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Petroleum Exploration and Development 2019年第1期46卷 153-162页

作者： GUO Jianchun TAO Liang ZENG Fanhui State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation in Southwest Petroleum University

Tight oil reservoirs in Songliao Basin were taken as subjects and a novel idealized refracturing well concept was proposed by considering the special parameters of volume fracturing horizontal wells, the refracturing potential of candidate wells were graded and prioritized, and a production prediction model of refracturing considering the stress sensitivity was established using numerical simulation method to sort out the optimal refracturing method and timing. The simulations show that: with the same perforation clusters, the order of fracturing technologies with contribution to productivity from big to small is refracturing between existent fractured sections, orientation diversion inside fractures, extended refracturing, refracturing of existent fractures; and the later the refracturing timing, the shorter the effective time. Based on this, the prediction model of breakdown pressure considering the variation of formation pressure was used to find out the variation pattern of breakdown pressure of different positions at different production time. Through the classification of the breakdown pressure, the times of temporary plugging and diverting and the amount of temporary plugging agent were determined under the optimal refracturing timing. Daily oil production per well increased from 2.3 t/d to 16.5 t/d in the field test. The research results provide important reference for refracturing optimization design of similar tight oil reservoirs.

关键词： Songliao Basin tight oil reservoirs refracturing volume fracturing breakdown pressure temporary plugging and diverting

Adsorption damage and control measures of slick-water fracturing fluid in shale reservoirs

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Petroleum Exploration and Development 2018年第2期45卷 336-342页

作者： GUO Jianchun LI Yang WANG Shibin State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation in Southwest Petroleum University Chengdu 610500 China

The slick-water polymer adsorption damage and control measures in shale were examined using a shale pack model of the Ordovician Wufeng Formation–Silurian Longmaxi Formation in the Changning block of the Sichuan Basin. The adsorption law of slick water under different displacement time, concentrations, p H values and temperatures of polymer were tested by traditional displacement experiment and UV-Vis spectrophotometer. The adsorption equilibrium time was 150 min, the amount of adsorption was proportional to the concentration of the polymer, and the maximum adsorption concentration was 1 800 mg/L. With the increase of p H value, the adsorption capacity decreased gradually, the adsorption capacity increased first and then decreased with the increase of temperature, and the adsorption capacity was the largest at 45 ?C. The adsorption patterns of polymers on shale were described by scanning electron microscopy and magnetic resonance imaging. It is proved that the adsorption of polymer on shale led to the destruction of the network structure of anionic polyacrylamide molecules, and the shale adsorption conformation was characterized qualitatively. Finally, according to the adsorption law and adsorption mechanism, it is proposed to reduce the adsorption quantity of polymer on shale surface by using hydrogen bond destruction agent. The effects of hydrogen bond destruction on four kinds of strong electronegative small molecules were compared, the hydrogen bond destroyer c was the best, which lowered the adsorption capacity by 5.49 mg/g and recovered permeability to 73.2%. The research results provide a reference for the optimization of construction parameters and the improvement of slickwater liquid system.

关键词： shale hydraulic fracturing slick-water polymer shale adsorption desorption

Effect of Ga addition on the magnetic properties and microstructure of nanocrystalline Nd_(12.3)Fe_(81.7)B_(6.0) ribbons

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Rare Metals 2011年第5期30卷 447-452页

作者： BAO Xiaoqian guo Xiaoyan GUO Jianchun GAO Xuexu State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Shandong Jinma Industrial Group Co. Ltd. Rizhao 276826 China

Nd 12.3 Fe 81.7 x Ga x B 6.0 （x = 0-1.8） ribbons were prepared by melt spinning at 22 m/s and subsequent annealing treatment. The influences of Ga addition and annealing conditions on the magnetic properties and microstructure of the nanocrystalline alloys were systematically investigated. After being annealed at 620℃ for 20 min, the J r and H ci increased from 0.85 T and 582.6 kA/m for Ga-free sample to 0.97 T and 734.6 kA/m for the x = 0.9 sample, respectively. The （BH） max for the x = 0.9 sample increased by about 40% from 96.3 to 135.5 kJ/m 3 compared with that of the Ga-free one. The significant improvement of magnetic properties originated from the refinement of grains in the samples by introducing Ga, which led to a stronger exchange coupling between the neighboring grains in comparison with that in Ga-free samples. The microstructure and magnetic properties of the samples depended strongly on annealing parameters, while the sensitivity of micro-structure to annealing conditions could be significantly suppressed by the addition of Ga element.

关键词： nanocrystalline alloys exchange coupling microstructure magnetic properties gallium

Epidemiological Characteristics of Human Anthrax-China,2018-2021

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China CDC weekly 2022年第35期4卷 783-787页

作者： Huijuan Zhang Enmin Zhang Mu guo Jinrong He Wei Li jianchun Wei National Institute for Communicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijingChina State Key Laboratory of Infectious Disease Prevention and Control BeijingChina Yunnan Institute for Endemic Disease Control and Prevention Dali CityYunnan ProvinceChina

Introduction:The epidemic of human anthrax is at a low level in China in recent years,but the reported incidence increased in 2021.In order to understand the current landscape of research and knowledge about anthrax in China,the epidemiological characteristics of anthrax in humans from 2018 to 2021 were analyzed and the prevention and control suggestions were proposed.Methods:Surveillance data of anthrax in humans and livestock,together with human outbreaks data during 2018-2021,were collected and analyzed by descriptive statistics methods.The number and proportion of outbreaks,cases and deaths by provincial-level administrative divisions(PLADs),clinical types,and contributing factors were calculated.Results:A total of 1,244 cases of human anthrax and 53 outbreaks were reported from 2018 to 2021 in China.While the incidence of anthrax declined from 2018 to 2020,it increased in 2021.The regions of anthrax were mainly located in the west and the northeast PLADs of China,though cases were reported in some central and eastern PLADs in 2021.Young and middle-aged men involved in animal husbandry were found to be at a higher risk of anthrax.All the reported outbreaks were associated with the exposure of infected livestock.A total of 296 livestock anthrax cases were reported.Conclusions:The increased incidence and wider geographical distribution of human anthrax in 2021 were found to be the result of inadequate supervision of diseased animals as well as updated diagnostic criteria.As such,the monitoring of risk factors and emergency preparation procedures should be strengthened at the national level.In addition,it is also critical to strengthen health education for high-risk occupational groups and strengthen professional training for local clinicians.Finally,more measures should be carried out to strengthen anthrax surveillance in livestock husbandry.

关键词： prevention husbandry strengthened

Plugging behaviors of temporary plugging particles in hydraulic fractures

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Petroleum Exploration and Development 2023年第2期50卷 464-472页

作者： GUO Jianchun ZHAN Li LU Qianli QI Tianjun LIU Yuxuan WANG Xin CHEN Chi GOU Xinghao State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China CCDC Downhole Service Company Chengdu 610052China PetroChina Research Institute of Petroleum Exploration and Development Beijing 100083China Engineering Technology Research Institute of PetroChina Southwest Oil&Gas Field Company Guanghan 618300China

Using the visualized experimental device of temporary plugging in hydraulic fractures, the plugging behaviors of temporary plugging particles with different sizes and concentrations in hydraulic fractures were experimentally analyzed under the conditions of different carrier fluid displacements and viscosities. The results show that the greater the carrier fluid viscosity and displacement, the more difficult it is to form a plugging layer, and that the larger the size and concentration of the temporary plugging particle, the less difficult it is to form a plugging layer. When the ratio of particle size to fracture width is 0.45, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle and the viscosity of the carrier fluid, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 20 kg/m^(3)or the viscosity of the carrier fluid is greater than 3 mPa·s. When the ratio of particle size to fracture width is 0.60, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 10 kg/m^(3). When the ratio of particle size to fracture width is 0.75, the formation of the plugging layer is basically not affected by other parameters, and a stable plugging layer can form within the experimental conditions. The formation process of plugging layer includes two stages and four modes. The main controlling factors affecting the formation mode are the ratio of particle size to fracture width, carrier fluid displacement and carrier fluid viscosity.

关键词： hydraulic fracture temporary plugging and diversion temporary plugging particle plugging characteristics construction parameters combination

A high salt tolerance and low adsorption drag reducer based on non-covalent enhancement

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Petroleum Exploration and Development 2020年第6期47卷 1333-1341页

作者： MA Yingxian ZHU Zhi GUO Jianchun ZHOU Han LI Jia XIONG Yujia MA Leyao Petroleum Engineering School Southwest Petroleum UniversityChengdu 610500China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China Downhole Service Company CNPC Chuanqing Drilling Engineering Company LimitedChengdu 610051China Geological Exploration and Development Research Institute CNPC Chuanqing Drilling Engineering Company LimitedChengdu 610051China Shengli Oil Production Plant Sinopec Shengli Oilfield BranchDongying 257000China

To formulate fluids with flowback water,produced water directly to improve the utilization rate of recycling and reduce the adsorption damage of slick water to reservoirs,a high salt tolerance and low adsorption drag reducer was designed and prepared by introducing polar cation fragments to enhance the non-covalent interactions between the chains.The drag reducer was characterized by IR and NMR.Friction resistance and viscosity tests were conducted to evaluate its salt resistance property.Static adsorption and dynamic adsorption retention tests were carried out to evaluate the damage of this reducer to shale reservoirs.The introduction of cation units into the molecular structure can weak the shielding effect of metal cations to some extent,so the drag reducer can keep a stable molecular structure and good resistant reducing performance under high salinity.The enhancement of non-covalent interaction between chains decreased the free polarity sites,further reduced the possibility of hydrogen bonding between drag reducer molecules and shale.In high salinity condition,both the adsorption capacity of the drag reducer on the shale surface and the average damage rate to the core permeability are low.Compared with the conventional salt-tolerant system,the overall liquid cost was reduced by 17%and the production per well increased by 44%.The application of this slick water system has achieved remarkable results.

关键词： shale hydraulic fracturing slick water drag reducer low adsorption high salt tolerance

An optimal fracture geometry design method of fractured horizontal wells in heterogeneous tight gas reservoirs

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Science China(Technological Sciences) 2016年第2期59卷 241-251页

作者： ZENG FanHui KE YuBiao GUO Jianchun State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation Southwest Petroleum University

In this work, the unified fracture design(UFD) is extended for the first time to the fractured horizontal wells in heterogeneous closed box-shaped tight gas reservoirs. Utilizing the direct boundary element method and influence function, the dimensionless fracture productivity index is obtained and expressed in the function of proppant volume and fracture geometry at the pseudo-steady state. With the iterative method, the effectively propped permeability, kfe, is corrected using the in-situ Reynolds number, N_(Re). The goal of this paper is to present a new UFD extension to design the proppant volume and the optimal fracture geometry. The results show that there exists an optimal proppant volume for a certain reservoir. The small aspect ratio(y_e/x_e) and high permeability reservoirs need short and wide fractures to diminish the non-Darcy effect. On the contrary, long and narrow fractures are required for the large aspect ratio and low permeability reservoirs. A small proppant volume is prone to creating long fractures, while a relatively large proppant volume creates wide fractures. The new extension can be used to evaluate the previous fracture parameters and design the following fracture parameters of the fractured horizontal well in heterogeneous tight gas reservoirs, with the non-Darcy effect taken into account.

关键词：压裂水平井设计方法致密气藏几何尺寸非均质裂缝水库非达西效应

hale gas reservoir modeling and production evaluation considering complex gas transport mechanisms and dispersed distribution of kerogen

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Petroleum Science 2021年第1期18卷 195-218页

作者： Jie Zeng Jishan Liu Wai Li Yee-Kwong Leong Derek Elsworth jianchun guo School of Engineering The University of Western Australia35 Stirling HighwayPerthWA 6009Australia Department of Energy and Mineral Engineering G3 Center and Energy InstituteThe Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China

Stimulated shale reservoirs consist of kerogen,inorganic matter,secondary and hydraulic fractures.The dispersed distribution of kerogen within matrices and complex gas flow mechanisms make production evaluation challenging.Here we establish an analytical method that addresses kerogen-inorganic matter gas transfer,dispersed kerogen distribution,and complex gas flow mechanisms to facilitate evaluating gas production.The matrix element is defined as a kerogen core with an exterior inorganic sphere.Unlike most previous models,we merely use boundary conditions to describe kerogen-inorganic matter gas transfer without the instantaneous kerogen gas source term.It is closer to real inter-porosity flow conditions between kerogen and inorganic matter.Knudsen diffusion,surface diffusion,adsorption/desorption,and slip corrected flow are involved in matrix gas flow.Matrix-fracture coupling is realized by using a seven-region linear flow model.The model is verified against a published model and field data.Results reveal that inorganic matrices serve as a major gas source especially at early times.Kerogen provides limited contributions to production even under a pseudo-steady state.Kerogen properties’influence starts from the late matrix-fracture inter-porosity flow regime,while inorganic matter properties control almost all flow regimes except the early-mid time fracture linear flow regime.The contribution of different linear flow regions is also documented.

关键词： Analytical solution Shale gas reservoir Well performance Kerogen and inorganic matter

Comparison of the clinical features and therapeutics of COVID-19 in cardio-cerebrovascular disease(CCVD)and non-CCVD patients

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Frontiers of Medicine 2021年第4期15卷 629-637页

作者： Yu Wang Lan Li Yuanjiang Pan Yu He Zuhua Chen Yunhao Xun Yuhan Xu Yilei guo Jiehong Yang jianchun guo Haitong Wan Institute of Cardio-cerebrovascular Disease Zhejiang Chinese Medical UniversityHangzhou 310053China Department of Chemistry Zhejiang UniversityHangzhou 310027China College of Pharmaceutical Science Zhejiang Chinese Medical UniversityHangzhou 310053China School of Basic Medical Sciences and Public Health Zhejiang Chinese Medical UniversityHangzhou 310053China Integrated TCM&Western Medicine Department Xixi Hospital of HangzhouHangzhou 310023China

Cardio-cerebrovascular disease(CCVD)is a major comorbidity of coronavirus disease 2019(COVID-19).However,the clinical characteristics and outcomes remain unclear.In this study,102 cases of COVID-19 from January 22,2020 to March 26,2020 in Xixi Hospital of Hangzhou were included.Twenty cases had pre-existing CCVD.Results showed that compared with non-CCVD patients,those with CCVD are more likely to develop severe disease(15%versus 1%),and the proportion of pneumonia severity index grade IV was significantly higher(25%versus 3.6%).Computed tomography images demonstrated that the proportion of multiple lobe lesion involvement was significantly higher in the CCVD group than in the non-CCVD group(90%versus 63.4%).Compared with non-CCVD group,the levels of C-reactive protein,fibrinogen,D-dimer,and serum amyloid-A were higher,whereas the total protein and arterial partial Pa02 were lower in the CCVD group.Although no statistical difference was observed in the outcomes between groups,CCVD patients received more intensive comprehensive treatment to improve COVID-19 symptoms compared with non-CCVD patients.Integrated Chinese and Western medicine treatments have certain advantages in controlling the severe conversion rate and mortality of COVID-19.In addition,given that COVID-19 patients are usually related to coagulation disorders and thrombosis risk,the application of Chinese medicine in promoting blood circulation and removing stasis should be strengthened.

关键词： COVID-19 cardio-cerebrovascular disease traditional Chinese medicine clinical features clinical therapeutics

An improved underwater acoustic communication channel estimation based on the A*OMP algorithm

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Chinese Journal of Acoustics 2023年第1期42卷 58-70页

作者： LIU Biao JIA Ning HUANG jianchun XIAO Dong JIA Yuqing guo Shengming MA Li Institute of Acoustics Chinese Academy of SciencesBeijing100190 Key Laboratory of Underwater Acoustic Environment Chinese Academy of SciencesBeijing100190 University of Chinese Academy of Sciences Beijing100049

A*Orthogonal Matching Pursuit(A*OMP)was modified and applied to underwater acoustic channel estimation,which outperformed than OMP.A*OMP is a pseudo-greedy algorithm,and can improve the problem of OMP algorithm falling into local optimization.Even though A*OMP has better performance than OMP,the channel estimation error cannot decrease as signal-to-noise ratio(SNR)increases.To solve the problem,the initialization procedure and termination criterion of A*OMP was modified for channel estimation,to select right initial searching path and avoid too many iterations which cause unknown errors.Based on orthogonal frequency division multiplexing(OFDM)system,numerical simulation results showed that the pilot interval did not obviously affect the performance of the modified A*OMP.And there was no channel estimation error floor for the modified A*OMP.The error of the proposed algorithm was reduced by two and one orders of magnitude respectively from those of OMP and A*OMP.The proposed method outperformed the OMP and traditional A*OMP algorithm in both estimation accuracy and communication performance,with bit error rate(BER)reductions of 42.0%and 4.7%,respectively.

关键词： channel communication estimation