Recharge Wells Research Articles

Simulation study on the clogging process of suspended matter in recharge of anti-filtration recharge well

ABSTRACT Anti-filtration recharge wells are a class of recharge facilities in groundwater reservoirs with their own anti-filtration function, and aquifer clogging is a key issue in recharge. In this paper, the process of recharging groundwater by rainfall flood water recharge from an anti-filtration recharge well was simulated by indoor sand column test, and the change of permeability coefficient, turbidity at the outlet, and the distribution of suspended particulate matter at the end of the experiment were measured and computed, so as to analyze and study the effect of filtration in anti-filtration recharge wells and carry out the contrast test with ordinary recharge wells without a recharge pool. Compared with ordinary recharge wells, the anti-filter layer in the recharge pool of anti-filtration recharge wells can largely remove suspended matter in recharge water and intercept suspended matter at the surface, thus preventing aquifer clogging, and it is recommended that the anti-filter layer should be cleaned up and replaced regularly according to the experimental results, and this study provides a reference for the practical application of anti-filtration recharge wells.

Identifying managed aquifer recharge and rain water harvesting sites and structures for storing non-conventional water using GIS-based multi-criteria decision analysis approach

In arid climates, conventional water resources are severely limited and stressed in the face of rapid population growth and future climate change. So, it is necessary to find alternative non-conventional water resources for use in drought situations. Additionally, the non-conventional water resources in these areas are not sufficient to meet future water demand. Therefore, non-conventional water resources can be adopted as a strategic reserve to bridge the gap between water supply and demand in case of emergency and drought events. These resources might include rainwater harvesting, treated wastewater, and desalinated seawater. Managed aquifer recharge (MAR) can be applied to store these resources in the hydrogeological system using Geo information System—Multi Criteria Decision Analysis (GIS-MCDA) approach for determining the suitable MAR location for storage. North-west Kingdom of Saudi Arabia area was chosen for this study because it is extremely arid, has high potential for social and economic development, and it has newly constructed non-conventional water infrastructures distributed throughout the area including water desalination plants, Tertiary Sewage Effluent (TSE) waste water plants, and flash-flood storage dams. To identify the suitable MAR site location and structure, different data related to aquifer hydrogeology, surface hydrology, hydrometeorology, and water quality were applied. Then, GIS-MCDA holistic approach was applied with aid of ordered weighting average (OWA) technique. Finally, two maps were created to show the MAR location and structure type. Potential map indicates that ~ 18.85% of the area is suitable for MAR installations. About 0.17% of the total area exhibited very high potential, where infiltration ponds can be applied, 1.86% had high potential for construction of check dams with diversion channels, and 16.82% had moderate potential for installation of recharge wells. Additionally, 56 MAR structures were proposed and a map showing their locations has been created. Thus, results indicated that the study area is promising for MAR installation. These maps could aid the decision makers to propose a sustainable development plan for the future water resources of the area.

Enhanced groundwater availability through rainwater harvesting and managed aquifer recharge in arid regions

Climate change in desert areas and semi-arid watersheds may offer a promising solution for the water scarcity problem that Bedouins and local inhabitants face. This study investigated the integrated water resources management in arid and semi-arid regions using rainwater harvesting in combination with the managed aquifer recharge (RWH-MAR) technique. The study also used recharge wells and storage dams to achieve the sustainability of groundwater supplies in the context of climate change and management of the flow to the Gulf of Suez. Therefore, different return periods of 10, 25, 50, and 100 years were considered for the annual flood volume resulting from those watersheds. Moreover, hydrologic modeling was carried out for the El Qaa plain area, South Sinai, Egypt, using the Watershed Modeling System (WMS) and the groundwater modeling of SEAWAT code. Our findings show that for different scenarios of climate change based on return periods of 10, 25, 50, and 100 years, the aquifer potentiality reached 24.3 MCM (million cubic meters) per year, 28.8 MCM, 36.7 MCM, and 49.4 MCM compared to 21.7 MCM at 2014 with storage of groundwater ranges 11.8%, 32.1%, 69%, and 127.4%, respectively. These findings have significant implications for the system of RWH-MAR and groundwater sustainability in El Qaa Plain, South Sinai. The RWH-MAR proved to be an effective approach that can be applied in different water-stressed and arid regions to support freshwater resources for sustainable future development and food security, as well as protect communities from extreme flash flood events.

Inclined Tubes Clarifier for Effective Removal of Suspended Solids from Canal Water Prior to Groundwater Recharge

Groundwater recharge, through surplus supplies of canal water, may prove to be an important strategy for replenishing the rapidly depleting groundwater in Punjab and managing sustainably the groundwater resources. However, presence of suspended silt load in the canal water results in clogging of recharge wells and subsequent reduction in recharge rates and capacity of filters. In present study, an inclined tubes clarifier having filtration capacity of 1.8 L s-1 was designed and fabricated to filter the silt-loaded canal water. In the clarifier, tubes of poly vinyl chloride (PVC) media of 1-m length were attached one over the other to form an inclined honeycomb like structure through which canal water enters as inflow from the bottom and the clarified water exits as outflow from the top of the clarifier. Efficacy of the designed clarifier was tested at different total suspended solids ranging from 500 to 3000 mg L-1 in the canal water and at pumping rates varying from 0.3 to 2.1 L s-1. The results revealed more than 85% sediment-removal efficiency of the clarifier at flow rates above 0.8 L s-1. The results further indicated that efficiency of removing total suspended solids (TSS) reduced drastically at inflow rates more than 1.2 L s-1. Also, at all the flow rates, the efficiency was 6% higher for water samples having TSS more than 2000 mg L-1 in comparison to samples having TSS less than 1000 mg L-1. The clarifier makes no significant difference to the values of total dissolved solids, electrical conductivity, total solids and pH of the canal water.

Identifying suitable zones for integrated aquifer recharge and flood control in arid Qatar using GIS-based multi-criteria decision-making

Groundwater resources in arid regions play a vital role in meeting water demands; however, they are facing rapid depletion due to unsustainable exploitation practices, exacerbated by climate change. Floods can present a unique opportunity for restoring groundwater levels and mitigating saltwater intrusion into aquifers. The use of properly managed floodwater for aquifer recharge offers a dual advantage by maximizing the potential of floods as a valuable water resource, while minimizing their negative impacts. In this work, we applied a GIS-based Multi-Criteria Decision-Making (MCDM) method, namely the Analytic Hierarchy Process (AHP), to delineate flood susceptible zones and groundwater recharge zones in Qatar, considering several influential topographical, hydrological, environmental, and anthropological criteria. The maps of flood susceptibility and groundwater recharge potential were validated using recent flooding events and existing recharge wells data, respectively. Sensitivity analysis was conducted on both variables to further assess their accuracy. The overlay analysis of the two validated maps suggests that approximately 64% of the Qatar peninsula presents medium to excellent suitability for aquifer recharge using floodwater. The areas best suited for floodwater-based recharge intervention are the northern and coastal regions of the peninsula, while the urban areas and southwestern area are less suitable. This study provides decision-makers with spatially explicit information on areas in Qatar that can be targeted for aquifer recharge projects using floodwater as well as recommendations on technical, economic, and regulatory considerations that require additional investigation. The approach employed can be effectively applied in similar flood-prone arid regions and is adaptable to diverse contexts.

Prediction of thermal front movement in geothermal reservoirs containing distributed natural fractures

When designing a reinjection scheme for geothermal development, one needs to predict the flow and thermal behavior between the recharge and discharge wells. Premature thermal front breakthrough is of great concern and is often observed in real fields. However, prediction methods based on homogeneous media are prone to overly optimistic estimates. In this study, geothermal reservoirs with vertical fractures which are discretely distributed in the permeable rock are considered, and the streamline simulation is developed and applied to evaluate the thermal front movement, represented by the characteristic times tD*. With 1000 simulation results for stochastically generated natural fracture systems, regression models are developed for the expected values of tD* with minimal information requirements on fracture parameters. In general, the fracture orientation θf has a stronger negative correlation with tD* than the total fracture length Σf. The intensity of natural fractures has opposing effects (delay or advance) on tD* depending on θf, and taking this effect into account improves the quality of the regression model. In addition, when the pressure difference between the doublet wells is available, the model accuracy is further improved by incorporating pressure data into the regression. The prediction models are of practical use for understanding the thermal behavior and designing a reinjection scheme in fractured geothermal reservoirs.

Synergizing Geophysical Analysis and Geotechnical for Artificial Recharge Well and Aquifer Studies: A Comprehensive Review

The harvesting of surface runoff stands as a pivotal process in artificially recharging groundwater, playing a crucial role in augmenting groundwater within aquifers. Groundwater recharge via recharge wells is one of the successful direct sub-surface methods. To pinpoint the most suitable locations for recharge wells, a combination of geophysical surveys, including Electrical Resistivity, Magnetic, and Electrologging surveys, was used. These geophysical surveys serve as essential tools for comprehending the sub-surface lithology and played a pivotal role in identifying distinct aquifers and determining their respective dimensions, thereby aiding in the precision of recharge well placement. Our objective is to review the various methods to assess the underground water storage capacity of the aquifer based on tests viz. Sieve Analysis, Soil Water Retention Capacity, and Lateral Permeability tests. These combination of theoretical and practical evaluations aim to determine the aquifer's potential for storing groundwater. Geophysical surveys are invaluable for deriving various relationships through diverse analyses. Moreover, exploring the correlation between geophysical methods, such as electrical resistivity, and shear strength parameters is essential for comprehending the strength characteristics of subsurface layers.

Economy of Scale of Energy Intensity in Aquifer Storage and Recovery (ASR)

More water utilities are adopting aquifer storage and recovery (ASR) to balance long-term water supply and demand. Due to large implementation and operation costs, ASR projects need to be optimized, particularly for energy use, which is a major operating expense. This study examines the relationships among energy use, recharge, and recovery at two ASR projects in the western United States. The major finding is an economy of scale for recovery processes, but not for gravity-fed recharge processes. The economy of scale found is as follows: the energy intensity recovered decreases with volume. This suggests it is more energy-efficient to recover large volumes of water in one interval instead of recovering smaller volumes at more frequent intervals. The H2Oaks recovery process experienced a 78% decrease in energy intensity from 0 to 50,000 m3 recovered, while the Sand Hollow site experienced a 43% decrease in energy intensity from 0 to 50,000 m3 recovered. Statistical analyses of the recovery process showed p values lower than 0.0001, R2 values between 0.43 and 0.57, and a RMSE value between 0.55 and 2.1, indicating the presence of a moderate correlation between energy and volume. This economy of scale has been observed in multiple instances in water and wastewater treatment. This finding not only has applications to ASR but also to all recovery or recharge wells, whether or not they are paired with each other. Furthermore, this study confirms the need for more reliable and accessible energy data to fully understand the implications of the energy–water nexus.

Urban Flood Mitigation by Implementing LIDs (Case Study: Bendung Watershed in Palembang City)

Urban areas continue to be affected by flooding, necessitating more sustainable and effective adaptation strategies and mitigation initiatives. This study investigates the potential flood reduction capability achieved through implementing various green infrastructures known as low-impact development (LID). The Bendung watershed, in the center of Palembang City, with a total area of 18.37 km2, is used as the study area to evaluate the performance of LID infrastructure in reducing flood parameters, including total runoff volume, peak runoff discharge, runoff coefficient, and flooding area. Five types of LID infrastructure were simulated, namely bio-retention cells, rain gardens, permeable pavements, rain barrels, and recharge wells. The flood simulations were performed using four design storms with 2-, 5-, 10-, and 25-year return periods. Hydrologic and hydraulic modeling and simulations were carried out using PCSWMM Professional 2D, and the results were integrated with ArcMap to map the flood inundation. The results of this study demonstrate that with only 9.81 percent of the area occupied by LIDs, a flood reduction of more than 30% can be achieved. In addition, implementing LIDs can help restore the watershed’s hydrological condition to its natural state, as indicated by the decrease in the runoff coefficient. Thus, implementing LIDs in a sustainable urban drainage system must be widely promoted in many urban areas, especially in developed countries like Indonesia. This study can be used as a reference for the local government and authorities to create policies and regulations to establish sustainable flood mitigation measures in Palembang City.

Development and application of an integrated system of dewatering and recharge for the deep foundation pit

A large amount of pumping in the deep foundation pit will reduce the groundwater level and lead to surface cracking, building settlement, ground collapse and spring water cut-off. And the groundwater recharge is a good control measure. An integrated system of dewatering and recharge for the deep foundation pit is developed, and it is mainly composed of a pumping system, an assembled water tank, a variable frequency pressure system, a cleaning and filtering system, a recharge pressure tank, a recharge well system and a central control system. This system can realize intelligent automatic control according to the monitoring data. It does not require staff to operate on site and can be remotely adjusted by computer or mobile phone. Taking a subway station under construction in Jinan as the background, the single well recharge test and the multiple wells recharge test were carried out. It can be found that with the increase of recharge pressure, the recharge volume gradually increases, but the increasing trend is smaller and smaller. The relationship between the groundwater level and the recharge volume is a logarithmic function. Blindly increasing recharge wells may not improve the overall reinjection volume, and the relationship between the number of recharge wells, the diameter of reinjection pipes and the maximum recharge capacity of the variable frequency pressure system needs to be comprehensively considered.

Numerical Simulation of Artificial Recharge Groundwater Effect on Overlying Soft Clay Compression Control

Soil deformation is prone to occur in the process of the foundation pit dewatering. A large number of metro existing tunnels are located in soft soil layers. The compression of soft soil poses a threat to metro existing tunnels. Previously, plenty of research on foundation pit dewatering is focused on the hydraulic head and deformation characteristics of the aquifer. However, the law of water releasing and compression deformation of overlying soft soil has not been taken seriously. In order to study the artificial recharge groundwater effect on overlying soft clay, a three-dimensional seepage–soil deformation coupling numerical model was established. The theoretical basis of the model is Darcy’s law and the principle of effective stress. A foundation pit located in Nanjing, China was selected as an example. The numerical model was used to simulate the hydraulic head and soil deformation caused by foundation pit dewatering and artificial recharge groundwater outside. The result shows that, due to the difference of hydraulic head between the aquifer and the aquitard reducing, it also has a good control effect on the deformation of the soft soil by recharging water into the aquifer. The location of recharge wells around the metro existing tunnel can control the soil deformation effectively, which could help to reduce the impact on the metro existing tunnel.

RECHARGE WELLS MODEL BASED ON SHAPE FACTORS FOR FLOOD MANAGEMENT IN KLOJEN DISTRICT, MALANG CITY

Urban flood areas hit various regions in Indonesia, such as what happened in Malang City. Flooding occurred in several areas of Klojen District, including Wilis Street, LetJen Suprapto Street in Samaan Village, Bareng Raya Street II in Bareng Village, Retawu Street, and Pulosari Street. This research uses a recharge well model based on shape factors to discuss flood mitigation. Data analysis includes existing floods, conditions of the study area, and an applied model adjusted to soil permeability in the research area. They were mapping the area (A) and coefficient C using ArcGIS 10.8 2023 software. The model applied is an infiltration well design constructed from a concrete buis at the top and soil pores at the bottom. The design rainfall calculation results are 592.112 mm/day. The results of the analysis show that there are a total of 30 channels from Samaan Village, Bareng Village, and Gading Kasri Village, whose channel capacity is unable, causing flooding. The geometric factor value of 3.14 m has a planned water inflow discharge of 1.7626 m3/second. Klojen sub-district requires 66 recharge wells to overcome the flooding. The application for constructing infiltration wells was carried out only in the Gading Kasri sub-district area, namely 11 infiltration wells. The infiltration well is planned to use a concrete buis with dimensions of 50x100 m, height L as deep as 2 m, bottom of porus in 1 m, and total depth of channel H is 3 m. Keywords: Recharge Wells; Shape Factors; Flood Management; Klojen Sub District.

Introducing an Innovative Design Approach for Drainage Systems: Facilitating Shallow Aquifer Recharge and Mitigating Flooding

Maringá, in southern Brazil, is undergoing a crisis with the alternation of dry and wet periods and floods caused by heavy rainfall along with the lack of infiltration of the stormwater. Due to a combination of these two opposite factors, the central lake of Ingá Park, which is an important urban park of the city, is suffering from water level reduction. This paper aims to verify if a sustainable drainage system design with infiltration wells can help recharge the surface aquifer. To this end, a stormwater drainage system simulation was conducted using SewerGEMS. Additionally, a calibrated shallow aquifer computational model was run in Visual Modflow Flex considering recharge wells to verify whether rainfall events impact the water levels of the surface aquifer. The results show that the sustainable intervention in a drainage system to increase stormwater infiltration has the potential to effectively recharge the shallow aquifers, while helping, at the same time, the drainage system, which is operating beyond design capacity, and the Ingá Park Lake. Thus, this study demonstrates that the sustainable design of drainage systems can help restore the springs inside the urban park. However, it is important to continuously monitor the wells’ heads and the hydrological variables. Also, for future studies, new models and simulations must be undertaken using the continuous monitoring data already available.

Agricultural Water Deficit Trends in Yemen

Globally, climate change is triggering shifts in water availability, especially across arid and desert landscapes similar to that in Yemen, where precipitation patterns are increasingly erratic. Here, we use water budget calculations, drought metrics, and trend analyses to examine climatic water deficits, with the aim of unraveling irrigation demands and overall water stress across Yemen. The results indicate that 94% of the influx is lost back to the atmosphere via evapotranspiration, 6% is converted to runoff, and only a negligible amount, generally less than 1%, is retained as storage. The results also show an unrelenting, statistically significant water deficit increase of 0.17 mm yr−1 on the Sen’s slope, at the critical Z-value of 0.005 across the country, for the past 63 years. Our findings challenge the conventional understanding of water deficits across Yemen and suggest that the country’s water resources situation is direr than was earlier documented. Further results show that while the water shortage mosaic across the country experiences interannual variations, their occurrence is significantly intensifying. As such, an immediate and radical modernization of integrated water management systems, including concerted investments in irrigation and artificial recharge wells, especially across the Arabian Sea Coast, the Red Sea Coast, and the Highlands, is strongly recommended.

Experimental Study on Groundwater Dewatering and Recharge of Deep Foundation Pit of a Subway Station in Jinan Water-Rich Area

A large amount of groundwater dewatering is beneficial to the foundation pit construction, but it will cause surface collapse, waste groundwater resources and damage the groundwater environment. In order to maintain the stability of groundwater level and the safety of surrounding buildings in the construction of deep foundation pit, the combination of dewatering and recharge is adopted. Taking the construction of deep foundation pit of a subway station in Jinan water-rich area as an example, the theoretical model of recharge quantity, stratum parameters and groundwater level was obtained through the backward derivation of the precipitation calculation model. 78 dewatering wells and 78 recharge wells were designed, and the on-site dewatering and recharge teat was carried out. The test results show that the water level of a single dewatering well decreases sharply in the initial stage of precipitation, and then the depth drops gradually to a stable level, and finally maintains a fixed value. The water inflow of a single well ranges from 34.54~57.07 m³/d, and the groundwater level can be lowered to 1.53~2.79 m below the foundation pit floor. The recharge volume of a single well in the natural recharge state is 146.88~ 241.44 m3/d, and the higher the recharge pressure, the stronger the recharge capacity of the recharge well. Through field test research, it is found that the recharge capacity of single well of recharge well is much greater than the pumping capacity of single well of dewatering well, and 56 recharge wells can make the recharge rate reach 100%, which optimizes the dewatering and recharge design of deep foundation pit.

Use of geophysical methods to evaluate soil sediments behind gabion check dams in the dry regions of southern Tunisia.

This study aims to detect sediment at six gabions check-dams distributed in the upstream and downstream areas of the Koutine catchment located in an arid area in the southeast of Tunisia and characterized by an annual mean precipitation of less than 200 mm. The detection of sediment is based on the Electrical Resistivity Tomography (ERT) method associated with topographic measurements. About ten lines were arranged, with 72 electrodes. The results of resistivity data obtained during field measurements were inverted into subsurface structures using least squares inversion techniques. The preliminary results indicate that the sediment can be identified using an ERT contour method. The obtained results are calibrated based on samples collected for laboratory analysis. The accuracy of the high-density ERT method was justified. The density increases with the sediment deposit depth. Topographic methods were used to estimate the surface and the relief of deposed sediments in the area monitored by the gabions check-dams. This study provides an approach based on the high-density electrical resistivity tomography method and a topographic investigation to estimate sediment yield behind gabion check-dams that control catchments. The sedimentary deposit of eroded soils reduces the effectiveness of the recharge structures. Consequently, the improvement of permeability at the level of the retention basins (by cleaning the settlement basin and creating recharge wells) is of great importance. The study results are beneficial for decision-makers to evaluate the existing soil conservation and water management plans, which can be further adjusted using appropriate soil erosion mitigation options based on scientific evidence.

Optimal Pollution Control and Pump-and-Fertilize Strategies in a Nitro-Polluted Aquifer, Using Genetic Algorithms and Modflow

Nitro-pollution in a confined aquifer may originate from its recharge area, e.g., agricultural sites, animal feedlots, septic tanks, and other waste disposal sites or from treated wastewater recharge wells. The latter case is studied. Existing water supply pumping wells should be protected for a given period. Instead of typically investigating optimal pump-and-treat or hydrodynamic pollution control management/remediation strategies, a novel combined pollution control and pump-and-fertilize (PAF) approach is proposed: protect existing wells with additional wells, considering pumped nitro-polluted groundwater as profitable reusable fertilizer rather than a pollutant to be remediated; convey pumped polluted water to an irrigation reservoir, considering nitrogen (N) uptake by irrigated crops in nearby farmlands and proportional decrease in fertilizer application, meaning profit. Optimization entails the operation of optimally located additional pumping wells with optimal flow rates, minimizing the sum of (i) annual pumping cost, (ii) pipe network (connecting additional wells and reservoir) amortization cost, and (iii) profit from retrieved N reuse. Modflow simulates a 3D flow field and advection-dispersion mass transport, while Genetic Algorithms (GAs) handle optimization. Various scenarios are simulated concerning crops’ retrieved N root uptake percentage, fertilizer, and energy market prices. The paper provides a data-ready optimization/decision support tool that creates a pool of alternative (sub)optimal management solutions/strategies.

Realizing Zero Delta Q Due to the Change of Land-Use Using Horizontal Recharge Pipe

Though recharge buildings such as recharge wells and bio pores have widely been implemented in the field, their design to reduce flood runoff is not as expected. This study aims to formulate recharge using the porous horizontal recharge pipelines (HRP) as a basis to calculate the needs of HRP purposely to achieve zero ΔQ due to the changes in land use. The experimental method uses PVC pipe 20cm in diameter, 2m; 4m; 6m; and 8m in length, with the middle part connected with a 100 cm high vertical pipe. The horizontal pipe was perforated with a pipe wall porosity of 0.006; 0.012; 0.018; 0.024; and 0.048 and wrapped in geotextile. The observation of the infiltration recharge -was conducted by filling the water and observing the decrease in the water level using the sensor and recording. The decline in water level was converted into infiltration recharge -for each high water pressure. The research was conducted in a horizontal pipe with holes below the groundwater surface on clay soil with a 6.89x10-7 cm/sec permeability. It was then found the correlation between infiltration recharge -and pipe wall porosity, pipe length, and water pressure height were obtained in the form of a regression equation of Q=0.0972*P0.025*L0.193*H2,179 with a correlation coefficient of 0.9136. The HRP implementation to meet zero ΔQ due to the changes in land use using the rational method has been produced in graphical form, while the hydrograph method was presented in the case form. In the Silandak watershed, with an area of 10.30 km2, there was an increase in the coefficient of drainage from 0.39 in 2002 to 0.58 in 2019. To achieve zero ΔQ of flood hydrograph of a 50-year return period, 4200 HRP units are needed. Thus, HRP can overcome flooding due to changes in land use. However, this research must still be developed by adding pipe diameter and soil permeability variables.

Optimization of Recharge Schemes for Deep Excavation in the Confined Water-Rich Stratum

With the excavation of a metro station in a confined water-rich stratum as our background, the sensitivity of four typical recharge parameters is analyzed by using numerical simulation. Based on the orthogonal analysis method, an optimal recharge scheme was obtained. The results show that the main influential factors of ground settlement and groundwater recovery are recharge pressure and recharge depth. The main influential factor of retaining structure deformation and influence radius of recharge is the distance between the recharge wells and the foundation pit. For the groundwater recharging of a deep excavation in the water-rich confined area of Jinan, China, the optimal effect can be achieved when setting recharge wells with a depth of 50 m arranged in a line with a spacing of 10 m at a horizontal distance of 20 m away from the retaining wall and recharge pressure is 40 kPa. With the same construction difficulty, the maximum settlement in optimized scheme decreased 71.19%, the flux of groundwater recovery increased 11.96%, the maximum horizontal displacement of the wall decreased 15.61%, and the influence radius of recharge enlarged 8.62% compared to original scheme.

Karst thermal reservoir tracer test and seepage characteristics analysis in Niutuozhen geothermal field in Xiong’an New Area

The carbonate rock karst thermal reservoir in the Niutuozhen geothermal field is a high-quality geothermal resource with significant development potential. However, due to the strong heterogeneity of karst thermal reservoirs, the connectivity between recharge and production wells is hard to determine, which seriously restricts the sustainable development of the Niutuozhen geothermal field. Therefore, this study revealed the hydraulic connection between the recharge and production well through the tracer test, quantitatively characterized the seepage characteristics of the reservoir combined with the numerical simulation, and proposed the deployment of the recharge well. The results show that the total recovery rate of the tracer is 0.42%, indicating that there are a small number of communication channels with a good hydraulic connection between the recharge and production well in the experimental area, and the recharge will not cause thermal breakthrough within a short time period. The velocity of recharge water can reach 359 m/d at the fastest, and the directions of dominant channels are concentrated in the NW, N, and E directions centered on the recharge well, this is consistent with the characteristics of regional fractures, recharge wells should be avoided to deployed in those directions. The results provide effective information for the prediction of the thermal breakthrough time and the accurate establishment of the thermal reservoir model in the Niutuozhen geothermal field, also provide a scientific basis for the sustainable utilization of the carbonate karst thermal reservoir geothermal resources.