Soil Samples ◽  
Two Stages

Oil soil samples were extracted using cyclohexane, petroleum ether and chloroformion by the ultrasonic method. The feasibility of the ultraviolet spectrophotometric method for rapid analysis of the oil content in the oil-contaminated soil was explored. The result indicates that compared with other test methodsultraviolet spectrophotometry can be a simple, quick and steady detection method of oil content in the oil-contaminated soil. The method of oil material extracted by cyclohexane is high efficiency and stable. When the temperature was between room temperature and 40°C, ultrasonic extraction time is 15 min, and the extraction efficiency turned out to be stable (greater than 94%) when solvent dosage exceeded 40mL. Two stages extraction could achieve the best effect with the extraction dosage of 20 mL for each stage.

The Sensitivity of the Focused Ultrasonic Method Used in Inclusion Testing of the Thick Steel Specimen

2013 ◽  
Vol 455 ◽  
pp. 253-260 ◽  
Author(s):  
Guo Xing Zhang ◽  
Yun Song Hua ◽  
Yan Wen Shen ◽  
Hong Wu Yang
Keyword(s):  
High Efficiency ◽  
Focal Length ◽  
Ultrasonic Method ◽  
Research Work ◽  
Steel Specimen ◽  
Inclusion Size ◽  
Ultrasonic Field ◽  
Large Size ◽  
Thick Steel ◽  
Testing Condition

For the task of evaluating the inclusions in the steel specimen under high efficiency testing condition, it is important to make it clear that what testing sensitivity the ultrasonic method can reach for a specimen of large size, especially a thick one. In this paper, this problem is researched and discussed. Before experimental researching, we simulated the focused ultrasonic field formed in the steel specimen by DPSM (Distributed Point Source Method), the frequency ranges from 7.5MHz to 15MHz. DPSM analysis reveals that the ultrasonic field of certain strength can be formed in the thick steel specimen of coarse grain, and the focused transducer of 15MHz is suitable for the inclusion evaluation of thick steel specimens. Then, with the help of a precise micro-step C-scan equipment and the 15Mhz transducer (13mm Diameter, 255mm focal length), the ultrasonic test sensitivity research work was carried out on the thick steel specimen, by the way of testing the inclusions which's size were as tiny as possible, and located as far from the testing surface as possible, and at last, the ultrasonic detection results were testified by mechanical dissection. The dissected inclusions which can be tested are grouped into 8 different grades by its size, it is demonstrated that the deepest inclusion can be tested in the specimen is about 80mm beneath the testing surface by ultrasonic method, and reflection area is about 0.02mm2, equivalent to a circle inclusion of diameter 0.16mm. In addition, there are some semi-quantitative relationships can be drawn among the grade of inclusion, the location depth of inclusion in the specimen, and the reflected ultrasonic signal strength from the inclusion, this give a way of evaluating the inclusion size in the thick steel specimen by the focused ultrasonic method.

Sign in / Sign up

Export Citation Format

Share Document