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
The Zoige Plateau,situated on the eastern edge of the Qinghai-Tibet Plateau,exhibits complex groundwater dynamics influenced by alpine hydrological processes and climatic variability.This study investigates the spatio...The Zoige Plateau,situated on the eastern edge of the Qinghai-Tibet Plateau,exhibits complex groundwater dynamics influenced by alpine hydrological processes and climatic variability.This study investigates the spatiotemporal evolution of groundwater in the Zoige alpine basin from 2002 to 2024 using an integrated approach that combines in-situ monitoring,GRACE satellite observations,and GLDAS model outputs.Using the Innovative Trend Analysis(ITA)method alongside conventional statistical techniques,we identified both seasonal fluctuations and long-term depletion trends.Groundwater levels exhibited clear wet–dry season contrasts and a cumulative decline of up to 2.3 m in grassland flatlands,corresponding to a long-term depletion rate of 0.4 cm/a as indicated by GRACE-derived groundwater storage.The most significant declines occurred in grassland zones,driven by wetland degradation and elevated evapotranspiration,while mountain regions showed slower losses(~0.1 cm/a)primarily supported by sustained snowmelt recharge.Through the integration of multi-source datasets,this study highlights the spatial heterogeneity and key drivers of groundwater variation,providing a robust framework for sustainable groundwater management under climatic and anthropogenic pressures in alpine wetland systems.展开更多
Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation...Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation over several decades,thereby overlooking the movement of slopes and failing to capture landslide dynamics.The long-term ground deformation map(GDM)derived from multi-temporal interferometric synthetic aperture radar(MT-InSAR)can effectively address the shortcomings.Fengjie County is an important area for geohazard management in the Three Gorges Reservoir Area(TGRA),China.Landslides in this area,however,cause significant socio-economic loss due to geological,tectonic,climatic,and anthropological factors.This research aims to integrate random forest(RF)with MT-InSAR to generate a landslide dynamic susceptibility map(LDSM)for Fengjie County,enhancing the reliability of landslide risk management.First,the RF model was employed to generate a static LSM,whereas MT-InSAR was utilized to obtain the GDM of the study area from January 2020 to June 2023.The static LSM and the GDM were subsequently integrated using a dynamic weight matrix to derive the LDSM.Our analysis covered a temporal framework spanning three years,focusing on spatiotemporal changes in landslide susceptibility levels and the influence of climate factors.Compared with the static LSM,the LDSM can promptly identify moving landslide areas,reduce high landslide susceptibility areas,and achieve greater accuracy.Moreover,the spatiotemporal changes in landslide susceptibility are regulated by the total annual rainfall,with wet years being more conducive to landslides than dry years.The proposed LDSM offers useful insights for the dynamic prevention and refined management of landslide hazards in the TGRA,significantly enhancing the resilience in this region.展开更多
Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake ha...Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment. In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths. The maximum horizontal stress in shallow depths （-20 m） is about 4.3 MPa, oriented N19°E, in the epicenter area at Yingxiu Town, about 9.7 MPa, oriented N51°W, at Baoxing County in the southwestern Longmenshan range, and about 2.6 MPa, oriented N39°E, near Kangding in the southernmost zone of the Longmenshan range. Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth. A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range, and is still moderate in the epicenter zone. These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.展开更多
Aeolian sand landforms in the Yarlung Zangbo River(YZR) valley are a special type of aeolian landform that has attracted the attention of many scholars. However, the spatial distribution as well as the formation mecha...Aeolian sand landforms in the Yarlung Zangbo River(YZR) valley are a special type of aeolian landform that has attracted the attention of many scholars. However, the spatial distribution as well as the formation mechanism of aeolian sand has rarely been reported with integrated studies. In this paper, for remote sensing interpretation, scanning electron microscopy(SEM), X-ray diffraction(XRD) and particle size distribution(PSD) methods were used to analyze the spatial distribution and the deposition characteristics of aeolian sand. Combined with wind data and topography, the main driving factors and the formation mechanism of aeolian sand landforms were also examined. In the middle reaches of the YZR valley, there is a total of 2324.43 km^2 of aeolian sand, especially on the north bank of the wide valleys. In different wide valleys, the aeolian sand landforms exhibit a decreasing trend from the upstream to the downstream regions in both the area and expansion rate of aeolian sand. The cyclonic vortexes generated by the westerly winds and glacial winds are the main driving factors for transporting alluvial sand to the riverbank areas to form aeolian dunes. There are three main types of sand dunes in the river valley: climbing dunes, lee dunes and circumfluent dunes. Climbing dunes and lee dunes are mostly located west of the Jiacha Gorge, and the circumfluent dunes are mostly located east of the Jiacha Gorge.展开更多
High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, Ch...High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images(UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient(μ=0.18) and turbulence(). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 mwhen the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope.This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.展开更多
Fossil fuels are undoubtedly important, and drilling technology plays an important role in realizing fossil fuel exploration;therefore, the prediction and evaluation of drilling efficiency is a key research goal in th...Fossil fuels are undoubtedly important, and drilling technology plays an important role in realizing fossil fuel exploration;therefore, the prediction and evaluation of drilling efficiency is a key research goal in the industry. Limited by the unknown geological environment and complex operating procedures, the prediction and evaluation of drilling efficiency were very difficult before the introduction of machine learning algorithms. This review statistically analyses rate of penetration(ROP) prediction models established based on machine learning algorithms;establishes an overall framework including data collection, data preprocessing, model establishment, and accuracy evaluation;and compares the effectiveness of different algorithms in each link of the process. This review also compares the prediction accuracy of different machine learning models and traditional models commonly used in this field and demonstrates that machine learning models are the most effective technical means in current ROP prediction modeling.展开更多
To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells...To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells were selected to carry out the running test of sand control string with pre-packed screen.Meanwhile,the running simulation was performed by using the Landmark software.The results show that the sand control packer and screen can be run smoothly in the wellbore with a dogleg angle of more than 20°/30 m and keep the structure stable.Additionally,the comprehensive friction coefficient is 0.4,under which and the simulation shows that the sand control string for hydrate exploitation can be run smoothly.These findings have important guiding significance for running the completion sand control string in natural gas hydrate exploitation.展开更多
A Ms 8.0 large earthquake occurred in Sichuan,China on May 12,2008（hereafter called 5.12 Earthquake）,and then a large debris flow happened in the quake-hit Qingping Township of Mianzhu county on August 13,2008（here...A Ms 8.0 large earthquake occurred in Sichuan,China on May 12,2008（hereafter called 5.12 Earthquake）,and then a large debris flow happened in the quake-hit Qingping Township of Mianzhu county on August 13,2008（hereafter called 8.13 Debris Flow）.The influence of two disasters on the changes in land use were analyzed by using highresolution aerial photos and satellite remote sensing images taken before and after the 5.12 Earthquake and 8.13 Debris Flow,the selection of suitable construction land were studied by learning experiences and lessons from the selection of resettlement areas and through field surveys and with land use transfer model and analytical model in combination with RS and GIS.The results showed that the influence of the 5.12 Earthquake on ecological environment was far greater than that of the 8.13 Debris Flow;there were more salient conflicts between population and land after the earthquake.Sites for post-disaster reconstruction should not be in disaster-prone areas or in gully-facing areas.Suitable land for settlement construction in I-1~I-5 low-hazard zones is optimal settlement areas for post-disaster reconstruction.展开更多
The primary cracks in the rock block undergo series of steps and finally disintegrate,during this procession,the radius affects the impact force of rock block in clastic flow.Therefore,it is essential to figure out th...The primary cracks in the rock block undergo series of steps and finally disintegrate,during this procession,the radius affects the impact force of rock block in clastic flow.Therefore,it is essential to figure out the evolution mechanism of crack propagation for the design of engineering protection.In this study,based on fracture mechanics and Hertz contact theory,collision happened between rock block and slope surface is assumed to be elastic contact.Based on the above assumption,the critical impact force of crack propagation is obtained,and a model used to calculate the crack propagation length in a single collision is established.Besides,a rock fall site in Jiuzhai Valley was used to verify the calculation model.According to the model,several key factors were identified to influence crack propagation length including falling height,initial equivalent radius,and recovery coefficient of slope surface.Moreover,as a result of the orthogonal experiment,the influence of those factors on the crack propagation length was ranked,normal recovery coefficient>initial radius>initial falling height.In addition,the kinetic energy of the rock block in the compression stage is transformed into elastic deformation energy,angular kinetic energy,and dissipated energy of crack propagation.Due to the increase of collisions,the kinetic energy is gradually transformed into angular kinetic energy,and the dissipated energy of crack propagation weights is reduced.In conclusion,the crack propagation in rock block is a complicated progress,which is affected by multiple factors,especially falling height,initial equivalent radius,and recovery coefficient of slope surface.Our study may provide guidance for the design of protective structure of clastic flows.展开更多
The morphological changes of deep-water channels have an important influence on the distributions of channel sand reservoirs,so it is important to explore the morphological change process of deep-water channel for the...The morphological changes of deep-water channels have an important influence on the distributions of channel sand reservoirs,so it is important to explore the morphological change process of deep-water channel for the exploration and development of deep-water oil and gas.Based on a typical sinuous Quaternary channel(Channel I)in the Taranaki Basin,New Zealand,a variety of seismic interpretation techniques were applied to quantitatively characterize the morphological characteristics of the Channel I,and the relationships between the quantitative parameters and the morphological changes of the Channel I,as well as the controlling factors affecting those morphological changes,were discussed.The results are as follows:(1)in the quantitative analysis,six parameters were selected:the channel depth,width,sinuosity,and aspect ratio(width/depth),the channel swing amplitude(λ)and the channel bend frequency(ω);(2)according to the quantitative morphological parameters of the channel(mainly including three parameters such as channel sinuosity,ωandλ),the Channel I was divided into three types:the low-sinuous channel(LSC),the high-sinuous channel(HSC),the moderate-sinuous channel(MSC).U-shaped channel cross-sections developed in the LSC,V-shaped channel cross-sections developed in the HSC,including inclined-V and symmetric-V cross-sections,and dish-shaped channel cross-sections developed in the MSC;(3)the morphological characteristics of the LSC and MSC were related to their widths and depths,while the morphology of the HSC was greatly affected by the channel width,a change in depth did not affect the HSC morphology;(4)the morphological changes of the Channel I were controlled mainly by the slope gradient,the restricted capacity of the channel and the differential in fluid properties.展开更多
How to find more effective way to stabilize the borehole wall in the fault gouge section is the key technical challenge to control the stability of the borehole wall in the Wenchuan fault gouge section during the proc...How to find more effective way to stabilize the borehole wall in the fault gouge section is the key technical challenge to control the stability of the borehole wall in the Wenchuan fault gouge section during the process of core drilling. Here we try to describe the characters of deep fault gouge in fracture zones from the undisturbed fault gouge samples which are obtained during the core drilling. The X- Ray Diffraction （XRD）, X-Ray Fluorescence （XRF） and Scanning Electron Microscope （SEM） provided the detailed information of the fault gouge＇s microscopic characteristics on the density, moisture content, expansibility, dispersity, permeability, tensile strength and other main physical-mechanical properties. Based on these systematic experimental studies above and analysis of the fault gouge instability mechanism, a new technical procedure to stabilize the borehole wall is proposed -- a low water and a low loss low permeability drilling fluid system that consists of 4% day ＋ 0.5% CMC-HV ＋ 2% S-1 ＋ 3%sulfonated asphalt ＋ 1% SMC ＋ 0.5% X-1 ＋ 0-5% T type lubricant ＋ barite for core drilling in fault gouge sections.展开更多
Deep-water channel systems are important petroleum reservoirs,and many have been discovered worldwide.Understanding deep-water channel sedimentary elements and evolution is helpful for deep-sea petroleum exploration a...Deep-water channel systems are important petroleum reservoirs,and many have been discovered worldwide.Understanding deep-water channel sedimentary elements and evolution is helpful for deep-sea petroleum exploration and development.Based on high-resolution 3D seismic data,the Miocene channel system in the deep-water Taranaki Basin,New Zealand,was analyzed by using seismic interpretation techniques such as interlayer attribute extraction and strata slicing.The channel system was divided into five composite channels(CC-I to CC-V)according to four secondary level channel boundaries,and sedimentary elements such as channels,slump deposits,inner levees,mass transport deposits,and hemipelagic drape deposits were identified in the channel system.The morphological characteristics of several composite channels exhibited stark variances,and the overall morphology of the composite channels changed from relatively straight to highly sinuous to relatively straight.The evolution of the composite channels involved a gradual and repeated process of erosion and filling,and the composite channels could be divided into three evolutionary stages:initial erosion-filling,later erosion-filling(multistage),and channel abandonment.The middle Miocene channel system may have formed as a consequence of combined regional tectonic activity and global climatic change,and its intricate morphological alterations may have been influenced by the channel's ability to self-regulate and gravity flow properties.When studying the sedimentary evolution of a large-scale deep-water channel system in the Taranaki Basin during the Oligocene-Miocene,which transitioned from a passive margin to plate convergence,it can be understood how tectonic activity affected the channel and can also provide a theoretical reference for the evolution of the deepwater channels in areas with similar tectonic conversion environments around the world.展开更多
The study of sequence stratigraphy often focuses on shallow marine and shelf-edge regions,while research on deep-sea stratigraphic sequences remains relatively weak.This study,based on highresolution 3D seismic data a...The study of sequence stratigraphy often focuses on shallow marine and shelf-edge regions,while research on deep-sea stratigraphic sequences remains relatively weak.This study,based on highresolution 3D seismic data and drilling information,utilized sequence stratigraphy and seismic sedimentology as guidelines,and employed seismic interpretation methods to performed a division of deepsea stratigraphic sequences within the Romney 3D seismic survey area in the deep-water Taranaki Basin,New Zealand.Furthermore,it analyzed the characteristics of typical depositional systems and their associated controlling factors.The findings are as follows:(1)Based on seismic reflection termination relationships and seismic facies characteristics,four second-order sequence boundaries and nine thirdorder sequence boundaries were identified,resulting in the delineation of three second-order sequences and twelve third-order sequences in the basin.(2)Five seismic facies were recognized,corresponding to five typical sedimentary bodies:mass transport deposits(MTDs),deep-water channel,levee deposits,deltaic deposits,and pelagic deposits.However,due to the relatively thin sedimentary thickness of carbonate sediments,the seismic facies characteristics of carbonate sediments cannot be discerned in seismic data,but can be identified based on well data.Deltaic sediments mainly developed during the rift stage of the basin,while carbonate sediments formed during the transition from a passive to an active margin.Deep-water channel and levee deposits and MTDs emerged during the active margin stage,while pelagic deposits are ubiquitous in marine environments.(3)The uplift of New Zealand's interior and climate-driven erosion caused the resurgence of clastic sediments,which began to be transported to the deep sea,the seafloor topography would directly affect the movement path of sediment gravity flow,and sediment supply can affect the development and evolution of sedimentary systems.(4)Event deposits boundaries,such as erosional scour surfaces formed by channels and unconformities created by MTDs,can serve as boundaries for the division of deep-water stratigraphic sequences.This study proposes a method for delineating deep-water stratigraphic sequences using event deposits,particularly suitable under conditions where the influence of relative sea-level changes on deep-water deposits is relatively weak.This research not only enhances the understanding of deep-water depositional sequences but also provides a reference for studies on the evolution of deep-water deposition and its controlling factors in research areas with similar geological backgrounds worldwide.展开更多
Abrasion,a complex physical phenomenon prevalent in natural and engineered structures,frequently causes significant functional failures in drainage channels under the debris flow impact force.This underscores critical...Abrasion,a complex physical phenomenon prevalent in natural and engineered structures,frequently causes significant functional failures in drainage channels under the debris flow impact force.This underscores critical knowledge gaps regarding abrasion effects on debris flow-scoured drainage structures.Through multi-stage field investigations and data analysis across four representative areas,this study proposes a classification system for abrasion phenomena and analyzes morphological characteristics across different drainage structures and debris flow types(rainy vs.glacial).Further,the study methodically uncovers the long-term spatiotemporal distribution,development,and progression of abrasion in drainage channels and check dams.Dynamic abrasion characteristics were evaluated using three key parameters per debris flow:average gully vertical drop,watershed relative cutting degree,and soil sample data.The findings indicate that rainy debris flows exhibit higher average vertical drops(max:0.933)compared to glacial debris flows(max:0.621).Glacial debris flows show greater relative watershed cutting degrees(range:0.15–0.3)than rainy types(range:0.075–0.2).Multiple influencing factors were compared to identify critical controls on abrasion intensity.Debris flow velocity distribution and particle gradation within channels emerged as the primary determinants of abrasion distribution.Notably,a higher proportion of viscous particles(grain size D<2 mm)leads to a significant increase in abrasion capacity(>20%).These findings quantitatively inform the optimization of debris flow mitigation,providing a critical foundation for improving structural design,wear repair techniques,and channel configuration.展开更多
Unlike strong earthquake-triggered or heavy rainfall-triggered landslides,silent large-scale landslides(SLL)occur without signifcant triggering factors and cause unexpected signifcant disaster risks and mass casualtie...Unlike strong earthquake-triggered or heavy rainfall-triggered landslides,silent large-scale landslides(SLL)occur without signifcant triggering factors and cause unexpected signifcant disaster risks and mass casualties.Understanding the initiation mechanism of SLLs is crucial for risk reduction.In this study,the mechanism of the Zhaobishan SLL was investigated,and the SLL was jointly controlled by weak-soil(fractured rock mass)and strong-water(abundant water replenishment)conditions under the impact of active tectonism and complex hydraulic properties.Strong tectonic uplift,high fault density,and historical earthquakes led to weak-soil conditions conducive to the Zhaobishan SLL.The combined efect of unique lithology,antiform,and cultivated land contributed to the water replenishment characteristics of extensive runof confuence(3.16 times that of the landslide body)and supported long-distance groundwater replenishment,thereby forming strongwater conditions for the landslide.The amplifed seepage amount caused the strength of the soil mass on the sliding surface to decrease to 0.4 times its initial strength,eventually triggering the Zhaobishan SLL,which occurred 4.6 days after the peak rainfall.Moreover,the landslide deposits have accumulated on the semi-diagenetic clay rock,thereby controlling the subsequent recurring debris fows in the Lengzi Gully.To reduce disaster risk of SLL in vulnerable mountainous regions,the water confuence area behind the main scarp of the landslides and the hysteresis characteristics between landslides and peak rainfall should be further considered,and recurring debris fows following massive landslides also should be focused.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supported by the projects"Investigation of Groundwater Resources in the Yellow River Basin of Sichuan Province(2023-2025)"(N5100012023000974)"Dynamic Evolution and Driving Mechanisms of Water Resources in the Zoige Wetland Based on Multi-Source Remote Sensing"(KJ-2025-062),funded by the Department of Natural Resources of Sichuan Province.
文摘The Zoige Plateau,situated on the eastern edge of the Qinghai-Tibet Plateau,exhibits complex groundwater dynamics influenced by alpine hydrological processes and climatic variability.This study investigates the spatiotemporal evolution of groundwater in the Zoige alpine basin from 2002 to 2024 using an integrated approach that combines in-situ monitoring,GRACE satellite observations,and GLDAS model outputs.Using the Innovative Trend Analysis(ITA)method alongside conventional statistical techniques,we identified both seasonal fluctuations and long-term depletion trends.Groundwater levels exhibited clear wet–dry season contrasts and a cumulative decline of up to 2.3 m in grassland flatlands,corresponding to a long-term depletion rate of 0.4 cm/a as indicated by GRACE-derived groundwater storage.The most significant declines occurred in grassland zones,driven by wetland degradation and elevated evapotranspiration,while mountain regions showed slower losses(~0.1 cm/a)primarily supported by sustained snowmelt recharge.Through the integration of multi-source datasets,this study highlights the spatial heterogeneity and key drivers of groundwater variation,providing a robust framework for sustainable groundwater management under climatic and anthropogenic pressures in alpine wetland systems.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.42225702)the Maria Skłodowska-Curie Action(MSCA)-UPGRADE(mUltiscale IoT equipPed lonG linear infRastructure resilience built and sustAinable DevelopmEnt)project-HORIZON-MSCA-2022-SE-01(Grant No.101131146)。
文摘Landslide susceptibility map(LSM)is a crucial tool for managing landslide hazards and identifying potential landslide areas.However,current LSMs rely primarily on static landslide-related factors with little variation over several decades,thereby overlooking the movement of slopes and failing to capture landslide dynamics.The long-term ground deformation map(GDM)derived from multi-temporal interferometric synthetic aperture radar(MT-InSAR)can effectively address the shortcomings.Fengjie County is an important area for geohazard management in the Three Gorges Reservoir Area(TGRA),China.Landslides in this area,however,cause significant socio-economic loss due to geological,tectonic,climatic,and anthropological factors.This research aims to integrate random forest(RF)with MT-InSAR to generate a landslide dynamic susceptibility map(LDSM)for Fengjie County,enhancing the reliability of landslide risk management.First,the RF model was employed to generate a static LSM,whereas MT-InSAR was utilized to obtain the GDM of the study area from January 2020 to June 2023.The static LSM and the GDM were subsequently integrated using a dynamic weight matrix to derive the LDSM.Our analysis covered a temporal framework spanning three years,focusing on spatiotemporal changes in landslide susceptibility levels and the influence of climate factors.Compared with the static LSM,the LDSM can promptly identify moving landslide areas,reduce high landslide susceptibility areas,and achieve greater accuracy.Moreover,the spatiotemporal changes in landslide susceptibility are regulated by the total annual rainfall,with wet years being more conducive to landslides than dry years.The proposed LDSM offers useful insights for the dynamic prevention and refined management of landslide hazards in the TGRA,significantly enhancing the resilience in this region.
基金the auspice of National Key Basic Project(973)(granted No.2008CB425702)National Science and Technology Project(granted No.SinoProbe-06)
文摘Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment. In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths. The maximum horizontal stress in shallow depths （-20 m） is about 4.3 MPa, oriented N19°E, in the epicenter area at Yingxiu Town, about 9.7 MPa, oriented N51°W, at Baoxing County in the southwestern Longmenshan range, and about 2.6 MPa, oriented N39°E, near Kangding in the southernmost zone of the Longmenshan range. Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth. A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range, and is still moderate in the epicenter zone. These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.
基金financially supported by the Foundation of China Geological Survey (DD20160297)National Natural Science Foundation of China (Grant No. 41877235)the National Key Research and Development Program of China (Grant No. 2017YFC1501000)
文摘Aeolian sand landforms in the Yarlung Zangbo River(YZR) valley are a special type of aeolian landform that has attracted the attention of many scholars. However, the spatial distribution as well as the formation mechanism of aeolian sand has rarely been reported with integrated studies. In this paper, for remote sensing interpretation, scanning electron microscopy(SEM), X-ray diffraction(XRD) and particle size distribution(PSD) methods were used to analyze the spatial distribution and the deposition characteristics of aeolian sand. Combined with wind data and topography, the main driving factors and the formation mechanism of aeolian sand landforms were also examined. In the middle reaches of the YZR valley, there is a total of 2324.43 km^2 of aeolian sand, especially on the north bank of the wide valleys. In different wide valleys, the aeolian sand landforms exhibit a decreasing trend from the upstream to the downstream regions in both the area and expansion rate of aeolian sand. The cyclonic vortexes generated by the westerly winds and glacial winds are the main driving factors for transporting alluvial sand to the riverbank areas to form aeolian dunes. There are three main types of sand dunes in the river valley: climbing dunes, lee dunes and circumfluent dunes. Climbing dunes and lee dunes are mostly located west of the Jiacha Gorge, and the circumfluent dunes are mostly located east of the Jiacha Gorge.
基金the support of Institute of Exploration Technology, Chinese Academy of Geological Sciences in helping us conduct the field surveysupported by the Sichuan Youth Science and Technology Foundation (2017JQ0051)+1 种基金the National Natural Science Foundation of China (41371185 and 41401195)the Social Science Research Foundation of Ministry of Education (Engineering and Technology Training Research) (15JDGC019)
文摘High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images(UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient(μ=0.18) and turbulence(). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 mwhen the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope.This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.
基金financially supported by CNOOC China Co., Ltd. Zhanjiang Branch (CNOOC-KJ135ZDXM3 8ZJ05ZJ)。
文摘Fossil fuels are undoubtedly important, and drilling technology plays an important role in realizing fossil fuel exploration;therefore, the prediction and evaluation of drilling efficiency is a key research goal in the industry. Limited by the unknown geological environment and complex operating procedures, the prediction and evaluation of drilling efficiency were very difficult before the introduction of machine learning algorithms. This review statistically analyses rate of penetration(ROP) prediction models established based on machine learning algorithms;establishes an overall framework including data collection, data preprocessing, model establishment, and accuracy evaluation;and compares the effectiveness of different algorithms in each link of the process. This review also compares the prediction accuracy of different machine learning models and traditional models commonly used in this field and demonstrates that machine learning models are the most effective technical means in current ROP prediction modeling.
基金supported jointly by one of the major projects of Basic and Applied Basic Research in Guangdong Province“Key Basic Theory Research for Natural Gas Hydrate Trial Production in Shenhu Pilot Test Area”(2020B0301030003)the project from Southern Marine Science&Engineering Guangdong Laboratory Guangzhou City“Research on New Closed Circulation Drilling Technology without Riser”(GML2019ZD0501)the special project for hydrate from China Geological Survey“Trial Production Implementation for Natural Gas Hydrate in Shenhu Pilot Test Area”(DD20190226)。
文摘To meet the requirements of marine natural gas hydrate exploitation,it is necessary to improve the penetration of completion sand control string in the large curvature borehole.In this study,large curvature test wells were selected to carry out the running test of sand control string with pre-packed screen.Meanwhile,the running simulation was performed by using the Landmark software.The results show that the sand control packer and screen can be run smoothly in the wellbore with a dogleg angle of more than 20°/30 m and keep the structure stable.Additionally,the comprehensive friction coefficient is 0.4,under which and the simulation shows that the sand control string for hydrate exploitation can be run smoothly.These findings have important guiding significance for running the completion sand control string in natural gas hydrate exploitation.
基金supported by the Directional Project (Grant No. KZCX2-EW-317)Western Light Project (Grant No. 09R2340340) of Chinese Academy of SciencesNational Natural Science Funds (Grant No. 41071350,41101552)
文摘A Ms 8.0 large earthquake occurred in Sichuan,China on May 12,2008（hereafter called 5.12 Earthquake）,and then a large debris flow happened in the quake-hit Qingping Township of Mianzhu county on August 13,2008（hereafter called 8.13 Debris Flow）.The influence of two disasters on the changes in land use were analyzed by using highresolution aerial photos and satellite remote sensing images taken before and after the 5.12 Earthquake and 8.13 Debris Flow,the selection of suitable construction land were studied by learning experiences and lessons from the selection of resettlement areas and through field surveys and with land use transfer model and analytical model in combination with RS and GIS.The results showed that the influence of the 5.12 Earthquake on ecological environment was far greater than that of the 8.13 Debris Flow;there were more salient conflicts between population and land after the earthquake.Sites for post-disaster reconstruction should not be in disaster-prone areas or in gully-facing areas.Suitable land for settlement construction in I-1~I-5 low-hazard zones is optimal settlement areas for post-disaster reconstruction.
基金funded by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA23090403)the Scientific Foundation of the Chinese Academy of Sciences(Grant No.KFZD-SW-425)the Key Research and Development Program of Sichuan Province(Grant No.2019YFG0460)。
文摘The primary cracks in the rock block undergo series of steps and finally disintegrate,during this procession,the radius affects the impact force of rock block in clastic flow.Therefore,it is essential to figure out the evolution mechanism of crack propagation for the design of engineering protection.In this study,based on fracture mechanics and Hertz contact theory,collision happened between rock block and slope surface is assumed to be elastic contact.Based on the above assumption,the critical impact force of crack propagation is obtained,and a model used to calculate the crack propagation length in a single collision is established.Besides,a rock fall site in Jiuzhai Valley was used to verify the calculation model.According to the model,several key factors were identified to influence crack propagation length including falling height,initial equivalent radius,and recovery coefficient of slope surface.Moreover,as a result of the orthogonal experiment,the influence of those factors on the crack propagation length was ranked,normal recovery coefficient>initial radius>initial falling height.In addition,the kinetic energy of the rock block in the compression stage is transformed into elastic deformation energy,angular kinetic energy,and dissipated energy of crack propagation.Due to the increase of collisions,the kinetic energy is gradually transformed into angular kinetic energy,and the dissipated energy of crack propagation weights is reduced.In conclusion,the crack propagation in rock block is a complicated progress,which is affected by multiple factors,especially falling height,initial equivalent radius,and recovery coefficient of slope surface.Our study may provide guidance for the design of protective structure of clastic flows.
基金The National Natural Science Foundation of China under contract Nos 42077410,41872112 and 42002031the Key Scientific Research Projects in University of Henan Province under contract No.18A170007.
文摘The morphological changes of deep-water channels have an important influence on the distributions of channel sand reservoirs,so it is important to explore the morphological change process of deep-water channel for the exploration and development of deep-water oil and gas.Based on a typical sinuous Quaternary channel(Channel I)in the Taranaki Basin,New Zealand,a variety of seismic interpretation techniques were applied to quantitatively characterize the morphological characteristics of the Channel I,and the relationships between the quantitative parameters and the morphological changes of the Channel I,as well as the controlling factors affecting those morphological changes,were discussed.The results are as follows:(1)in the quantitative analysis,six parameters were selected:the channel depth,width,sinuosity,and aspect ratio(width/depth),the channel swing amplitude(λ)and the channel bend frequency(ω);(2)according to the quantitative morphological parameters of the channel(mainly including three parameters such as channel sinuosity,ωandλ),the Channel I was divided into three types:the low-sinuous channel(LSC),the high-sinuous channel(HSC),the moderate-sinuous channel(MSC).U-shaped channel cross-sections developed in the LSC,V-shaped channel cross-sections developed in the HSC,including inclined-V and symmetric-V cross-sections,and dish-shaped channel cross-sections developed in the MSC;(3)the morphological characteristics of the LSC and MSC were related to their widths and depths,while the morphology of the HSC was greatly affected by the channel width,a change in depth did not affect the HSC morphology;(4)the morphological changes of the Channel I were controlled mainly by the slope gradient,the restricted capacity of the channel and the differential in fluid properties.
基金supported by the Land&Resources Ministry of China,the China Geological Survey and the research institute of prospecting technology in the Chinese Academy of Geological Sciences,sincere thanks heresupported by National Natural Science Foundation of China(Grant Nos.41272331,51204027)the State Key Laboratory of Geohazard Prevention&Geoenvironment Protection(Grant Nos.SKLGP2012Z007,SKLGP2014Z001,SKLGP2015Z010)
文摘How to find more effective way to stabilize the borehole wall in the fault gouge section is the key technical challenge to control the stability of the borehole wall in the Wenchuan fault gouge section during the process of core drilling. Here we try to describe the characters of deep fault gouge in fracture zones from the undisturbed fault gouge samples which are obtained during the core drilling. The X- Ray Diffraction （XRD）, X-Ray Fluorescence （XRF） and Scanning Electron Microscope （SEM） provided the detailed information of the fault gouge＇s microscopic characteristics on the density, moisture content, expansibility, dispersity, permeability, tensile strength and other main physical-mechanical properties. Based on these systematic experimental studies above and analysis of the fault gouge instability mechanism, a new technical procedure to stabilize the borehole wall is proposed -- a low water and a low loss low permeability drilling fluid system that consists of 4% day ＋ 0.5% CMC-HV ＋ 2% S-1 ＋ 3%sulfonated asphalt ＋ 1% SMC ＋ 0.5% X-1 ＋ 0-5% T type lubricant ＋ barite for core drilling in fault gouge sections.
基金The National Natural Science Foundation of China under contract Nos 42077410 and 41872112。
文摘Deep-water channel systems are important petroleum reservoirs,and many have been discovered worldwide.Understanding deep-water channel sedimentary elements and evolution is helpful for deep-sea petroleum exploration and development.Based on high-resolution 3D seismic data,the Miocene channel system in the deep-water Taranaki Basin,New Zealand,was analyzed by using seismic interpretation techniques such as interlayer attribute extraction and strata slicing.The channel system was divided into five composite channels(CC-I to CC-V)according to four secondary level channel boundaries,and sedimentary elements such as channels,slump deposits,inner levees,mass transport deposits,and hemipelagic drape deposits were identified in the channel system.The morphological characteristics of several composite channels exhibited stark variances,and the overall morphology of the composite channels changed from relatively straight to highly sinuous to relatively straight.The evolution of the composite channels involved a gradual and repeated process of erosion and filling,and the composite channels could be divided into three evolutionary stages:initial erosion-filling,later erosion-filling(multistage),and channel abandonment.The middle Miocene channel system may have formed as a consequence of combined regional tectonic activity and global climatic change,and its intricate morphological alterations may have been influenced by the channel's ability to self-regulate and gravity flow properties.When studying the sedimentary evolution of a large-scale deep-water channel system in the Taranaki Basin during the Oligocene-Miocene,which transitioned from a passive margin to plate convergence,it can be understood how tectonic activity affected the channel and can also provide a theoretical reference for the evolution of the deepwater channels in areas with similar tectonic conversion environments around the world.
基金the National Natural Science Foundation of China(Grant Nos.42077410 and 41872112).We acknowledge the insights and efforts of journal editor(Jie Hao)and three anonymous reviewers that improved the quality of the manuscript.
文摘The study of sequence stratigraphy often focuses on shallow marine and shelf-edge regions,while research on deep-sea stratigraphic sequences remains relatively weak.This study,based on highresolution 3D seismic data and drilling information,utilized sequence stratigraphy and seismic sedimentology as guidelines,and employed seismic interpretation methods to performed a division of deepsea stratigraphic sequences within the Romney 3D seismic survey area in the deep-water Taranaki Basin,New Zealand.Furthermore,it analyzed the characteristics of typical depositional systems and their associated controlling factors.The findings are as follows:(1)Based on seismic reflection termination relationships and seismic facies characteristics,four second-order sequence boundaries and nine thirdorder sequence boundaries were identified,resulting in the delineation of three second-order sequences and twelve third-order sequences in the basin.(2)Five seismic facies were recognized,corresponding to five typical sedimentary bodies:mass transport deposits(MTDs),deep-water channel,levee deposits,deltaic deposits,and pelagic deposits.However,due to the relatively thin sedimentary thickness of carbonate sediments,the seismic facies characteristics of carbonate sediments cannot be discerned in seismic data,but can be identified based on well data.Deltaic sediments mainly developed during the rift stage of the basin,while carbonate sediments formed during the transition from a passive to an active margin.Deep-water channel and levee deposits and MTDs emerged during the active margin stage,while pelagic deposits are ubiquitous in marine environments.(3)The uplift of New Zealand's interior and climate-driven erosion caused the resurgence of clastic sediments,which began to be transported to the deep sea,the seafloor topography would directly affect the movement path of sediment gravity flow,and sediment supply can affect the development and evolution of sedimentary systems.(4)Event deposits boundaries,such as erosional scour surfaces formed by channels and unconformities created by MTDs,can serve as boundaries for the division of deep-water stratigraphic sequences.This study proposes a method for delineating deep-water stratigraphic sequences using event deposits,particularly suitable under conditions where the influence of relative sea-level changes on deep-water deposits is relatively weak.This research not only enhances the understanding of deep-water depositional sequences but also provides a reference for studies on the evolution of deep-water deposition and its controlling factors in research areas with similar geological backgrounds worldwide.
基金supported by the National Natural Science Foundation of China(Grant No.41807300)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0902)+3 种基金the National Key Research and Development Program of China(Grant No.2023YFC3007101)the Open Foundation of the Key Laboratory of Life Search and Rescue Technology for Earthquake and Geological Disaster,Ministry of Emergency Management of China(NO.LSR2501)the Research Project of Sichuan Provincial Department of Natural Resources(Grant No.KJ-2024-011)We would like to thank MogoEdit(https://www.mogoedit.com)for its English editing during the preparation of this manuscript.
文摘Abrasion,a complex physical phenomenon prevalent in natural and engineered structures,frequently causes significant functional failures in drainage channels under the debris flow impact force.This underscores critical knowledge gaps regarding abrasion effects on debris flow-scoured drainage structures.Through multi-stage field investigations and data analysis across four representative areas,this study proposes a classification system for abrasion phenomena and analyzes morphological characteristics across different drainage structures and debris flow types(rainy vs.glacial).Further,the study methodically uncovers the long-term spatiotemporal distribution,development,and progression of abrasion in drainage channels and check dams.Dynamic abrasion characteristics were evaluated using three key parameters per debris flow:average gully vertical drop,watershed relative cutting degree,and soil sample data.The findings indicate that rainy debris flows exhibit higher average vertical drops(max:0.933)compared to glacial debris flows(max:0.621).Glacial debris flows show greater relative watershed cutting degrees(range:0.15–0.3)than rainy types(range:0.075–0.2).Multiple influencing factors were compared to identify critical controls on abrasion intensity.Debris flow velocity distribution and particle gradation within channels emerged as the primary determinants of abrasion distribution.Notably,a higher proportion of viscous particles(grain size D<2 mm)leads to a significant increase in abrasion capacity(>20%).These findings quantitatively inform the optimization of debris flow mitigation,providing a critical foundation for improving structural design,wear repair techniques,and channel configuration.
基金supported by the National Natural Science Foundation of China(Grant No.U20A20110)the Second Tibetan Plateau Scientifc Expedition and Research Program(STEP)of China(Grant No.2019QZKK0902)+1 种基金the Youth Innovation Promotion Association CAS(ID 2020367)the International Cooperation Overseas Platform Project,Chinese Academy of Sciences(Grant No.131C11KYSB20200033).
文摘Unlike strong earthquake-triggered or heavy rainfall-triggered landslides,silent large-scale landslides(SLL)occur without signifcant triggering factors and cause unexpected signifcant disaster risks and mass casualties.Understanding the initiation mechanism of SLLs is crucial for risk reduction.In this study,the mechanism of the Zhaobishan SLL was investigated,and the SLL was jointly controlled by weak-soil(fractured rock mass)and strong-water(abundant water replenishment)conditions under the impact of active tectonism and complex hydraulic properties.Strong tectonic uplift,high fault density,and historical earthquakes led to weak-soil conditions conducive to the Zhaobishan SLL.The combined efect of unique lithology,antiform,and cultivated land contributed to the water replenishment characteristics of extensive runof confuence(3.16 times that of the landslide body)and supported long-distance groundwater replenishment,thereby forming strongwater conditions for the landslide.The amplifed seepage amount caused the strength of the soil mass on the sliding surface to decrease to 0.4 times its initial strength,eventually triggering the Zhaobishan SLL,which occurred 4.6 days after the peak rainfall.Moreover,the landslide deposits have accumulated on the semi-diagenetic clay rock,thereby controlling the subsequent recurring debris fows in the Lengzi Gully.To reduce disaster risk of SLL in vulnerable mountainous regions,the water confuence area behind the main scarp of the landslides and the hysteresis characteristics between landslides and peak rainfall should be further considered,and recurring debris fows following massive landslides also should be focused.
