Tectonism is one of the dominant factors affecting the shale pore structure.However,the control of shale pore structure by tectonic movements is still controversial,which limits the research progress of shale gas accu...Tectonism is one of the dominant factors affecting the shale pore structure.However,the control of shale pore structure by tectonic movements is still controversial,which limits the research progress of shale gas accumulation mechanism in the complex tectonic region of southern China.In this study,34 samples were collected from two exploratory wells located in different tectonic locations.Diverse experiments,e.g.,organic geochemistry,XRD analysis,FE-SEM,low-pressure gas adsorption,and high-pressure mercury intrusion,were conducted to fully characterize the shale reservoir.The TOC,Ro,and mineral composition of the shale samples between the two wells are similar,which reflects that the shale samples of the two wells have proximate pores-generating capacity and pores-supporting capacity.However,the pore characteristics of shale samples from two wells are significantly different.Compared with the stabilized zone shale,the porosity,pore volume,and specific surface area of the deformed zone shale were reduced by 60.61%,64.85%,and 27.81%,respectively.Moreover,the macroscopic and fine pores were reduced by 54.01%and 84.95%,respectively.Fault activity and uplift denudation are not conducive to pore preservation,and the rigid basement of Huangling uplift can promote pore preservation.These three factors are important reasons for controlling the difference in pore structure between two wells shales.We established a conceptual model of shale pores evolution under different tectonic preservation conditions.This study is significant to clarify the scale of shale gas formation and enrichment in complex tectonic regions,and helps in the selection of shale sweet spots.展开更多
Latent variable models can effectively determine the condition of essential rotating machinery without needing labeled data.These models analyze vibration data via an unsupervised learning strategy.Temporal preservati...Latent variable models can effectively determine the condition of essential rotating machinery without needing labeled data.These models analyze vibration data via an unsupervised learning strategy.Temporal preservation is necessary to obtain an informative latent manifold for the fault diagnosis task.In a temporalpreserving context,two approaches exist to develop a condition-monitoring methodology:offline and online.For latent variable models,the available training modes are not different.While many traditional methods use offline training,online training can dynamically adjust the latent manifold,possibly leading to better fault signature extraction from the vibration data.This study explores online training using temporal-preserving latent variable models.Within online training,there are two main methods:one focuses on reconstructing data and the other on interpreting the data components.Both are considered to evaluate how they diagnose faults over time.Using two experimental datasets,the study confirms that models from both training modes can detect changes in machinery health and identify faults even under varying conditions.Importantly,the complementarity of offline and online models is emphasized,reassuring their versatility in fault diagnostics.Understanding the implications of the training approach and the available model formulations is crucial for further research in latent variable modelbased fault diagnostics.展开更多
[Objective] This study aimed to investigate the effect of different short-term preservation conditions on mycelial growth of Morchella conica, and search for opti- mum preservation conditions. [Method] M. conica strai...[Objective] This study aimed to investigate the effect of different short-term preservation conditions on mycelial growth of Morchella conica, and search for opti- mum preservation conditions. [Method] M. conica strains in tubes were preserved at two temperature treatments 10 ℃/5 ℃ （day/night） and 15℃/10 ℃（day/night） in scat- tered light or dark for 30 or 60 d. The strain preserved at 4 ℃ dark for 90 d was the control （CK）. So, a total of nine treatments were prepared in this study. [Result] Mycelial growth of M. conica preserved at 10 ℃/5 ℃ was better than that at 15 ℃/10 ℃ and control. The colony color and aerial hyphae of strains preserved in scattered light was also better than that in dark. Additionally, the preservation time showed no distinct effect on mycelial growth at 10 ℃/5 ℃. So the time could be lengthened. But the maximal preservation time was 60 d at 15 ℃/10 ℃. Therefore, preserved under the appropriate conditions of 10 ℃/5 ℃, scattered light for 30 d, the strain had the neat colony edge, moderate aerial mycelia, dense mycelia, lower sectoral variation, uniform mycelial growth rate and high dry weight of mycelia.展开更多
The Upper Ordovician-Lower Silurian Longmaxi Shale in the Upper Yangtze block represents one of the most important shale gas plays in China. The shale composition, porosity, organic thermal maturity, and methane sorpt...The Upper Ordovician-Lower Silurian Longmaxi Shale in the Upper Yangtze block represents one of the most important shale gas plays in China. The shale composition, porosity, organic thermal maturity, and methane sorption were investigated at the Qilongcun section in the Dingshan area, southeastern Sichuan Basin. The results show that the Upper Ordovician-Lower Silurian Longmaxi Shale contains： （1） sapropelic I organic matter; （2） a 40-m thick bedded sequence where total organic carbon （TOC） content is 〉 2%; （3） a 30-m thick layer at the base of the Longmaxi Shale with a brittle mineral content higher than 50%; and （4） a mean methane adsorption capacity of 1.80 cm3/g （7 MPa pressure）. A positive correlation between TOC and sorbed gas indicates that organic matter content exerts an important control on methane storage capacity. Based on the analysis of the shale reservoir characteristics, the lower member of the Longmaxi Shale can thus be considered a favorable stratum for shale gas exploration and exploitation. It has similar reservoir characteristics with the Longmaxi Shale in the Jiaoshiba area tested with a high-yield industrial gas flow. However, based on tectonic analysis, differences in the level of industrial gas flow between the low-yield study area and the high-yield Jiaoshiba area may result from different tectonic preservation conditions. Evidence from these studies indicates the shale gas potential of the Longmaxi Shale is constrained by the reservoir and preservation conditions.展开更多
^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source ...^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source and migration path of key fluids related to development of hydrocarbon, hydrocarbon preservation condition are then discussed further. Comprehensive research, based on the paleo-fluid, the property of formation water and the deformation intensity etc., indicates that the preservation conditions in the Shizhu synclinorium zone and Fangdoushan anticlinorium zone are the most predominant in the central Yangtze. Three sets of fluid systems in the Shizhu synclinorium zone are identified. Little fluid exchange occurs between the upper-middle fluid system and the lower fluid system, so two independent preservation units have developed. Both the Permian and the Triassic in the upper preservation units and the Dengying Formation of the Sinian and the lower Cambrian in the lower preservation units have good preservation conditions. The preservation condition in the lower association （Z-S） located in the Huaguoping synclinorium zone in the western Hubei and Hunan is better than that in other tectonic units, where the fluids in the lower association migrated vertically across strata when the fluid isolating intervals were destroyed, the regional seals are absent and the conditions for the preservation of hydrocarbon accumulations are totally destroyed. The preservation condition is increasingly more favorable from the western Jiangxi and Hunan to the western Hubei ＆ eastern Chongqing on the whole.展开更多
In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin,a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth B...In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin,a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth Basin,the Jiaoshiba shale gas reservoirs in Sichuan Basin and potential shale gas reservoirs in Guizhou Province.The results show that the "Sandwich"structure is of great importance for shale gas accumulation.Therein to,the "Sandwich"structure is a kind of special reservoir-cap rock assemblage which consist of limestone or dolomite on the top,mudstone or shale layer in the middle and limestone or dolomite at the bottom.In consideration of the Mesozoic-Paleozoie in the Lower Yangtze,and Laoshan Uplift with weak Paleozoic deformation and thrust fault sealing On both flanks of the Laoshan Uplift,a conclusion can be drawn that the preservation conditions of shale gas probably developed "Sandwich" structures in the Lower Cambrian and Permian,which are key layers for the breakthrough of shale gas in the South Yellow Sea.Moreover,the preferred targets for shale gas drilling probably locate at both flanks of the Laoshan Uplift.展开更多
As shallow resources are increasingly depleted,the mechanics'theory and testing technology of deep insitu rock has become urgent.Traditional coring technologies obtain rock samples without retaining the in-situ en...As shallow resources are increasingly depleted,the mechanics'theory and testing technology of deep insitu rock has become urgent.Traditional coring technologies obtain rock samples without retaining the in-situ environmental conditions,leading to distortion of the measured parameters.Herein,a coring and testing systems retaining in-situ geological conditions is presented:the coring system that obtains in-situ rock samples,and the transfer and testing system that stores and analyzes the rocks under a reconstructed environment.The ICP-Coring system mainly consists of the pressure controller,active insulated core reactor and insulation layer and sealing film.The ultimate bearing strength of 100 MPa for pressurepreservation,temperature control accuracy of 0.97%for temperature-retained are realized.CH_(4)and CO permeability of the optimized sealing film are as low as 3.85 and 0.33 ppm/min.The average tensile elongation of the film is 152.4%and the light transmittance is reduced to 0%.Additionally,the pressure and steady-state temperature accuracy for reconstructing the in-situ environment of transfer and storage system up to 1%and±0.2 is achieved.The error recorded of the noncontact sensor ring made of lowdensity polymer is less than 6%than that of the contact test.The system can provide technical support for the deep in-situ rock mechanics research,improving deep resource acquisition capabilities and further clarifying deep-earth processes.展开更多
With the application of artificial intelligence technology in the power industry,the knowledge graph is expected to play a key role in power grid dispatch processes,intelligent maintenance,and customer service respons...With the application of artificial intelligence technology in the power industry,the knowledge graph is expected to play a key role in power grid dispatch processes,intelligent maintenance,and customer service response provision.Knowledge graphs are usually constructed based on entity recognition.Specifically,based on the mining of entity attributes and relationships,domain knowledge graphs can be constructed through knowledge fusion.In this work,the entities and characteristics of power entity recognition are analyzed,the mechanism of entity recognition is clarified,and entity recognition techniques are analyzed in the context of the power domain.Power entity recognition based on the conditional random fields (CRF) and bidirectional long short-term memory (BLSTM) models is investigated,and the two methods are comparatively analyzed.The results indicated that the CRF model,with an accuracy of 83%,can better identify the power entities compared to the BLSTM.The CRF approach can thus be applied to the entity extraction for knowledge graph construction in the power field.展开更多
Initial labor market conditions affect how individuals build their human capital and look for jobs and thus can have long-term effects on their income levels,work performance,and career development.Based on data from ...Initial labor market conditions affect how individuals build their human capital and look for jobs and thus can have long-term effects on their income levels,work performance,and career development.Based on data from the Urban Household Survey(UHS)of urban households in China from 1986 to 2009,we perform an empirical test of how initial labor market conditions affect the employability of individuals.Our research shows that people’s future incomes suffer if they start out in an adverse job market.Each percentage point of increase in the unemployment rate at an individual’s entry into the labor market is associated with a two-percentage-point drop in his or her average annual income.Even after looking at different parts of the job market and sample groups,this conclusion still holds.In the context of global economic instability,our findings may assist government policymakers in addressing adverse labor market conditions.展开更多
Significant breakthroughs of shale gas exploration have been made in Lower Cambrian and Sinian shale in the north margin of the Yangtze Block,South China.The drill wells with industrial gas flow located in the souther...Significant breakthroughs of shale gas exploration have been made in Lower Cambrian and Sinian shale in the north margin of the Yangtze Block,South China.The drill wells with industrial gas flow located in the southern margin of the Huangling dome.Base on the geological survey,2D seismic,geochronological and drill wells data,the tectonic evolution history of Huangling dome was studied,and its control effect on the preservation condition of shale gas was discussed.The result shows that the Huangling dome might undergo four tectonic stages:(1)About 800 Ma,granite intrusion in the Huangling dome basement,primarily of granites replaced metamorphism rocks;(2)800-200 Ma,no significant tectonic movement with slowly buried history;(3)From 200 Ma,multi-phase uplift and the sedimentary rocks was eroded in the core of the Huangling dome.Shale gas in the Cambrian and Sinian strata was well preserved in the margin of the Huangling dome as the following reasons:(1)The Sinian shale was buried about 7.8 km indepth during Middle Jurassic,source rocks have a suitable thermal maturity for shale gas;(2)The rigid basement of the Huangling dome was mainly composed by homogeneity granite,without intensive deformation.As the main challenges of the widely distributed Lower Cambrian and Sinian shale are highmaturity and intensive deformation,a geological unit with a dome probably is a favorable zone for the old age shale gas.Therefore,it indicates that the adjacent zone of the Xuefengshan,Shennongjia and Hannan are the geological units with a dome and probably have potentials for the exploration of shale in the Lower Cambrian and Sinian.展开更多
The existing modern traditional methods of estimation of the technical condition of buildings structure after seismic influences do not give a full picture of integrity of a construction.Besides,these methods are not ...The existing modern traditional methods of estimation of the technical condition of buildings structure after seismic influences do not give a full picture of integrity of a construction.Besides,these methods are not suitable for difficult complexes and responsible objects since they are based on expert estimation and do not give quantitative values of parameters.The problem of creation of展开更多
Qiangtang Basin is located in the middle of Tethys, which is the famous oil and gas accumulation belt of the world. one of the few exploration areas in our continental petroleum industry at present. Previous studies s...Qiangtang Basin is located in the middle of Tethys, which is the famous oil and gas accumulation belt of the world. one of the few exploration areas in our continental petroleum industry at present. Previous studies show that this basin is a “composite basin" which has experienced, from Late Paleozoic to Cenozoic, a long time geological evolution. The major of this basin formed at Late Permian to Early Cretaceous, and its deformation generated after Late Cretaceous. The present part is just the remnants of the proto basin.Qiangtang Basin, about 180000km\+2, is located in the west part of Qiangtang\|Qamdo Terrane with Triassic Jurassic system as the main exploration systems.The tectonic framework of the basin displays the characteristic of one central uplift between the northern and the southern depressions, among of which the maximum burial depth of the substratums is 7km deep at Tubocuo in the northern depression. The deformation of the basin developed different kinds of structural styles, including compressive, wrench and extensive as well as inversive structures.The thickness of effective hydrocarbon source rocks (mudstone and carbonate rocks) is over 1500m, and the organic matter types are mainly of type I and type Ⅱ. In general the abundance of organic matter of the carbonate rocks is 0 1%～0 3%, the hydrocarbon generating potential (S1+S2) being 0 01～0 195mg/g. The abundance of organic matter of mudstone is generally over 0 5%, with the maximum over 2%. Its hydrocarbon generating potential is 0 018～28 1mg/g, and the organic matter is mainly at the mature to highly mature stage. More than 30 oil seeps have been found in the area, of which three are oil liquid ones and the others are solid bitumen and soft bitumen. Oil bearing rocks are concentrated in the Middle Upper Jurassic and Upper Triassic. Oil to source correlation analysis shows that the liquid oil is derived from the strata with oil reserves.The oil and gas shows, especially liquid oil seeps, indicate that the area experienced a history of hydrocarbon generation and migration. Preliminary prospecting shows that there exist two kinds of reservoirs: clastic rocks and carbonate rocks. The porosity of some carbonate reservoirs is up to 15%, which is favorable to the storage of oil and gas. Gypsum layers (single layer is generally 20～40m) are extensively distributed in Middle Jurassic of the Qiangtang Basin. Since Mesozoic marine strata in the basin has been strongly deformed and exposured on the surface of the earth during the Cenozoic, compared with other general bearing hydrocarbon basins, the preservative condition of Qiangtang Basin appears to be poor, but there still has a good prospects of exploration because of the Mesozoic strata containing abundant pliable layers such as gypsums and shales.展开更多
Although carbon isotope reversal and its reasons in shale gas reservoirs have been widely recognized,the application of the reversal is yet to be investigated.A study on high-maturity shale from Wufeng and Longmaxi Fo...Although carbon isotope reversal and its reasons in shale gas reservoirs have been widely recognized,the application of the reversal is yet to be investigated.A study on high-maturity shale from Wufeng and Longmaxi Formations in the Sichuan Basin not only reveals the relationship between the degree of isotopes inversion and the production capacity(e.g.,estimated ultimate recovery(EUR))of the gas well but also indicates the preservation conditions of shale gas reservoirs.(1)Although there are differences in gas isotopes in different shale gas reservoirs,the isotope fractionation of shale gas is small during the production stage of gas wells,even when the wellbore pressure drops to zero.The main cause of the difference in carbon isotopes and their inversion degree can be the uplift time during the Yanshan period and the formation pressure relief degree of shale gas reservoirs in distinct structural positions.Thus,carbon isotope inversion is a good indicator of shale gas preservation condition and EUR of shale gas wells.(2)The degree of carbon isotope inversion correlates strongly with shale gas content and EUR.The calculation formula of shale-gas recoverable reserves was established using△δ^(13)C(δC_(1)-δC_(2))and EUR.(3)The gas loss rate and total loss amount can be estimated using the dynamic reserves and isotopic difference values of gas wells in various shale gas fields,which also reflects the current methane loss,thereby demonstrating great potential for evaluating global methane loss in shales.展开更多
基金supported by the National Natural Science Foundation of China (42122017,41821002)the Hubei Provincial Natural Science Foundation of China (2020CFB501)+1 种基金the Shandong Provincial Key Research and Development Program (2020ZLYS08)the Independent innovation research program of China University of Petroleum (East China) (21CX06001A)。
文摘Tectonism is one of the dominant factors affecting the shale pore structure.However,the control of shale pore structure by tectonic movements is still controversial,which limits the research progress of shale gas accumulation mechanism in the complex tectonic region of southern China.In this study,34 samples were collected from two exploratory wells located in different tectonic locations.Diverse experiments,e.g.,organic geochemistry,XRD analysis,FE-SEM,low-pressure gas adsorption,and high-pressure mercury intrusion,were conducted to fully characterize the shale reservoir.The TOC,Ro,and mineral composition of the shale samples between the two wells are similar,which reflects that the shale samples of the two wells have proximate pores-generating capacity and pores-supporting capacity.However,the pore characteristics of shale samples from two wells are significantly different.Compared with the stabilized zone shale,the porosity,pore volume,and specific surface area of the deformed zone shale were reduced by 60.61%,64.85%,and 27.81%,respectively.Moreover,the macroscopic and fine pores were reduced by 54.01%and 84.95%,respectively.Fault activity and uplift denudation are not conducive to pore preservation,and the rigid basement of Huangling uplift can promote pore preservation.These three factors are important reasons for controlling the difference in pore structure between two wells shales.We established a conceptual model of shale pores evolution under different tectonic preservation conditions.This study is significant to clarify the scale of shale gas formation and enrichment in complex tectonic regions,and helps in the selection of shale sweet spots.
文摘Latent variable models can effectively determine the condition of essential rotating machinery without needing labeled data.These models analyze vibration data via an unsupervised learning strategy.Temporal preservation is necessary to obtain an informative latent manifold for the fault diagnosis task.In a temporalpreserving context,two approaches exist to develop a condition-monitoring methodology:offline and online.For latent variable models,the available training modes are not different.While many traditional methods use offline training,online training can dynamically adjust the latent manifold,possibly leading to better fault signature extraction from the vibration data.This study explores online training using temporal-preserving latent variable models.Within online training,there are two main methods:one focuses on reconstructing data and the other on interpreting the data components.Both are considered to evaluate how they diagnose faults over time.Using two experimental datasets,the study confirms that models from both training modes can detect changes in machinery health and identify faults even under varying conditions.Importantly,the complementarity of offline and online models is emphasized,reassuring their versatility in fault diagnostics.Understanding the implications of the training approach and the available model formulations is crucial for further research in latent variable modelbased fault diagnostics.
文摘[Objective] This study aimed to investigate the effect of different short-term preservation conditions on mycelial growth of Morchella conica, and search for opti- mum preservation conditions. [Method] M. conica strains in tubes were preserved at two temperature treatments 10 ℃/5 ℃ （day/night） and 15℃/10 ℃（day/night） in scat- tered light or dark for 30 or 60 d. The strain preserved at 4 ℃ dark for 90 d was the control （CK）. So, a total of nine treatments were prepared in this study. [Result] Mycelial growth of M. conica preserved at 10 ℃/5 ℃ was better than that at 15 ℃/10 ℃ and control. The colony color and aerial hyphae of strains preserved in scattered light was also better than that in dark. Additionally, the preservation time showed no distinct effect on mycelial growth at 10 ℃/5 ℃. So the time could be lengthened. But the maximal preservation time was 60 d at 15 ℃/10 ℃. Therefore, preserved under the appropriate conditions of 10 ℃/5 ℃, scattered light for 30 d, the strain had the neat colony edge, moderate aerial mycelia, dense mycelia, lower sectoral variation, uniform mycelial growth rate and high dry weight of mycelia.
基金supported by Science and Technology Support Program of Sichuan Province(No.15ZC1390)National Natural Science Foundation of China(No.41102064)
文摘The Upper Ordovician-Lower Silurian Longmaxi Shale in the Upper Yangtze block represents one of the most important shale gas plays in China. The shale composition, porosity, organic thermal maturity, and methane sorption were investigated at the Qilongcun section in the Dingshan area, southeastern Sichuan Basin. The results show that the Upper Ordovician-Lower Silurian Longmaxi Shale contains： （1） sapropelic I organic matter; （2） a 40-m thick bedded sequence where total organic carbon （TOC） content is 〉 2%; （3） a 30-m thick layer at the base of the Longmaxi Shale with a brittle mineral content higher than 50%; and （4） a mean methane adsorption capacity of 1.80 cm3/g （7 MPa pressure）. A positive correlation between TOC and sorbed gas indicates that organic matter content exerts an important control on methane storage capacity. Based on the analysis of the shale reservoir characteristics, the lower member of the Longmaxi Shale can thus be considered a favorable stratum for shale gas exploration and exploitation. It has similar reservoir characteristics with the Longmaxi Shale in the Jiaoshiba area tested with a high-yield industrial gas flow. However, based on tectonic analysis, differences in the level of industrial gas flow between the low-yield study area and the high-yield Jiaoshiba area may result from different tectonic preservation conditions. Evidence from these studies indicates the shale gas potential of the Longmaxi Shale is constrained by the reservoir and preservation conditions.
基金supported by the National Natural Science Foundation(41072082)National Basic Research Program of China(No.2005CB422106)national key subject constructional item of mineralogy,petrology and mineral deposit(SZD0407)and backup candidate fund of academic and technical senior scholar in Sichuan Province
文摘^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source and migration path of key fluids related to development of hydrocarbon, hydrocarbon preservation condition are then discussed further. Comprehensive research, based on the paleo-fluid, the property of formation water and the deformation intensity etc., indicates that the preservation conditions in the Shizhu synclinorium zone and Fangdoushan anticlinorium zone are the most predominant in the central Yangtze. Three sets of fluid systems in the Shizhu synclinorium zone are identified. Little fluid exchange occurs between the upper-middle fluid system and the lower fluid system, so two independent preservation units have developed. Both the Permian and the Triassic in the upper preservation units and the Dengying Formation of the Sinian and the lower Cambrian in the lower preservation units have good preservation conditions. The preservation condition in the lower association （Z-S） located in the Huaguoping synclinorium zone in the western Hubei and Hunan is better than that in other tectonic units, where the fluids in the lower association migrated vertically across strata when the fluid isolating intervals were destroyed, the regional seals are absent and the conditions for the preservation of hydrocarbon accumulations are totally destroyed. The preservation condition is increasingly more favorable from the western Jiangxi and Hunan to the western Hubei ＆ eastern Chongqing on the whole.
基金the Project of China Geological Survey (DD20160512, DD20160346)Science and Technology Development Fund Project of Shinan District (2018-4-006-ZH)+2 种基金Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology,Ministry of Land and Resources (MRE201311)National Natural Science Foundation (41776075,41702162)Natural Science Foundation of Shandong Province of China (ZR2017BD034).
文摘In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin,a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth Basin,the Jiaoshiba shale gas reservoirs in Sichuan Basin and potential shale gas reservoirs in Guizhou Province.The results show that the "Sandwich"structure is of great importance for shale gas accumulation.Therein to,the "Sandwich"structure is a kind of special reservoir-cap rock assemblage which consist of limestone or dolomite on the top,mudstone or shale layer in the middle and limestone or dolomite at the bottom.In consideration of the Mesozoic-Paleozoie in the Lower Yangtze,and Laoshan Uplift with weak Paleozoic deformation and thrust fault sealing On both flanks of the Laoshan Uplift,a conclusion can be drawn that the preservation conditions of shale gas probably developed "Sandwich" structures in the Lower Cambrian and Permian,which are key layers for the breakthrough of shale gas in the South Yellow Sea.Moreover,the preferred targets for shale gas drilling probably locate at both flanks of the Laoshan Uplift.
基金supported by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams(No.2019ZT08G315)National Natural Science Foundation of China(No.51827901,U2013603,and 52004166)。
文摘As shallow resources are increasingly depleted,the mechanics'theory and testing technology of deep insitu rock has become urgent.Traditional coring technologies obtain rock samples without retaining the in-situ environmental conditions,leading to distortion of the measured parameters.Herein,a coring and testing systems retaining in-situ geological conditions is presented:the coring system that obtains in-situ rock samples,and the transfer and testing system that stores and analyzes the rocks under a reconstructed environment.The ICP-Coring system mainly consists of the pressure controller,active insulated core reactor and insulation layer and sealing film.The ultimate bearing strength of 100 MPa for pressurepreservation,temperature control accuracy of 0.97%for temperature-retained are realized.CH_(4)and CO permeability of the optimized sealing film are as low as 3.85 and 0.33 ppm/min.The average tensile elongation of the film is 152.4%and the light transmittance is reduced to 0%.Additionally,the pressure and steady-state temperature accuracy for reconstructing the in-situ environment of transfer and storage system up to 1%and±0.2 is achieved.The error recorded of the noncontact sensor ring made of lowdensity polymer is less than 6%than that of the contact test.The system can provide technical support for the deep in-situ rock mechanics research,improving deep resource acquisition capabilities and further clarifying deep-earth processes.
基金supported by Science and Technology Project of State Grid Corporation(Research and Application of Intelligent Energy Meter Quality Analysis and Evaluation Technology Based on Full Chain Data)
文摘With the application of artificial intelligence technology in the power industry,the knowledge graph is expected to play a key role in power grid dispatch processes,intelligent maintenance,and customer service response provision.Knowledge graphs are usually constructed based on entity recognition.Specifically,based on the mining of entity attributes and relationships,domain knowledge graphs can be constructed through knowledge fusion.In this work,the entities and characteristics of power entity recognition are analyzed,the mechanism of entity recognition is clarified,and entity recognition techniques are analyzed in the context of the power domain.Power entity recognition based on the conditional random fields (CRF) and bidirectional long short-term memory (BLSTM) models is investigated,and the two methods are comparatively analyzed.The results indicated that the CRF model,with an accuracy of 83%,can better identify the power entities compared to the BLSTM.The CRF approach can thus be applied to the entity extraction for knowledge graph construction in the power field.
基金supported by the General Project of the National Natural Science Fund of China(NSFC)“China’s Labor Market Matching Efficiency and Economic Effects”(Grant No.71973015)the Major Project of the National Social Science Fund of China(NSSFC)“Study on Enhancing Employment Priority for Stable Job Growth”(Grant No.21ZDA098).
文摘Initial labor market conditions affect how individuals build their human capital and look for jobs and thus can have long-term effects on their income levels,work performance,and career development.Based on data from the Urban Household Survey(UHS)of urban households in China from 1986 to 2009,we perform an empirical test of how initial labor market conditions affect the employability of individuals.Our research shows that people’s future incomes suffer if they start out in an adverse job market.Each percentage point of increase in the unemployment rate at an individual’s entry into the labor market is associated with a two-percentage-point drop in his or her average annual income.Even after looking at different parts of the job market and sample groups,this conclusion still holds.In the context of global economic instability,our findings may assist government policymakers in addressing adverse labor market conditions.
基金This research is financially supposed by China Gelogical Survey project(1211302108020,DD20160177,DD20190081)
文摘Significant breakthroughs of shale gas exploration have been made in Lower Cambrian and Sinian shale in the north margin of the Yangtze Block,South China.The drill wells with industrial gas flow located in the southern margin of the Huangling dome.Base on the geological survey,2D seismic,geochronological and drill wells data,the tectonic evolution history of Huangling dome was studied,and its control effect on the preservation condition of shale gas was discussed.The result shows that the Huangling dome might undergo four tectonic stages:(1)About 800 Ma,granite intrusion in the Huangling dome basement,primarily of granites replaced metamorphism rocks;(2)800-200 Ma,no significant tectonic movement with slowly buried history;(3)From 200 Ma,multi-phase uplift and the sedimentary rocks was eroded in the core of the Huangling dome.Shale gas in the Cambrian and Sinian strata was well preserved in the margin of the Huangling dome as the following reasons:(1)The Sinian shale was buried about 7.8 km indepth during Middle Jurassic,source rocks have a suitable thermal maturity for shale gas;(2)The rigid basement of the Huangling dome was mainly composed by homogeneity granite,without intensive deformation.As the main challenges of the widely distributed Lower Cambrian and Sinian shale are highmaturity and intensive deformation,a geological unit with a dome probably is a favorable zone for the old age shale gas.Therefore,it indicates that the adjacent zone of the Xuefengshan,Shennongjia and Hannan are the geological units with a dome and probably have potentials for the exploration of shale in the Lower Cambrian and Sinian.
文摘The existing modern traditional methods of estimation of the technical condition of buildings structure after seismic influences do not give a full picture of integrity of a construction.Besides,these methods are not suitable for difficult complexes and responsible objects since they are based on expert estimation and do not give quantitative values of parameters.The problem of creation of
文摘Qiangtang Basin is located in the middle of Tethys, which is the famous oil and gas accumulation belt of the world. one of the few exploration areas in our continental petroleum industry at present. Previous studies show that this basin is a “composite basin" which has experienced, from Late Paleozoic to Cenozoic, a long time geological evolution. The major of this basin formed at Late Permian to Early Cretaceous, and its deformation generated after Late Cretaceous. The present part is just the remnants of the proto basin.Qiangtang Basin, about 180000km\+2, is located in the west part of Qiangtang\|Qamdo Terrane with Triassic Jurassic system as the main exploration systems.The tectonic framework of the basin displays the characteristic of one central uplift between the northern and the southern depressions, among of which the maximum burial depth of the substratums is 7km deep at Tubocuo in the northern depression. The deformation of the basin developed different kinds of structural styles, including compressive, wrench and extensive as well as inversive structures.The thickness of effective hydrocarbon source rocks (mudstone and carbonate rocks) is over 1500m, and the organic matter types are mainly of type I and type Ⅱ. In general the abundance of organic matter of the carbonate rocks is 0 1%～0 3%, the hydrocarbon generating potential (S1+S2) being 0 01～0 195mg/g. The abundance of organic matter of mudstone is generally over 0 5%, with the maximum over 2%. Its hydrocarbon generating potential is 0 018～28 1mg/g, and the organic matter is mainly at the mature to highly mature stage. More than 30 oil seeps have been found in the area, of which three are oil liquid ones and the others are solid bitumen and soft bitumen. Oil bearing rocks are concentrated in the Middle Upper Jurassic and Upper Triassic. Oil to source correlation analysis shows that the liquid oil is derived from the strata with oil reserves.The oil and gas shows, especially liquid oil seeps, indicate that the area experienced a history of hydrocarbon generation and migration. Preliminary prospecting shows that there exist two kinds of reservoirs: clastic rocks and carbonate rocks. The porosity of some carbonate reservoirs is up to 15%, which is favorable to the storage of oil and gas. Gypsum layers (single layer is generally 20～40m) are extensively distributed in Middle Jurassic of the Qiangtang Basin. Since Mesozoic marine strata in the basin has been strongly deformed and exposured on the surface of the earth during the Cenozoic, compared with other general bearing hydrocarbon basins, the preservative condition of Qiangtang Basin appears to be poor, but there still has a good prospects of exploration because of the Mesozoic strata containing abundant pliable layers such as gypsums and shales.
基金supported by the National Natural Science Foundation of China(Grant No.41872124,42202175&No.42130803)。
文摘Although carbon isotope reversal and its reasons in shale gas reservoirs have been widely recognized,the application of the reversal is yet to be investigated.A study on high-maturity shale from Wufeng and Longmaxi Formations in the Sichuan Basin not only reveals the relationship between the degree of isotopes inversion and the production capacity(e.g.,estimated ultimate recovery(EUR))of the gas well but also indicates the preservation conditions of shale gas reservoirs.(1)Although there are differences in gas isotopes in different shale gas reservoirs,the isotope fractionation of shale gas is small during the production stage of gas wells,even when the wellbore pressure drops to zero.The main cause of the difference in carbon isotopes and their inversion degree can be the uplift time during the Yanshan period and the formation pressure relief degree of shale gas reservoirs in distinct structural positions.Thus,carbon isotope inversion is a good indicator of shale gas preservation condition and EUR of shale gas wells.(2)The degree of carbon isotope inversion correlates strongly with shale gas content and EUR.The calculation formula of shale-gas recoverable reserves was established using△δ^(13)C(δC_(1)-δC_(2))and EUR.(3)The gas loss rate and total loss amount can be estimated using the dynamic reserves and isotopic difference values of gas wells in various shale gas fields,which also reflects the current methane loss,thereby demonstrating great potential for evaluating global methane loss in shales.
