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Fracture geometry and breakdown pressure of radial borehole fracturing in multiple layers

Petroleum Science 2024年第1期21卷 430-444页

作者： Yu-Ning Yong Zhao-Quan Guo Shou-Ceng Tian Lu-Yao Ma Tian-Yu Wang Mao Sheng national Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Beijing Petroleum Machinery company limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smart Energy Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

Radial borehole fracturing that combines radial boreholes with hydraulic fracturing is anticipated to improve the output of tight oil and gas *** paper aims to investigate fracture propagation and pressure characteristics of radial borehole fracturing in multiple layers.A series of laboratory experiments with artificial rock samples(395 mm×395 mm×395 mm)was conducted using a true triaxial fracturing *** crucial factors corresponding to the vertical distance of adjacent radial borehole layers(vertical distance),the azimuth and diameter of the radial borehole are *** results show that radial borehole fracturing in multiple layers generates diverse fracture *** types of fractures are identified based on the connectivity between hydraulic fractures and radial *** vertical distance significantly influences fracture propagation perpendicular to the radial borehole *** increase in the vertical distance impedes fracture connection across multiple radial borehole layers and reduces the fracture propagation distance along the radial borehole *** azimuth also influences fracture propagation along the radial borehole *** the azimuth reduces the guiding ability of radial boreholes,which makes the fracture quickly curve to the maximum horizontal stress *** breakdown pressure correlates with diverse fracture geometries *** the fractures connect multi-layer radial boreholes,increasing the vertical distance decreases the breakdown *** the azimuth and increasing the diameter also decrease the breakdown *** extrusion force exists between the adjacent fractures generated in radial boreholes in multiple rows,which plays a crucial role in enhancing the guiding ability of radial boreholes and results in higher breakdown *** research provides valuable theoretical insights for the field application of radial borehole fracturing technology in tight oil and g

关键词： Multi-layer radial boreholes Hydraulic fracturing Fracture propagation Pressure characteristic

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Pavement Pothole Detection System Based on Deep Learning and Binocular Vision

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Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Tian Guan Jianyuan Cai Yu Wang Wei Yang Xiaobo Chang Yi Han School of Automobile Chang'an University china national Heavy Duty Truck group company limited

Due to strong vibrations and the impact on high-speed vehicles， road potholes may cause discomfort to passengers， damaging the durability of the suspension and the integrity of the cargo. Therefore， a road pothole detection system is proposed， which uses deep learning and binocular vision for precise detection in the front. Based on the impact of road surface potholes on human driving behavior decisions of manually driven vehicles， which can cause drivers to slow down or stop， change driving routes， or even increase accident risks， road surface potholes can be divided into three categories: severe potholes (deep and large potholes)， non damaged road surfaces (flat surfaces without obvious potholes or damage)， and completely damaged road surfaces (there may be large areas of potholes， cracks， or other structural damage). 6848 road surface pit condition recognition datasets were constructed using a vehicle mounted binocular camera. group attention shuffling block (CASB) is designed to enhance the expression of channel and spatial feature information in road images， while improving the existing shuffling network (ShuffleNetv2). This establishes a ShuffleNetv2 (CASB ShuffleNetv2) model based on mixed attention for identifying the state of road potholes. The experimental results show that the model has better accuracy than the basic model and can effectively detect road potholes. Due to the varying sizes of potholes on the road surface， small potholes may only require slight avoidance， while large potholes may cause serious vehicle damage. And there are different visual effects on the vertical distance of the pit. To address the aforementioned issues， the LabelImg image annotation tool was used to manually annotate the pothole areas， in order to construct a dataset for detecting 2029 road pothole areas. We replaced the ordinary convolution in the CenterNet feature extraction network with pyramid convolution with multiple receptive fields， and designed a feature fusion mo

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CO_(2)flooding in shale oil reservoir with radial borehole fracturing for CO_(2)storage and enhanced oil recovery

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Petroleum Science 2024年第1期21卷 519-534页

作者： Jia-Cheng Dai Tian-Yu Wang Jin-Tao Weng Kang-Jian Tian Li-Ying Zhu Gen-Sheng Li State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China china national Oil and Gas Exploration and Development company limited Beijing100034China

This study introduces a novel method integrating CO_(2)flooding with radial borehole fracturing for enhanced oil recovery and CO_(2)underground storage,a solution to the limited vertical stimulation reservoir volume in horizontal well fracturing.A numerical model is established to investigate the production rate,reservoir pressure field,and CO_(2)saturation distribution corresponding to changing time of CO_(2)flooding with radial borehole fracturing.A sensitivity analysis on the influence of CO_(2)injection location,layer spacing,pressure difference,borehole number,and hydraulic fractures on oil production and CO_(2)storage is *** CO_(2)flooding process is divided into four *** in layer spacing will significantly improve oil production rate and gas storage ***,serious gas channeling can occur when the spacing is lower than 20 *** the pressure difference between the producer and injector,the borehole number,the hydraulic fracture height,and the fracture width can also increase the oil production rate and gas storage *** analysis shows that layer spacing and fracture height greatly influence gas storage and oil *** outcomes are expected to provide a theoretical basis for the efficient development of shale oil reservoirs in the vertical direction.

关键词： Shale oil Radial borehole fracturing Embedded discrete fracture model Enhanced oil recovery Carbon storage

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Minimizing interfacial energy losses in inverted perovskite solar cells by a dipolar stereochemical 2D perovskite interface

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Journal of Energy Chemistry 2024年第3期90卷 496-503,I0011页

作者： Junjie Qian Jingjing He Qihang Zhang Chenyue Zhu Shilin Chen Zhanpeng Wei Xuesong Leng Ziren Zhou Benben Shen Yu Peng Qiang Niu Shuang Yang Yu Hou Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China national Enterprise Technology Center Inner Mongolia Erdos Electric Power and Metallurgy Group Company LimitedOrdos 016064Inner MongoliaChina

Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and ***,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic ***,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium *** pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the ***,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type ***,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.

关键词： Perovskite solar cells Dipole interlayer Stereochemistry Non-radiative recombination

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Early warning of core network capacity in space-terrestrial integrated networks

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Journal of Systems Engineering and Electronics 2024年第4期35卷 855-864页

作者： HAN Sai LI Ao ZHANG Dongyue ZHU Bin WANG Zelin WANG Guangquan MIAO Jie MA Hongbing china Unicom Research Institute Beijing 100044China china United Network Communications group company limited Beijing 100033China

With the rapid development of low-orbit satellite com-munication networks both domestically and internationally,space-terrestrial integrated networks will become the future development *** space and terrestrial networks with limi-ted resources,the utilization efficiency of the entire space-terres-trial integrated networks resources can be affected by the core network *** order to improve the response efficiency of core networks expansion construction,early warning of the core network elements capacity is *** on the inte-grated architecture of space and terrestrial network,multidimen-sional factors are considered in this paper,including the number of terminals,login users,and the rules of users’migration during *** artifical intelligence(AI)technologies,the regis-tered users of the access and mobility management function(AMF),authorization users of the unified data management(UDM),protocol data unit(PDU)sessions of session manage-ment function(SMF)are predicted in combination with the num-ber of login users,the number of ***,the core network elements capacity can be predicted in *** proposed method is proven to be effective based on the data from real network.

关键词： space-terrestrial integrated networks core network element capacity artificial intelligent(AI)

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Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

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Deep Underground Science and Engineering 2024年第2期3卷 247-254页

作者： Shunyu Yue Ruifeng Miao Huihang Cheng Maohua Zhong Xiujun Yang Department of Engineering Physics Institute of Public Safety ResearchTsinghua UniversityBeijingChina Shanxi Province Expressway group limited Liability company Shanxi Expressway group Shuoshen Co. LtdShuozhouChina Research Institute of Highway Ministry of Transport RIOH Transport ConsultantsLtdBeijingChina

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea *** solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust *** order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were *** changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were *** this basis,the optimal smoke control strategy was proposed for different fire *** research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

关键词： sidewall smoke extraction system small‐scale fire tests smoke control

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Automatic Road Tunnel Crack Inspection Based on Crack Area Sensing and Multiscale Semantic Segmentation

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Computers, Materials & Continua 2024年第4期79卷 1679-1703页

作者： Dingping Chen Zhiheng Zhu Jinyang Fu Jilin He College of Mechanical and Electrical Engineering Central South UniversityChangsha410083China Department of Geotechnical Guangdong Hualu Transportation Technology Company LimitedGuangzhou510000China national Engineering Research Center of High-Speed Railway Construction Technology Changsha410075China

The detection of crack defects on the walls of road tunnels is a crucial step in the process of ensuring travel safetyand performing routine tunnel maintenance. The automatic and accurate detection of cracks on the surface of roadtunnels is the key to improving the maintenance efficiency of road tunnels. Machine vision technology combinedwith a deep neural network model is an effective means to realize the localization and identification of crackdefects on the surface of road *** propose a complete set of automatic inspection methods for identifyingcracks on the walls of road tunnels as a solution to the problem of difficulty in identifying cracks during manualmaintenance. First, a set of equipment applied to the real-time acquisition of high-definition images of walls inroad tunnels is designed. Images of walls in road tunnels are acquired based on the designed equipment, whereimages containing crack defects are manually identified and selected. Subsequently, the training and validationsets used to construct the crack inspection model are obtained based on the acquired images, whereas the regionscontaining cracks and the pixels of the cracks are finely labeled. After that, a crack area sensing module is designedbased on the proposed you only look once version 7 model combined with coordinate attention mechanism (CAYOLOV7) network to locate the crack regions in the road tunnel surface images. Only subimages containingcracks are acquired and sent to the multiscale semantic segmentation module for extraction of the pixels to whichthe cracks belong based on the DeepLab V3+ network. The precision and recall of the crack region localizationon the surface of a road tunnel based on our proposed method are 82.4% and 93.8%, respectively. Moreover, themean intersection over union (MIoU) and pixel accuracy (PA) values for achieving pixel-level detection accuracyare 76.84% and 78.29%, respectively. The experimental results on the dataset show that our proposed two-staged

关键词： Road tunnel crack inspection crack area sensing multiscale semantic segmentation CA-YOLO V7 DeepLab V3+

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Tracing Sources of Geochemical Anomalies in a Deeply Buried Volcanic-Related Hydrothermal Uranium Deposit:the Daguanchang Deposit,Northern Hebei Province,North china Craton

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Journal of Earth Science 2024年第4期35卷 1186-1195页

作者： Yangyang Zhang Yuelong Chen Dapeng Li Huan Kang Mingliang Fang Yunliang Xu School of Earth Science and Resources China University of GeosciencesBeijing100083China State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing100083China Jinchuan group company limited Jinchang737104China china-Explo Tian Cheng(Beijing)Technology company limited Beijing100093China

Radon(Rn)and helium(He)gases from uranium decay form distinct anomalies related to buried uranium *** order to trace the geochemical anomalous sources from the volcanic-related uranium deposits in deeply buried areas,systematical Rn contents and He isotope ratios were analyzed from the Daguanchang uranium *** soil gas Rn concentrations above the deep uranium are ten times higher than those in barren areas,indicating that instantaneous Rn content measurements can be used to detect deeply buried *** helium isotope ratios(^(3)He/^(4)He)of the unmineralized samples from the mineralized drill hole(ZK1)are relatively lower and uniform compared to those of the samples from no-mineral drill hole(ZK2).However,the Th and U contents of the drill core samples from ZK1 are slightly lower than those of the samples from ZK2,indicating that the lower 3He/4He ratios in ZK1 are most likely due to the addition of 4He from underlying uranium *** differences in the instantaneous Rn contents are consistent with the variations in the He isotope ratios of the drill core *** results demonstrate that soil gas Rn and ^(3)He/^(4)He ratios are useful tracers and can indicate the existence of deeply buried volcanic-related hydrothermal uranium ores.

关键词： tracers radon helium ^(3)He/^(4)He ratio uranium deposits Daguanchang deposit

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Performance Analysis of an Efficient Integration System of Coal-Fired Power Plant,Solar Thermal Energy and CO_(2)Capture

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Journal of Thermal Science 2024年第4期33卷 1509-1522页

作者： WANG Yuhao WANG Ruilin LIU Lanhua XING Chenjian GUO Yafei YANG Qingshan YING Jiaheng SUN Jian LI Wenjia LIU Yuanyuan ZHAO Chuanwen School of Energy and Mechanical Engineering Nanjing Normal UniversityNanjing210023China china Huadian group Co.LTD.Shanghai Branch Shanghai200120China Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University) Ministry of Education of ChinaTianjin300350China Huadian Zhengzhou Mechanical Design Institute company limited Zhengzhou450046China

Coal-fired power plant is a major contributor to greenhouse gas *** post-combustion capture is a promising method for CO_(2)emission reduction but the high thermal demand is *** address this issue,solar thermal energy and CO_(2)capture are jointly integrated into the coal-fired power plant in this *** solar thermal energy is employed to meet the heat requirement of the CO_(2)capture process,thereby avoiding the electricity loss caused by self-driven CO_(2)***,the heat released from the carbonation reaction of MgO adsorbent is integrated into the steam Rankine *** partially substituting the extracted steam for feedwater heating,the electricity output of the power plant is further *** to the results from the developed model,the system could achieve a CO_(2)capture rate of 86.5%and an electricity output enhancement of 9.8%compared to the reference system,which consists of a self-driven CO_(2)capture coal-fired power plant and PV generation *** operational strategy is also optimized and the amount of CO_(2)emission reduction on a typical day is increased by 11.06%.This work shows a way to combine fossil fuels and renewable energy for low carbon emissions and efficient power generation.

关键词： CO_(2)capture parabolic trough collector solar aided coal-fired electricity generation

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Alkali Tolerance of Concrete Internal Curing Agent Based on Sodium Carboxymethyl Starch

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 82-90页

作者：陈梅花刘荣进 CHEN Ping JING Daiyan WAN Dandan FU Siyuan College of Materials Science and Engineering Guilin University of TechnologyGuilin 541004China Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building Materials Guilin 541004China Guangxi Maibu New Material limited company Guilin 541004China

Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of *** alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw *** results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali *** water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is *** application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore *** compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.

关键词： alkali tolerance sodium carboxymethyl starch internal curing agent compressive strength

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