In the Sichuan Basin,seismic activity has been low historically,but in the past few decades,a series of moderate to strong earthquakes have occurred.Especially since 2015,earthquake activity has seen an unprecedented ...In the Sichuan Basin,seismic activity has been low historically,but in the past few decades,a series of moderate to strong earthquakes have occurred.Especially since 2015,earthquake activity has seen an unprecedented continuous growth trend,and the magnitude of events is increasing.Following the M5.7 Xingwen earthquake on 18 Dec.2018,which was suggested to be induced by shale gas hydraulic fracturing,a swarm of earthquakes with a maximum magnitude up to M6.0 struck Changning and the surrounding counties.Questions arose about the possible involvement of industrial actions in these destructive events.In fact,underground fluid injection in salt mine fields has been occurring in the Sichuan Basin for more than70 years.Disposal of wastewater in natural gas fields has also continued for about 40 years.Since 2008,injection for shale gas development in the southern Sichuan Basin has increased rapidly.The possible link between the increasing seismicity and increasing injection activity is an important issue.Although surrounded by seismically active zones to the southwest and northwest,the Sichuan Basin is a rather stable region with a wide range of geological settings.First,we present a brief review of earthquakes of magnitude 5 or higher since 1600 to obtain the long-term event rate and explore the possible link between the rapidly increasing trend of seismic activity and industrial injection activities in recent decades.Second,based on a review of previous research results,combined with the latest data,we describe a comprehensive analysis of the characteristics and occurrence conditions of natural and injection-induced major seismic clusters in the Sichuan Basin since 1700.Finally,we list some conclusions and insights,which provide a better understanding of why damaging events occur so that they can either be avoided or mitigated,point out scientific questions that need urgent research,and propose a general framework based on geomechanics for assessment and management of earthquake-related risks.展开更多
二氧化碳地质封存(CO2Capture and Storage,CCS)项目应当评估诱发地震的潜在可能性。中强震、强震危及人类生命财产安全,有感地震甚至微震也对CO2储区的盖层完整性构成威胁,增加泄漏风险。地热开发、页岩气开发及油气增产等的水压致裂...二氧化碳地质封存(CO2Capture and Storage,CCS)项目应当评估诱发地震的潜在可能性。中强震、强震危及人类生命财产安全,有感地震甚至微震也对CO2储区的盖层完整性构成威胁,增加泄漏风险。地热开发、页岩气开发及油气增产等的水压致裂过程中都伴随有地下流体的注入,且时有地震诱发的案例。诱发地震活动通常在流体注入压力较高时沿已有断层发生,因此可通过应力分析等对其发生机理进行研究。超临界状态CO2密度比水小,在地层深部可能会形成密度流或者与构造中先存的水岩发生相互作用,进而导致渗透率和压力变化并引发地震活动。综述了全球相关的研究进展,主要从地震成因机理入手,考虑超临界CO2性质的特殊性,结合商业尺度和实验尺度的流体注入项目和地震监测分析,研究其对储区盖层完整性的影响。以期通过适当的选址、注入方法及监测方案的优化来避免破坏性地震的发生。展开更多
Rockburst represents a very dangerous phenomenon in deep underground mining in unfavourable conditions such as great depth, high horizontal stress, proximity of important tectonic structures, and unmined pillars. The ...Rockburst represents a very dangerous phenomenon in deep underground mining in unfavourable conditions such as great depth, high horizontal stress, proximity of important tectonic structures, and unmined pillars. The case study describes a recorded heavy rockburst in the Czech part of the Upper Silesian Coal Basin, which occurred during longwall mining near the protective pillar. The artificial dividing of geological blocks and creation of mining protective pillars(shaft pillars, crosscut pillars etc.) is a dangerous task in light of rockbursts occurring mainly due to overstressing of remaining pillars. A simple model of this situation is presented. Natural and mining conditions are analysed and presented in detail as well as registered seismicity during longwall mining in the area. Recorded rockbursts in the area of interest are described and their causes discussed. Many rockbursts near protective pillars were recorded in this mining region. Methodical instructions for rockburst prevention in proximity of protective pillars as well as for gates driving were devised based on the evaluation of rockburst causes. The paper presents these principles for prevention.展开更多
This paper outlines the results obtained from real time microseismic monitoring of an opencast coal mine in South India.The objective of the study is to investigate the stress changes within the rockmass along the slo...This paper outlines the results obtained from real time microseismic monitoring of an opencast coal mine in South India.The objective of the study is to investigate the stress changes within the rockmass along the slope due to underground mine development operation and their impact on the stability of the highwall slope.The installed microseismic systems recorded the seismic triggerings down toà2 moment magnitude.In general,most of the events recorded during the monitoring period are weak in seismic energy.The study adopts a simple and more reliable tool to characterize the seismically active zone for assessing the stability of the highwall in real time.The impact of underground working on the slope is studied on the basis of the seismic event impact contours and seismic clusters.During the monitoring period,it is observed that the intensity of the overall microseismic activity along the slope due to the mine development operations did not cause any adverse impact on the highwall stability.展开更多
Seismic hazard assessment and risk mitigation depend critically on rapid analysis and characterization of earthquake sequences.Increasing seismicity in shale gas blocks of the Sichuan Basin,China,has presented a serio...Seismic hazard assessment and risk mitigation depend critically on rapid analysis and characterization of earthquake sequences.Increasing seismicity in shale gas blocks of the Sichuan Basin,China,has presented a serious challenge to monitoring and managing the seismicity itself.In this study,to detect events we apply a machine-learning-based phase picker(PhaseNet)to continuous seismic data collected between November 2015 and November 2016 from a temporary network covering the Weiyuan Shale Gas Blocks(SGB).Both P-and S-phases are picked and associated for location.We refine the velocity model by using detected explosions and earthquakes and then relocate the detected events using our new velocity model.Our detections and absolute relocations provide the basis for building a high-precision earthquake catalog.Our primary catalog contains about 60 times as many earthquakes as those in the catalog of the Chinese Earthquake Network Center(CENC),which used only the sparsely distributed permanent stations.We also measure the local magnitude and achieve magnitude completeness of ML0.We relocate clusters of events,showing sequential migration patterns overlapping with horizontal well branches around several well pads in the Wei202 and Wei204 blocks.Our results demonstrate the applicability of a machine-learning phase picker to a dense seismic network.The algorithms can facilitate rapid characterization of earthquake sequences.展开更多
A major natural hazard associated with LGOM （Legnica-Glogow Copper Mining） mining is the dynamic phenomena occurrence, physically observed as seismic tremors. Some of them generate effects in the form of relaxations...A major natural hazard associated with LGOM （Legnica-Glogow Copper Mining） mining is the dynamic phenomena occurrence, physically observed as seismic tremors. Some of them generate effects in the form of relaxations or bumps. Long-term observations of the rock mass behaviour indicate that the degree of seismic hazard, and therefore also seismic activity in the LGOM area, is affected by the great depth of the copper deposit, high-strength rocks as well as the ability of rock mass to accumulate elastic energy. In this aspect, the effect of the characteristics of initial stress tensor and the orientation of considered mining panel in regards to its components must be emphasised. The primary objective of this study is to answer the question, which of the factors considered as ＂influencing＂ the dynamic phenomena occurrence in copper mines have a statistically significant effect on seismic activity and to what extent. Using the general linear model procedure, an attempt has been made to quantify the impact of different parameters, including the depth of deposit, the presence of goaf in the vicinity of operating mining panels and the direction of mining face advance, on seismic activity based on historical data from 2000 to 2010 concerned with the dynamic phenomena recorded in different mining panels in Rudna mine. The direction of mining face advance as well as the goaf situation in the vicinity of the mining panel are of the greatest interest in the case of the seismic activity in LGOM. It can be assumed that the appropriate manipulation of parameters of mining systems should ensure the safest variant of mining method under specific geological and mining conditions.展开更多
In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismi...In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismicity,and potential for leakage associated with deep underground carbon dioxide(CO2) injection.Model simulations demonstrate that seismic events large enough to be felt by humans require brittle fault properties and continuous fault permeability allowing pressure to be distributed over a large fault patch to be ruptured at once.Heterogeneous fault properties,which are commonly encountered in faults intersecting multilayered shale/sandstone sequences,effectively reduce the likelihood of inducing felt seismicity and also effectively impede upward CO2leakage.A number of simulations show that even a sizable seismic event that could be felt may not be capable of opening a new flow path across the entire thickness of an overlying caprock and it is very unlikely to cross a system of multiple overlying caprock units.Site-specific model simulations of the In Salah CO2storage demonstration site showed that deep fractured zone responses and associated microseismicity occurred in the brittle fractured sandstone reservoir,but at a very substantial reservoir overpressure close to the magnitude of the least principal stress.We conclude by emphasizing the importance of site investigation to characterize rock properties and if at all possible to avoid brittle rock such as proximity of crystalline basement or sites in hard and brittle sedimentary sequences that are more prone to injection-induced seismicity and permanent damage.展开更多
Large amounts of carbon dioxide(CO2) should be injected in deep saline formations to mitigate climate change,implying geomechanical challenges that require further understanding.Pressure build-up induced by CO2injecti...Large amounts of carbon dioxide(CO2) should be injected in deep saline formations to mitigate climate change,implying geomechanical challenges that require further understanding.Pressure build-up induced by CO2injection will decrease the effective stresses and may affect fault stability.Geomechanical effects of overpressure induced by CO2injection either in the hanging wall or in the foot wall on fault stability are investigated.CO2injection in the presence of a low-permeable fault induces pressurization of the storage formation between the injection well and the fault.The low permeability of the fault hinders fluid flow across it and leads to smaller overpressure on the other side of the fault.This variability in the fluid pressure distribution gives rise to differential total stress changes around the fault that reduce its stability.Despite a significant pressure build-up induced by the fault,caprock stability around the injection well is not compromised and thus,CO2leakage across the caprock is unlikely to happen.The decrease in fault stability is similar regardless of the side of the fault where CO2is injected.Simulation results show that fault core permeability has a significant effect on fault stability,becoming less affected for high-permeable faults.An appropriate pressure management will allow storing large quantities of CO2without inducing fault reactivation.展开更多
In order to explore the influence of coal mining disturbance on the rockburst occurring in fault zone, this research constructed a mechanical model for the evolution of fault stress, and analyzed the influence of the ...In order to explore the influence of coal mining disturbance on the rockburst occurring in fault zone, this research constructed a mechanical model for the evolution of fault stress, and analyzed the influence of the ratio of horizontal stress to vertical stress on the stability of fault, and the spatial distribution of the stress in fault zone as well as its evolution rule. Furthermore, the rockburst danger at different spatial areas of fault zone was predicated. Results show that: when both sides of the working face are mined out, the fault zone in the working face presents greater horizontal and vertical stresses at its boundaries but exhibits smaller stresses in its middle section; however, the ratio of horizontal stress to vertical stress is found to be greater at middle section and smaller at boundaries. As the working face advances towards the fault, the horizontal and vertical stresses of the fault firstly increases and then decreases; conversely,the ratio of horizontal stress to vertical stress keeps decreasing all the time. Therefore, if the fault zones are closer to the goaf and the coal wall, the stress ratio will be smaller, and the fault slip will be more prone to occur, therefore rockburst danger will be greater. This research results provide guidance for the rockburst prevention and hazard control of the coal mining in fault zone.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
基金support of the State Scholarship Fund of China(Grant No.201804190004)。
文摘In the Sichuan Basin,seismic activity has been low historically,but in the past few decades,a series of moderate to strong earthquakes have occurred.Especially since 2015,earthquake activity has seen an unprecedented continuous growth trend,and the magnitude of events is increasing.Following the M5.7 Xingwen earthquake on 18 Dec.2018,which was suggested to be induced by shale gas hydraulic fracturing,a swarm of earthquakes with a maximum magnitude up to M6.0 struck Changning and the surrounding counties.Questions arose about the possible involvement of industrial actions in these destructive events.In fact,underground fluid injection in salt mine fields has been occurring in the Sichuan Basin for more than70 years.Disposal of wastewater in natural gas fields has also continued for about 40 years.Since 2008,injection for shale gas development in the southern Sichuan Basin has increased rapidly.The possible link between the increasing seismicity and increasing injection activity is an important issue.Although surrounded by seismically active zones to the southwest and northwest,the Sichuan Basin is a rather stable region with a wide range of geological settings.First,we present a brief review of earthquakes of magnitude 5 or higher since 1600 to obtain the long-term event rate and explore the possible link between the rapidly increasing trend of seismic activity and industrial injection activities in recent decades.Second,based on a review of previous research results,combined with the latest data,we describe a comprehensive analysis of the characteristics and occurrence conditions of natural and injection-induced major seismic clusters in the Sichuan Basin since 1700.Finally,we list some conclusions and insights,which provide a better understanding of why damaging events occur so that they can either be avoided or mitigated,point out scientific questions that need urgent research,and propose a general framework based on geomechanics for assessment and management of earthquake-related risks.
文摘二氧化碳地质封存(CO2Capture and Storage,CCS)项目应当评估诱发地震的潜在可能性。中强震、强震危及人类生命财产安全,有感地震甚至微震也对CO2储区的盖层完整性构成威胁,增加泄漏风险。地热开发、页岩气开发及油气增产等的水压致裂过程中都伴随有地下流体的注入,且时有地震诱发的案例。诱发地震活动通常在流体注入压力较高时沿已有断层发生,因此可通过应力分析等对其发生机理进行研究。超临界状态CO2密度比水小,在地层深部可能会形成密度流或者与构造中先存的水岩发生相互作用,进而导致渗透率和压力变化并引发地震活动。综述了全球相关的研究进展,主要从地震成因机理入手,考虑超临界CO2性质的特殊性,结合商业尺度和实验尺度的流体注入项目和地震监测分析,研究其对储区盖层完整性的影响。以期通过适当的选址、注入方法及监测方案的优化来避免破坏性地震的发生。
基金the project of the Institute of Clean Technologies for Mining and Utilisation of Raw Materials for Energy Use–Sustainability Programme of Czech Republic (No.LO1406)supported by a project for the long-term conceptual development of research organisations (No.RVO:68145535)
文摘Rockburst represents a very dangerous phenomenon in deep underground mining in unfavourable conditions such as great depth, high horizontal stress, proximity of important tectonic structures, and unmined pillars. The case study describes a recorded heavy rockburst in the Czech part of the Upper Silesian Coal Basin, which occurred during longwall mining near the protective pillar. The artificial dividing of geological blocks and creation of mining protective pillars(shaft pillars, crosscut pillars etc.) is a dangerous task in light of rockbursts occurring mainly due to overstressing of remaining pillars. A simple model of this situation is presented. Natural and mining conditions are analysed and presented in detail as well as registered seismicity during longwall mining in the area. Recorded rockbursts in the area of interest are described and their causes discussed. Many rockbursts near protective pillars were recorded in this mining region. Methodical instructions for rockburst prevention in proximity of protective pillars as well as for gates driving were devised based on the evaluation of rockburst causes. The paper presents these principles for prevention.
基金the S&T project ‘‘High resolution microseismic monitoring for early detection and analysis of slope failure in opencast mines’’ funded by inistry of Coal,Government of IndiaThe Singareni Collieries Co Ltd (SCCL),Andhra Pradesh
文摘This paper outlines the results obtained from real time microseismic monitoring of an opencast coal mine in South India.The objective of the study is to investigate the stress changes within the rockmass along the slope due to underground mine development operation and their impact on the stability of the highwall slope.The installed microseismic systems recorded the seismic triggerings down toà2 moment magnitude.In general,most of the events recorded during the monitoring period are weak in seismic energy.The study adopts a simple and more reliable tool to characterize the seismically active zone for assessing the stability of the highwall in real time.The impact of underground working on the slope is studied on the basis of the seismic event impact contours and seismic clusters.During the monitoring period,it is observed that the intensity of the overall microseismic activity along the slope due to the mine development operations did not cause any adverse impact on the highwall stability.
基金supported by the Hong Kong Research Grants Council(No.14303721 and N_CUHK430/16)Faculty of Science,CUHK,National Natural Science Foundation of China(Grants No.41804015,41661164035)+1 种基金National Key R&D Program of China(2018YFC1504501-02)by the Stanford Center for Induced and Triggered Seismicity。
文摘Seismic hazard assessment and risk mitigation depend critically on rapid analysis and characterization of earthquake sequences.Increasing seismicity in shale gas blocks of the Sichuan Basin,China,has presented a serious challenge to monitoring and managing the seismicity itself.In this study,to detect events we apply a machine-learning-based phase picker(PhaseNet)to continuous seismic data collected between November 2015 and November 2016 from a temporary network covering the Weiyuan Shale Gas Blocks(SGB).Both P-and S-phases are picked and associated for location.We refine the velocity model by using detected explosions and earthquakes and then relocate the detected events using our new velocity model.Our detections and absolute relocations provide the basis for building a high-precision earthquake catalog.Our primary catalog contains about 60 times as many earthquakes as those in the catalog of the Chinese Earthquake Network Center(CENC),which used only the sparsely distributed permanent stations.We also measure the local magnitude and achieve magnitude completeness of ML0.We relocate clusters of events,showing sequential migration patterns overlapping with horizontal well branches around several well pads in the Wei202 and Wei204 blocks.Our results demonstrate the applicability of a machine-learning phase picker to a dense seismic network.The algorithms can facilitate rapid characterization of earthquake sequences.
文摘A major natural hazard associated with LGOM （Legnica-Glogow Copper Mining） mining is the dynamic phenomena occurrence, physically observed as seismic tremors. Some of them generate effects in the form of relaxations or bumps. Long-term observations of the rock mass behaviour indicate that the degree of seismic hazard, and therefore also seismic activity in the LGOM area, is affected by the great depth of the copper deposit, high-strength rocks as well as the ability of rock mass to accumulate elastic energy. In this aspect, the effect of the characteristics of initial stress tensor and the orientation of considered mining panel in regards to its components must be emphasised. The primary objective of this study is to answer the question, which of the factors considered as ＂influencing＂ the dynamic phenomena occurrence in copper mines have a statistically significant effect on seismic activity and to what extent. Using the general linear model procedure, an attempt has been made to quantify the impact of different parameters, including the depth of deposit, the presence of goaf in the vicinity of operating mining panels and the direction of mining face advance, on seismic activity based on historical data from 2000 to 2010 concerned with the dynamic phenomena recorded in different mining panels in Rudna mine. The direction of mining face advance as well as the goaf situation in the vicinity of the mining panel are of the greatest interest in the case of the seismic activity in LGOM. It can be assumed that the appropriate manipulation of parameters of mining systems should ensure the safest variant of mining method under specific geological and mining conditions.
基金funded by the Assistant Secretary for Fossil Energy,National Energy Technology Laboratory,National Risk Assessment Partnership of the U.S. Department of Energy under Contract No.DEAC02-05CH11231a Swiss National Science Foundation(SNSF) Ambizione Energy grant(PZENP2_160555)
文摘In the light of current concerns related to induced seismicity associated with geological carbon sequestration(GCS),this paper summarizes lessons learned from recent modeling studies on fault activation,induced seismicity,and potential for leakage associated with deep underground carbon dioxide(CO2) injection.Model simulations demonstrate that seismic events large enough to be felt by humans require brittle fault properties and continuous fault permeability allowing pressure to be distributed over a large fault patch to be ruptured at once.Heterogeneous fault properties,which are commonly encountered in faults intersecting multilayered shale/sandstone sequences,effectively reduce the likelihood of inducing felt seismicity and also effectively impede upward CO2leakage.A number of simulations show that even a sizable seismic event that could be felt may not be capable of opening a new flow path across the entire thickness of an overlying caprock and it is very unlikely to cross a system of multiple overlying caprock units.Site-specific model simulations of the In Salah CO2storage demonstration site showed that deep fractured zone responses and associated microseismicity occurred in the brittle fractured sandstone reservoir,but at a very substantial reservoir overpressure close to the magnitude of the least principal stress.We conclude by emphasizing the importance of site investigation to characterize rock properties and if at all possible to avoid brittle rock such as proximity of crystalline basement or sites in hard and brittle sedimentary sequences that are more prone to injection-induced seismicity and permanent damage.
基金the support from the"EPFL Fellows"fellowship program co-funded by Marie Curie,FP7(Grant No.291771)partial support from the"TRUST"project of the European Community's Seventh Framework Programme FP7/2007-2013(Grant No.309607)+2 种基金the"FracRisk"project of the European Community's Horizon 2020 Framework Programme H2020-EU.3.3.2.3(Grant No.640979)sponsored by SCCER-SoE(Switzerland)(Grant No.KTI.2013.288)Swiss Federal Office of Energy(SFOE)project CAPROCK(Grant No.810008154)
文摘Large amounts of carbon dioxide(CO2) should be injected in deep saline formations to mitigate climate change,implying geomechanical challenges that require further understanding.Pressure build-up induced by CO2injection will decrease the effective stresses and may affect fault stability.Geomechanical effects of overpressure induced by CO2injection either in the hanging wall or in the foot wall on fault stability are investigated.CO2injection in the presence of a low-permeable fault induces pressurization of the storage formation between the injection well and the fault.The low permeability of the fault hinders fluid flow across it and leads to smaller overpressure on the other side of the fault.This variability in the fluid pressure distribution gives rise to differential total stress changes around the fault that reduce its stability.Despite a significant pressure build-up induced by the fault,caprock stability around the injection well is not compromised and thus,CO2leakage across the caprock is unlikely to happen.The decrease in fault stability is similar regardless of the side of the fault where CO2is injected.Simulation results show that fault core permeability has a significant effect on fault stability,becoming less affected for high-permeable faults.An appropriate pressure management will allow storing large quantities of CO2without inducing fault reactivation.
基金Financial support for this work,provided by the National Natural Science Foundation of China(Nos.51104150,51204165,51404243)the Twelfth Five-Year National Science and Technology Support Program of China(No.2012BAK09B01)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China,are gratefully acknowledged
文摘In order to explore the influence of coal mining disturbance on the rockburst occurring in fault zone, this research constructed a mechanical model for the evolution of fault stress, and analyzed the influence of the ratio of horizontal stress to vertical stress on the stability of fault, and the spatial distribution of the stress in fault zone as well as its evolution rule. Furthermore, the rockburst danger at different spatial areas of fault zone was predicated. Results show that: when both sides of the working face are mined out, the fault zone in the working face presents greater horizontal and vertical stresses at its boundaries but exhibits smaller stresses in its middle section; however, the ratio of horizontal stress to vertical stress is found to be greater at middle section and smaller at boundaries. As the working face advances towards the fault, the horizontal and vertical stresses of the fault firstly increases and then decreases; conversely,the ratio of horizontal stress to vertical stress keeps decreasing all the time. Therefore, if the fault zones are closer to the goaf and the coal wall, the stress ratio will be smaller, and the fault slip will be more prone to occur, therefore rockburst danger will be greater. This research results provide guidance for the rockburst prevention and hazard control of the coal mining in fault zone.
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.
