The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and ...The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.展开更多
Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the ...Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.展开更多
Intercity mobility lays the foundation for capital flow,information flow,and knowledge flow,etc.,and is important for promoting regional integration.Although many scholars have studied intercity mobility in extensive ...Intercity mobility lays the foundation for capital flow,information flow,and knowledge flow,etc.,and is important for promoting regional integration.Although many scholars have studied intercity mobility in extensive well-developed urban agglomerations,few studies have examined the characteristics of intercity mobility at the county level and its impact on regionalization in western China.This study takes the Guanzhong Plain urban agglomeration(GPUA)as a case to study the geographical law of intercity mobility and then explore its impact on regionalization.The results obtained show that intercity mobility network exhibits a hub and spoke patterns focusing on major municipal districts at the county level.We also found a corridor effect that counties with higher travel volumes are mostly located along the trunk high speed railway(HSR)lines.Unlike previous studies,the distribution of intercity mobility is more concentrated than that of population and exhibits a super-linear behavior rule.There are the differences in gravity law for overall trips,weekday trips,weekend trips,and holiday trips.With the decrease of travel duration,the effect of attraction of destination is weakening,but the influence of distance decay is increasing.Finally,the spatial organization is still administrative-centric and is dominated by intraprefecture and intra-provincial development.Moreover,the coupled degree between network-based regionalization and attribute-based regionalization shows a decreasing trend from administrative via cultural to physical factors.These findings enrich the research on the intercity mobility and the regionalization in inland developing urban agglomerations.展开更多
时间序列聚类中的相似度度量方法选择已成为研究热点。目前大多数的聚类方法使用欧式距离进行相似性度量,但欧式距离进行度量对结构复杂的时间序列适用性较差,不能很好的提高聚类的准确性。提出一种基于动态时间弯曲(Dynamic Time Warpi...时间序列聚类中的相似度度量方法选择已成为研究热点。目前大多数的聚类方法使用欧式距离进行相似性度量,但欧式距离进行度量对结构复杂的时间序列适用性较差,不能很好的提高聚类的准确性。提出一种基于动态时间弯曲(Dynamic Time Warping)的PAM(Partitioning Around Medoids)算法,该方法在PAM算法的基础上引入DTW,以发现时间序列中的相似模式,增强对时间序列的偏移、振幅变化等情况的鲁棒性。在UCR数据集上的实验结果验证了PAM-DTW的准确率和稳定性优于传统算法。展开更多
In this paper,the small-signal modeling of the Indium Phosphide High Electron Mobility Transistor(InP HEMT)based on the Transformer neural network model is investigated.The AC S-parameters of the HEMT device are train...In this paper,the small-signal modeling of the Indium Phosphide High Electron Mobility Transistor(InP HEMT)based on the Transformer neural network model is investigated.The AC S-parameters of the HEMT device are trained and validated using the Transformer model.In the proposed model,the eight-layer transformer encoders are connected in series and the encoder layer of each Transformer consists of the multi-head attention layer and the feed-forward neural network layer.The experimental results show that the measured and modeled S-parameters of the HEMT device match well in the frequency range of 0.5-40 GHz,with the errors versus frequency less than 1%.Compared with other models,good accuracy can be achieved to verify the effectiveness of the proposed model.展开更多
文摘The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.
基金Supported by Leading Talent Program of Autonomous Region(2022TSYCLJ0070)PetroChina Prospective and Basic Technological Project(2021DJ0108)Natural Science Foundation for Outstanding Young People in Shandong Province(ZR2022YQ30).
文摘Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.
基金Under the auspices of National Natural Science Foundation of China(No.42371189)Central University Basic Research Fund of China(No.24ZYYB017)。
文摘Intercity mobility lays the foundation for capital flow,information flow,and knowledge flow,etc.,and is important for promoting regional integration.Although many scholars have studied intercity mobility in extensive well-developed urban agglomerations,few studies have examined the characteristics of intercity mobility at the county level and its impact on regionalization in western China.This study takes the Guanzhong Plain urban agglomeration(GPUA)as a case to study the geographical law of intercity mobility and then explore its impact on regionalization.The results obtained show that intercity mobility network exhibits a hub and spoke patterns focusing on major municipal districts at the county level.We also found a corridor effect that counties with higher travel volumes are mostly located along the trunk high speed railway(HSR)lines.Unlike previous studies,the distribution of intercity mobility is more concentrated than that of population and exhibits a super-linear behavior rule.There are the differences in gravity law for overall trips,weekday trips,weekend trips,and holiday trips.With the decrease of travel duration,the effect of attraction of destination is weakening,but the influence of distance decay is increasing.Finally,the spatial organization is still administrative-centric and is dominated by intraprefecture and intra-provincial development.Moreover,the coupled degree between network-based regionalization and attribute-based regionalization shows a decreasing trend from administrative via cultural to physical factors.These findings enrich the research on the intercity mobility and the regionalization in inland developing urban agglomerations.
文摘时间序列聚类中的相似度度量方法选择已成为研究热点。目前大多数的聚类方法使用欧式距离进行相似性度量,但欧式距离进行度量对结构复杂的时间序列适用性较差,不能很好的提高聚类的准确性。提出一种基于动态时间弯曲(Dynamic Time Warping)的PAM(Partitioning Around Medoids)算法,该方法在PAM算法的基础上引入DTW,以发现时间序列中的相似模式,增强对时间序列的偏移、振幅变化等情况的鲁棒性。在UCR数据集上的实验结果验证了PAM-DTW的准确率和稳定性优于传统算法。
基金Supported by the National Natural Science Foundation of China(62201293,62034003)the Open-Foundation of State Key Laboratory of Millimeter-Waves(K202313)the Jiangsu Province Youth Science and Technology Talent Support Project(JSTJ-2024-040)。
文摘In this paper,the small-signal modeling of the Indium Phosphide High Electron Mobility Transistor(InP HEMT)based on the Transformer neural network model is investigated.The AC S-parameters of the HEMT device are trained and validated using the Transformer model.In the proposed model,the eight-layer transformer encoders are connected in series and the encoder layer of each Transformer consists of the multi-head attention layer and the feed-forward neural network layer.The experimental results show that the measured and modeled S-parameters of the HEMT device match well in the frequency range of 0.5-40 GHz,with the errors versus frequency less than 1%.Compared with other models,good accuracy can be achieved to verify the effectiveness of the proposed model.
