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The reservoir characteristics and their controlling factors of the sublacustrine fan in the Paleogene Dongying Formation, Bohai Sea,China

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Journal of Palaeogeography 2024年第1期13卷 127-148页

作者： Xiao-Jun Pang Guan-Min Wang Meng Zhao Qing-Bin Wang Xue-Fang Zhang School of Geosciences China University of Petroleum(East China)QingdaoShandong 266580China Tianjin Branch of China National Offshore Oil Corporation Limited Tianjin 300459China

Sublacustrine fan is an important element in continental lacustrine basins and is significant for reservoir exploration. Oil and gas resources have been found in the sublacustrine fan sandstone reservoirs of the Paleogene Dongying Formation in the Bohai Sea. In this study, the characteristics of the sublacustrine fan reservoirs and the controlling factors are studied using information from logging, cores, physical properties,casting thin sections, X-ray diffraction of clay minerals, vitrinite reflectance, rock pyrolysis, manometry data,and 3D seismic data. The sublacustrine fans of the Dongying Formation in the LD10, QHD34, and BZ21 structures show high-quality reservoirs with porosity >15 % and permeability >5 m D. The main controlling factors of the high-quality reservoirs are attributed to the favorable sedimentary facies type and negligible compaction,and cementation, substantial dissolution of K-feldspar, overpressure, and the development of faults and fractures. A high-quality sublacustrine fan reservoir model has been established to explain how these factors affected the physical properties. The favorable targets for oil and gas exploration in the Dongying Formation of Bohai Sea include undercompacted sandy debris flow reservoirs showing the dissolution of K-feldspar, and the reservoirs which are connected to the source rocks by faults. This study provides insights to establish the relationship between sedimentology, diagenesis and reservoir quality. The results of this study are significant for the exploration and development of the sublacustrine fan sandstone reservoirs in the Bohai Sea and analogous sandstone reservoirs elsewhere.

关键词： Sublacustrine fan High-quality reservoir Dissolution Overpressure fault Bohai Sea

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Application of Gaussian Beam Summation Migration in Reflected In-seam Wave Imaging

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 276-284页

作者： HAN Jianguang LÜQingtian ZHANG Zhiheng YANG Shun WANG Shuo Chinese Academy of Geological Sciences Beijing 100037China Shandong Taishan Resources Exploration Co. Ltd.Jinan 250104China

The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine production.In-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working faces.However,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging technique.This study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave data.Firstly,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam waves.Thereafter,imaging is performed using the GBS migration technique.The feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and throws.By applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.

关键词： reflected in-seam wave Gaussian beam summation migration numerical tests fault

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A Novel Recovery Strategy to Suppress Subsequent Commutation Failure in an LCC-Based HVDC

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Protection and Control of Modern Power Systems 2024年第1期9卷 38-51页

作者： Changsheng Su Chunya Yin Fengting Li Lu Han 不详 School of Electrical Engineering Xinjiang UniversityUrumqi 830017China

A subsequent commutation failure(SCF)can easily occur during the recovery process after a first commutation failure(1st CF).This paper analyzes the interaction mechanism of extinction angle,AC voltage,DC current and firing angle,and reveals that the complex coupling relationship during the dynamic process after the 1st CF has a significant effect on the SCF.The mathematical equations when considering different fault durations,fault severities and AC system strengths are then established.An AC fault voltage detection method based on reactive power and fault duration is also proposed to measure the fault severity,and an SCF inhibition control strategy(SCFICS)based on AC fault detection and reactive power control is subsequently proposed.This can not only inhibit the SCF,but also enhance the DC recovery speed effectively.Finally,based on the SCFICS,a simulation model is built,and the simulation results with different cases indicate that the SCFICS can effectively inhibit the SCF with good recovery performance,for three-phase-to-ground(TPG)and single-phase-to-ground faults,and with a fault inductance range of 0.01 H to 1 H.

关键词： fault extinction angle

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A Deep Generative Model with Multiscale Features Enabled Industrial Internet of Things for Intelligent fault Diagnosis of Bearings

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Research 2023年第3期6卷 57-68页

作者： He-xuan Hu Yicheng Cai Qiang Hu Ye Zhang Key Laboratory of Water Big Data Technology of Ministry of Water Resources Hohai UniversityNanjing 211100P.R.China College of Computer and Information Hohai UniversityNanjing 211100P.R.China

Effective condition monitoring and fault diagnosis of bearings can not only maximize the life of rolling bearings and prevent unexpected shutdowns caused by equipment failures but also eliminate unnecessary costs and waste caused by excessive maintenance.However,the existing deep-learning-based bearing fault diagnosis models have the following defects.First of all,these models have a large demand for fault data.Second,the previous models only consider that single-scale features are generally less effective in diagnosing bearing faults.Therefore,we designed a bearing fault data collection platform based on the Industrial Internet of Things,which is used to collect bearing status data from sensors in real time and feed it back into the diagnostic model.On the basis of this platform,we propose a bearing fault diagnosis model based on deep generative models with multiscale features(DGMMFs)to solve the above problems.The DGMMF model is a multiclassification model,which can directly output the abnormal type of the bearing.Specifically,the DGMMF model uses 4 different variational autoencoder models to augment the bearing data and integrates features of different scales.Compared with single-scale features,these multiscale features contain more information and can perform better.Finally,we conducted a large number of related experiments on the real bearing fault datasets and verified the effectiveness of the DGMMF model using multiple evaluation metrics.The DGMMF model has achieved the highest value under all metrics,among which the value of precision is 0.926,the value of recall is 0.924,the value of accuracy is 0.926,and the value of F1 score is 0.925.

关键词： fault bearings diagnosis

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Reliability analysis of large-diameter high-grade-steel natural gas pipelines under fault action

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Petroleum Science 2022年第5期19卷 2387-2398页

作者： Xiao-Ting Gu Xue-Rui Zang Zhen-Yong Zhang Peng Yang Wen-Zhen Miao Ping Cao Bin Zhao School of Petroleum Engineering Yangtze UniversityWuhan430100HubeiChina Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100HubeiChina College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao266580ShandongChina China Petroleum Pipeline Engineering Corporation Langfang065000HebeiChina China Petroleum Pipeline Engineering Co. Ltd.Langfang065000HebeiChina Sinopec Zhongyuan Petroleum Engineering Design Co. Ltd.Zhengzhou450000HenanChina Sinopec Jianghan Petroleum Engineering Design Co. Ltd.Wuhan430223HubeiChina College of Geophysics and Oil Resources Yangtze UniversityWuhan430100HubeiChina

There are a lot of researches on qualitative aseismatic measures for buried gas pipeline crossing movable faults.But a few of them are quantitative,especially in the size and shape of the trench.The paper first established the finite element model of the strain of buried pipeline crossing a fault which effected by the size and shape of the trench.And it obtained new soil spring stiffness which considered different buried depth,bottom width of trench,trench slope and elastic modulus of soil.The mechanical analysis model of pipeline is established,and the limit state equation of pipeline is fitted.The reliability and sensitivity of the natural gas pipeline under fault action are analysed by a Monte Carlo method,and the error and accuracy are verified.When the pipeline is under tension,the sensitivity from large to small is buried depth,sand friction angle,pipe diameter,pipeline displacement,trench bottom width,trench depth,clay cohesion,trench slope and clay friction angle;when the pipeline is under pressure,the trench depth and clay cohesion have great influence.The findings of this study provide a reference for pipeline design and safety evaluation under fault action.

关键词： Trench parameters Natural gas pipeline fault Soil-pipeline interaction Soil spring stiffness

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Study on the influencing factors to reduce the recovery time of superconducting tapes and coils for the DC superconducting fault current limiter applications

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High Voltage 2022年第3期7卷 483-495页

作者： Bin Xiang Wenqing Wang Hongxu Li Lei Gao Zhiyuan Liu Yingsan Geng Jianhua Wang Youping Tu Department of Electrical Engineering State Key Laboratory of Electrical Insulation and Power EquipmentXi'an Jiaotong UniversityXi'anChina State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

Superconducting fault current limiters(SFCLs)are important in improving the stability of electrical power systems.However,the existing resistive-type DC SFCL has a long re-covery time,which cannot meet the requirements of power system auto-reclosure.Thus,it is necessary to investigate the methods of reducing recovery time of SFCLs.In the simulations on superconducting tapes,there is a lack of investigation about the effects of design factors of superconducting tapes and coils such as material,thickness,coil radius,coil winding method on recovery characteristics.The objective of this study is to obtain the effects of material and geometric properties of superconducting tapes and coils on recovery characteristics and obtain methods to reduce the recovery time.The recovery times under different conducting currents are also compared by simulations and exper-iments to verify simulation accuracy.The maximum error is below 40%and most of the cases have an error below 10%.Besides,by increasing tape thickness,the recovery time can be reduced by 22%.Tape materials and coil winding methods can be designed ac-cording to the auto-reclosure and current-limiting requirements of the power systems.The research provided directions for the design of superconducting tape and super-conducting coil for resistive-type DC SFCLs.

关键词： fault winding conducting

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Improved information entropy weighted vague support vector machine method for transformer fault diagnosis

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High Voltage 2022年第3期7卷 510-522页

作者： Hongru Zhang Jiaxiang Sun Kaining Hou Qingquan Li Hongshun Liu Shandong Provincial Key Laboratory of UHV Transmission Technology and Equipment School of Electrical EngineeringShandong UniversityJinanChina

A combined model based on improved information entropy and vague support vector machine(IVSVM)is introduced into transformer fault diagnosis using dissolved gas analysis in oil(DGA).The improved information entropy method is used to obtain the weights of each gas and to weight the raw data,and the processed training data and the corresponding fault types are inputted into the vague support vector machine(VSVM)model to obtain classifiers.Firstly,the training data are weighted by the improved information entropy method to discretise the original data from the mixed state for subsequent classifier training.Then,the vague set divides the events into true,false and unknown factors,which can optimise the sub-interface of SVM and improve the accuracy of the boundary point clas-sification.Finally,fault data from the literature and actual collections are selected for training and testing.By comparing with the widely used ratio method and artificial intelligence method,it can be concluded that the method described herein can effectively improve the accuracy of fault diagnosis.The result shows that this method has better applicability when facing actual fault type classification with higher data similarity.

关键词： fault entropy artificial

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Modelling and analysis of half-/full-bridge hybrid MMC when riding through DC-side pole-to-ground fault

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High Voltage 2022年第3期7卷 496-509页

作者： Zhen He Jiabing Hu Lei Lin Pingliang Zeng School of Automation Hangzhou Dianzi UniversityHangzhouChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhanChina

In a modular multilevel converter-based high-voltage direct current(MMC-HVDC)system,the dc fault ride through(FRT)control is an effective way to deal with a dc-side pole-to-ground(PTG)fault.However,the setting of FRT duration brings potential hazards:1)MMC will face the risk of“secondary short circuit”if FRT duration is short;2)ac grid may have power angle stability issue if FRT duration is long.To avoid these hazards and provide theoretical guidance for the FRT duration setting,transient behaviour of dc fault current during the PTG FRT stage is explored in this work.Firstly,challenges of the transient analysis are summarised as non-linearity and high-order issues.In light of this,numerical and Hilbert-Huang Transformation methods are introduced to evaluate the non-linearity issue.It is found that the path of MMC from dc current to dc internal voltage is weakly non-linear.Hence,a linear transient model is built to analyse the dc fault current.By participation factor analysis,the order of the proposed model is further reduced,so that an analytical expression of the dc fault current is approximately derived.Based on the analytical expression,regularities and mechanism of dc fault current are fully revealed.Application of the transient analysis to the setting of FRT duration is elaborated in detail.Finally,the PSCAD/EMTDC simulation verifies the validity of the proposed model and analytical expression.

关键词： fault ground setting

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Stability control measures for roof cutting and NPR supporting of mining roadways in fault areas of kilometre-deep coal mine

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Journal of Mountain Science 2023年第10期20卷 3051-3065页

作者： SUN Xiao-ming WANG Jian ZHANG Yong ZHAO Wen-chao GUO Zhi-biao HE Man-chao CHEN Feng MIAO Cheng-yu State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 10oo83China School of Civil Engineering Nanyang Institute of TechnologyNanyang 4730ooChina

The study focuses on the stability control measures for mining roadways in fault zones of deep mines,using Daqiang Coal Mine as a case study.The control system under consideration,referred to as"pre-splitting cutting roof+NPR anchor cable"(PSCR-NPR),is subjected to scrutiny through theoretical analysis,numerical modelling,and field trials.Furthermore,a comprehensive analysis is undertaken to evaluate the stability control mechanism of this particular technology.The study provides evidence that the utilization of deep-hole directional energy-concentrated blasting facilitates the attainment of directional roof cutting in roadways.The aforementioned procedure leads to the formation of a uniform structural surface on the roof of the roadway and causes modifications in the surrounding geological formation.The examination of the lateral abutment pressure and shear stress distribution,both prior to and subsequent to roof cutting,indicates that the implementation of pre-splitting techniques leads to a noteworthy reduction in pressure.The proposition of incorporating the safety factor Q for roof cutting height is suggested as a method to augment comprehension of the pressure relief phenomenon in the field of engineering.The analysis of numerical simulation has indicated that the optimal pressure relief effect of a mining roadway in a fault area is attained when the value of Q is 1.8.The NPR anchor cable exhibits noteworthy characteristics,including a high level of prestress,continuous resistance,and substantial deformation.After the excavation of the roadway,a notable reduction in radial stress occurs,leading to the reinstatement of the three-phase stress state in the surrounding rock.This restoration is attributed to the substantial prestress exerted on the radial stress.The termination point of the NPR anchor cable is strategically positioned within a stable rock formation,allowing for the utilization of the mechanical characteristics of the deep stable rock mass.This positioning serves to improve the load-bearing capac

关键词： Kilometre-deep mine fault Mining roadway Pre-splitting cutting roof High pre-stress NPR anchor cable

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Molecular pyrolysis process and gas production characteristics of 3-element mixed insulation oil under thermal fault

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High Voltage 2022年第6期7卷 1130-1140页

作者： Dawei Feng Ge Chen Xiaoyu Yan Jian Hao Ruijin Liao State Key Lab of Reliability and Intelligence of Electrical Equipment School of Electrical EngineeringHebei University of TechnologyTianjinChina Hebei International Joint Research Center for Reliability and Intelligence of Modern Electrical Equipment TianjinChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Mixed insulation oil is considered as a desired substitute for traditional mineral oil.A novel 3-element mixed insulation oil has been developed in our previous works,whose parameters satisfy the mineral oil standard(IEC 60296:2012).In the application of transformer oil,dissolved gas analysis is an effective method for insulation fault diagnosis.Thermal fault is a common and typical fault in transformers;however,the pyrolysis process and gas production characteristics of mixed insulation oil under thermal fault remain unknown.In this study,the pyrolysis process and gas production characteristics of 3-element mixed insulation oil have been studied through simulation and experiments,and mineral oil is equally treated for comparison.Results show that the gas production characteristics of mixed oil are closely related to its base oils,and 3-element mixed insulation oil generates more H_(2)and C_(2)H_(6)under thermal fault,in which the percentage of H_(2)in the mixed oil is always three times that in the mineral oil.More CO_(2)is produced in mixed oil under thermal fault because of ester bonds;C_(2)H_(4)is also a main characteristic gas for mixed insulation oil under thermal fault,and its proportion increases continuously with the increase of temperature.For mineral oil,the weight loss temperature in thermogravimetric(TG)curve corresponds to evaporation rather than decomposition.Natural esters have poor thermal stability according to simulation results,but they possess high flash point and weight loss temperature in the TG curve primarily because of their large average molecular weight.

关键词： insulation fault pyrolysis

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