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Slicing capacity-centered mode selection and resource optimization for network-assisted full-duplex cell-free distributed massive MIMO systems

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Science China(Information Sciences) 2024年第1期67卷 203-220页

作者： Jie WANG Jiamin LI Pengcheng ZHU Dongming WANG Hongbiao ZHANG Yue HAO Bin SHENG National Mobile Communications research Laboratory Southeast University 2. Purple Mountain Laboratories China Mobile research Institute

Network-assisted full-duplex(NAFD) cell-free distributed massive multiple-input multipleoutput(MIMO) systems enable uplink(UL) and downlink(DL) communications within the same timefrequency resources,which potentially reduce latency by avoiding the overhead of switching UL/DL ***,how to choose UL/DL modes remains an important factor affecting system *** the dramatic increase in the number of users and access points(APs),massive access brings significant overhead in the mode ***,the different quality of service(QoS) among users also makes the effective utilization of resources *** one of the most promising technologies in sixth-generation(6G),network slicing enables the adaptive configuration of limited UL/DL resources through the resource isolation assisted NAFD ***,we propose a slicing capacity-centered *** this scheme,APs are motivated by slicing requirements and associated slices to form different *** mode selection and resource allocation are performed within each subsystem to reduce overhead and improve resource *** implement this scheme efficiently,a double-layer deep reinforcement learning(DRL)mechanism is used to realize the joint optimization of mode selection and resource *** results show that the slicing capacity-centered scheme can effectively improve resource utilization and reduce overhead.

关键词： network-assisted full-duplex network slicing mode selection resource optimization deep reinforcement learning

Analysis method and experimental study of ice accumulation detection signal based on Lamb waves

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Chinese Journal of Aeronautics 2024年第8期37卷 388-403页

作者： Yanxin ZHANG Hongjian ZHANG Xian YI Binrui WU Xianlei GUAN Jianjun XIONG Key Laboratory of Icing and Anti/De-icing China Aerodynamics Research and Development CenterMianyang 621000China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

A quantitative identification method for in-flight icing has the capability to significantly enhance the safety of aircraft *** guided waves have the unique advantage of detecting icing in a relatively large area,but quantitative identification of ice layers is a *** this paper,a quantitative identification method of ice accumulation based on ultrasonic guided waves is ***,a simulation model for the wave dynamics of piezoelectric coupling in three dimensions is established to analyze the propagation characteristics of Lamb waves in a structure consisting of an aluminum plate and an ice *** wavelet transform method is utilized to extract the Time of Flight(ToF)or Time of Delay(ToD)of S_(0)/B_(1) mode waves,which serves as a characteristic parameter to precisely determine and assess the level of ice ***,an experimental system is developed to evaluate the feasibility of Lamb waves-based icing real-time detection in the presence of spray ***,a combination of the Hampel median filter and the moving average filter is developed to analyze ToF/ToD *** simulation results reveal a positive correlation between geometric dimensions(length,width,thickness)of the ice layer and ToF/ToD of B1 mode waves,indicating their potential as indicators for quantifying ice *** results of real-time icing detection indicate that ToF/ToD will reach greater peak values with the growth of the arbitrary-shaped ice layer until saturation to effectively predict the simulation *** study lays a foundation for the practical application of quantitative icing detection via ultrasonic guided waves.

关键词： Ice Ice accumulation Ultrasonic sensor Ultrasonic guided wave Lamb wave Wavelet transform

A new method for quantitative evaluation of shale laminae using electrical image logging

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Energy Geoscience 2024年第3期5卷 93-102页

作者： Zhou Feng Hongliang Wu Weilin Yan Han Tian Jiandong Zheng Chaoliu Li Kewen Wang research Institute of Petroleum Exploration and development CNPCBeijing100083China Exploration and development research Institute Daqing OilfieldCNPCHelongjiang163311China

Shale oil reservoirs are generally characterized by complex mineral compositions, rapid lithofacies changes, and thin laminae. Explorations have confirmed that the type and density of shale laminae significantly influence reservoir quality, highlighting the importance of accurately identifying these laminae through well logging for effective shale reservoir evaluation. Presently, relevant technologies primarily focus on the qualitative identification of shale laminae using vertical slab images from image logs. However, influenced by the complex borehole conditions and image logging quality, this approach is less effective in identifying millimeter-scale laminae. This study proposes a new method for achieving high-resolution slab images and quantitatively evaluating the laminae using electrical image logs. The new method effectively improves the processing accuracy of slab images by delicately flattening and aligning the button electrode curves derived from electrical image logs point by point. Meanwhile, it allows for the accurate quantitative evaluation of the lamina number through precise identification of peaks and troughs in microelectrode curves. As demonstrated by the applications in shale oil reservoirs in the Gulong area in Daqing and the Ganchagou area in Qinghai, the proposed method can significantly improve accuracy compared to traditional slab images. Furthermore, the lamination index calculated using this method is highly consistent with the lamina number observed in cores. This study provides a new technical method for the quantitative lamina evaluation and rock structure analysis of shale reservoirs.

关键词： Shale oil Slab image Lamina evaluation Lamination index

An ensemble and cost-sensitive learning-based root cause diagnosis scheme for wireless networks with spatially imbalanced user data distribution

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Science China(Information Sciences) 2024年第7期67卷 331-332页

作者： Qi WANG Zhiwen PAN Nan LIU National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories

Root cause diagnosis, a key component of self-healing, plays a vital role in fault management. The spatially imbalanced network key performance indicators (KPIs) reported by users increase the difficulty of identifying root *** [1,2], the image inpainting technique is inspired to address issues caused by sparse reports across the coverage area.

关键词： Wireless networks

Low-Temperature Reforming Products Coupling Spark Plug on Gasoline Compression Ignition and Combustion Characteristics under Low-Load Condition

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Journal of Thermal Science 2024年第6期33卷 2386-2398页

作者： LIU Long LI Mingkun CAO Qun WANG Yang WANG Xichang College of Power and Energy Engineering Harbin Engineering University China Helicopter research and development Institute

Gasoline compression combustion engine has the advantages of low emission and high efficiency,which is very promising for research,but it is difficult to apply under low-load *** has the characteristics of low reactivity;in the case of low thermodynamic state in the cylinder,the fire delay period of the fuel is longer,and the combustion phase is relatively lagging,which will lead to the increase of combustion cycle fluctuations,and even difficult to ignite and other adverse combustion *** order to improve the combustion stability of Gasoline Compression Ignition（GCI） engine under low-load condition and expand the limit of low-load combustion boundary,gasoline was reformed without catalyst under the boundary condition of reforming temperature of 488 K and reforming equivalent ratio of 8,and the concentration of reformed product was measured by a gas detection ***,the coupling of the reformed product and spark plug with GCI engine under low-load condition was investigated to analyze the effect on engine combustion and *** results showed that the initial combustion timing of the low-load GCI engine was late,but the addition of reformed products could advance the combustion phase,shorten the combustion duration,reduce single-cycle NOxemission,and improve the small-load operation characteristics of GCI *** spark plug ignition on the basis of adding reformed products could further improve the problem of combustion stability under low-load GCI *** the optimization effect became more obvious as the ignition position of the spark plug moves ***,spark plug ignition would cause local high temperature areas,resulting in an increase in NOxemission.

关键词： combustion emission gasoline low-temperature reform spark plug

Fine description of unconventional clastic oil reservoirs

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Petroleum research 2024年第2期9卷 289-303页

作者： Huanqing Chen research Institute of Petroleum Exploration&development PetroChinaChina

The latest researches reveal that studies on unconventional clastic oil reservoirs in China generally lag far behind those in other countries in respect of content and *** study presents the definition and classification of unconventional oil reservoirs and analyzes the problems in the fine description of unconventional oil *** key content of the fine description of unconventional oil reservoirs is summarized from four aspects:fine fracture characterization based on fine structure interpretation,reservoir architecture characterization based on sedimentary facies,characteristics of nanoscale microscopic pore structure of reservoir,and evaluation of source rock and“sweet spot zone”.Finally,this study suggests that development of fine description of unconventional clastic oil reservoirs in the future should focus on rock brittleness analysis and fracture modeling,geophysical characterization of unconventional clastic oil reservoirs,fluid description of tight reservoirs,and physical/numerical simulation experiments of unconventional oil reservoirs.

关键词： Unconventional clastic reservoir Fine reservoir description Oil sand Tight oilShale oil Fracture characterization Nanoscale microscopic pore structure Sweet spot

Application of sparse S transform network with knowledge distillation in seismic attenuation delineation

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Petroleum Science 2024年第4期21卷 2345-2355页

作者： Nai-Hao Liu Yu-Xin Zhang Yang Yang Rong-Chang Liu Jing-Huai Gao Nan Zhang School of Information and Communications Engineering Xi'an Jiaotong University School of Software Engineering Xi'an Jiaotong University PetroChina research Institute of Petroleum Exploration and development (RIPED) CNPC research Institute of Exploration and development Yumen Oilfield Company CNPC

Time-frequency analysis is a successfully used tool for analyzing the local features of seismic ***, it suffers from several inevitable limitations, such as the restricted time-frequency resolution,the difficulty in selecting parameters, and the low computational efficiency. Inspired by deep learning,we suggest a deep learning-based workflow for seismic time-frequency analysis. The sparse S transform network(SSTNet) is first built to map the relationship between synthetic traces and sparse S transform spectra, which can be easily pre-trained by using synthetic traces and training labels. Next, we introduce knowledge distillation(KD) based transfer learning to re-train SSTNet by using a field data set without training labels, which is named the sparse S transform network with knowledge distillation(KD-SSTNet).In this way, we can effectively calculate the sparse time-frequency spectra of field data and avoid the use of field training labels. To test the availability of the suggested KD-SSTNet, we apply it to field data to estimate seismic attenuation for reservoir characterization and make detailed comparisons with the traditional time-frequency analysis methods.

关键词： S transform Deep learning Knowledge distillation Transfer learning Seismic attenuation delineation

Characteristics and genesis of tuffaceous shale oil lithofacies:A case study of Lucaogou Formation in Santanghu Basin

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Petroleum research 2024年第1期9卷 37-47页

作者： Dongsheng Xiao Xiong fei Xu Jilun Kang Yiting Zhang PetroChina Tuha Oilfield Company Exploration and development research Institute China

Lucaogou Formation in the Santanghu Basin is a special lacustrine fine-grained sedimentary deposits rich in volcanic debris and carbonate,with abundant shale oil ***,understanding of shale oil characteristics and genesis remains ***,sedimentary environment,and formation mechanisms of tuffaceous shale oil are investigated based on core and thin section observations,X-ray diffraction,field emission SEM and geochemical *** show that three mixed lithofacies types are developed in Lucaogou Formation:blocky tuff,laminated tuffaceous dolomite,and laminated dolomitic *** lithofacies types are characterized by high content of felsic and dolostone,widespread organic matter,and low clay *** of tuffaceous shale oil sweet spots is primarily influenced by four factors:inputting of volcanic ash as a high-quality source rocks and reservoirs provides good material basis;devitrification of volcanic glass,calcitization,and dissolution are crucial for formation of reservoirs;expulsion of source rocks with high-abundance organic matter expulsion facilitates migration and accumulation of hydrocarbon in adjacent reservoirs;fracture development improves reservoir permeability to form highly productive sweet *** analyzing characteristics and genesis of tuffaceous shale oil,the main controlling factors of reservoir physical property and oil saturation are clarified,which is of great significance for selection of shale oil exploration zones.

关键词： shale oil Tuffaceous Formation mechanism Lucaogou formation Santanghu basin

A log-based method for fine-scale evaluation of lithofacies and its applications to the Gulong shale in the Songliao Basin,Northeast China

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Energy Geoscience 2024年第3期5卷 189-202页

作者： Weilin Yan Chunyan Wang Shujun Yin Zheng Wen Jiandong Zheng Xiuli Fu Zhou Feng Zhaoqian Zhang Jianhua Zhu Exploration and development research Institute of Daqing Oilfield Company Limited PetroChinaDaqingHeilongjiang163002China research Institute of Petroleum Exploration&development PetroChinaBeijing100083China

The Gulong shale demonstrates high clay content and pronounced thin laminations,with limited vertical variability in log curves,complicating lithofacies *** comprehend the distribution and compositional features of lithofacies in the Gulong shale for optimal sweet spot selection and reservoir stimulation,this study introduced a lithofacies classification scheme and a log-based lithofacies evaluation ***,theΔlgR method was utilized for accurately determining the total organic carbon(TOC)content;a multi-mineral model based on element-to-mineral content conversion coefficients was developed to enhance mineral composition prediction accuracy,and the microresistivity curve variations derived from formation micro-image(FMI)log were used to compute lamination density,offering insights into sedimentary *** this method,integrating TOC content,sedimentary structures,and mineral compositions,the Qingshankou Formation is classified into four lithofacies and 12 sublithofacies,displaying 90.6%accuracy compared to core description *** classification results reveal that the northern portion of the study area exhibits more prevalent fissile felsic shales,siltstone interlayers,shell limestones,and ***,the upper section primarily exhibits organic-rich felsic shale and siltstone interlayers,the middle part is characterized by moderate organic quartz-feldspathic shale and siltstone/carbonate interlayers,and the lower section predominantly features organic-rich fissile felsic/clayey felsic *** various sublithofacies in relation to seven petrophysical parameters,oil test production,and fracturing operation conditions indicates that the organic-rich felsic shales in the upper section and the organic-rich/clayey felsic shales in the lower section possess superior physical properties and oil content,contributing to smoother fracturing operation and enhanced production,thus emerging as dominant ***

关键词： Lithofacies division Formation micro-image(FMI)log Lithoscanner logging Fine-scale log-based evaluation Gulong shale