The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this p...The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been done.In this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B satellites.The observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic storm.Densities observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the southern.The TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were higher.Swarm-B data exhibit near-symmetry between the hemispheres.In addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric near-symmetry.The South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%difference.From the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite hemisphere.NRLMSISE00 model simulations were also performed on this geomagnetic storm.TADs are absent in the NRLMSISE00 simulations.The satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both hemispheres.Therefore,use of the density simulation of NRLMSISE00 may lead to large errors in satellite drag calculations and orbit predictions.We suggest that the high temporal and spatial resolution of direct density observations by the TM-1 constellation satellites can provide an autonomous and reliable basis for correction and improvement of atmospheric models.展开更多
The seepage mechanism plays a crucial role in low-permeability gas reservoirs.Compared with conventional gas reservoirs,low-permeability sandstone gas reservoirs are characterized by low porosity,low permeability,stro...The seepage mechanism plays a crucial role in low-permeability gas reservoirs.Compared with conventional gas reservoirs,low-permeability sandstone gas reservoirs are characterized by low porosity,low permeability,strong heterogeneity,and high water saturation.Moreover,their percolation mechanisms are more complex.The present work describes a series of experiments conducted considering low-permeability sandstone cores under pressuredepletion conditions(from the Xihu Depression in the East China Sea Basin).It is shown that the threshold pressure gradient of a low-permeability gas reservoir in thick layers is positively correlated with water saturation and negatively correlated with permeability and porosity.The reservoir stress sensitivity is related to permeability and rock composition.Stress sensitivity is generally low when permeability is high or in the early stage of gas reservoir development.It is also shown that in sand conglomerates,especially the more sparsely filled parts,the interstitial materials among the conglomerates can be rapidly dislodged from the skeleton particles under stress.This material can therefore disperse,migrate,and block the pore throat producing serious,stress-sensitive damage.展开更多
Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, ...Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, a seismic sedimentology interpretation method and workflow for point bar char- acterization is built. Firstly, the influences of seismic frequency and sandstone thickness on seismic re- flection are analyzed by outcrop detection with ground penetrating radar (GPR) and seismic forward modeling. It is found that (1) sandstone thickness can influence seismic reflection of point bar architecture. With the increasing of sandstone thickness from 1/4 wavelength (λ) to λ/2, seismic reflection geometries various from ambiguous reflection, "V" type reflection to "X" type reflection; (2) seismic frequency can influence reservoirs' seismic reflection geometry. Seismic events follow inclined lateral aggradation surfaces, which is isochronic depositional boundaries, in high frequency seismic data while the events extend along lithologic surfaces, which are level, in low frequency data. Secondly, strata slice interpretation method for thin layer depositional characterization is discussed with seismic forward modeling. Lastly, a method and workflow based on the above study is built which includes seismic frequency analysis, 90° phasing, stratal slicing and integrated interpretation of slice and seismic profile. This method is used in real data study in Tiger shoal, the Gulf of Mexico. Two episodes of meandering fluvial deposition is recognized in the study layer. Sandstone of the lower unit, which is formed in low base level stage, distributes limited. Sandstone distribution dimension and channel sinuosity become larger in the upper layer, which is high base level deposition.展开更多
3D geocellular modeling is increasingly essential in the petroleum industry;it brings together all petroleum disciplines,and it is commonly used in simulation and production forecast.However,modeling slope and deep-wa...3D geocellular modeling is increasingly essential in the petroleum industry;it brings together all petroleum disciplines,and it is commonly used in simulation and production forecast.However,modeling slope and deep-water turbidite reservoirs using conventional modeling methods pose a significant challenge due to the structural complexity and thin-beds associated with these reservoirs.Through the innovative modeling technology of PaleoScan,the reservoirs in Sub member 3 of the third member of the Shahejie Formation are modeled to understand the structural framework.The resulting model is populated with petrophysical properties i.e.,porosity and permeability to predict their lateral and vertical distribution within these sandstone reservoirs.The study suggests that the reservoir in the highstand system tract(HST)is characterized by the clinoforms configuration framework.The reservoir is highly faulted mainly in the northern and southeastern parts of the depression.The sedimentary layers are deposited across the slope and downlapping,thinning,and terminating toward to the west.The two isochore surface maps reveal sediment thickness variation and depositional trends within each individual depositional layer.The zones or areas that corresponds to low values on the thickness maps suggest minor uplifts associated with intensive faulting in the Eocene period.These topographical highs played a fundamental role in distributing the sediments delivered to the basin from distant sources.The maps reveal that sediments that filled the basin appear to come from different source points,primarily delivered from the north,southeast,and northeast of the basin with varying depositional trends.The modeled porosity and permeability indicate that the delta fed turbidite reservoirs are characterized by medium to high porosity values of 10e20%and low to medium permeability values of 30-410mD,respectively.The porosity values increase to the southeast and toward the basinwards(west)while permeability varies within the individual sedimentary layers.The distribution of porosity and permeability is not uniform vertically.This suggests the presence of mixed none-reservoir layers with locally and periodically deposited sandstone reservoirs within the stratigraphic during rapid delta progradation.The HST is characterized by six different delta progradation cycles;each phase produced locally deposited lacustrine turbidite sandstones in the basin,which are essential reservoirs in this Formation.The innovative PaleoScan interpretation technology has successfully created a high-resolution 3D reservoir model of this complex geology-such innovative technology is vital to similar complex geology globally.展开更多
Lunar exploration is deemed crucial for uncovering the origins of the Earth-Moon system and is the first step for advancing humanity’s exploration of deep space.Over the past decade,the Chinese Lunar Exploration Prog...Lunar exploration is deemed crucial for uncovering the origins of the Earth-Moon system and is the first step for advancing humanity’s exploration of deep space.Over the past decade,the Chinese Lunar Exploration Program(CLEP),also known as the Chang’e(CE)Project,has achieved remarkable milestones.It has successfully developed and demonstrated the engineering capability required to reach and return from the lunar surface.Notably,the CE Project has made historic firsts with the landing and on-site exploration of the far side of the Moon,along with the collection of the youngest volcanic samples from the Procellarum KREEP Terrane.These achievements have significantly enhanced our understanding of lunar evolution.Building on this success,China has proposed an ambitious crewed lunar exploration strategy,aiming to return to the Moon for scientific exploration and utilization.This plan encompasses two primary phases:the first crewed lunar landing and exploration,followed by a thousand-kilometer scale scientific expedition to construct a geological cross-section across the lunar surface.Recognizing the limitations of current lunar exploration efforts and China’s engineering and technical capabilities,this paper explores the benefits of crewed lunar exploration while leveraging synergies with robotic exploration.The study refines fundamental lunar scientific questions that could lead to significant breakthroughs,considering the respective engineering and technological requirements.This research lays a crucial foundation for defining the objectives of future lunar exploration,emphasizing the importance of crewed missions and offering insights into potential advancements in lunar science.展开更多
Key questions on solar wind-Moon interaction are reviewed.As the nearest celestial body to Earth,Moon’s space environment is distinctive to Earth’s mainly because of lack of a significant atmosphere/ionosphere and a...Key questions on solar wind-Moon interaction are reviewed.As the nearest celestial body to Earth,Moon’s space environment is distinctive to Earth’s mainly because of lack of a significant atmosphere/ionosphere and a global magnetic field.From a global respective,solar wind can bombard its surface,and the solar wind materials cumulated in the soil record the evolution of the Solar System.Many small-scale remanent magnetic fields are scattered over the lunar surface and,just as planetary magnetic fields protect planets,they are believed to divert the incident solar wind and shield the local lunar surface beneath,thus producing unique local surface environment that is critical to activities of human beings/facilities,thus providing unique landing sites to explore the origins of lunar swirls and remanent magnetic fields.Evidences have hinted that this local interaction,however,may be also distinct with the interacting scenario on planets,and the specific process has not been revealed because of lack of in situ observations in the near-Moon space or on the ground.The global and local solar wind interactions of the Moon represent 2 types of characteristic interaction of celestial bodies with stellar wind in deep space,i.e.,the interactions of nonmagnetized bodies and of small-scale magnetized bodies,both of which may occur on asteroids and Mars.The deep-space celestial bodies,either difficult or impossible to reach for human beings or artificial satellites,are hard to measure,and the exploration of the Moon can reveal the mystery of stellar wind interaction on these bodies.展开更多
基金funded by the China Manned Space Program (Grant Y59003AC40)TM-1 Constellation Atmospheric Density Detector (Grant E3C1162110)
文摘The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been done.In this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B satellites.The observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic storm.Densities observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the southern.The TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were higher.Swarm-B data exhibit near-symmetry between the hemispheres.In addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric near-symmetry.The South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%difference.From the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite hemisphere.NRLMSISE00 model simulations were also performed on this geomagnetic storm.TADs are absent in the NRLMSISE00 simulations.The satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both hemispheres.Therefore,use of the density simulation of NRLMSISE00 may lead to large errors in satellite drag calculations and orbit predictions.We suggest that the high temporal and spatial resolution of direct density observations by the TM-1 constellation satellites can provide an autonomous and reliable basis for correction and improvement of atmospheric models.
基金carried out at the National Natural Science Foundation of China(Nos.41672129,U19B200129)http://www.nsfc.gov.cn/and the National Science and technology Major Projects of China(No.2016ZX05027-004).
文摘The seepage mechanism plays a crucial role in low-permeability gas reservoirs.Compared with conventional gas reservoirs,low-permeability sandstone gas reservoirs are characterized by low porosity,low permeability,strong heterogeneity,and high water saturation.Moreover,their percolation mechanisms are more complex.The present work describes a series of experiments conducted considering low-permeability sandstone cores under pressuredepletion conditions(from the Xihu Depression in the East China Sea Basin).It is shown that the threshold pressure gradient of a low-permeability gas reservoir in thick layers is positively correlated with water saturation and negatively correlated with permeability and porosity.The reservoir stress sensitivity is related to permeability and rock composition.Stress sensitivity is generally low when permeability is high or in the early stage of gas reservoir development.It is also shown that in sand conglomerates,especially the more sparsely filled parts,the interstitial materials among the conglomerates can be rapidly dislodged from the skeleton particles under stress.This material can therefore disperse,migrate,and block the pore throat producing serious,stress-sensitive damage.
基金supported by the China Postdoctoral Science Foundation (No.2012M521366)the Shandong University of Science and Technology Scientific Research Startup Fund for Introduction of Talent (No.2013RCJJ009)the National Natural Science Foundation of China (No.41202092)
文摘Reservoir architecture of meandering river deposition is complex and traditional seismic facies interpretation method cannot characterize it when layer thickness is under seismic vertical reso- lution. In this study, a seismic sedimentology interpretation method and workflow for point bar char- acterization is built. Firstly, the influences of seismic frequency and sandstone thickness on seismic re- flection are analyzed by outcrop detection with ground penetrating radar (GPR) and seismic forward modeling. It is found that (1) sandstone thickness can influence seismic reflection of point bar architecture. With the increasing of sandstone thickness from 1/4 wavelength (λ) to λ/2, seismic reflection geometries various from ambiguous reflection, "V" type reflection to "X" type reflection; (2) seismic frequency can influence reservoirs' seismic reflection geometry. Seismic events follow inclined lateral aggradation surfaces, which is isochronic depositional boundaries, in high frequency seismic data while the events extend along lithologic surfaces, which are level, in low frequency data. Secondly, strata slice interpretation method for thin layer depositional characterization is discussed with seismic forward modeling. Lastly, a method and workflow based on the above study is built which includes seismic frequency analysis, 90° phasing, stratal slicing and integrated interpretation of slice and seismic profile. This method is used in real data study in Tiger shoal, the Gulf of Mexico. Two episodes of meandering fluvial deposition is recognized in the study layer. Sandstone of the lower unit, which is formed in low base level stage, distributes limited. Sandstone distribution dimension and channel sinuosity become larger in the upper layer, which is high base level deposition.
基金The work has been financially supported by the National Science and Technology Major Project of China(Grant number 2016ZX05027-004-002&2016ZX05031001-001-003)the National Natural Science Foundation of China(Grant numbers 41672129&41772139).
文摘3D geocellular modeling is increasingly essential in the petroleum industry;it brings together all petroleum disciplines,and it is commonly used in simulation and production forecast.However,modeling slope and deep-water turbidite reservoirs using conventional modeling methods pose a significant challenge due to the structural complexity and thin-beds associated with these reservoirs.Through the innovative modeling technology of PaleoScan,the reservoirs in Sub member 3 of the third member of the Shahejie Formation are modeled to understand the structural framework.The resulting model is populated with petrophysical properties i.e.,porosity and permeability to predict their lateral and vertical distribution within these sandstone reservoirs.The study suggests that the reservoir in the highstand system tract(HST)is characterized by the clinoforms configuration framework.The reservoir is highly faulted mainly in the northern and southeastern parts of the depression.The sedimentary layers are deposited across the slope and downlapping,thinning,and terminating toward to the west.The two isochore surface maps reveal sediment thickness variation and depositional trends within each individual depositional layer.The zones or areas that corresponds to low values on the thickness maps suggest minor uplifts associated with intensive faulting in the Eocene period.These topographical highs played a fundamental role in distributing the sediments delivered to the basin from distant sources.The maps reveal that sediments that filled the basin appear to come from different source points,primarily delivered from the north,southeast,and northeast of the basin with varying depositional trends.The modeled porosity and permeability indicate that the delta fed turbidite reservoirs are characterized by medium to high porosity values of 10e20%and low to medium permeability values of 30-410mD,respectively.The porosity values increase to the southeast and toward the basinwards(west)while permeability varies within the individual sedimentary layers.The distribution of porosity and permeability is not uniform vertically.This suggests the presence of mixed none-reservoir layers with locally and periodically deposited sandstone reservoirs within the stratigraphic during rapid delta progradation.The HST is characterized by six different delta progradation cycles;each phase produced locally deposited lacustrine turbidite sandstones in the basin,which are essential reservoirs in this Formation.The innovative PaleoScan interpretation technology has successfully created a high-resolution 3D reservoir model of this complex geology-such innovative technology is vital to similar complex geology globally.
基金supported by the National Natural Science Foundation of China(L2224032)the Research Project on the Discipline Development Strategy of Academic Divisions of the Chinese Academy of Sciences(XK2022DXC004).
文摘Lunar exploration is deemed crucial for uncovering the origins of the Earth-Moon system and is the first step for advancing humanity’s exploration of deep space.Over the past decade,the Chinese Lunar Exploration Program(CLEP),also known as the Chang’e(CE)Project,has achieved remarkable milestones.It has successfully developed and demonstrated the engineering capability required to reach and return from the lunar surface.Notably,the CE Project has made historic firsts with the landing and on-site exploration of the far side of the Moon,along with the collection of the youngest volcanic samples from the Procellarum KREEP Terrane.These achievements have significantly enhanced our understanding of lunar evolution.Building on this success,China has proposed an ambitious crewed lunar exploration strategy,aiming to return to the Moon for scientific exploration and utilization.This plan encompasses two primary phases:the first crewed lunar landing and exploration,followed by a thousand-kilometer scale scientific expedition to construct a geological cross-section across the lunar surface.Recognizing the limitations of current lunar exploration efforts and China’s engineering and technical capabilities,this paper explores the benefits of crewed lunar exploration while leveraging synergies with robotic exploration.The study refines fundamental lunar scientific questions that could lead to significant breakthroughs,considering the respective engineering and technological requirements.This research lays a crucial foundation for defining the objectives of future lunar exploration,emphasizing the importance of crewed missions and offering insights into potential advancements in lunar science.
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(grant no.XDB41000000)the National Natural Science Foundation of China(41941001 and L2224032)the Chinese Academy of Sciences(XK2022DXC004).
文摘Key questions on solar wind-Moon interaction are reviewed.As the nearest celestial body to Earth,Moon’s space environment is distinctive to Earth’s mainly because of lack of a significant atmosphere/ionosphere and a global magnetic field.From a global respective,solar wind can bombard its surface,and the solar wind materials cumulated in the soil record the evolution of the Solar System.Many small-scale remanent magnetic fields are scattered over the lunar surface and,just as planetary magnetic fields protect planets,they are believed to divert the incident solar wind and shield the local lunar surface beneath,thus producing unique local surface environment that is critical to activities of human beings/facilities,thus providing unique landing sites to explore the origins of lunar swirls and remanent magnetic fields.Evidences have hinted that this local interaction,however,may be also distinct with the interacting scenario on planets,and the specific process has not been revealed because of lack of in situ observations in the near-Moon space or on the ground.The global and local solar wind interactions of the Moon represent 2 types of characteristic interaction of celestial bodies with stellar wind in deep space,i.e.,the interactions of nonmagnetized bodies and of small-scale magnetized bodies,both of which may occur on asteroids and Mars.The deep-space celestial bodies,either difficult or impossible to reach for human beings or artificial satellites,are hard to measure,and the exploration of the Moon can reveal the mystery of stellar wind interaction on these bodies.