Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to...Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.展开更多
The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in eff...The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.展开更多
Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction ...Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.展开更多
Hot dry rock(HDR)geothermal energy is a kind of widely distributed clean energy with huge reserves.However,its commercial development has been constrained by reservoir stimulation.In the early stage of HDR geothermal ...Hot dry rock(HDR)geothermal energy is a kind of widely distributed clean energy with huge reserves.However,its commercial development has been constrained by reservoir stimulation.In the early stage of HDR geothermal energy development,properly determining spatial distribution patterns of natural fractures in HDR reservoirs can effectively guide reservoir stimulation.This study analyzes the spatial distribution of natural fractures by using FracMan software based on the actual geological data and log data of well M-2 in the Matouying Uplift area,Hebei Province.The fracture parameters are counted and Monte Carlo simulation technique is introduced to optimize the parameters,which makes the natural fracture model more accurate and reliable.Furthermore,this study simulates hydraulic fracturing using the model combined with the actual in-situ stress parameters and the construction scheme.As verified by fitting the changes in simulated wellhead pressure during hydraulic fracturing with the actual wellhead pressure data detected during construction,the methods for natural fracture modeling used in this study are scientific and reasonable.The preliminary prediction results show that the displacement design scheme with a pump displacement of 2.0-3.0 m^(3)/min,4.0-5.5 m^(3)/min and 6-7 m^(3)/min in the early,middle and late stages,respectively,has good fracturing effect.The results of this study can be utilized as a reference for preparing development schemes for HDR reservoirs.展开更多
The sediment flux data, measured from a dry-hot valley of the Longchuan River, a tributary of the lower Jinsha River, were analyzed with Mann-Kendall test, Seasonal Mann-Kendall test and Sen’s test. In both the upper...The sediment flux data, measured from a dry-hot valley of the Longchuan River, a tributary of the lower Jinsha River, were analyzed with Mann-Kendall test, Seasonal Mann-Kendall test and Sen’s test. In both the upper reaches (Xiaohekou) and the lower reaches (Xiaohuangguayuan), the sediment fluxes showed a significant increase from 1970 to 2001, despite the fact that the water discharge did not change significantly during the period and numerous reservoir constructions which contribute to the trap of sediment. This can be attributed to the intensification of human activities, especially the activities related to land surface disturbances such as deforestation and afforestation, expansion of agriculture land, and road constructions. This increase is more significant in the lower reaches of the river observed at the place of Xiaohuangguayuan due to the dry-hot climate. The profound increase in sediment flux has significant implications for effective management of the sedimentation problems of the on-going Three Gorges Reservoir.展开更多
An analytical methodology for reservoir characterization was applied in the central and southwestern zones of Los Humeros geothermal field(LHGF). This study involves analysis of temperature, pressure,enthalpy and perm...An analytical methodology for reservoir characterization was applied in the central and southwestern zones of Los Humeros geothermal field(LHGF). This study involves analysis of temperature, pressure,enthalpy and permeability in wells and their distribution along the area. The wells located in the central western side of the geothermal field are productive, whereas those located at the central-eastern side are non-productive. Through temperature profiles, determined at steady state in the analyzed wells, it was observed that at bottom conditions(approximately 2300 m depth), temperatures vary between 280 and360℃. The temperatures are higher at the eastern side of central zone of LHGF. A review of transient pressure tests, laboratory measurements of core samples, and correlation of circulation losses during drilling suggest that permeability of the formation is low. The enthalpy behavior in productive wells shows a tendency of increase in the steam fraction. It was found that productivity behavior has inverse relation with permeability of rock formation. Further, it is observed that an imbalance exists between exploitation and recharge. It is concluded from the results that the wells located at central-eastern area have low permeability and high temperature, which indicates possibility of heat storage.展开更多
We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a singl...We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a single porosity. However, it considers local thermal non-equilibrium between solid rock matrix and fluid flowing in the factures and employs two energy conservation equations to describe heat transfer in the rock matrix and in the fractures, respectively, enabling the modeling and analyses of convective heat exchange in the heat reservoir. Another salient feature of this model is its capability of simulating the complete subsurface heat exchange process in EGS. The EGS subsurface geometry of interest physically consists of multiple domains： open channels for injection and production wells, the artificial heat reservoir, and the rocks enclosing the heat reservoir, while computationally we treat it as a single-domain of multiple sub-regions associated with different sets of characteristic properties （porosity and permeability, etc.）. This circumvents typical difficulties about matching boundary conditions between sub-domains in traditional multi-domain approaches and facilitates numerical implementation and simulation of the complete subsurface heat exchange process. This model is used to perform a comprehensive parametric study with respect to an imaginary doublet EGS. Effects of several parameters, including the permeability of heat reservoir, heat exchange coefficient in the heat reservoir, the specific area of fractures in the heat reservoir, and thermal compensation from surrounding rocks, on the heat extraction efficiency and EGS lifetime are analyzed.展开更多
基金funded by the“Hot Dry Rock Resources Exploration and Production Demonstration Project”of the China Geological Survey(DD20190131,DD20190135,DD20211336).
文摘Hot dry rock(HDR)is a kind of clean energy with significant potential.Since the 1970s,the United States,Japan,France,Australia,and other countries have attempted to conduct several HDR development research projects to extract thermal energy by breaking through key technologies.However,up to now,the development of HDR is still in the research,development,and demonstration stage.An HDR exploration borehole(with 236℃ at a depth of 3705 m)was drilled into Triassic granite in the Gonghe Basin in northwest China in 2017.Subsequently,China Geological Survey(CGS)launched the HDR resources exploration and production demonstration project in 2019.After three years of efforts,a sequence of significant technological breakthroughs have been made,including the genetic model of deep heat sources,directional drilling and well completion in high-temperature hard rock,large-scale reservoir stimulation,reservoir characterization,and productivity evaluation,reservoir connectivity and flow circulation,efficient thermoelectric conversion,monitoring,and geological risk assessment,etc.Then the whole-process technological system for HDR exploration and production has been preliminarily established accordingly.The first power generation test was completed in November 2021.The results of this project will provide scientific support for HDR development and utilization in the future.
基金Funded by the“Investigation and Evaluation of the Hot Dry Rock Resources in the Guide-Dalianhai Area of the Gonghe Basin,Qinghai”(DD20211336,DD20211337,DD20211338)“Hot Dry Rock Resources Exploration and Production Demonstration Project”(DD20230018)of the China Geological Survey。
文摘The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.
基金Research Foundation of the Department of Natural Resources of Hunan ProvinceGrant/Award Number:20230101DZ+7 种基金Natural Science Foundation of Hunan ProvinceGrant/Award Number:2023JJ20062National Key Research and Development Program of ChinaGrant/Award Number:2022YFC2903704National Natural Science Foundation of ChinaGrant/Award Number:52104112Science and Technology Innovation Program of Hunan Province of ChinaGrant/Award Number:2023RC3051。
文摘Based on a comprehensive review of domestic and foreign literature, this article discusses the technical difficulties and development status of enhanced geothermal system(EGS) concerning the thermal energy extraction of deep hot dry rock(HDR) reservoirs and proposes suggestions for the research focus of numerical simulation of HDR reservoir stimulation. Additionally, it summarizes the existing methods and mainstream working fluids for HDR reservoir stimulation. The article emphasizes the significance of factors such as well location, production well depth, artificial fracture orientation, and complexity in optimizing the thermal production efficiency of the EGS. Furthermore, this article delves into a detailed discussion on the influence of fracture spacing, fracture permeability,fracture length, fluid injection rate, and injected fluid temperature on the performance of the EGS. In light of the thermo-hydro-mechanical coupling challenges associated with high-temperature reservoirs, it is suggested that future research efforts should focus on investigating the impact of thermo-induced stresses on the stability of the artificial fracture network within the EGS during long-term(>30 years) circulation of hot and cold fluids.
文摘Hot dry rock(HDR)geothermal energy is a kind of widely distributed clean energy with huge reserves.However,its commercial development has been constrained by reservoir stimulation.In the early stage of HDR geothermal energy development,properly determining spatial distribution patterns of natural fractures in HDR reservoirs can effectively guide reservoir stimulation.This study analyzes the spatial distribution of natural fractures by using FracMan software based on the actual geological data and log data of well M-2 in the Matouying Uplift area,Hebei Province.The fracture parameters are counted and Monte Carlo simulation technique is introduced to optimize the parameters,which makes the natural fracture model more accurate and reliable.Furthermore,this study simulates hydraulic fracturing using the model combined with the actual in-situ stress parameters and the construction scheme.As verified by fitting the changes in simulated wellhead pressure during hydraulic fracturing with the actual wellhead pressure data detected during construction,the methods for natural fracture modeling used in this study are scientific and reasonable.The preliminary prediction results show that the displacement design scheme with a pump displacement of 2.0-3.0 m^(3)/min,4.0-5.5 m^(3)/min and 6-7 m^(3)/min in the early,middle and late stages,respectively,has good fracturing effect.The results of this study can be utilized as a reference for preparing development schemes for HDR reservoirs.
基金National BasicResearch Program of China(also called 973program)(project No.2003CB415105-6)National University of Singapore(NUS grantnumber R-109-000-034-112).
文摘The sediment flux data, measured from a dry-hot valley of the Longchuan River, a tributary of the lower Jinsha River, were analyzed with Mann-Kendall test, Seasonal Mann-Kendall test and Sen’s test. In both the upper reaches (Xiaohekou) and the lower reaches (Xiaohuangguayuan), the sediment fluxes showed a significant increase from 1970 to 2001, despite the fact that the water discharge did not change significantly during the period and numerous reservoir constructions which contribute to the trap of sediment. This can be attributed to the intensification of human activities, especially the activities related to land surface disturbances such as deforestation and afforestation, expansion of agriculture land, and road constructions. This increase is more significant in the lower reaches of the river observed at the place of Xiaohuangguayuan due to the dry-hot climate. The profound increase in sediment flux has significant implications for effective management of the sedimentation problems of the on-going Three Gorges Reservoir.
基金support to the Instituto Nacional de Electricidad y Energias Limpias (INEEL)
文摘An analytical methodology for reservoir characterization was applied in the central and southwestern zones of Los Humeros geothermal field(LHGF). This study involves analysis of temperature, pressure,enthalpy and permeability in wells and their distribution along the area. The wells located in the central western side of the geothermal field are productive, whereas those located at the central-eastern side are non-productive. Through temperature profiles, determined at steady state in the analyzed wells, it was observed that at bottom conditions(approximately 2300 m depth), temperatures vary between 280 and360℃. The temperatures are higher at the eastern side of central zone of LHGF. A review of transient pressure tests, laboratory measurements of core samples, and correlation of circulation losses during drilling suggest that permeability of the formation is low. The enthalpy behavior in productive wells shows a tendency of increase in the steam fraction. It was found that productivity behavior has inverse relation with permeability of rock formation. Further, it is observed that an imbalance exists between exploitation and recharge. It is concluded from the results that the wells located at central-eastern area have low permeability and high temperature, which indicates possibility of heat storage.
文摘We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a single porosity. However, it considers local thermal non-equilibrium between solid rock matrix and fluid flowing in the factures and employs two energy conservation equations to describe heat transfer in the rock matrix and in the fractures, respectively, enabling the modeling and analyses of convective heat exchange in the heat reservoir. Another salient feature of this model is its capability of simulating the complete subsurface heat exchange process in EGS. The EGS subsurface geometry of interest physically consists of multiple domains： open channels for injection and production wells, the artificial heat reservoir, and the rocks enclosing the heat reservoir, while computationally we treat it as a single-domain of multiple sub-regions associated with different sets of characteristic properties （porosity and permeability, etc.）. This circumvents typical difficulties about matching boundary conditions between sub-domains in traditional multi-domain approaches and facilitates numerical implementation and simulation of the complete subsurface heat exchange process. This model is used to perform a comprehensive parametric study with respect to an imaginary doublet EGS. Effects of several parameters, including the permeability of heat reservoir, heat exchange coefficient in the heat reservoir, the specific area of fractures in the heat reservoir, and thermal compensation from surrounding rocks, on the heat extraction efficiency and EGS lifetime are analyzed.
