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

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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

Naive-LSTM enabled service identification of edge computing in power internet of things

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The Journal of China Universities of Posts and Telecommunications 2024年

作者： Bai Huifeng Huo Chao Zhang Ganghong Yin Zhibin beijing SmartChip Microelectronics technology company limited

Great challenges and demands are presented by increasing edge computing services for current Power Internet of Things (Power IoT) to deal with serious diversity and complexity of these services. To improve the matching degree between edge computing and complex services， the services identification function is necessary for Power IoT. This article proposes a naive long short-term memory (Naive-LSTM) based services identification scheme of edge computing devices in the Power IoT， where the Naive-LSTM model makes full use of the most simplified structure and conducts discretization of the LSTM model. Moreover， the Naive-LSTM based services identification scheme can generate the probability output result to determine the task schedule police of Power IoT. After well learning operation， these Naive-LSTM classification engine module in edge computing devices of Power IoT can perform services identification， by obtaining key characteristics from various services traffics. Testing results show that the Naive-LSTM based services identification scheme is feasible and efficient in improving the edge computing ability of the Power IoT.

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A review of reservoir damage during hydraulic fracturing of deep and ultra-deep reservoirs

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Petroleum Science 2024年第1期21卷 384-409页

作者： Kun Zhang Xiong-Fei Liu Dao-Bing Wang Bo Zheng Tun-Hao Chen Qing Wang Hao Bai Er-Dong Yao Fu-Jian Zhou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing102617China Tuha Downhole Operation company CNPC Xibu Drilling Engineering Company LimitedShanshan838200XinjiangChina

Deep and ultra-deep reservoirs have gradually become the primary focus of hydrocarbon exploration as a result of a series of significant discoveries in deep hydrocarbon exploration *** reservoirs present unique challenges due to their deep burial depth(4500-8882 m),low matrix permeability,complex crustal stress conditions,high temperature and pressure(HTHP,150-200℃,105-155 MPa),coupled with high salinity of formation ***,the costs associated with their exploitation and development are exceptionally *** deep and ultra-deep reservoirs,hydraulic fracturing is commonly used to achieve high and stable *** hydraulic fracturing,a substantial volume of fluid is injected into the ***,statistical analysis reveals that the flowback rate is typically less than 30%,leaving the majority of the fluid trapped within the ***,hydraulic fracturing in deep reservoirs not only enhances the reservoir permeability by creating artificial fractures but also damages reservoirs due to the fracturing fluids *** challenging“three-high”environment of a deep reservoir,characterized by high temperature,high pressure,and high salinity,exacerbates conventional forms of damage,including water sensitivity,retention of fracturing fluids,rock creep,and proppant *** addition,specific damage mechanisms come into play,such as fracturing fluid decomposition at elevated temperatures and proppant diagenetic reactions at HTHP ***,the foremost concern in deep oil and gas development lies in effectively assessing the damage inflicted on these reservoirs by hydraulic fracturing,comprehending the underlying mechanisms,and selecting appropriate ***'s noteworthy that the majority of existing studies on reservoir damage primarily focus on conventional reservoirs,with limited attention given to deep reservoirs and a lack of systematic *** light of this,our approach entails initially summarizin

关键词： Artificial fracture Deep and ultra-deep reservoir Fracture conductivity Fracturing fluid Hydraulic fracturing Reservoir damage

Active metasurface via magnetic control for tri-channel polarization multiplexing holography

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Chinese Optics Letters 2024年第4期22卷 112-118页

作者：毕钰黄玲玲李拓王长红邹晓峰周朗康果果 Shandong Inspur Artificial Intelligence Research Institute company limited Jinan 250013China MIIT Key Laboratory of Photonics Information technology School of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China

Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied,the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.

关键词： active metasurface magneto-optical effect polarization multiplexing holography dynamic holographic display

Modeling analysis of cobalt-based Fischer-Tropsch catalyst particles

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Chinese Journal of Chemical Engineering 2024年第6期70卷 82-92页

作者： Huashuai Wu Gang Wang Yong Yang Yongwang Li College of Chemical Engineering and technology Taiyuan University of TechnologyTaiyuan 030024China National Energy Research&Development Center for Coal to Liquid Fuels Synfuels China CompanyLimitedBeijing 101400China

The influences of particle size,shape,and catalyst distribution on the reactivity and hydrocarbon product selectivity of a cobalt-based catalyst for Fischer-Tropsch synthesis were investigated in the present work.A self-consistent kinetic model for Fischer-Tropsch reaction proposed here was found to correlate experimental data well and hence was used to describe the consumption rates of reactants and formation rates of hydrocarbon *** perturbed-chain statistical associating fluid theory equation of state was used to describe vapor-liquid equilibrium behavior associated with Fischer-Tropsch *** interaction between intraparticle diffusion and Fischer-Tropsch reaction was investigated in *** showed that in order to avoid the adverse influence of intraparticle diffusional limitations on catalyst reactivity and product selectivity,the use of small particles is *** eggshell spherical particles are shown to keep the original catalyst reactivity and enhance the selectivity of heavy hydrocarbon *** suitable layer thickness for a spherical particle with a diameter of 2 mm is nearly 0.15 *** the same outer diameter of 2 mm,the catalyst reactivity and heavy product selectivity of hollow cylindrical particles with a layer thickness of 0.25 mm are found to be larger than eggshell spherical *** the viewpoint of catalytic performance,hollow cylindrical particles are a better choice for industrial applications.

关键词： Fischer-Tropsch synthesis Kinetic modeling Vapor-liquid equilibria Numerical simulation Intraparticle diffusion Particle shapes

Integrated Frequency-constrained Scheduling Considering Coordination of Frequency Regulation Capabilities from Multi-source Converters

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 261-274页

作者： Jiaming Li Ying Qiao Zongxiang Lu Wei Ma Xin Cao Rongfu Sun the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China the China Suntien Green Energy limited company Shijiazhuang 050011China the State Grid Jibei Electric Power company Beijing 100054China

As the proportion of renewable energy(RE)increases,the inertia and the primary frequency regulation(FR)capability of the power system ***,ensuring frequency security in the scheduling model has become a new technical requirement in power systems with a high share of *** to a shortage of conventional synchronous generators,the frequency support of multi-source converters has become an indispensable part of the system frequency resources,especially variable-speed wind turbine generation(WTG)and battery energy storage(BES).Quantitative expression of the FR capability of multi-source converters is necessary to construct frequency-constrained scheduling ***,the frequency support performance of these converter-interfaced devices is related to their working states,operation modes,and parameters,and the complex coupling of these factors has not been fully exploited in existing *** this study,we propose an integrated frequency-constrained scheduling model considering the coordination of FR capabilities from multi-source *** FR control strategies and variable FR parameters for WTG with or without reserved power are modeled,and multi-target allocation of BES capacity between tracking dispatch instruction and emergency FR is ***,the variable FR capabilities of WTG and BES are embedded into the integrated frequency-constrained scheduling *** nonlinear constraints for frequency security are precisely linearized through an improved iteration-based *** effectiveness of the proposed model is verified in a modified IEEE 24-bus standard *** results suggest that the coordinated participation of BES and WTG in FR can effectively reduce the cost of the scheduling model while meeting frequency security constraints.

关键词： Battery energy storage(BES) wind turbine generation(WTG) frequency regulation(FR) frequency security power system scheduling

Fracture behavior and mechanism of highly fragmented steel cylindrical shell under explosive loading

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Defence technology（防务技术） 2024年第6期36卷 122-132页

作者： Kang Wang Peng Chen Xingyun Sun Yufeng Liu Jiayu Meng Xiaoyuan Li Xiongwei Zheng Chuan Xiao Xi'an Modern Chemistry Research Institute Xi'an 710065China Shanxi Jiangyang Chemical company limited Taiyuan 030051China Central Iron&Steel Research Institute company limited Beijing 100081China China Research and Development Academy of Machinery Equipment Beijing 100089China

An in-depth understanding of the fracture behavior and mechanism of metallic shells under internal explosive loading can help develop material designs for warheads and regulate the quantity and mass distribution of the fragments *** study investigated the fragmentation performance of a new high-carbon silicon-manganese(HCSiMn)steel cylindrical shell through fragment recovery *** with the conventional 45Cr steel shell,the number of small mass fragments produced by the HCSi Mn steel shell was significantly increased with a scale parameter of 0.57 g fitted by the Weibull distribution *** fragmentation process of the HCSi Mn shell exhibited more brittle tensile fracture characteristics,with the microcrack damage zone on the outer surface being the direct cause of its high *** the one hand,the doping of alloy elements resulted in grain refinement by forming metallographic structure of tempered sorbite,so that microscopic intergranular fracture reduces the characteristic mass of the fragments;on the other hand,the distribution of alloy carbides can exert a"pinning"effect on the substrate grains,causing more initial cracks to form and propagate along the brittle carbides,further improving the shell *** the killing power radius for light armored vehicles was slightly reduced by about 6%,the dense killing radius of HCSiMn steel projectile against personnel can be significantly increased by about 26%based on theoretical *** results provided an experimental basis for high fragmentation warhead design,and to some extent,revealed the correlation mechanism between metallographic structure and shell fragmentation.

关键词： Projectile fragmentation Fragment mass distribution Fracture mode Metallographic structure Damage power

A hybrid machine learning optimization algorithm for multivariable pore pressure prediction

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Petroleum Science 2024年第1期21卷 535-550页

作者： Song Deng Hao-Yu Pan Hai-Ge Wang Shou-Kun Xu Xiao-Peng Yan Chao-Wei Li Ming-Guo Peng Hao-Ping Peng Lin Shi Meng Cui Fei Zhao School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhou213164JiangsuChina Tubular Goods Research Institute of CNPC Beijing102249China CNPC Engineering technology R&D company limited Beijing102206China

Pore pressure is essential data in drilling design,and its accurate prediction is necessary to ensure drilling safety and improve drilling *** methods for predicting pore pressure are limited when forming particular structures and *** this paper,a machine learning algorithm and effective stress theorem are used to establish the transformation model between rock physical parameters and pore *** study collects data from three *** 1 had 881 data sets for model training,and Wells 2 and 3 had 538 and 464 data sets for model *** this paper,support vector machine(SVM),random forest(RF),extreme gradient boosting(XGB),and multilayer perceptron(MLP)are selected as the machine learning algorithms for pore pressure *** addition,this paper uses the grey wolf optimization(GWO)algorithm,particle swarm optimization(PSO)algorithm,sparrow search algorithm(SSA),and bat algorithm(BA)to establish a hybrid machine learning optimization algorithm,and proposes an improved grey wolf optimization(IGWO)*** IGWO-MLP model obtained the minimum root mean square error(RMSE)by using the 5-fold cross-validation method for the training *** the pore pressure data in Well 2 and Well 3,the coefficients of determination(R^(2))of SVM,RF,XGB,and MLP are 0.9930 and 0.9446,0.9943 and 0.9472,0.9945 and 0.9488,0.9949 and *** achieves optimal performance on both training and test data,and the MLP model shows a high degree of *** indicates that the IGWO-MLP is an excellent predictor of pore pressure and can be used to predict pore pressure.

关键词： Pore pressure Grey wolf optimization Multilayer perceptron Effective stress Machine learning

Wellbore Cleaning Degree and Hydraulic Extension in Shale Oil Horizontal Wells

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Fluid Dynamics & Materials Processing 2024年第3期20卷 661-670页

作者： Xin Ai Mian Chen College of Petroleum Engineering China University of Petroleum(Beijing)BeijingChina Daqing Oil Field company limited DaqingChina

The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.

关键词： Shale oil horizontal well hydraulic extension wellbore cleaning degree pressure distribution mechanism analysis