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Analysis of sensitivity to hydrate blockage risk in natural gas gathering pipeline

Petroleum Science 2024年第4期21卷 2723-2733页

作者： Ao-Yang Zhang Meng Cai Na Wei Hai-Tao Li Chao Zhang Jun Pei Xin-Wei Wang State Key Laboratory of Oil and Gas reservoir Geology and Exploitation Southwest Petroleum University research Institute of Production Engineering Daqing Oilfield Co.Ltd.

During the operational process of natural gas gathering and transmission pipelines, the formation of hydrates is highly probable, leading to uncontrolled movement and aggregation of hydrates. The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines, resulting in production reduction, shutdowns, and pressure build-ups. Consequently, a cascade of risks is prone to occur. To address this issue, this study focuses on the operational process of natural gas gathering and transmission pipelines, where a comprehensive framework is established. This framework includes theoretical models for pipeline temperature distribution, pipeline pressure distribution, multiphase flow within the pipeline, hydrate blockage, and numerical solution methods. By analyzing the influence of inlet temperature, inlet pressure, and terminal pressure on hydrate formation within the pipeline, the sensitivity patterns of hydrate blockage risks are derived. The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate, potentially mitigating pipeline blockage during natural gas transportation. Furthermore, an increase in inlet temperature and terminal pressure, and a decrease in inlet pressure, results in a displacement of the most probable location for hydrate blockage towards the terminal station. However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system, contradicting the operational goal of energy efficiency and reduction of energy consumption. Consequently, for high-pressure gathering pipelines, measures such as raising the inlet temperature or employing inhibitors, electrical heat tracing, and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation. Moreover, considering abnormal conditions such as gas well production and pipeline network s

关键词： Natural gas hydrates Gathering pipeline Temperature variation Hydrate formation rate Sensitivity analysis

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River width and depth as key factors of diurnal activity energy expenditure allocation for wintering Spot-billed Ducks in the Xin'an River basin

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Avian research 2024年第1期15卷 116-122页

作者： Chao Yu Xuying Lu Deli Sun Mengnan Chu Xueyun Li Qun Li College of Life and Environmental Sciences Huangshan UniversityHuangshan245021China Environment Conservation research centre of Xin’an River basin Huangshan UniversityHuangshan 245021China Department of Resources Conservation Southern Anhui National Wildlife Rescue CenterXiuning 245400China

Rivers are important habitats for wintering ***,they are easily influenced by natural and human *** important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal *** compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy ***,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or *** this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River basin from October 2021 to March *** allocation of time and energy expenditure for activity in both normal and disturbed environments was *** results showed that foraging accounted for the highest percentage of time and energy ***,foraging decreased in the disturbed environment than that in the normal *** behavior showed the opposite trend,while other behaviors were similar in both *** total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and *** results oppose the compensatory foraging hypothesis in favor of increased *** optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy *** study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental *** these changes can help understand the maximum fitness of wi

关键词： Diurnal behavior activities River factors Time and energy expenditure allocation Wintering Spot-billed Duck Xin’an River basin

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Rapid recovery of desert shrubs is attributed to imbalance of water supply to demand after disturbance in Northwest China

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Ecological Processes 2024年第2期13卷 118-129页

作者： Hai Zhou Xiangyan Feng Zhibin He Qiyue Yang Heng Ren Wenzhi Zhao Linze Inland River basin research Station Chinese Ecosystem Research Network Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences University of Chinese Academy of Sciences

Background Disturbance is a key driver of changes in terrestrial ecosystems, especially in water limited regions. In the desert ecosystem of Northwest China, shrubs are often foraged by camels and this causes the shrubs lost their aboveground tissues. Although the aboveground tissue could recover after the disturbance, the mechanisms of resprouts' recovery after the disturbance are still poorly understood. We investigated the morphological and physiological characteristics and root water uptake sources of resprouts and non-disturbed seedlings of four desert shrub species that were often foraged by *** The results showed that the resprouts grew rapidly after the removal of aboveground tissue. The height and aboveground biomass of resprouts reached the level of 5-year-old seedlings following a growing season. Compared to un-disturbed seedlings, higher leaf water potential, leaf hydraulic conductance and photosynthesis rate were observed in resprouts, indicating that resprouts grew rapidly after disturbance. Furthermore, we found that the root water uptake source did not change after disturbance. This indicated that the roots of resprouts kept intact water uptake capacity after disturbance, which could keep supplying sufficient water to the aboveground tissue. Due to the removal of aboveground tissue of the resprouts, the water demand of aboveground tissue decreased, which induced an imbalance of water supply from roots to demand of aboveground tissues of resprouts. This explained the improved physiological performance and rapid recovery of resprouts after *** The imbalance of water supply to demand contributes to the rapid recovery of desert shrubs after disturbance. The findings provide insight into the eco-physiological mechanism for the maintenance of desert ecosystems that are facing disturbance.

关键词： Disturbance Resprout Physiological performance Shrub Water uptake source

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Temperature trends and its elevation-dependent warming over the Qilian Mountains

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Journal of Mountain Science 2024年第2期21卷 500-510页

作者： ZHAO Peng HE Zhibin MA Dengke WANG Wen QIAN Lihui School of Computer Science Huainan Normal UniversityHuainan 232038China Linze Inland River basin research Station Key Laboratory of Inland River Basin ScienceNorthwest Institute of Eco-Environment and ResourceChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Understanding temperature variability especially elevation dependent warming(EDW)in high-elevation mountain regions is critical for assessing the impacts of climate change on water resources including glacier melt,degradation of soils,and active layer *** means that temperature is warming faster with the increase of *** this study,we used observed temperature data during 1979-2017 from 23 meteorological stations in the Qilian Mountains(QLM)to analyze temperature trend with Mann-Kendall(MK)test and Sen’s slope *** showed that the warming trends for the annual temperature followed the order of T_min>T_mean>T_max and with a shift both occurred in *** and summer temperature have a higher increasing trend than that in autumn and winter.T_mean shifts occurred in 1996 for spring and summer,in 1997 for autumn and winter.T_max shifts occurred in 1997 for spring and 1996 for summer.T_min shifts occurred in 1997 for spring,summer and winter as well as in 1999 for *** mean diurnal temperature range(DTR)shows a significant decreasing trend(-0.18°C/10a)from 1979 to *** mean DTR shows a significant decreasing trend(-0.26°C/10a)from 1979 to 2017 with a shift occurred in *** removing longitude and latitude factors,we can learn that the warming enhancement rate of average annual temperature is 0.0673°C/km/10a,indicating that the temperature warming trend is accelerating with the continuous increase of *** increase rate of elevation temperature is 0.0371°C/km/10a in spring,0.0457°C/km/10a in summer,0.0707°C/km/10a in autumn,and 0.0606°C/km/10a in winter,which indicates that there is a clear EDW in the *** main causes of warming in the Qilian Mountains are human activities,cloudiness,ice-snow feedback and El Nino phenomenon.

关键词： Climate change Qilian Mountains Warming rates DTR Elevation-dependent warming

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Impact of wetting-drying cycles and acidic conditions on the soil aggregate stability of yellow‒brown soil

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Journal of Mountain Science 2024年第6期21卷 2075-2090页

作者： XIA Zhenyao NI Yuanzhen LIU Deyu WANG Di XIAO Hai Key Laboratory of Geological Hazards on Three Gorges reservoir Area Ministry of EducationYichang 443002China College of Civil Engineering&Architecture China Three Gorges UniversityYichang 443002China Engineering research Center of Eco-environment in Three Gorges reservoir Region Ministry of EducationChina Three Gorges UniversityYichang 443002China

Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external *** study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate *** yellow‒brown soil from the Three Gorges reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2,3,4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH=3,4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression *** results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of ***,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate *** wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest *** soil aggregate stability is significantly correlated with the pH,Ca^(2+),Mg^(2+),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggre

关键词： Yellow‒brown soil Wetting-drying cycles Acidic conditions Soil aggregate stability Soil disintegration

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Evaluation of soil loss severity and ecological restoration approach for sustainable agriculture in the Hindu Kush, Karakoram and Himalaya region

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Journal of Mountain Science 2024年第5期21卷 1509-1521页

作者： Arshad ASHRAF Imran AHMAD Climate Energy and Water Research InstituteNational Agricultural Research Centre(NARC)Islamabad 44000Pakistan

Soil erosion has resulted in removal of the topsoils containing fine soil particles and plant nutrients, causing decrease in soil fertility in the Hindu Kush, Karakoram and Himalaya(HKH) region. The existing production of cereal crop grains has been reduced to one third of the potential crop grains production owing to land degradation and poor farming practices. It is necessary to assess risk of soil loss and identify appropriate controlling measures to address issues of low agriculture productivity and water insecurity in the region. In the present study, severity of soil loss was predicted using Revised Universal Loss Equation(RUSLE) and ecological measures were identified for sustainable mountain agriculture in the HKH region of Upper Indus basin, Pakistan. Overall 62.6% area was found to have very low risk of soil loss, i.e., 100 t/(ha·yr) in about 6.8% and 7.4% areas respectively. The mean rate of soil loss was about 41.9 t/(ha·yr) in the Hindu Kush, 31.1 t/(ha·yr) in the Himalayas, 18.8 t/(ha·yr) in the Karakoram and overall 29.7 t/(ha·yr) in the three HKH ranges. As such no considerable measures have been adopted by the communities for restoration of the degraded areas except raising fruit/farm trees and supporting limited social forestry for their livelihoods. The slopes cleared for cultivation and susceptible to erosion may be stabilized through sowing/planting of multi-purpose plant species and formation of proper bench terraces. The conservation of forest ecosystem and pastures at higher elevations would help in reducing overland water flow, risk of flash flood hazard and minimizing sediment loads in the downstream. It is essential to adopt site-specific resource conservation techniques and restore possible ecosystem health for sustainable agriculture and economic developm

关键词： Climate change Erodibility Indus basin Land degradation Slope stabilization

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Insights into in-situ imbibition behavior of fracturing fluid in propped shale fractures based on nuclear magnetic resonance:A case study from Longmaxi Formation shale,Sichuan basin,China

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Petroleum Science 2024年第1期21卷 410-429页

作者： Jing-Jing Guo Kai-Xiang Di Lie-Hui Zhang Yu-Long Zhao Hui-Ying Tang Rui-Han Zhang Ye Tian National Key Laboratory of Oil and Gas reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina

Shale gas is an important component of unconventional oil and gas *** the imbibition behavior is helpful to optimize flowback parameters and enhance gas *** imbibition studies have focused on shale matrix,and the pressure conditions discussed were mostly *** initial imbibition behavior begins from propped fractures to matrix,but there are few studies working on explaining the imbibition behavior in propped fractures or the phenomenon of many shale wells exhibit higher productivity after a“soaking”***,propped fracture samples were designed for imbibition and migration *** order to accurately study the mechanism and main influencing factors of fracturing fluid imbibition and migration in propped and unpropped shale fractures under high temperature and high pressure,a series of experiments based on nuclear magnetic resonance(NMR)were carried *** showed that NMR T_(2) spectra of all samples exhibited a bimodal *** final imbibition volume of fracturing fluid was positively related to pressure and fracture *** imbibition effect of fracturing fluid was more evident in matrix pores under high *** the migration during soaking stage,the fracturing fluid gradually migrated from large pores to small pores and gradually displaced the shale gas from the matrix,thus allowing the water blocking in propped fractures to self-unlock to some *** permeability decreased in the imbibition stage,while it recovered in the migration stage to some extent.

关键词： Forced imbibition Migration Soaking NMR T_(2)spectra Propped fracture Permeability recovery

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Nitrogen accumulation in a big lake affected by groundwater discharge in Central Yangtze River basin

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Journal of Earth Science 2024年

作者： Liansong Tang Rui Ma Lin Jingjing Ying Liang Xue Jiang Hubei Key Laboratory of Yangtze River basin Environmental Aquatic Science， School of Environmental Studies and State Key Laboratory of Biogeology and Environmental Geology， China University of Geosciences Changjiang basin Ecology and Environment Monitoring and Scientific research Center，Changjiang basin Ecology and Environment Administration， Ministry of Ecology and Environment

Nitrogen pollution is a major cause of lake eutrophication， garnering global concern for its detrimental impact on lake-water quality. However， the intricate interplay between lakes and groundwater in the accumulation and release of nitrogen remains largely overlooked. Using Honghu Lake as a case study， a large lake in the Yangtze River basin long plagued by nitrogen pollution， this study analyzed the temporal shifts in its water area from 1990 to 2021 using remote-sensing image classification algorithms. From 1990 to 2005， the natural water area of Hong Lake decreased by 72%. The transformation of much of this area into aquaculture zones and agricultural lands has led to a substantial influx of pollutants， culminating in the degradation of the water quality. Despite efforts to restore the natura water area post ban on aquaculture activities， the water quality of the lake remains compromised， indicating other pollution sources menacing the ecosystem of the lake. Field investigations conducted in 2011 and 2019 unveiled substantially higher concentrations of NH4-N and NO3-N in groundwater compared to lake water， with a discernible upward trajectory in pollutant levels over time. The18O mass-balance model was employed to assess groundwater flow dynamics， revealing an estimated lacustrine groundwater discharge of 0.71×106m3/d， underscoring the substantial annual influx of pollutants into the lake via groundwater pathways. Through a comprehensive analysis of surface water and groundwater quality trends within the study area， this research provides novel evidence implicating groundwater as a formidable contributor to the persistent nitrogen pollution afflicting Honghu Lake.

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Coupling effect analysis of dam break flood spread and building collapse based on numerical simulation

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Science China Technological Sciences 2024年第11期67卷 3571-3584页

作者： SONG TianXu LIU JiaHong MEI Chao ZHANG MengXue WANG Hao NAZLI Sana State Key Laboratory of Simulation and Regulation of Water Cycle in River basin China Institute of Water Resources and Hydropower Research Key Laboratory of River basin Digital Twinning of Ministry of Water Resources Engineering and Technology research Center for Water Resources and Hydrogeology of the Ministry of Water Resources

Large-scale floods induced by dam failures could cause significant structural damage to buildings and massive loss of life. The coupling effect of large-scale flood spread and building collapse has complex impacts on the entire flow field, affecting flood risk assessment and building vulnerability evaluation. In this paper, a dynamic elevation change model designed to seamlessly interface with a structural vulnerability assessment model to investigate the interaction effect between floods and buildings is presented. The efficiency of the framework was validated by reconstructing the Gleno Dam-Break flood in Italy. Subsequently, a hydrodynamic model of the Jinsha-Yalong River that considers dynamic building collapse was established. The proposed model was compared with two traditional building treatment approaches and one that ignored the buildings. The results show that the interaction between the flood and buildings decreases the low-velocity area(below 1 m/s) by 7.44%-9.56% while increasing the high velocity area(above 4 m/s) by 10.71%-11.96%. Traditional and neglecting building treatments provide preliminary insights into densely built areas, and the latter could be an alternative for simplification because it can represent the worst-case *** collapse in response to large-scale floods typically occurs in four stages: flood spread, rapid expansion, gradual expansion, and flood recession. This analysis offers novel perspectives on flood prediction and simulations where the floodplain may contain buildings. This method could be useful for assessing structural vulnerability associated with large building stocks and developing flood mitigation strategies in densely populated areas.

关键词： dam break flood risk structural vulnerability building collapse urban area

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Distribution characteristics and removal rate of antibiotics and antibiotic resistance genes in different treatment processes of two drinking water plants

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Frontiers of Environmental Science & Engineering 2024年第9期18卷 143-152页

作者： Jun Wang Mingtao Huang Bolin Li Hassan Ibrahim Mohamed Huanjie Song Gezi Li Ying Yu Han Zhang Weimin Xie School of Resource and Environmental Engineering Wuhan University of TechnologyWuhan 430070China Wuhan Lingang Economic and Technological Development Zone Service Industry Development Investment Group Co.Ltd. Wuhan 430040China Civil Engineering Department Faculty of EngineeringAssiut UniversityAssiut 71516Egypt Changjiang basin Ecology Environment and Monitoring and Scientific research Center Changjiang Basin Ecology and Environment AdministrationMinistry of Ecological EnvironmentWuhan 430010China

Emerging pollutants,such as antibiotics and antibiotic-resistance genes,are becoming increasingly important sources of safety and health *** water safety,which is closely related to human health,should receive more attention than natural water body ***,minimal research has been performed on the efficacy of existing treatment processes in water treatment plants for the removal of antibiotics and antibiotic resistance *** address this research gap,this study detected and analyzed six main antibiotics and nine antibiotic resistance genes in the treatment processes of two drinking water plants in *** were collected over three months and then detected and analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry and fluorescence *** total concentrations of antibiotics and antibiotic resistance genes in the influent water of the two water plants were characterized as December>March>*** precipitation and filtration processes of the Zou Maling Water Plant and Yu Shidun Water Plant successfully removed the *** ozone-activated carbon process increased the removal rate of most antibiotics to 100%.However,a large amount of antibiotic resistance gene residues remained in the effluents of the two water *** experiments demonstrated that the existing ozone-activated carbon processes could not effectively remove antibiotic resistance *** study provides a reference for the optimization of drinking water treatment processes for antibiotics and antibiotic resistance gene removal.

关键词： Antibiotics Antibiotics resistance genes Water treatment process unit Spatiotemporal distribution Removal efficacy

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