Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.L...Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.Leveraging high temporal and spatial resolution observations from ground-based and space-borne instruments,we have identified a two-sided-loop jet originating from magnetic reconnection between threads within a single filament.Our observations show that as two initially crossing filamentary threads within the filament converge,reconnection takes place at their intersection.In the Doppler images,distinct redshift and blueshift signals are observed at the locations where the filament threads intersected.This process generates a two-sided-loop jet with outflow speeds of 22.2 and 62.5 km s^(-1).Following reconnection,the original crossing threads transform into two parallel threads that subsequently separate at speeds of 2.8 and 8.3kms^(-1).This observation offers a new perspective on the mechanisms responsible for jet formation.展开更多
Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and...Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and deformation of the three ferrofluid droplets are studied in this paper.Results show that there are four modes(i.e.,the three droplets'direct coalescence(TC),the coalescence of two droplets and the subsequent planetary motion with the third droplet(CAP),the three droplets'planetary motion(TP),and the independent spin(IS))for the three ferrofluid droplets,dependent on the magnetic Bond number(Bom)and the initial distance(d0)between two of the droplets.It is found that the decrease in d0and the increase in Bomcan make the droplets'mode change from the IS to the planetary motion,and then turn to the CAP.Furthermore,reducing Bomor d0is helpful for the droplets to become merged.展开更多
Based on the Fliigge shell theory, equations of motion of ring-stiffened thin-walled cylindrical shells conveying fluid are developed with the aid of the Hamilton＇s principle. Analysis is carried out on the vibration...Based on the Fliigge shell theory, equations of motion of ring-stiffened thin-walled cylindrical shells conveying fluid are developed with the aid of the Hamilton＇s principle. Analysis is carried out on the vibration and stability of the ring-stiffened shells conveying fluid, and the effects of fluid velocity, the Young modulus, the size, and the number of the ring stiffeners on the natural frequency and the instability characteristics are examined. It is found that stiffeners can reduce the number of circumferential waves for the fundamental mode, and increase the shell＇s natural frequency, and thus the critical fluid velocity. For the number of longitudinal half waves being equal to one, the natural frequency and the corresponding critical fluid velocity are the largest for the internal-ring stiffened shell and are the smallest for the symmetrical-ring stiffened shell. The natural frequencies and the corresponding critical fluid velocity predicted by the established model increase with the increase in the Young modulus, the size, or the number of the stiffeners.展开更多
Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their moveme...Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and search.This article mainly reviews the research progress of biomimetic water strider robots.First,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are summarized.The basic equations of water strider movement are then described.Next,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure dominance.Based on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is discussed.This article provides new insights for the design of biomimetic water strider robots.展开更多
Castleman disease （CD） is an uncommon non-clonal lymphoproliferative disorder with unknown etiology. No standard therapy is recommended for relapsed/refractory CD patients, thus requiring development of novel experi...Castleman disease （CD） is an uncommon non-clonal lymphoproliferative disorder with unknown etiology. No standard therapy is recommended for relapsed/refractory CD patients, thus requiring development of novel experimental approaches. Our cohort of three adult patients with multicentric CD （MCD） were treated with refractory to traditional chemotherapy lenalidomide-containing regimens （10-25 mg lenalidomide perorally administered on days 1-21 in 28-day cycle） as second- to fourth-line treatment. Partial remission was achieved in first plasma-cell CD patient, who relapsed seven months after autologous hematopoietic stem cell transplantation and then failed to respond to four cycles of chemotherapy. Partial remission was obtained in second patient with CD and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome. Third case showed complete remission with complete disappearance of pleural effusion and ascites and normalization of platelet count. To conclude, encouraging clinical responses were achieved in cohort of three patients with lenalidomide-based regimen, though long-term efficacy remains to be observed. We propose further investigation of therapeutic potential of this drug in treating MCD.展开更多
Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,smal...Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,small sweet spot areas,and poor distribution continuity.Thus,identifying the“sweet spots”in shale oil reservoirs is critical for the efficient exploration and development of terrestrial shale oil.This study targets the siltstone type(Class-Ⅱshale oil)and pure shale type(Class-Ⅲshale oil)of the Chang 7 Member in the Ordos Basin,and identifies three stratigraphic units,namely the hydrocarbon accumulation unit,hydrocarbon generation unit,and hydrocarbon retention unit,which together constitute the in-source“shale oil system”.The hydrocarbon accumulation unit is mainly siltstone,where the hydrocarbons are migrated from shales.It has favorable porethroat network connectivity with a pore connectivity ratio of 32–57%,being the siltstone-type sweet spots.The hydrocarbon generation unit is mainly composed of high-TOC mudstone/shale and is the main contributor to in-source hydrocarbon generation and expulsion.This unit has high three-dimensional connectivity(28–30%),as shown by the pore-throat network model,associated with vertical paths for hydrocarbon expulsion.The hydrocarbon retention unit is mainly composed of low-TOC mudstone/shale retaining self-generated and migrated hydrocarbons.The pore connectivity rate is 17–42%,and the pore-throat network connectivity direction is uneven.Light and low-carbon-number hydrocarbons are preferentially trapped or even sealed in small pores of the retention unit,forming the typical mudstone/shale-type sweet spots.In the process called shale oil intrasource migration,the oil migrates in source rocks causing component fractionation,which allows more shale oil to enrich in the hydrocarbon accumulation and retention units to form sweet spots,compared with the hydrocarbon generation unit.The migration paths include the one from mudstone/shale to siltstone interlayers and that from the high-TOC mudstone/shale intervals to the low-TOC intervals.The in-source accumulation of shale oil shows the differentiated enrichment model featuring“high-TOC mudstone/shale generating hydrocarbons,low-TOC mudstone/shale retaining hydrocarbons,siltstone accumulating hydrocarbons and multiple intra-source migration paths”.In the Ordos Basin,the organic-lean(TOC 1–3%)mudstone/shale intervals appear to be the sweet spots of shale oil,where there are abundant medium-short-chain hydrocarbons retained with high flowability.After fracturing stimulation,their production conditions may be even superior to those of siltstones.This proposed idea changes the previous strategy to look for sweet spots in high-TOC intervals derived from the shale gas industry.展开更多
Acquired thrombotic thrombocytopenic purpura （TTP） is a rare life-threatening thrombotic microangiopathy. This study aimed to provide a profile of the diagnosis and management of patients with acquired TTP collected...Acquired thrombotic thrombocytopenic purpura （TTP） is a rare life-threatening thrombotic microangiopathy. This study aimed to provide a profile of the diagnosis and management of patients with acquired TTP collected in 10 years in a single center in southeast China. A total of 60 patients diagnosed with acute acquired TTP from March 2005 to August 2015 were enrolled. Among the 60 patients, 52 patients presented with their first episodes, and eight patients had two or more episodes. The median age at presentation was 49 （range, 17 to 78） years with a female predominance （male：female ratio, 1：1.60）. ADAMTS 13 activity were analyzed in 43 patients, among whom 33 （76.7%） patients had a baseline level of 〈 5%. Mortality was 30%. Plasma exchange （PEX） was performed in 62 of 69 （89.9%） episodes. Corticosteroids were administered in 54 of 69 （78.3%） episodes. Other immunosuppressants （e.g., vincristine, cyclosporine, and cyclosporin） were used in 7 of 69 （10.1%） episodes. Rituximab was documented in 4 patients with refractory/relapsed TTP for 5 episodes, showing encouraging results. In conclusion, the diagnosis of TTP depended on a comprehensive analysis of clinical data. Plasma ADAMTS13 activity assay helped confirm a diagnosis. PEX was the mainstay of the therapy, and rituximab can be used in relapsed/refractory disease.展开更多
The excitation mechanism of coronal quasi-period fast-propagating(QFP)wave trains remains unresolved.Using Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory observations,we study a narrow and a broad...The excitation mechanism of coronal quasi-period fast-propagating(QFP)wave trains remains unresolved.Using Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory observations,we study a narrow and a broad QFP wave trains excited one after another during the successive eruptions of filaments hosted within a fan-spine magnetic system on October 20,2013.The consecutive occurrence of these two types of QFP wave trains in the same event provides an excellent opportunity to explore their excitation mechanisms and compare their physical parameters.Our observational results reveal that narrow and broad QFP wave trains exhibit distinct speeds,periods,energy fluxes,and relative intensity amplitudes,although originating from the same active region and being associated with the same GOES C2.9 flare.Using wavelet analysis,we find that the narrow QFP wave train shares a similar period with the flare itself,suggesting its possible excitation through the pulsed energy release in the magnetic reconnection process that generated the accompanying flare.On the other hand,the broad QFP wave train appears to be associated with the energy pulses released by the successive expansion and unwinding of filament threads.Additionally,it is plausible that the broad QFP wave train was also excited by the sequential stretching of closed magnetic field lines driven by the erupting filament.These findings shed light on the different excitation mechanisms and origins of the QFP wave trains.展开更多
The Qingcheng oilfield,the largest shale oil field in China,was discovered in 2019 in source rock of Chang 7 Member of Mesozoic Yanchang Formation,Changqing Oilfield in Ordos Basin,with newly increased proven geologic...The Qingcheng oilfield,the largest shale oil field in China,was discovered in 2019 in source rock of Chang 7 Member of Mesozoic Yanchang Formation,Changqing Oilfield in Ordos Basin,with newly increased proven geological reserves of 358 million tons,predicted geological reserves of 693 million tons,and a total of 1.051 billion tons of shale oil resources.This achieves a historic breakthrough in exploration of shale oil in Chang 7 Member.In recent years,focusing on key issues,such as whether there develop sweet spots in source rock,whether commercial oil production capacity can be formed,and whether scale-effective development can be achieved,studies about geological conditions for shale oil accumulation have been continuously carried out,key supporting technologies have been developed,and a series of theoretical innovations and technological breakthroughs have been achieved in oil exploration in source rocks.The results indicate that shale oil accumulation in Chang 7 Member is controlled by following factors.Firstly,lacustrine black shale,dark mudstone and other high-quality source rocks lay a material foundation for shale oil formation.Secondly,sandy deposits intercalated within black shale and dark mudstones are exploration sweet spots,and sandbody combination types are controlled by morphology of bottom of the lacustrine basin.Thirdly,reservoir properties are good due to development of micro-nano pore throats.Finally,reservoirs with high oil saturation and high gas-oil ratio are formed due to high-intensity oil charging in source rock.Effective matching of multiple factors is a key for shale oil accumulation in Chang 7 Member in Ordos Basin.Through innovation of key supporting technologies,exploration and development technologies for shale oil are developed,and substantial breakthrough on exploration and development of shale oil is realized.The first application of logging-seismic combination technology in loess plateau improves significantly quality of 3D seismic data,which effectively guides prediction of sandy sweet spots.Three-quality well logging technology is used for further evaluation of geological and engineering sweet spots of shale oil.With volumetric fracturing technology based on precise segmentation of long horizontal wells,initial daily oil production of individual well is increased from previously 10 tons to more than 18 tons.The exploration breakthrough in source rocks in Chang 7 Member in Qingcheng oilfield provides an important resource base for the second accelerated development of Changqing Oilfield.It is predicated that oil production from shale in Chang 7 Member in Qingcheng oilfield will reach three million tons in 2022 and five million tons in 2025.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.12303062 and 12203043)the Sichuan Science and Technology Program(2023NSFSC1351,2025ZNSFSC0315)+1 种基金Key Laboratory of Detection and Application of Space Effect in Southwest Sichuan at Leshan Normal University,Education Department of Sichuan Province(No.ZDXM20241002)Project Supported by the Specialized Research Fund for State Key Laboratory of Solar Activity and Space Weather。
文摘Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.Leveraging high temporal and spatial resolution observations from ground-based and space-borne instruments,we have identified a two-sided-loop jet originating from magnetic reconnection between threads within a single filament.Our observations show that as two initially crossing filamentary threads within the filament converge,reconnection takes place at their intersection.In the Doppler images,distinct redshift and blueshift signals are observed at the locations where the filament threads intersected.This process generates a two-sided-loop jet with outflow speeds of 22.2 and 62.5 km s^(-1).Following reconnection,the original crossing threads transform into two parallel threads that subsequently separate at speeds of 2.8 and 8.3kms^(-1).This observation offers a new perspective on the mechanisms responsible for jet formation.
基金Project supported by the National Natural Science Foundation of China(No.12372263)。
文摘Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and deformation of the three ferrofluid droplets are studied in this paper.Results show that there are four modes(i.e.,the three droplets'direct coalescence(TC),the coalescence of two droplets and the subsequent planetary motion with the third droplet(CAP),the three droplets'planetary motion(TP),and the independent spin(IS))for the three ferrofluid droplets,dependent on the magnetic Bond number(Bom)and the initial distance(d0)between two of the droplets.It is found that the decrease in d0and the increase in Bomcan make the droplets'mode change from the IS to the planetary motion,and then turn to the CAP.Furthermore,reducing Bomor d0is helpful for the droplets to become merged.
基金supported by the National Natural Science Foundation of China (No. 50908094)the Ph. D. Programs Foundation of Ministry of Education of China (No. 20100142120071)the Natural Science Foundation of Hubei Province (No. 2010CDB02204)
文摘Based on the Fliigge shell theory, equations of motion of ring-stiffened thin-walled cylindrical shells conveying fluid are developed with the aid of the Hamilton＇s principle. Analysis is carried out on the vibration and stability of the ring-stiffened shells conveying fluid, and the effects of fluid velocity, the Young modulus, the size, and the number of the ring stiffeners on the natural frequency and the instability characteristics are examined. It is found that stiffeners can reduce the number of circumferential waves for the fundamental mode, and increase the shell＇s natural frequency, and thus the critical fluid velocity. For the number of longitudinal half waves being equal to one, the natural frequency and the corresponding critical fluid velocity are the largest for the internal-ring stiffened shell and are the smallest for the symmetrical-ring stiffened shell. The natural frequencies and the corresponding critical fluid velocity predicted by the established model increase with the increase in the Young modulus, the size, or the number of the stiffeners.
基金supported in part by the National Natural Science Foundation of China(No.11972170).
文摘Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and search.This article mainly reviews the research progress of biomimetic water strider robots.First,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are summarized.The basic equations of water strider movement are then described.Next,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure dominance.Based on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is discussed.This article provides new insights for the design of biomimetic water strider robots.
文摘Castleman disease （CD） is an uncommon non-clonal lymphoproliferative disorder with unknown etiology. No standard therapy is recommended for relapsed/refractory CD patients, thus requiring development of novel experimental approaches. Our cohort of three adult patients with multicentric CD （MCD） were treated with refractory to traditional chemotherapy lenalidomide-containing regimens （10-25 mg lenalidomide perorally administered on days 1-21 in 28-day cycle） as second- to fourth-line treatment. Partial remission was achieved in first plasma-cell CD patient, who relapsed seven months after autologous hematopoietic stem cell transplantation and then failed to respond to four cycles of chemotherapy. Partial remission was obtained in second patient with CD and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome. Third case showed complete remission with complete disappearance of pleural effusion and ascites and normalization of platelet count. To conclude, encouraging clinical responses were achieved in cohort of three patients with lenalidomide-based regimen, though long-term efficacy remains to be observed. We propose further investigation of therapeutic potential of this drug in treating MCD.
基金funded by the National Natural Science Foundation of China(Grant Nos.41902151,42172180,41830431,and 41902144)the Petro China Scientific Research and Technology Development Project(Grant No.2021DJ1802)。
文摘Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,small sweet spot areas,and poor distribution continuity.Thus,identifying the“sweet spots”in shale oil reservoirs is critical for the efficient exploration and development of terrestrial shale oil.This study targets the siltstone type(Class-Ⅱshale oil)and pure shale type(Class-Ⅲshale oil)of the Chang 7 Member in the Ordos Basin,and identifies three stratigraphic units,namely the hydrocarbon accumulation unit,hydrocarbon generation unit,and hydrocarbon retention unit,which together constitute the in-source“shale oil system”.The hydrocarbon accumulation unit is mainly siltstone,where the hydrocarbons are migrated from shales.It has favorable porethroat network connectivity with a pore connectivity ratio of 32–57%,being the siltstone-type sweet spots.The hydrocarbon generation unit is mainly composed of high-TOC mudstone/shale and is the main contributor to in-source hydrocarbon generation and expulsion.This unit has high three-dimensional connectivity(28–30%),as shown by the pore-throat network model,associated with vertical paths for hydrocarbon expulsion.The hydrocarbon retention unit is mainly composed of low-TOC mudstone/shale retaining self-generated and migrated hydrocarbons.The pore connectivity rate is 17–42%,and the pore-throat network connectivity direction is uneven.Light and low-carbon-number hydrocarbons are preferentially trapped or even sealed in small pores of the retention unit,forming the typical mudstone/shale-type sweet spots.In the process called shale oil intrasource migration,the oil migrates in source rocks causing component fractionation,which allows more shale oil to enrich in the hydrocarbon accumulation and retention units to form sweet spots,compared with the hydrocarbon generation unit.The migration paths include the one from mudstone/shale to siltstone interlayers and that from the high-TOC mudstone/shale intervals to the low-TOC intervals.The in-source accumulation of shale oil shows the differentiated enrichment model featuring“high-TOC mudstone/shale generating hydrocarbons,low-TOC mudstone/shale retaining hydrocarbons,siltstone accumulating hydrocarbons and multiple intra-source migration paths”.In the Ordos Basin,the organic-lean(TOC 1–3%)mudstone/shale intervals appear to be the sweet spots of shale oil,where there are abundant medium-short-chain hydrocarbons retained with high flowability.After fracturing stimulation,their production conditions may be even superior to those of siltstones.This proposed idea changes the previous strategy to look for sweet spots in high-TOC intervals derived from the shale gas industry.
文摘Acquired thrombotic thrombocytopenic purpura （TTP） is a rare life-threatening thrombotic microangiopathy. This study aimed to provide a profile of the diagnosis and management of patients with acquired TTP collected in 10 years in a single center in southeast China. A total of 60 patients diagnosed with acute acquired TTP from March 2005 to August 2015 were enrolled. Among the 60 patients, 52 patients presented with their first episodes, and eight patients had two or more episodes. The median age at presentation was 49 （range, 17 to 78） years with a female predominance （male：female ratio, 1：1.60）. ADAMTS 13 activity were analyzed in 43 patients, among whom 33 （76.7%） patients had a baseline level of 〈 5%. Mortality was 30%. Plasma exchange （PEX） was performed in 62 of 69 （89.9%） episodes. Corticosteroids were administered in 54 of 69 （78.3%） episodes. Other immunosuppressants （e.g., vincristine, cyclosporine, and cyclosporin） were used in 7 of 69 （10.1%） episodes. Rituximab was documented in 4 patients with refractory/relapsed TTP for 5 episodes, showing encouraging results. In conclusion, the diagnosis of TTP depended on a comprehensive analysis of clinical data. Plasma ADAMTS13 activity assay helped confirm a diagnosis. PEX was the mainstay of the therapy, and rituximab can be used in relapsed/refractory disease.
基金supported by the National Natural Science Foundation of China(Grant No.12303062)the Natural Science Foundation for Youths of Sichuan Province(Grant No.2023NSFSC1351)+4 种基金the Project Supported by the Specialized Research Fund for State Key Laboratoriessupported by the National Natural Science Foundation of China(Grant No.12173083)the Yunnan Science Foundation for Distinguished Young Scholars(Grant No.202101AV070004)the Researchers Supporting Project(Grant Nos.RSPD2023R993,and RSPD2024R993),King Saud University,Riyadh,Saudi ArabiaISSI-BJ for supporting the international team“Magnetohydrodynamic wave trains as a tool for probing the solar corona”。
文摘The excitation mechanism of coronal quasi-period fast-propagating(QFP)wave trains remains unresolved.Using Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory observations,we study a narrow and a broad QFP wave trains excited one after another during the successive eruptions of filaments hosted within a fan-spine magnetic system on October 20,2013.The consecutive occurrence of these two types of QFP wave trains in the same event provides an excellent opportunity to explore their excitation mechanisms and compare their physical parameters.Our observational results reveal that narrow and broad QFP wave trains exhibit distinct speeds,periods,energy fluxes,and relative intensity amplitudes,although originating from the same active region and being associated with the same GOES C2.9 flare.Using wavelet analysis,we find that the narrow QFP wave train shares a similar period with the flare itself,suggesting its possible excitation through the pulsed energy release in the magnetic reconnection process that generated the accompanying flare.On the other hand,the broad QFP wave train appears to be associated with the energy pulses released by the successive expansion and unwinding of filament threads.Additionally,it is plausible that the broad QFP wave train was also excited by the sequential stretching of closed magnetic field lines driven by the erupting filament.These findings shed light on the different excitation mechanisms and origins of the QFP wave trains.
基金supported by the National Research Council of Science and Technology Major Project of China(No.2016ZX05050,No.2017ZX05001002)National Key Basic Research Project of China(973 Program)(No.2014CB239003).
文摘The Qingcheng oilfield,the largest shale oil field in China,was discovered in 2019 in source rock of Chang 7 Member of Mesozoic Yanchang Formation,Changqing Oilfield in Ordos Basin,with newly increased proven geological reserves of 358 million tons,predicted geological reserves of 693 million tons,and a total of 1.051 billion tons of shale oil resources.This achieves a historic breakthrough in exploration of shale oil in Chang 7 Member.In recent years,focusing on key issues,such as whether there develop sweet spots in source rock,whether commercial oil production capacity can be formed,and whether scale-effective development can be achieved,studies about geological conditions for shale oil accumulation have been continuously carried out,key supporting technologies have been developed,and a series of theoretical innovations and technological breakthroughs have been achieved in oil exploration in source rocks.The results indicate that shale oil accumulation in Chang 7 Member is controlled by following factors.Firstly,lacustrine black shale,dark mudstone and other high-quality source rocks lay a material foundation for shale oil formation.Secondly,sandy deposits intercalated within black shale and dark mudstones are exploration sweet spots,and sandbody combination types are controlled by morphology of bottom of the lacustrine basin.Thirdly,reservoir properties are good due to development of micro-nano pore throats.Finally,reservoirs with high oil saturation and high gas-oil ratio are formed due to high-intensity oil charging in source rock.Effective matching of multiple factors is a key for shale oil accumulation in Chang 7 Member in Ordos Basin.Through innovation of key supporting technologies,exploration and development technologies for shale oil are developed,and substantial breakthrough on exploration and development of shale oil is realized.The first application of logging-seismic combination technology in loess plateau improves significantly quality of 3D seismic data,which effectively guides prediction of sandy sweet spots.Three-quality well logging technology is used for further evaluation of geological and engineering sweet spots of shale oil.With volumetric fracturing technology based on precise segmentation of long horizontal wells,initial daily oil production of individual well is increased from previously 10 tons to more than 18 tons.The exploration breakthrough in source rocks in Chang 7 Member in Qingcheng oilfield provides an important resource base for the second accelerated development of Changqing Oilfield.It is predicated that oil production from shale in Chang 7 Member in Qingcheng oilfield will reach three million tons in 2022 and five million tons in 2025.
