Installation Of Wells Research Articles

Evaluating Preventive Measures for Flooding from Groundwater: A Case Study

Groundwater (GW) flooding mechanisms differ from river flooding, both spatially and temporally, and preventative methods against groundwater flooding must take this into account. Although groundwater flooding caused by a rise of river water seldom occurs, it can occasionally become severe and last for a long time if the river is significantly flooded. In the southwest portion of the research domain, Friedrichshafen, Germany, with a few urban communities, the level of the groundwater table was discovered to be roughly 1 m below the surface. In the study region, it is typical for the bottom level of the foundation of a single-story building to extend up to a depth of about 1.5 m. Therefore, flood mitigation methods are taken into account for the southwest portion of the study region. In this study, FEFLOW is used to explore the preventative methods for groundwater flooding caused by river water increase in urban settings, the spread of contamination, and the strategizing of effective mitigation solutions for flooding. The installation of a pumping well, drainage, and a barrier in the affected area are three different flood control strategies that are taken into consideration for the study area. Pumping well installation, reducing up to 1.5 m of hydraulic head, was found to be the most effective flood control measure locally in a small region. By contrast, removing groundwater by building drainage and barriers was shown to be ineffective for lowering the groundwater table over an extended region, and was significantly more expensive than the installation of wells. Additionally, when river flooding is taken into account, compared to the default scenario where no intake of water from the river is included along the western border of the study area, it was discovered that the spread of pollution (nitrate concentration) is significantly greater.

Partial Cases of Stressed-Deformed Condition of Casing and Pump Compressor Pipes

Abstract Threaded joints are the most technological for piling up in the fields. However, violations of standard threaded joints account for 70% of all complications in pipe processing and production. These malfunctions result in significant material losses, reduced well productivity, and contamination of the wells and environmental pollution. Particularly acute is the loss of these sealed joints during exploration and development of gas and gas condensate fields. The necessary increase in volumes and intensification of hydrocarbon energy production is envisaged by the increase of drilling depth, construction of slopes and horizontal wells. Horizontal drilling and fracturing are used to produce shale gas. The efficiency and safety of the operation of oil and gas wells in complex mining and technical conditions depend on the quality and reliability of casing and pumping columns, which requires the modernization of machinery and technology for the installation of wells. The most technological for column fitting in the fisheries sector is threaded joints. However, breach of standard threaded connections causes 70% of all complications with pump housings and columns. This leads to significant material losses, reduced production of raw materials, contamination of the interior and the environment. Therefore, the urgent task is to improve the threaded joints by increasing their reliability and efficiency under heavy workloads.

Transmissividade e coeficiente de armazenamento obtidos a partir da difusividade em aquíferos confinados não drenantes

Um conjunto de 18.000 valores teóricos de Difusividade (D) variando entre 0,012 m2/s e 8.914 m2/s, em aquífero confinado, foi gerado aleatoriamente por um programa de computador, desenvolvido no âmbito do estudo, que utiliza um código para a solução da equação de Theis. Esse mesmo programa calculou 200 tempos de reação t0 de poços de observação posicionados a 15 distâncias diferentes do poço produtor, para 6 vazões diferentes, o que resultou na obtenção de 18.000 pares (t0, D) obtidos aleatoriamente. A partir desses pares e de seus desdobramentos, e utilizando ajustes de leis potenciais e ajustes de leis logarítmicas, foi possível chegar à expressão analítica que fornece D em função da distância r do poço produtor a um poço de observação (m), e do tempo de reação t0 (min) observado neste último. Uma vez obtida a difusividade D, são apresentadas fórmulas que permitem desmembrá-la em seu dividendo (s’= rebaixamento num dado tempo t’ em min) e seu divisor , de forma unívoca. Os resultados obtidos para D, T e S são validados por comparação com 40 valores desses parâmetros obtidos em 15 testes de aquífero realizados durante a década de 1980 no Aquífero Cabeças no Vale do Gurguéia, Piauí/Brasil. Esta abordagem é válida para a obtenção de valores confiáveis de D, T e S, de modo a respaldar a elaboração adequada de projetos de poços e de baterias de poços.

Avaliação do perigo de contaminação das águas subterrâneas por fontes pontuais nos municípios do Vale do Taquari – RS

Avaliar o risco de contaminação dos aquíferos é uma importante ferramenta para a proteção da qualidade da água subterrânea, e como gestão para a alocação de novos empreendimentos, instalação de poços e delimitação de áreas de maior perigo. A região do Vale do Taquari apresenta 432 poços em situação de bombeamento e equipados, extraindo água principalmente para abastecimento doméstico e animal. Por isso, é fundamental mapear o perigo de contaminação da água subterrânea, que compreende a sobreposição de dois mapas, o de vulnerabilidade natural do aquífero, obtido através do método DRASTIC, e o das fontes potenciais de contaminação, classificadas de acordo com o método POSH. Os resultados demonstram que a maior representatividade no mapa de vulnerabilidade pertence ao valor moderado, com 79%, seguido por reduzido, com 16%, e elevado 5%. A multiplicação entre os mapas evidenciou que a classificação de perigo moderada corresponde a 46% da área analisada, seguida por reduzido com 38%, desprezível com 10% e por fim 6% com índice elevado, concentrado no município de Estrela. Além disso foi possível constatar que 56 poços se encontram nas zonas analisadas. Espera-se que esse trabalho seja importante para os municípios com o intuito de preservar as áreas de elevada vulnerabilidade, assim como alertar áreas com alto perigo de contaminação. E que sirva de motivação para o detalhamento do mapeamento de índices, solos e geologia da região do Vale do Taquari.

Novel Well Completions in Small Diameter Coreholes Created Using Portable Rock Drills

AbstractDifficult access conditions have limited techniques for groundwater system characterization and monitoring in bedrock exposed landscapes. This condition is common in the mining industry and resulted in the development of lightweight portable drills. This paper describes how these drills were used at a contaminated site to understand the groundwater flow system by adapting piezometer designs, ensuring effective seals to obtain reliable hydraulic head, hydrochemistry, and contaminant concentrations. Two drilling machines were evaluated: the Shaw Portable Core Drill™ fits in a backpack and can advance continuously cored rock holes, nominal 51 millimeters (mm) diameter, to depths up to approximately 15 meters (m); and the larger Winkie Drill™ requires a two or more people to mobilize and can advance continuously cored holes, nominal 48 mm diameter, to depths of approximately 45 m. The resulting small diameter coreholes were accommodated in the design of each well using a seal created by injecting grout into a semipermeable fabric sleeve. This “fabric sleeve” serves as a means to contain the grout and ensures that the entire annulus above the screen is sealed without loss of grout into the formation, allowing the well to perform as a piezometer. To develop and demonstrate this methodology for groundwater monitoring in bedrock, the two drills were used in drainages located along the slopes of an elevated sandstone outcrop near Los Angeles, California. Unique insights into the groundwater flow system of this bedrock environment, which would otherwise be unattainable, were achieved. This methodology overcomes the accessibility limitations of conventional drilling methods that prevent installation of wells in remote and rugged mountainous terrains.

Using Sealed Wells to Measure Water Levels Beneath Streams and Floodplains.

The design of wells beneath streams and floodplains has often employed with tall standpipes to prevent incursion of surface water into the well during flood events. Here, an approach has been presented to minimise the infrastructure demands in these environments by sealing the well top (e.g., prevent water entering the well) and monitor the total pressure in the water column using an absolute (non-vented) pressure transducer. The sealed well design was tested using a laboratory experiment where the total pressure responses were monitored in both an unsealed and sealed well, while the water level was varied. It is observed that, whether the well is sealed or not, the total pressure at a given depth in the aquifer will be equal to that within the well. This indicates that the sealed well design is a viable alternative to tall standpipes and also facilitates installation of wells beneath streams and floodplains.

Particle tracking analysis of river–aquifer interaction via bank infiltration techniques

Induced bank infiltration (BI) is commonly implemented in other countries, but remains new and unexplored in Malaysia. Increasing river pollution could affect drinking water resources. Given the threat of pollution to raw water sources, applying induced BI to sustain water management is essential. This paper presents a case study of the BI method, which evaluates the effects of groundwater pumping and BI operation on the installation of wells as well as determines the effect of pumping rate on flow paths, travel time, the size of the pumping and capture zone delineation, and groundwater mixing in a pumping well in Jenderam Hilir, Malaysia. The proposed method performs infiltration safely and achieves the ideal pumping rate. Numerical modeling packages, MODFLOW and MODPATH (particle tracking) were used. Results indicate that the migration of river water into the aquifer is generally slow and depends on the pumping rate and distance from well to the river. Most water arrives at the well by the end of a pumping period of 1–5 days at 3,072 m3/day for test wells DW1 and DW2, and during simultaneous pumping for DW2 and PW1 for a well located 36 and 18 m, respectively, from the river. During the 9.7-day pumping period, 33 % of the water pumped from the DW1 well was river water, and 38 % from DW2 throughout 4.6 days was river water. The models provide necessary information for water operators in the design and construction of pumping and sampling schedules of BI practices.

Using particle tracking as a tool sustainable bank infiltration techniques: a case study in an alluvial area

This study was inspired by the Klang Valley water crisis, for which bank infiltration (BI) is considered a potential solution. This paper presents a case study of the BI techniques, which evaluates the effects of groundwater pumping and BI operation on the installation of wells. This study also determines the effect of pumping rate on flow paths, travel time, the size of the pumping and capture zone delineation, and groundwater mixing in a pumping well in Jenderam Hilir, Malaysia. The proposed method performs infiltration safely and achieves the ideal pumping rate. Numerical modeling packages, MODFLOW and MODPATH (particle tracking) were used. Results indicate that the migration of river water into the aquifer is generally slow and depends on the pumping rate and distance from well to the river. Most water arrives at the well by the end of a pumping period of 1 to 5 days at 3,072 m3/day for test wells DW1 and DW2, and during simultaneous pumping for DW2 and PW1 for a well located 36 and 18 m, respectively, from the river. During the 9.7-day pumping period, 33 % of the water pumped from the DW1 well was river water, and 38 % of the water pumped from DW2 throughout 4.6 days was river water.

A geomorphological mapping approach for the assessment of seabed geohazards and risk

Exploration and development of offshore hydrocarbon resources has advanced into remote deepwater regions over the last decade and poses significant technical challenges for the design and installation of wells and facilities at extreme water depths. Seafloor and shallow subsurface processes and conditions in these areas are complex and generally poorly understood, and the geohazards to development are larger scale and fundamentally different to those encountered onshore; consequently the geohazard risk to deepwater development projects is potentially significant and requires careful evaluation and mitigation during the front-end planning and engineering design stages of projects. There are no established industry standards or methods for the assessment of geohazards and engineering-quality geophysical data at the scale of development. The paper describes an integrated and systematic map-based approach for the assessment and mitigation of seabed geohazards and risk to proposed deepwater development. The approach employs a multi-disciplinary team working with engineering-quality field calibrated data to accurately map and assess seafloor ground conditions and ensure that development proposals are not exposed to intolerable geohazard risk. The approach taken is very similar to the practice of establishing geological models for land-based engineering projects, in which the complete geological history of the site is used to characterise and predict the performance of the ground. Such an approach is routine for major projects on land but so far does not seem to be common practice in the offshore industry. The paper illustrates the seafloor geomophological mapping approach developed. The products are being used to optimise development layouts to avoid geohazards where possible and to support site-specific engineering design of facilities based on a detailed understanding of the potential geohazard loadings and associated risk.

Research Spotlight: A less invasive method to measure groundwater permeability

Hydraulic conductivity quantifies how easily water moves through aquifers, a factor important for management of water resources, the design of wells, and remediation of contaminated sites. It typically shows strong spatial fluctuations, so determining hydraulic conductivity usually involves extensive, invasive, and often expensive installation of wells or sampling sites within the aquifer.

Dynamic optimal ground water remediation including fixed and operation costs.

In time-varying ground water remediation, the lack of an optimal control algorithm to simultaneously consider fixed costs and time-varying operating costs makes it nearly impossible to obtain an optimal solution. This study presents a novel algorithm that integrates a genetic algorithm (GA) and constrained differential dynamic programming (CDDP) to solve this time-varying ground water remediation problem. A GA can easily incorporate the fixed costs associated with the installation of wells. However, using a GA to solve for time-varying policies would dramatically increase the computational resources required. Therefore, the CDDP is used to handle the subproblems associated with time-varying operating costs. A hypothetical case study that incorporates fixed and time-varying operating costs is presented to demonstrate the effectiveness of the proposed algorithm. Simulation results indicate that the fixed costs can significantly influence the number and locations of wells, and a notable total cost savings can be realized by applying the novel algorithm herein.

Effects of Sampling Well Construction on H2Measurements Made for Characterization of Redox Conditions in a Contaminated Aquifer

Measurement of hydrogen, H2, has been suggested for characterization of redox levels in groundwater and has recently been used in the delineation of redox processes in contaminated aquifer. In this investigation, we evaluate the influence of materials and age of the well on the H2 measurements performed in a leachate-contaminated sandy aquifer at the Grindsted Landfill, Denmark, Four types of small diameter wells were tested, covering a range of materials (teflon, PVC, black iron, and stainless steel) and installation methods (driven wells and bailer techniques). The results suggest that the following precautions are taken in order to obtain valid measurements of H2: (1) all iron parts should be avoided as well materials, (2) PVC, teflon, and probabaly stainless steel are suitable materials for wells, (3) wells for monitoring H2 levels shall rest for a period from installation till sampling (our experiences indicate approximately 3 months) before their readings can be trusted, and (4) installation of wells or heavy mechanical work in the subsoil can affect the H2 levels in nearby wells.

Case history of one of the few successful Superfund remediation sites: A site at Salinas, California, USA

In 1985, a former tire manufacturing plant surrounded by agricultural fields in the Salinas Valley was designated a Superfund Site by the US Environmental Protection Agency. The plant had been operating for seventeen years, from 1963 until 1980. When dismantling of the plant was started, it was determined that toxic hydrocarbon solvents and oils from the plant had contaminated soil and groundwater in alluvial deposits alongside the plant. It was determined later that the groundwater contamination also lay beneath the agricultural fields in a narrow groundwater plume that extends about 4.3 km downgradient from the plant. Because of the complex architecture of the aquifer system, the gradient, and extensive pumping of agricultural wells, the contaminants migrated northwestward and downward to deeper levels away from the plant. The agricultural fields are underlain by an unconfined shallow aquifer and by a system of confined aquifers that extend to more than 180 m below surface. Aquifers are discontinuous beds of channel sand and gravel; confining beds are overbank clay and silt, and estuarine clay. Geophysical data, logs of existing agricultural and other wells, and careful consideration of the stratigraphic architecture of the depositional environment provided the basis for a conceptual hydrogeologic model and for locating characterization wells for detailed visual and geophysical logging and hydrologic testing. Successive refinements of the characterization by sequential installation of wells indicated optimal locations for installation of extraction and monitoring wells. Validity of the concept of the hydrogeologic regime was verified by close match of predictions made by modeling with the later results of pumping from the extraction wells in a pump-and-treat system. Successful remediation was accomplished by analyzing data from 110 agricultural wells, the few domestic water wells, nearly 200 sequentially installed stratigraphic-characterization and monitoring wells, 25 extraction wells, and by close cooperation among federal, state and local agencies, and the ranchers and growers. Total contaminants recovered from activated-charcoal strippers of the treatment system totalled < 230 kg. Large quantities were harmlessly volatilized and dispersed into the atmosphere by air strippers and by agricultural sprinkling systems spraying water onto the fields. Crop testing showed no contamination of food crops. The activity has taken seven years and has cost more than US$22 million.

A Practical Approach to the Design, Operation, and Monitoring of In Situ Soil‐Venting Systems

AbstractWhen operated properly, in situ soil venting or vapor extraction can be one of the most cost‐effective remediation processes for soils contaminated with gasoline, solvents, or other relatively, volatile compounds. The components of soil‐venting systems are typically off‐the‐shelf items, and the installation of wells and trenches can be done by reputable environmental firms. However, the design, operation, and monitoring of soil‐venting systems are not trivial. In fact, choosing whether or not venting should be applied at a given site is a difficult decision in itself. If one decides to utilize venting, design criteria involving the number of wells, well spacing, well location, well construction, and vapor treatment systems must be addressed. A series of questions must be addressed to decide if venting is appropriate at a given site and to design cost‐effective in situ soil‐venting systems. This series of steps and questions forms a “decision tree” process. The development of this approach is an attempt to identify the limitations of in situ soil venting, and subjects or behavior that are currently difficult to quantify and for which future study is needed.

A Comparison of Office‐Derived vs. Field‐Derived Water Table Maps for a Sandy Unconfined Aquifer

AbstractThis study compares the accuracy of two types of water table maps both of which were constructed with the object of optimizing future mapping efforts in similar environments. The. first type of map is based solely on office information, with no field verification. The second type of map is based on careful field mapping using numerous measurement points.The office‐derived maps were based on topography, surface water features, existing reports, maps and data in the files of the Wisconsin Geological and Natural History Survey; the data were not field‐verified. The field‐derived maps used a dense network of 236 piezometers at 176 sites in an area of approximately 170 square miles. The field project was much more expensive and labor‐intensive than was the construction of office‐derived maps for the same area.The two methods produce water table maps which agree to an appreciable extent, the greatest agreement being in areas having ground water‐fed streams. Differences in water table elevations indicated by the two methods range from negligible to approximately 5 feet. Thus, depending upon the availability of existing information, relatively accurate water table elevations can be delineated in similar sandy unconfined aquifers without time‐consuming and expensive field work that drilling and piezometer installation entails.Preliminary construction of office‐derived water table maps enables researchers to use their resources efficiently. In some situations, expensive installation of wells and piezometers for a regional monitoring network may add little accuracy to the regional map. For localized problems, collection of additional field data will always be necessary, but can be guided by the office‐derived maps. The authors caution that this technique may only be applicable to sandy, unconfined aquifers in humid climates.

Notes on determining the effective distance to a line of recharge

Increasing emphasis has been given in recent years to the installation of wells in sand and gravel deposits along perennial streams. Under favorable conditions water enters the aquifer from the adjacent stream so that the safe yield is not limited by recharge from local precipitation [see “References” at end of paper, Jeffords, 1946]. Some of the installations tested, however, have not been successful. At times the preliminary investigations have been inadequate, and often quantitative hydrologic techniques have been applied without adequate consideration of the existing local conditions.