On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the m...On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as, hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method--the sequential self-calibration （SSC） method--is developed to calibrate a hydraulic conductivity field, initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error （MSE）, is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.展开更多
The effectiveness of an injection-based remediation strategy is primarily governed by accurate understanding of reagent delivery and ensuring uniform distribution within the reactive zone. In IRZ （in situ reactive z...The effectiveness of an injection-based remediation strategy is primarily governed by accurate understanding of reagent delivery and ensuring uniform distribution within the reactive zone. In IRZ （in situ reactive zone） design, the required reagent strength, injection volumes, injection rates, injection frequency, injection and monitoring well spacing, and the cost and time to achieve remediation goals are governed by the hydrogeology of the site. A properly designed tracer test is capable of providing critical above mentioned site-specific information, to assist with full scale design of an IRZ. This paper describes that implementing tracer testing to support remedial design can result in enhanced design efficiency, added assurance in full-scale implementation and ultimately resulted in substantial cost savings. Therefore, it is recommended that the broader practitioner community adopt this technique as a best practice for effective and optimum in situ remediation system design.展开更多
The validity of Local Cubic Law （LCL） is an important issue to study groundwater flow and transport in fractured media. According to laboratory simulaion tests, the average velocity with a lower gradient in a single...The validity of Local Cubic Law （LCL） is an important issue to study groundwater flow and transport in fractured media. According to laboratory simulaion tests, the average velocity with a lower gradient in a single fracture is calculated by the LCL, which is compared with the measured average velocity. Then dye tracer test is designed and completed. The evidence for non-LCL, is drawn from the results of the simulation tests and the dye tracer tests. Then the Reynolds number of groundwater is calculated, the critical value of Re for laminar flow is discussed in a single fracture under different conditions. The motion types for groundwater flow have been discussed.展开更多
In this paper,the main factors impacting the plug flow pattern of a clearwell were investigated by integrating pilot-scale,full-scale clearwell tracer testing and computa-tional fluid dynamics(CFD)simulation.It was fo...In this paper,the main factors impacting the plug flow pattern of a clearwell were investigated by integrating pilot-scale,full-scale clearwell tracer testing and computa-tional fluid dynamics(CFD)simulation.It was found that pilot tracer testing,full-scale tracer testing and CFD simulation all demonstrated that the correlation between the ratio of t_(10)/T and L/W can be approximately expressed by:t_(10)/T=0.1894ln(L/W)−0.0494.This study confirmed that the installation of baffles within clearwells is an efficient way to optimize their configuration.In addition,the inlet velocity has a minimal contribution to the ratio of t_(10)/T.However,the ratio of turning channel width to channel width(d/W)significantly contributes to the ratio of t_(10)/T.The optimal ratio of d/W is 0.8-1.2 for maintaining better plug flow pattern.The number of turning channels is one of the main factors that impact the ratio of t_(10)/T.When increasing the number of turning channels,a lower ratio of t_(10)/T is obtained.展开更多
This paper focuses on the study of the evolutionary mechanism governing the temperature field of geothermal reservoir under low-temperature tailwater reinjection conditions,which is crucial for the sustainable geother...This paper focuses on the study of the evolutionary mechanism governing the temperature field of geothermal reservoir under low-temperature tailwater reinjection conditions,which is crucial for the sustainable geothermal energy management.With advancing exploitation of geothermal resources deepens,precise understanding of this mechanism becomes paramount for devising effective reinjection strategies,optimizing reservoir utilization,and bolstering the economic viability of geothermal energy development.The article presents a comprehensive review of temperature field evolution across diverse heterogeneous thermal reservoirs under low-temperature tailwater reinjection conditions,and analyzes key factors influ-encing this evolution.It evaluates existing research methods,highlighting their strengths and limitations.The study identifies gaps in the application of rock seepage and heat transfer theories on a large scale,alongside the need for enhanced accuracy in field test results,particularly regarding computational effi-ciency of fractured thermal reservoir models under multi-well reinjection conditions.To address these shortcomings,the study proposes conducting large-scale rock seepage and heat transfer experiments,coupled with multi-tracer techniques for field testing,aimed at optimizing fractured thermal reservoir models'computational efficiency under multi-well reinjection conditions.Additionally,it suggests integrat-ing deep learning methods into research endeavors.These initiatives are of significance in deepening the understanding of the evolution process of the temperature field in deep thermal reservoirs and enhancing the sustainability of deep geothermal resource development.展开更多
基金This study is partially supported by the Program of Outstanding Overseas Youth Chinese Scholar,the National Natural Science Foundation of China (No. 40528003)partially supported by USA National Science Foundation.
文摘On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as, hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method--the sequential self-calibration （SSC） method--is developed to calibrate a hydraulic conductivity field, initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error （MSE）, is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.
文摘The effectiveness of an injection-based remediation strategy is primarily governed by accurate understanding of reagent delivery and ensuring uniform distribution within the reactive zone. In IRZ （in situ reactive zone） design, the required reagent strength, injection volumes, injection rates, injection frequency, injection and monitoring well spacing, and the cost and time to achieve remediation goals are governed by the hydrogeology of the site. A properly designed tracer test is capable of providing critical above mentioned site-specific information, to assist with full scale design of an IRZ. This paper describes that implementing tracer testing to support remedial design can result in enhanced design efficiency, added assurance in full-scale implementation and ultimately resulted in substantial cost savings. Therefore, it is recommended that the broader practitioner community adopt this technique as a best practice for effective and optimum in situ remediation system design.
基金Project supported by the National Natural Science Foundation of China (Grant No :40202027) and Fok Ying Tung Ed-ucation Foundation (Grant No :91079)
文摘The validity of Local Cubic Law （LCL） is an important issue to study groundwater flow and transport in fractured media. According to laboratory simulaion tests, the average velocity with a lower gradient in a single fracture is calculated by the LCL, which is compared with the measured average velocity. Then dye tracer test is designed and completed. The evidence for non-LCL, is drawn from the results of the simulation tests and the dye tracer tests. Then the Reynolds number of groundwater is calculated, the critical value of Re for laminar flow is discussed in a single fracture under different conditions. The motion types for groundwater flow have been discussed.
基金This work was supported by the National High-Tech Research and Development(863)Program of China(Grant No.2002AA601120)by the Foundation from Beijing Science and Technol-ogy Commission(Grant No.D0605004040421).
文摘In this paper,the main factors impacting the plug flow pattern of a clearwell were investigated by integrating pilot-scale,full-scale clearwell tracer testing and computa-tional fluid dynamics(CFD)simulation.It was found that pilot tracer testing,full-scale tracer testing and CFD simulation all demonstrated that the correlation between the ratio of t_(10)/T and L/W can be approximately expressed by:t_(10)/T=0.1894ln(L/W)−0.0494.This study confirmed that the installation of baffles within clearwells is an efficient way to optimize their configuration.In addition,the inlet velocity has a minimal contribution to the ratio of t_(10)/T.However,the ratio of turning channel width to channel width(d/W)significantly contributes to the ratio of t_(10)/T.The optimal ratio of d/W is 0.8-1.2 for maintaining better plug flow pattern.The number of turning channels is one of the main factors that impact the ratio of t_(10)/T.When increasing the number of turning channels,a lower ratio of t_(10)/T is obtained.
基金funded by the National Nature Science Foundation of China(No.42272350)Scientific research project of Hunan Institute of Geology(No.HNGSTP202211)+2 种基金Hunan Province key research and development project(No.2022SK2070)Geological survey project of Department of Natural Resources of Shanxi Province(No.Jinfencai[2021-0009]G009-C05)the Foundation of Shanxi Key Laboratory for Exploration and Exploitation of Geothermal Resources(No.SX202202).
文摘This paper focuses on the study of the evolutionary mechanism governing the temperature field of geothermal reservoir under low-temperature tailwater reinjection conditions,which is crucial for the sustainable geothermal energy management.With advancing exploitation of geothermal resources deepens,precise understanding of this mechanism becomes paramount for devising effective reinjection strategies,optimizing reservoir utilization,and bolstering the economic viability of geothermal energy development.The article presents a comprehensive review of temperature field evolution across diverse heterogeneous thermal reservoirs under low-temperature tailwater reinjection conditions,and analyzes key factors influ-encing this evolution.It evaluates existing research methods,highlighting their strengths and limitations.The study identifies gaps in the application of rock seepage and heat transfer theories on a large scale,alongside the need for enhanced accuracy in field test results,particularly regarding computational effi-ciency of fractured thermal reservoir models under multi-well reinjection conditions.To address these shortcomings,the study proposes conducting large-scale rock seepage and heat transfer experiments,coupled with multi-tracer techniques for field testing,aimed at optimizing fractured thermal reservoir models'computational efficiency under multi-well reinjection conditions.Additionally,it suggests integrat-ing deep learning methods into research endeavors.These initiatives are of significance in deepening the understanding of the evolution process of the temperature field in deep thermal reservoirs and enhancing the sustainability of deep geothermal resource development.
