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Flux of organic carbon burial and carbon emission from a large reservoir: implications for the cleanliness assessment of hydropower

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Science Bulletin 2019年第9期64卷 603-611页

作者： Fushun Wang Yunchao Lang Cong-Qiang Liu Yong Qin Ningxiao Yu Baoli Wang School of Environmental and Chemical Engineering Shanghai University Institute of Surface-Earth System Sciences Tianjin University

Accurately quantifying the budget of carbon sources and sinks in hydropower reservoirs is important for evaluating the cleanliness of hydroelectricity. However, current research on carbon emissions from reservoirs has rarely taken into account the organic carbon(OC) buried in sediment. Only greenhouse gas emissions from the water-air interface at reservoirs have been examined, which would result in an overestimation of the greenhouse effect of reservoirs. In November 2017, this study investigated the distribution of sediment in the Hongfeng reservoir(HFR) in southwest China, a typical large hydropower reservoir, by using an underwater seismology monitoring system. We estimated the flux of OC into sediment using the results of a sediment survey and a dataset compiled from references. Our results show that, the HFR retained 200,715 t of OC in the sediment since its impounding after dam construction to the sampling year of 2017, when the average burial flux was 3,521 t-C aà1(106 g C aà1) and the modern burial flux was 5,449 t-C aà1. After excluding the exogenous OC, the modern valid carbon sink of the sediment was 4,632 t per year. Under the current state of the reservoir, taking the modern valid carbon sink value, the carbon emissions from the reservoir's surface, and the discharge water from the dam into consideration, the net carbon sink of the HFR is found to be 1,098.9 t-C aà1. If the hydroelectricity generated by the reservoir is converted to a carbon sink, then the total net carbon sink becomes 12,972.9 t-C aà1.This work argues that both reservoir sediment and hydroelectricity are important carbon sinks and both should be included in assessments of the greenhouse effects of reservoirs.

关键词： The Hongfeng reservoir Sediment Carbon sink Underwater seismology method

Destratification and oxygenation efficiency of a water-lifting aerator system in a deep reservoir:Implications for optimal operation

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Journal of Environmental Sciences 2018年第11期30卷 9-19页

作者： Yang Li Tinglin Huang Xinlin Tan Zizhen Zhou Weixing Ma Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi'an University of Architecture and Technology Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and Technology

Thermal stratification is a common phenomenon in lakes and reservoirs and has a significant influence on water quality dynamics. Heihe reservoir is a canyon-shaped reservoir in Shaanxi Province with strong thermal stratification. Therefore, eight water-lifting aerators （WLAs） were installed in this reservoir, which could overcome thermal stratification and increase oxygenation with gas flows between 20 and 50 m3/hr, and oxygenate the hypolimnion with gas flows less than 20 m3/hr. To examine the destratification efficiency of the WLA system, we used a three- dimensional hydrodynamic module based on MIKE 3 to simulate the thermal structure of Heihe reservoir and compared the simulations with measured data. Results showed that operation of the WLA system promoted water mixing and effectively oxygenated the hypolimnion. Through the established energy utilization assessment method, the energy utilization efficiency of the WLA system was between 5.36% and 7.30%, indicating the capability of the technique for destratification in such a large reservoir. When the surface water temperature dropped to the theoretical mixed water temperature calculated by the energy utilization assessment method, reducing gas flow could save energy. This would prevent anaerobic conditions from occurring in the bottom water and maintain good water quality in Heihe reservoir.

关键词： reservoir Thermal stratification Numerical simulation Water-lifting aerator Mixing Oxygenation

A vertically integrated eutrophication model and its application to a river-style reservoir-Fuchunjiang,China

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Journal of Environmental Sciences 2009年第3期21卷 319-327页

作者： WU Tingfeng LUOLiancong QIN Boqiang CUI Guangbai YUZuoming YAO Zhiming State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China College of Hydrology and Water Resources Hohai University Nanjing 210098 China Hangzhou Research Institute of Environmental Sciences Hangzhou 310014 China Administrative Division of Qingshan reservoir Hangzhou 311305 China

Based on a 2-D hydrodynamic model, a vertically integrated eutrophication model was developed. The physical sub-model can be used for calculation of water density at different depths, and the water quality sub-model was used for calculation of algal growth. The cohesive and non-cohesive sediments were simulated separately with different methods. The light extinction coefficient used in the underwater light regime sub-model was linearly related to the sum of sediment and phytoplankton biomass. Some components less important to the model were simplified to improve practicability and calculation efficiency. Using field data from Fuchunjiang reservoir, we calculated the sensitivity of ecological parameters included in this model and validated the model. The results of sensitivity analysis showed that the parameters strongly influenced the phytoplankton biomass, including phytoplankton maximum growth rate, respiration rate, non-predatory mortality rate, settling rate, zooplankton maximum filtration rate, specific extinction coefficient for suspended solids and sediment oxygen demand rate. The model was calibrated by adjusting these parameters. Total chlorophyll α （chl-α） concentrations at different layers in the water column were reproduced very well by the model simulations. The simulated chl-α values were positively correlated to the measured values with Pearson correlation coefficient of 0.92. The mean difference between measured and simulated chl-α concentrations was 12% of the measured chl-α concentration. Measured and simulated DO concentrations were also positively correlated （r = 0.74） and the mean difference was 4% of measured DO concentrations. The successful validation of model indicated that it would be very useful in water quality management and algal bloom prediction in Fuchunjiang reservoir and a good tool for water quality regulation of other fiver-style reservoirs.

关键词： fiver-style reservoir eutrophication numerical model Fuchunjiang reservoir

Shale Gas Resource Potential in the Upper Yangtze Area

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Shale Gas Resource Potential in the Upper Yangtze Area

reservoir Characteristics and Preservation Conditions of Longmaxi Shale in the Upper Yangtze Block, South China

2011 International Conference on Materials for Renewable Energy & Environment(ICMREE 2011)

作者： Jin Wenzheng School of Energy Resources Key Laboratory of Marine reservoir Evolution and Hydrocarbon Accumulation Mechanism Ministry of Education China University of Geosciences(Beijing) Beijing 100083 ChinaZhang Jinchuan Ding Wenlong Tang Xuan School of Energy Resources Key Laboratory of Marine reservoir Evolution and Hydrocarbon Accumulation Mechanism Ministry of Education China University of Geosciences(Beijing) Beijing 100083 China

Through analysis of geological setting,shale characteristics and basic reservoir characteristics,it is concluded that there is a great distribution of marine shale and this area has the basic geographical conditions for large-scale gathering of shale gas,and thus offering huge shale gas resources and broad prospects for exploration

关键词： geological setting reservoir marine shale shale gas Upper Yangtze Area

来源： cnki会议评论

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2182-2205页

作者： RAN Bo LIU Shugen Luba JANSA SUN Wei YANG Di WANG Shiyu YE Yuehao Christopher XIAO ZHANHG Jian ZHAI Cangbo LUO Chao ZHANG Changjun State Key Laboratory of Oil and Gas reservoir Geology and Exploitation Chengdu University of Technology Chengdu 610059 China Geological Survey of Canada-Atlantic & Department of Earth Sciences Dalhousie University Halifax N.S. Canada Research Institute of Yanchang Petroleum (Group) Co. Ltd Xi 'an 710075 China University of Houston 4800 Calhoun Rd Houston TX 77004 USA Wuxi Institute of Petroleum Geology SINOPEC Exploration and Production Research Institute Wuxi214151 China

The Upper Ordovician-Lower Silurian Longmaxi Shale in the Upper Yangtze block represents one of the most important shale gas plays in China. The shale composition, porosity, organic thermal maturity, and methane sorption were investigated at the Qilongcun section in the Dingshan area, southeastern Sichuan Basin. The results show that the Upper Ordovician-Lower Silurian Longmaxi Shale contains：（1） sapropelic I organic matter; （2） a 40-m thick bedded sequence where total organic carbon （TOC） content is 〉 2%; （3） a 30-m thick layer at the base of the Longmaxi Shale with a brittle mineral content higher than 50%; and （4） a mean methane adsorption capacity of 1.80 cm3/g （7 MPa pressure）. A positive correlation between TOC and sorbed gas indicates that organic matter content exerts an important control on methane storage capacity. Based on the analysis of the shale reservoir characteristics, the lower member of the Longmaxi Shale can thus be considered a favorable stratum for shale gas exploration and exploitation. It has similar reservoir characteristics with the Longmaxi Shale in the Jiaoshiba area tested with a high-yield industrial gas flow. However, based on tectonic analysis, differences in the level of industrial gas flow between the low-yield study area and the high-yield Jiaoshiba area may result from different tectonic preservation conditions. Evidence from these studies indicates the shale gas potential of the Longmaxi Shale is constrained by the reservoir and preservation conditions.

关键词： Longmaxi Shale shale gas reservoir Upper Yangtze block preservation condition

Shallow groundwater nitrogen responses to different land use managements in the riparian zone of Yuqiao reservoir in North China

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Journal of Environmental Sciences 2008年第6期20卷 652-657页

作者： LU Haiming YIN Chengqing Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Nanjing Hydraulic Research Institute State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing 210029 China

This field study investigated the nitrogen concentrations in the shallow groundwater from an ephemeral stream and four land uses： cropland, two-year restored （2yr） and five-years restored （Syr） woodlands, fishponds, and the nitrogen flux in the riparian zone of Yuqiao reservoir. The groundwater nitrate-N concentrations in cropland were the highest among the four land uses. Total dissolved nitrogen （TDN） and nitrate-N concentrations in the 2yr woodland were significantly （p 〈 0.05） higher than in 5yr woodland. The lowest nitrogen concentrations were detected in fishponds. Nitrate-N was the main form in cropland and 2yr woodland, whereas both nitrate-N and dissolved organic nitrogen （DON） were the main species in 5yr woodland and fishponds. But, ammonium-N was the main form in the ephemeral stream. During the rainy season, the groundwater flow with dissolved nitrogen drains from upland into the reservoir along the hydraulic gradient. The woodland between the cropland and reservoir could act as a buffer to retain shallow groundwater nitrogen. The dominant form of ammonium-N in the groundwater TDN pool in ephemeral stream indicated that nitrogen from the village and orchard in upland flowed into the reservoir via subsurface flow. The fishpond was not an important pollution source for nitrogen transfer via shallow groundwater.

关键词： nitrogen groundwater reservoir fishpond cropland woodland riparian zone

Moiré Synaptic Transistor for Homogeneous-Architecture reservoir Computing

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Chinese Physics Letters 2023年第11期40卷 100-107页

作者：王鹏飞陈墨雨谢永勤潘晨 Kenji Watanabe Takashi Taniguchi 程斌梁世军缪峰 Institute of Brain-Inspired Intelligence National Laboratory of Solid State MicrostructuresSchool of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China Institute of Interdisciplinary Physical Sciences School of ScienceNanjing University of Science and TechnologyNanjing 210094China Research Center for Functional Materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan

reservoir computing has been considered as a promising intelligent computing paradigm for effectively processing complex temporal information.Exploiting tunable and reproducible dynamics in the single electronic device have been desired to implement the “reservoir” and the “readout” layer of reservoir computing system.Two-dimensional moiré materials,with an artificial lattice constant many times larger than the atomic length scale,are one type of most studied artificial quantum materials in community of material science and condensed-matter physics over the past years.These materials are featured with gate-tunable periodic potential and electronic correlation,thus varying the electric field allows the electrons in the moiré potential per unit cell to exhibit distinct and reproducible dynamics,showing great promise in robust reservoir computing.Here,we report that a moiré synaptic transistor can be used to implement the reservoir computing system with a homogeneous reservoir-readout architecture.The synaptic transistor is fabricated based on an h-BN/bilayer graphene/h-BN moiré heterostructure,exhibiting ferroelectricity-like hysteretic gate voltage dependence of resistance.Varying the magnitude of the gate voltage enables the moiré transistor to switch between long-term memory and shortterm memory with nonlinear dynamics.By employing the short-and long-term memories as the reservoir nodes and weights of the readout layer,respectively,we construct a full-moiré physical neural network and demonstrate that the classification accuracy of 90.8% can be achieved for the MNIST(Modified National Institute of Standards and Technology) handwritten digits database.Our work would pave the way towards the development of neuromorphic computing based on moiré materials.

关键词： transistor tunable reservoir

reservoir formation cycle of Tarim Basin, NW China

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Chinese Science Bulletin 1997年第3期42卷 245-248页

作者： Lu, XX Zhang, YW Jin, ZJ University of Petroleum Beijing China

CYCLICITY of basin development and evolution gives rise to several sets of source beds in Tarim Basin. Many times of generation and expulsion of hydrocarbon caused many times of petroleum accumulation and reservoir formation, and many times of tectonic activity probably resulted in the re-distribution and complete destruction of formed reservoirs. It will help us to recognize the patterns of petroleum accumulation in Tarim Basin and direct the

关键词： reservoir formation cycle reservoir evolution Tarim Basin.

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国外测井专利

国外测井技术 2024年第1期45卷 21-21,31,39,54,67,76,80,98,110,125页

作者：确定储层非均质性以优化钻井位置不详

1.公开(公告)号:US20230323760A1 Prediction of wireline logs using artificial neural networks使用人工神经网络预测电缆测井摘要:Methods and systems,including computer programs encoded on a computer storage medium are described for implementing a system that predicts wireline logs used in well drilling operations at a subsurface region.The system derives inputs from a first wireline log and includes a predictive model based on a neural network trained to generate data predictions.The predictive model processes the inputs derived from the first wireline log through layers of the neural network to generate a prediction that identifies multiple second wireline logs for a reservoir in the subsurface region.Based on the multiple second wireline logs,the system controls well drilling operations that simulate hydrocarbon production at the reservoir.

关键词： operations system reservoir