Articoli di riviste: "Reservoirs"

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Khaydarov, Aziz, Tursunoy Apakxujayeva e Dinislam Atakulov. "Influence of geographical location on reservoir vegetation formation". E3S Web of Conferences 401 (2023): 01013. http://dx.doi.org/10.1051/e3sconf/202340101013.

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The paper provides information on the vegetation cover area on the reservoir bottom. In the growing shortage of water resources, one of the important tasks is to improve methods for estimating reservoir volume. The vegetation cover of reservoirs influences the quality of the water supply. While the bottom of some reservoirs is drained, this bottom is covered with vegetation, but this trend is not observed in all reservoirs. The Talimarjan and Charvak reservoirs were selected as study sites. As a method, spatial data were selected that were collected using GIS. The results have shown that when the Talimarjan Reservoir is impounded, a considerable part of the reservoir is covered by vegetation of different species, while the bottom of the Charvak Reservoir remains without vegetation. The intensity of eutrophication processes in the reservoir may cause excess nutrients and change the reservoir’s water quality in the near future. To prevent such a situation, reducing the number of plants in the reservoir and increasing water exchange is necessary.

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Iqbal, Khairul, Moh Abduh e ,. Variadi. "Simulation of Multi Reservoir Operation Rules with Interconnected Tunnel and Water Transfer". Aceh International Journal of Science and Technology 12, n. 2 (5 settembre 2023): 285–96. http://dx.doi.org/10.13170/aijst.12.2.32532.

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The multi-reservoir operation rules require accuracy in developing its technical parameters. This is done to prevent operational failure in one of the reservoirs. The water transfer concept is to manage the water resources distribution between the receiving watershed and the donor watershed. The availability of transferable water must be prioritized, meeting the water demand of the donor reservoir. Storage capacity in both reservoirs aims to meet water demand, especially in the recipient. The elevation of the interconnecting tunnel is the minimum limit for water use in simulation. The interconnected tunnels' location and capacity will determine the multi-reservoir's operation rule. The interconnected tunnel in the Rukoh Tiro reservoir transfers water in the operation of the two reservoirs. The simulation is carried out in three seasons, considering the inflow of each watershed, the reservoir's downstream water demand, and the reservoir's technical conditions. The simulation results of the Rukoh Tiro reservoir operated simultaneously in all three seasons show that the fulfillment of irrigation water demand can reach 100% as needed. The water transfer process through interconnected tunnels occurs throughout the year. The reservoir operating rule is expected to be a reference in the multi-reservoir operation to obtain an optimal reservoir operating rule.

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Fitriana, Indri Rahmandhani, Djoko Legono e Heriantono Waluyadi. "Reservoir sedimentation regime analysis: case study of Kedungombo reservoir and Sermo reservoir". MEDIA KOMUNIKASI TEKNIK SIPIL 27, n. 1 (20 agosto 2021): 80–87. http://dx.doi.org/10.14710/mkts.v27i1.35978.

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The Kedungombo and the Sermo Reservoirs have problems in fulfilling basic services because of sedimentation. Sedimentation that occurs in each of the reservoirs would form a specific reservoir sedimentation pattern that is supposed to be similar because the hydrology and physiography conditions of the reservoir's catchment area are similar. This study aims to determine the dynamics of sedimentation patterns that occur in the dead storage for reviewing the characteristics/sedimentation regime of the two reservoirs. The analysis was carried out by processing bathymetrical data which were processed into a digital terrain model (DTM) using ArcGIS. Furthermore, the storage volume, sedimentation volume, storage percentage, and specific reservoir sedimentation rate are calculated. The results showed that the two reservoirs showed an increase in sedimentation volume each year so that the reservoir characteristic curve shifted from the plan graph. The dead storage capacity of Kedungombo Reservoir is 100% in 1989 to 43% in 2016 and 100% of Sermo Reservoir in 1997 to 58% in 2011. The specific reservoir sedimentation rate, i.e. 0.0031 and 0.0042 million m3/year/km2 for the Kedungombo Reservoir (between 1989 and 2016) and the Sermo Reservoir (between 1997 and 2011) respectively, indicating that the two reservoirs are in the same regime

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Li, Shuangshuang, Junli Li, Weibing Du, Shuaiqi Liu, Haoyu Wang e Jingyu Jin. "Combining Satellite Images and the Hydraulic Engineering Archive to Map the Processes of Reservoir Construction in Xinjiang". Remote Sensing 16, n. 2 (12 gennaio 2024): 328. http://dx.doi.org/10.3390/rs16020328.

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Reservoirs are essential hydraulic facilities for water resource allocation in Xinjiang. Since the 1950s, many reservoirs have been constructed for oasis water resource utilization in Xinjiang, enhancing the storage capacity of water resources. There are a few intact and open reservoir archives containing both geolocations and hydraulic attributes, such as the reservoir completion year, which can facilitate our understanding of the correlation between hydraulic engineering and oasis expansion. This paper mapped all the reservoirs of Xinjiang using Sentinel-2 MSI images from 2022. It associated their attributes with the reservoir’s extent, such as the capacity, area, complete year, altitude, etc., by consulting historical almanac data to establish a full elemental dataset with both geographic and attribute information. Furthermore, the spatial variability and historical process of the reservoirs were discussed against geomorphic information and oasis evolution. The results showed that 804 reservoirs were mapped cumulatively in Xinjiang up to 2022, and 1960–1980 and 2005–2010 are the rapidly developed periods. The construction history of the reservoirs indicates that reservoirs’ locations have the spatial tendency to shift from being in oasis plain areas to mountainous areas, and the newly built reservoirs showed a trend of miniaturization in area and maximization in volume.

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Valluri, Manoj Kumar, Jimin Zhou, Srikanta Mishra e Kishore Mohanty. "CO2 Injection and Enhanced Oil Recovery in Ohio Oil Reservoirs—An Experimental Approach to Process Understanding". Energies 13, n. 23 (26 novembre 2020): 6215. http://dx.doi.org/10.3390/en13236215.

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Process understanding of CO2 injection into a reservoir is a crucial step for planning a CO2 injection operation. CO2 injection was investigated for Ohio oil reservoirs which have access to abundant CO2 from local coal-fired power plants and industrial facilities. In a first of its kind study in Ohio, lab-scale core characterization and flooding experiments were conducted on two of Ohio’s most prolific oil and gas reservoirs—the Copper Ridge dolomite and Clinton sandstone. Reservoir properties such as porosity, permeability, capillary pressure, and oil–water relative permeability were measured prior to injecting CO2 under and above the minimum miscibility pressure (MMP) of the reservoir. These evaluations generated reservoir rock-fluid data that are essential for building reservoir models in addition to providing insights on injection below and above the MMP. Results suggested that the two Ohio reservoirs responded positively to CO2 injection and recovered additional oil. Copper Ridge reservoir’s incremental recovery ranged between 20% and 50% oil originally in place while that of Clinton sandstone ranged between 33% and 36% oil originally in place. It was also deduced that water-alternating-gas injection schemes can be detrimental to production from tight reservoirs such as the Clinton sandstone.

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Zhou, Tianqi, Hongqi Yuan, Fengming Xu e Rigen Wu. "Tight Sandstone Reservoir Characteristics and Controlling Factors: Outcrops of the Shanxi Formation, Liujiang River Basin, North China". Energies 16, n. 10 (16 maggio 2023): 4127. http://dx.doi.org/10.3390/en16104127.

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Tight sandstone reservoirs are of interest due to their potentially favorable prospects for hydrocarbon exploration. A better understanding of tight sandstone outcrop reservoir characteristics and their influencing factors is thus needed. By laboratory observation, thin section analysis, and experimental analysis, the current work carried out a detailed investigation of densely sampled tight sandstone outcrops of the Shanxi Formation in the Liujiang River Basin, paving the way for further research on rock types, reservoir spatial distribution, physical properties, and their key controlling factors. The application of the Pressure Pulse Attenuation Method made it possible to determine the porosity and permeability, as well as the analysis of debris composition and filling content. The findings indicate that the main rock type of the tight sandstone outcrop reservoirs in the Shanxi Formation in the Liujiang River Basin is lithic quartz sandstone, some of which contains fine sand-bearing argillaceous siltstone, giving them very low porosity (average porosity of 4.34%) and low permeability (average permeability of 0.023 mD) reservoirs. Secondary pores—mostly dissolved pores among and in grains—are widely developed in the target region. In addition, diagenesis primarily includes mechanical compaction, cementation, and dissolution. The main controlling factors of tight sandstone reservoirs in the target region are sedimentation, diagenesis, and tectonics, whereby sedimentation affects reservoir physical properties that become better as the clast size increases, reservoir properties are negatively impacted by compaction and cementation, and reservoir properties are somewhat improved due to dissolution and the impact of tectonism. In addition, the tilt of the crust will produce faults during the tectonic action, generating reservoir cracks that improve the reservoir’s physical properties. This study tends to be helpful in the prediction of high-quality reservoirs in the Permian Shanxi Formation in North China and can also be used for analogy of high-quality reservoirs in similar areas with complete outcrops.

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LIU, YANFENG, YUETIAN LIU, LU SUN e JIAN LIU. "MULTISCALE FRACTAL CHARACTERIZATION OF HIERARCHICAL HETEROGENEITY IN SANDSTONE RESERVOIRS". Fractals 24, n. 03 (30 agosto 2016): 1650032. http://dx.doi.org/10.1142/s0218348x16500328.

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Heterogeneities affecting reservoirs often develop at different scales. Previous studies have described these heterogeneities using different parameters depending on their size, and there is no one comprehensive method of reservoir evaluation that considers every scale. This paper introduces a multiscale fractal approach to quantify consistently the hierarchical heterogeneities of sandstone reservoirs. Materials taken from typical depositional pattern and aerial photography are used to represent three main types of sandstone reservoir: turbidite, braided, and meandering river system. Subsequent multiscale fractal dimension analysis using the Bouligand–Minkowski method characterizes well the hierarchical heterogeneity of the sandstone reservoirs. The multiscale fractal dimension provides a curve function that describes the heterogeneity at different scales. The heterogeneity of a reservoir’s internal structure decreases as the observational scale increases. The shape of a deposit’s facies is vital for quantitative determination of the sedimentation type, and thus enhanced oil recovery. Characterization of hierarchical heterogeneity by multiscale fractal dimension can assist reservoir evaluation, geological modeling, and even the design of well patterns.

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Jin, Jiaxu, Hongyue Zhang, Liang Xu, Kelin Zhou e Xiangfeng Lv. "Stability Analysis of Downstream Dam Expansion Tailings Pond". Advances in Civil Engineering 2022 (2 giugno 2022): 1–13. http://dx.doi.org/10.1155/2022/1809736.

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The buildup of tailings in China has expanded dramatically with economic development and industrial demand, and the safety of tailings reservoirs has become increasingly serious. Due to the difficulty in finding a new reservoir site, the expansion approach of building a new tailings dam downstream of the original reservoir area was investigated. The stability of the tailings reservoir after expansion was calculated using the traditional dynamic and static stability solution method and taking into account the unpredictability of dam construction materials and tailings material parameters in the reservoir area. The results reveal that throughout the tailings accumulation process in the new reservoir, the tailings will build a back pressure slope at the original reservoir’s initial dam, which can considerably improve the original reservoir’s dynamic and static stability. The Monte Carlo method clearly outperforms older methods for tailing pond stability analysis. The results of this paper’s calculations will give a theoretical foundation and practical reference for the later management and maintenance of such tailings reservoirs, as well as fresh ideas and insights for comparable projects due to limited site selection.

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Su, Chang, Gang Zhao, Yee-Chung Jin e Wanju Yuan. "Semi-Analytical Modeling of Geological Features Based Heterogeneous Reservoirs Using the Boundary Element Method". Minerals 12, n. 6 (24 maggio 2022): 663. http://dx.doi.org/10.3390/min12060663.

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The objective of this work is to innovatively apply the boundary element method (BEM) as a general modeling strategy to deal with complicated reservoir modeling problems, especially those related to reservoir heterogeneity and fracture systems, which are common challenges encountered in the practice of reservoir engineering. The transient flow behaviors of reservoirs containing multi-scale heterogeneities enclosed by arbitrarily shaped boundaries are modeled by applying BEM. We demonstrate that a BEM-based simulation strategy is capable of modeling complex heterogeneous reservoirs with robust solutions. The technology is beneficial in making the best use of geological modeling information. The governing differential operator of fluid flow within any locally homogeneous domain is solved along its boundary. The discretization of a reservoir system is only made on the corresponding boundaries, which is advantageous in closely conforming to the reservoir’s geological description and in facilitating the numerical simulation and computational efforts because no gridding within the flow domain is needed. Theoretical solutions, in terms of pressure and flow rate responses, are validated and exemplified for various reservoir–well systems, including naturally fractured reservoirs with either non-crossing fractures or crossing fractures; fully compartmentalized reservoirs; and multi-stage, fractured, horizontal wells with locally stimulated reservoir volumes (SRVs) around each stage of the fracture, etc. A challenging case study for a complicated fracture network system is examined. This work demonstrates the significance of adapting the BEM strategy for reservoir simulation due to its flexibility in modeling reservoir heterogeneity, analytical solution accuracy, and high computing efficiency, in reducing the technical gap between reservoir engineering practice and simulation capacity.

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Chang, S. P., e S. M. Chuang. "Eutrophication study of twenty reservoirs in Taiwan". Water Science and Technology 44, n. 6 (1 settembre 2001): 19–26. http://dx.doi.org/10.2166/wst.2001.0331.

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Taiwan is an island off the southeastern coast of China with total area of roughly 36,000 km2. The geographic position of Taiwan is between 21° 45′ 25″ to 25° 56′ 31″ north latitude and 119° 18′ 3″ to 124° 34′ 30″ east longitude and includes both tropical and subtropical areas. The study was carried out at twenty main reservoirs in Taiwan area from 1994 to 1998. The study revealed that the water quality of most reservoirs gradually deteriorated during the study period. Total phosphorus concentrations over 60 μg/L were observed in 12.5% of these reservoirs in 1994, but in 22.2% of these reservoirs in 1998. Total nitrogen concentrations over 1.0 mg/L were observed in 37.5% of these reservoirs in 1994, but in 94.4% of these reservoirs in 1998. Secchi disc transparency below 2 m was observed in 75% of these reservoirs in 1994, but in 83.3% of these reservoirs in 1998. Chlorophyll a concentrations over 15 mg/m3 were observed in 12.5% of these reservoirs in 1994, but in 27.8% of these reservoirs in 1998. The TN:TP mass ratios (wt/wt) of all the studied reservoirs except Akungting Reservoir, Fongshan Reservoir, and Chengching Reservoir are higher than 16. The study results on nutrient limitation indicated that phosphorus is the primary limiting nutrient in Taiwan reservoirs except Akungting Reservoir, Fongshan Reservoir, and Chengching Reservoir.

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Van Den Hoek, Jamon, Augusto Getirana, Hahn Jung, Modurodoluwa Okeowo e Hyongki Lee. "Monitoring Reservoir Drought Dynamics with Landsat and Radar/Lidar Altimetry Time Series in Persistently Cloudy Eastern Brazil". Remote Sensing 11, n. 7 (6 aprile 2019): 827. http://dx.doi.org/10.3390/rs11070827.

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Tropical reservoirs are critical infrastructure for managing drinking and irrigation water and generating hydroelectric power. However, long-term spaceborne monitoring of reservoir storage is challenged by data scarcity from near-persistent cloud cover and drought, which may reduce volumes below those in the observational record. In evaluating our ability to accurately monitor long-term reservoir volume dynamics using spaceborne data and overcome such observational challenges, we integrated optical, lidar, and radar time series to estimate reservoir volume dynamics across 13 reservoirs in eastern Brazil over a 12-year (2003–2014) period affected by historic drought. We (i) used 1560 Landsat images to measure reservoir surface area; (ii) built reservoir-specific regression models relating surface area and elevation from ICESat GLAS and Envisat RA-2 data; (iii) modeled volume changes for each reservoir; and (iv) compared modeled and in situ reservoir volume changes. Regression models had high goodness-of-fit (median RMSE = 0.89 m and r = 0.88) across reservoirs. Even though 88% of an average reservoir’s volume time series was based on modeled area–elevation relationships, we found exceptional agreement (RMSE = 0.31 km3 and r = 0.95) with in situ volume time series, and accurately captured seasonal recharge/depletion dynamics and the drought’s prolonged drawdown. Disagreements in volume dynamics were neither driven by wet/dry season conditions nor reservoir capacity, indicating analytical efficacy across a range of monitoring scenarios.

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Wang, Dong, Jin Yun Deng, Yi Tian Li e Juan Juan Fang. "Study on the Impounding Process Optimization of Cascade Reservoirs in Upper Changjiang River". Applied Mechanics and Materials 353-356 (agosto 2013): 2520–26. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2520.

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Overlapping storage periods of the cascade reservoirs would lead to the unreasonable using of the water resources, and each reservoir in the cascade might not be filled, that would influence the comprehensive benefit of the cascade reservoirs. In this paper, the Runoff regulation model of the cascade reservoirs is established and verified, the flood regulating calculation of the Xiluodu-Xiangjiaba-Three Gorges cascade reservoirs is done, and based on the flood regulating calculation, the earliest dates of the starting impounding of the cascade reservoirs are as below: Xiluodu and Xiangjiaba reservoirs are both not earlier than Sep.11, and Three Gorges Reservoir is not earlier than Sep.1. Then by using the comparative analysis and based on an overall analysis of generating electricity and transport of the cascade reservoirs, the most reasonable impounding date are calculated as below: the Xiluodu reservoir starts impounding in Sep.1, the Xiangjiaba reservoir starts impounding in Oct.1, and the Three Gorges Reservoir starts impounding in Sep.1.

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Lü, Xiuxiang, Weiwei Jiao, Xinyuan Zhou, Jianjiao Li, Hongfeng Yu e Ning Yang. "Paleozoic Carbonate Hydrocarbon Accumulation Zones in Tazhong Uplift, Tarim Basin, Western China". Energy Exploration & Exploitation 27, n. 2 (aprile 2009): 69–90. http://dx.doi.org/10.1260/0144-5987.27.2.69.

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Diverse types of marine carbonate reservoirs have been discovered in the Tazhong Uplift, Tarim Basin, and late alteration of such reservoirs is obvious. The marine source rocks of the Cambrian-lower Ordovician and the middle-upper Ordovician provided abundant oil and gas for hydrocarbon accumulation. The hydrocarbons filled various reservoirs in multiple stages to form different types of reservoirs from late Caledonian to early Hercynian, from late Hercynian to early Indosininan and from late Yanshanian to Himalayan. All these events greatly complicated hydrocarbon accumulation. An analysis of the discovered carbonate reservoirs in the Tazhong Uplift indicated that the development of a reservoir was controlled by subaerial weathering and freshwater leaching, sedimentation, early diagenesis, and alteration by deep fluids. According to the origin and lateral distribution of reservoir beds, the hydrocarbon accumulation zones in the Tazhong area were identified as: karsted reservoirs, reef/bank reservoirs, dolomite interior reservoirs, and hydrothermal reservoirs. Such carbonate hydrocarbon accumulation zones are distributed mainly in specific areas of the Tazhong uplift, respectively. Because of differences in the mechanism of reservoir formation, the reservoir space, capability, type and distribution of reservoirs are often different in different carbonate hydrocarbon accumulation zones.

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Munadi, Suprajitno, Samsul Hidayat, Julikah Julikah, Oki Hendriana e Eko Susanto. "UNDERSTANDING NATURALLY FRACTURED RESERVOIRS". Scientific Contributions Oil and Gas 31, n. 2 (21 marzo 2022): 28–34. http://dx.doi.org/10.29017/scog.31.2.1003.

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Naturally fractured reservoir differs from clastic reservoirs in the sense that the concepts of porous media which were usually applied for clastic reservoir analysis must be modified. This means that handling naturally fractured reservoir is also different compared to handling clastic reservoir. The porosity may be changed a bit bigger but the permeability is drastically changed. Also at a depth where rock layers are usually tight, naturally fractured reservoirs converts it to become a good reservoirs. Naturally fractured reservoirs can be found in some part of the Indonesian basin which may contribute a considerable additional reserves in the near future.

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Qi, Chang Jun, Yuan Zhai, Bao Hong Lu e Qing Gai Wang. "Research on Vertical Distribution of Water Temperature in Different Regulation Reservoirs". Advanced Materials Research 955-959 (giugno 2014): 3190–97. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.3190.

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The vertical distribution of the reservoir water temperature depends on the scale of the reservoir, regulation manners, as well as the hydrological and geological conditions near reservoir areas. Based on water temperature observation from three different regulation reservoirs, this paper analyses the vertical distribution of these reservoirs water temperature. The preliminary conclusions are: for multi-annual regulation reservoirs, the upper zones usually have stable temperature stratification structures, while the lower zones have constant low temperature; for annual regulation reservoirs, water temperature distribution changes with depth; for the daily regulation reservoirs with low water depths present mixed vertical distributions of water temperature.

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Wilopo, Wahyu, Hendy Setiawan e Doni Prakasa Eka Putra. "Evaluation of Artificial Reservoir Management in Sleman Regency, Yogyakarta Special Region". Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan 17, n. 3 (14 ottobre 2020): 205–14. http://dx.doi.org/10.14710/presipitasi.v17i3.205-214.

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The Indonesian government has promoted reservoir (embung) development programs throughout Indonesia. This program is primarily designed at supporting agricultural irrigation, especially in the dry season. However, in its implementation, there are often many obstacles both in technical and management, causing the main purpose of the reservoir construction cannot be achieved optimally. Therefore, this study aims to evaluate the condition of the reservoir located in Sleman Regency, Yogyakarta Special Region, in terms of physical, institutional, and management constraints. The study was conducted through a direct survey of 9 reservoirs and interviews with managers and residents around the reservoir. The results showed that two reservoirs have small damage in the reservoir building, three reservoirs do not yet have managers, and three reservoirs have not functioned following the purpose of reservoirs development. The obstacle often found in managing reservoirs is the unclear structure for the management of the reservoir, and the existing management is not effectively working. Therefore, the regulation of using reservoir water is not available. It is necessary to have a management organization involving the community and village government where the reservoir is located and also community beneficiaries of agricultural irrigation to guarantee its function and sustainability.

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Baljyan, Pargev, Arestak Sarukhanyan e Eleonora Avanesyan. "Study of sediment deposition processes and assessment of the change in the W-H characteristics of the madaghis reservoir". EUREKA: Physics and Engineering, n. 1 (19 gennaio 2023): 3–12. http://dx.doi.org/10.21303/2461-4262.2023.002757.

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The accumulation of sediments in reservoir is always a problem. Over time, these accumulations occupy the volume meant for water management, dramatically reducing the reservoir's effectiveness. The environment of the river basin below the reservoir undergoes significant changes. In this regard, assessing changes in volumetric W-H characteristics, particularly in reservoirs built on high turbidity rivers, is critical. The Mataghis Reservoir on Tartar River was chosen as the object of study. The quantity of accumulated sediments was established by original measurements and was calculated in three hydrologic ways at distinct stages of operation. The actual graphs showing the reservoir's W-H volumetric characteristics were made two decades after commissioning and are still in use. According to the findings, over 70 per cent of the reservoir volume has been filled with sediments over the course of the reservoir's thirty-year operation. A theoretical model of the sediment buildup process in basins has been created. Separate parameters have been created for the deposition of bottom sediments entering the reservoir and suspended particles in the flow. Based on them, the patterns of distribution of accumulated sediments according to the length and height of the reservoir were drawn out. The vertical pulsation velocity and the results of studies for determining the minimum rate of soil particle flow were used. To solve sedimentation problems in operating and newly constructed reservoirs, a methodology for evaluating changes in the amount of collected water and changes in the volume of water control, as well as a theoretical method for projecting their future behavior, can be applied

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Lubkov, M. V., e K. O. Mosiichuk. "MODELING OF THE OPTIMAL INSTALLATION OF HORIZONTAL WELLS IN WEAKLY PERMEABLE ANISOTROPIC GAS-BEARING RESERVOIRS". PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY Number, n. 18(68) (1 dicembre 2023): 108–19. http://dx.doi.org/10.31471/2304-7399-2023-18(68)-108-119.

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In order to increase gas production in anisotropic weakly permeable hard reaching reservoirs on the base of combined finite-element-difference method for the non-stationary anisotropic Leibenzon problem of piezoconductivity we have carried out a numerical simulation of the distribution of pressure drop around a horizontal production well in an anisotropic weakly permeable gas-bearing reservoir. We have established that the efficiency of gas recovery around a horizontal production well and, accordingly, its productivity significantly depends on the location of the well in a weakly permeable anisotropic gas-bearing reservoir. Based on the obtained results, for effective exploitation of the anisotropic weakly permeable gas reservoirs, it is necessary to place horizontal production wells in areas with relatively low shear anisotropy of the reservoir’s permeability. If it possible, artificially to increase the parameters of permeability around the production well and gas infiltration on the boundaries of the considered reservoir’s area, it will contribute to increasing of the gas yield and prolonging the productivity of the well during reservoir’s exploitation. At the placing of horizontal wells in anisotropic gas reservoirs, the most effective installation is that would ensure all around supply of the gas phase. This is, on the one hand, there was no blocking of gas from the side of reduced permeability, and on another hand, there was no rapid depletion of the reservoir from the side of increased permeability, and it was ensured a free access of gas to the well from all possible directions. We have shown that the location of the horizontal well in the diagonal direction to the main axes of anisotropy is universal relatively different directions of gas flow, therefore, such location is productive and effective as one.

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Cheng, Hong. "The Enhanced Oil Recovery Effect of Nitrogen-Assisted Gravity Drainage in Karst Reservoirs with Different Genesis: A Case Study of the Tahe Oilfield". Processes 11, n. 8 (2 agosto 2023): 2316. http://dx.doi.org/10.3390/pr11082316.

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For the Tahe Oilfield, there are multiple sets of karst reservoirs with different genesis developed in carbonate fracture-vuggy reservoirs and the varying karst reservoir type has a considerable influence on the distribution of residual oil. The complex characteristics of different karst reservoirs and the difficulty in producing the remaining oil in the middle and lower part of the reservoir greatly restrict the recovery effects. This work managed to comprehensively investigate the action mechanism of nitrogen-assisted gravity drainage (NAGD) on remaining oil in reservoirs with different karst genesis through modeling and experiments. Based on geological characteristics and modeling results, a reservoir-profile model considering reservoir type, fracture distribution, and the fracture–cave combination was established, the displacement experiments of main reservoirs such as the epikarst zone, underground river, and fault karst were carried out, and the oil–gas–water multiphase flow was visually analyzed. The remaining oil state before and after NAGD was studied, and the difference in recovery enhancement in different genetic karst reservoirs was quantitatively compared. The results show that NAGD was helpful in enhancing oil recovery (EOR) for reservoirs with different karst genesis. NAGD technique has the greatest increasing effect on the sweep efficiency of the fault-karst reservoir, followed by the epikarst zone reservoir, and the smallest in the underground river reservoir. The results of this research will facilitate an understanding of the EOR effect of karst-reservoir types on NAGD and provide theory and technical support for the high-efficiency development in varying karst reservoirs in the Tahe Oilfield.

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Amer, Manar M., e Dahlia A. Al-Obaidi. "Methods Used to Estimate Reservoir Pressure Performance: A Review". Journal of Engineering 30, n. 06 (1 giugno 2024): 83–107. http://dx.doi.org/10.31026/j.eng.2024.06.06.

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Reservoir pressure plays a significant role in all reservoir and production engineering studies. It is crucial to characterize petroleum reservoirs: by detecting fluid movement, computing oil in place, and calculating the recovery factor. Knowledge of reservoir pressure is essential for predicting future production rates, optimizing well performance, or planning enhanced oil recovery strategies. However, applying the methods to investigate reservoir pressure performance is challenging because reservoirs are large, complex systems with irregular geometries in subsurface formations with numerous uncertainties and limited information about the reservoir's structure and behavior. Furthermore, many computational techniques, both numerical and analytical, have been utilized to examine reservoir pressure performance. This paper summarizes the concepts and applications of traditional and novel ways to investigate reservoir pressure changes over time. It provides a comprehensive review that assists the reader in recognizing and distinguishing between various techniques for obtaining an accurate description of reservoir pressure behavior during production, such as the reservoir simulation method, material balance equation approach, time-lapse seismic data, and modern artificial intelligence methods. Thus, the central concept of these procedures and a list of the authors' research are discussed.

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Cao, Zhiguo, Suolin Jing, Lujun Wang, Fanbao Meng e Yanning Han. "Influence of spatial structure migration of overlying strata on water storage of underground reservoir in coal mine". PLOS ONE 19, n. 1 (29 gennaio 2024): e0292357. http://dx.doi.org/10.1371/journal.pone.0292357.

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Underground reservoir technology for coal mines can realize the coordinated development of coal exploitation and water protection in water-shortage-prone areas. The seepage effect of the floor seriously affects the safety of underground reservoirs under the action of mining damage and seepage pressure. Focusing on the problem of floor seepage in underground reservoirs, a spatial mechanical model of underground reservoirs was established. The main factors affecting the seepage of the surrounding rock were studied. The seepage pressure law in different stages of spatial structure evolution of overlying strata was explored. The results showed that pressure change was the main factor affecting the stability of a reservoir’s surrounding rock. The pore space between the broken and fractured rock in the water-flowing fractured zone was the main water storage space, which was directly related to the development of a breaking arch. According to the spatial structure evolution process of the overlying strata, the water storage state of an underground reservoir was divided into two stages and three situations. The seepage pressure was mainly affected by the water pressure and the overlying strata weight. The water pressure was affected by the reservoir head height, and the overlying strata weight was mainly affected by the overlying strata thickness.

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Luo, Yutian, Zhengming Yang, Zhenxing Tang, Sibin Zhou, Jinwei Wu e Qianhua Xiao. "Longitudinal Reservoir Evaluation Technique for Tight Oil Reservoirs". Advances in Materials Science and Engineering 2019 (6 gennaio 2019): 1–8. http://dx.doi.org/10.1155/2019/7681760.

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Abstract (sommario):

Reservoir evaluation is a method for classifying reservoirs and the description of heterogeneity quantitatively. In this study, according to the characteristics of longitudinal physical properties of tight oil reservoirs, advanced experimental techniques such as nuclear magnetic resonance, high pressure mercury intrusion, and X-ray diffraction were adopted; the flow capacity, reservoir capacity, ability to build an effective displacement system, and the ability to resist damage in reservoir reconstruction were considered as evaluation indexes; average throat radius, percentage of movable fluid, start-up pressure gradient, and the content of clay minerals were taken as the evaluation parameters. On the above basis, a longitudinal evaluation technique for tight oil reservoirs was established. The reservoir was divided into four categories by using this method. The reservoirs with a depth 2306.54 m–2362.07 m were mainly type I and II reservoirs, and the reservoirs with a depth of 2362.07 m–2391.30 m were mainly reservoirs of type II and III. The most effective development was water injection in the upper section and gas injection in the lower section.

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23

Zhou, Chao, Na Sun, Lu Chen, Yi Ding, Jianzhong Zhou, Gang Zha, Guanglei Luo, Ling Dai e Xin Yang. "Optimal Operation of Cascade Reservoirs for Flood Control of Multiple Areas Downstream: A Case Study in the Upper Yangtze River Basin". Water 10, n. 9 (14 settembre 2018): 1250. http://dx.doi.org/10.3390/w10091250.

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Abstract (sommario):

The purpose of a flood control reservoir operation is to prevent flood damage downstream of the reservoir and the safety of the reservoir itself. When a single reservoir cannot provide enough storage capacity for certain flood control points downstream, cascade reservoirs should be operated together to protect these areas from flooding. In this study, for efficient use of the reservoir storage, an optimal flood control operation model of cascade reservoirs for certain flood control points downstream was proposed. In the proposed model, the upstream reservoirs with the optimal operation strategy were considered to reduce the inflow of the reservoir downstream. For a large river basin, the flood routing and time-lag cannot be neglected. So, dynamic programming (DP) combined with the progressive optimality algorithm (POA) method, DP-POA, was proposed. Thus, the innovation of this study is to propose a two-stage optimal reservoir operation model with a DP-POA algorithm to solve the problem of optimal co-operation of cascade reservoirs for multiple flood control points downstream during the flood season. The upper Yangtze River was selected as a case study. Three reservoirs from upstream to downstream, Xiluodu, Xiangjiaba and the Three Gorges reservoirs (TGR) in the upper Yangtze River, were taken into account. Results demonstrate that the two-stage optimization algorithm has a good performance in solving the cascade reservoirs optimization problem, because the inflow of reservoir downstream and the division volumes were largely reduced. After the optimal operation of Xiluodu and Xiangjiaba reservoirs, the average reduction of flood peak for all these 13 typical flood hydrographs (TFHs) is 13.6%. Meanwhile, the cascade reservoirs can also store much more storm water during a flood event, and the maximum volumes stored in those two reservoirs upstream in this study can reach 25.2 billion m3 during a flood event. Comprising the proposed method with the current operation method, results demonstrate that the flood diversion volumes at the flood control points along the river decrease significantly.

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24

Юсупова, K. Yusupova, Корсак, M. Korsak, Мошаров, Sergey Mosharov, Кроленко e M. Krolenko. "The Forecast of Phytoplankton Spring Blossoming in the Uchinsky Reservoir". Safety in Technosphere 4, n. 1 (25 febbraio 2015): 12–17. http://dx.doi.org/10.12737/8226.

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Abstract (sommario):

Increase of water treatment efficiency in water supply systems during the spring period directly depends on the forecast accuracy related to mass blossoming of phytoplankton in drinking reservoirs. Object of research is the Uchinsky reservoir – the drinking reservoir having insignificant its own water collection area, and fed by water of Moscow Canal. The data on seasonal phytoplankton dynamics received in Akulovsky Hydrosite Laboratory of the MCUE "Mosvodokanal" for two stations: Pestovo (reservoir’s headwater) and Listvyanka (reservoir’s lower part), and also actinometric data of continuous supervision from 1998 to 2003 performed by Lomonosov Moscow State University’s Geographical faculty Meteorological Observatory (MOMGU) have been used in this work. Results of mathematical modeling for dependence of start date and peak values of phytoplankton’s spring blossoming in the Uchinsky reservoir depending on intensity of total solar radiation during the period preceding the phytoplankton blossoming have been presented. It has been established that the more solar energy streams’ values in the range of photosynthetic active radiation (PhAR) will be received by the reservoir surface in the middle of February, the later peaks of phytoplankton’s spring blossoming will be observed. Research results represent undoubted interest for the analysis of reservoir’s light factor influence on phytoplankton’s seasonal dynamics, and also for the exact forecast related to beginning of phytoplankton’s spring blossoming in drinking reservoirs when planning water treatment actions.

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25

Silva, Suelen Cristina Alves da, Armando Carlos Cervi, Cleusa Bona e André Andrian Padial. "Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication". Acta Limnologica Brasiliensia 26, n. 2 (giugno 2014): 129–42. http://dx.doi.org/10.1590/s2179-975x2014000200004.

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Abstract (sommario):

AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i) through two‑way ANOVAs considering the stand extent (m) and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand); and ii) through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

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26

Quan, Yufei, Yang Xu, Ran Mo, Xin Huang, Saijin Ji, Huili Wang, Zirui Li e Bin Xu. "A Comprehensive Model for Assessing Synergistic Revenue–Cost for the Joint Operation of a Complex Multistakeholder Reservoir System". Water 15, n. 22 (8 novembre 2023): 3896. http://dx.doi.org/10.3390/w15223896.

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Abstract (sommario):

The joint operation of a multiobjective multistakeholder reservoir system enhances the revenues of downstream-compensated reservoirs at the expense of increasing the operation cost of upstream-compensating reservoirs. Challenges in quantifying the synergistic revenue–cost tradeoffs with incomplete information arise from difficulties in multistakeholder, high-dimensional, and combinational joint optimal operation modeling. This study proposed an equivalent aggregated reservoir multiobjective operation and synergistic revenue–cost assessment model. The proposed methodology includes three parts. Module I constructs revenue indexes covering energy production, water supply, ecological protection, and shipping objectives and uses the maximum outflow change degree as a surrogate “cost” index. Module II defines “aggregated reservoirs” that aggregate upstream reservoirs within the same river system as a single reservoir, reducing model complexity with the least information. Module III evaluates the revenue–cost tradeoffs under various operation scenarios. The following conclusions were derived from a 27-reservoir system: (1) The model complexity was reduced by 67.18% with precision preserved. (2) Key compensating reservoirs are identified via tradeoff curves, which are reservoirs controlling high streamflow with large storage. (3) Upstream compensating reservoirs homogenize the inflows of downstream-compensated reservoirs to increase the downstream synergistic revenue by sacrificing upstream benefit. The proposed method provides a new approach for revenue–cost estimation via the joint optimal operation of a multistakeholder-reservoir system.

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27

Kjaran, Snorri Páll. "Geothermal Reservoir Engineering Experience in Iceland". Hydrology Research 17, n. 4-5 (1 agosto 1986): 417–38. http://dx.doi.org/10.2166/nh.1986.0033.

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Abstract (sommario):

Geothermal reservoir engineering studies have been carried out in Iceland for years concurrently with the utilization of the various geothermal fields. This has been essential in order to understand the responses of the reservoirs to exploitation. The importance of geothermal energy has grown steadily in the past decades relative to other primary energy resources, providing at present about 40% of the total energy consumed in Iceland. In this article the experience gained from exploiting Icelandic geothermal reservoirs is reviewed. The geological setting of the hydrothermal system is described as well as geophysical exploration methods. Several field examples are presented, demonstrating the effects that exploitation has on the geothermal reservoir's response.

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28

Kim, Donghyun, Jongsung Kim, Wonjoon Wang, Haneul Lee e Hung Soo Kim. "On Hypsometric Curve and Morphological Analysis of the Collapsed Irrigation Reservoirs". Water 14, n. 6 (14 marzo 2022): 907. http://dx.doi.org/10.3390/w14060907.

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Abstract (sommario):

The impact of irrigation reservoirs requires investigation through hydrological analysis to identify the flood control functions of these reservoirs. However, there is insufficient information concerning important geographical, morphological, and topographic characteristics, such as the reservoir cross-section. Therefore, this study aimed to identify the morphological and topographic characteristics of reservoirs using geographical information instead of measurement data. Ten reservoirs, including the Ga-Gog reservoir located in Miryang City, South Korea, were selected. The topographic information of the reservoirs was obtained using topographic maps and GIS techniques. Based on this information, the volume (V)-area (A)-depth (H) relationship and the hypsometric curve (HC) according to the relative area (a/A) and relative height (h/H) were created. A comparison of the reservoir volume, estimated using topographic information, with the measured volume revealed an error rate between 0.23% and 14.27%. In addition, two collapsed reservoirs located near Miryang City were investigated by creating V-A-H relationships and HCs using topographic information. The morphological characteristics of the reservoirs were identified by analyzing the (1) morphology index, (2) full water storage area-levee height relationship, and (3) full water storage area relationship. The analysis results showed that the collapsed reservoirs had high water depth and a large area relative to other reservoirs. Similar types of reservoirs were grouped by conducting a cluster analysis using basic properties such as the basin area, storage, and levee height. The cluster analysis results, based on HC analysis, grouped the reservoirs into three shapes: convex upward (youthful stage), relatively flat (mature stage), and convex downward (old stage). The HCs of the collapsed reservoirs exhibited a convex downward shape, indicating that they were subjected to considerable erosion due to aging. Moreover, this considerable erosion caused a large quantity of sediment to accumulate in the reservoirs, resulting in an insufficient allowable storage capacity of the reservoir because the flood control capacity was reduced, which may have led to their collapse during heavy rainfalls. Therefore, the identification of potential causes of reservoir collapse through the morphological characteristics and HCs of reservoirs are expected to support the operation and management of reservoirs to reduce flood damage.

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Lee, Ji Ho, e Kun Sang Lee. "Multiphase, Multicomponent Simulation for Flow and Transport during Polymer Flood under Various Wettability Conditions". Journal of Applied Mathematics 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/101670.

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Abstract (sommario):

Accurate assessment of polymer flood requires the understanding of flow and transport of fluids involved in the process under different wettability of reservoirs. Because variations in relative permeability and capillary pressure induced from different wettability control the distribution and flow of fluids in the reservoirs, the performance of polymer flood depends on reservoir wettability. A multiphase, multicomponent reservoir simulator, which covers three-dimensional fluid flow and mass transport, is used to investigate the effects of wettability on the flow process during polymer flood. Results of polymer flood are compared with those of waterflood to evaluate how much polymer flood improves the oil recovery and water-oil ratio. When polymer flood is applied to water-wet and oil-wet reservoirs, the appearance of influence is delayed for oil-wet reservoirs compared with water-wet reservoirs due to unfavorable mobility ratio. In spite of the delay, significant improvement in oil recovery is obtained for oil-wet reservoirs. With respect to water production, polymer flood leads to substantial reduction for oil-wet reservoirs compared with water-wet reservoirs. Moreover, application of polymer flood for oil-wet reservoirs extends productive period which is longer than water-wet reservoir case.

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30

Heidari, Hadi, Baptiste Francois e Casey Brown. "Possibility Assessment of Reservoir Expansion in the Conterminous United States". Hydrology 9, n. 10 (7 ottobre 2022): 175. http://dx.doi.org/10.3390/hydrology9100175.

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Abstract (sommario):

Reservoir expansion is commonly considered an adaptation strategy to attenuate water shortage conditions. In many locations in the United States, there are ongoing discussions about the effectiveness and feasibility of reservoir expansion with regard to the growing drought conditions and a consequent significant decrease in surface water. This study investigates if the expansion of the existing Unites States reservoirs should be still considered an effective and adequate management solution to cope with water shortages. To this end, we have defined three reservoir expansion metrics to assess the efficiency, feasibility, and usefulness of increasing the storage capacity of 304 reservoirs across the conterminous United States (CONUS). The efficiency metric is defined as the ratio of reservoir average storage to maximum active storage. The feasibility metric is defined as the ratio of reservoir average annual inflow to maximum active storage and the usefulness metric is described as the ratio of the reservoir average annual excess inflow (average annual inflow–maximum active storage) to the average intensity of water shortages. The finding indicates that most reservoirs in Colorado and Utah currently have high or very high efficiency metrics meaning that these reservoirs are, on average, more than half full while most reservoirs in Texas have low or medium efficiency metrics indicating that these reservoirs are, on average, less than half full. Additionally, the feasibility metrics indicate that reservoir expansion in most western and southern states may not be fruitful because the average annual inflow to reservoirs is less than their maximum active storage over the historical period. Nevertheless, the usefulness metrics show that reservoir expansion can be a useful adaptation strategy to mitigate or attenuate water shortages for some reservoirs in California and Colorado while it cannot considerably decrease the intensity of water shortages in Texas. Findings from this study highlight the utility of the assessment of reservoir expansion at a regional scale considering both available freshwater as an input to reservoirs and the potential water shortage conditions as the main trigger.

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Gao, Bole, Fei Tian, Renfang Pan, Wenhao Zheng, Rong Li, Tianjun Huang e Yisheng Liu. "Hydrothermal Dolomite Paleokarst Reservoir Development in Wolonghe Gasfield, Sichuan Basin, Revealed by Seismic Characterization". Water 12, n. 2 (20 febbraio 2020): 579. http://dx.doi.org/10.3390/w12020579.

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Abstract (sommario):

Hydrothermal dolomite paleokarst reservoir is a type of porous carbonate reservoir, which has a secondary porosity and can store a large amount of oil and gas underground. The reservoir is formed by magnesium-rich hydrothermal fluids during the karstification and later stages of the transformation. Due to the strong heterogeneity and thin thickness of hydrothermal dolomite paleokarst reservoirs, it is a real challenge to characterize the spatial distribution of the reservoirs. In this paper, we studied the hydrothermal dolomite paleokarst reservoir in the Wolonghe gasfield of the eastern Sichuan Basin. First, based on detailed observations of core samples, the characteristics and storage space types of the dolomite reservoir were described. Secondly, the petrophysical parameters of the paleokarst reservoirs were analyzed, and then the indicator factor for the dolomite reservoirs was established. Thirdly, using the time–depth conversion method, the geological characteristics near boreholes were connected with a three-dimensional (3D) seismic dataset. Several petrophysical parameters were predicted by prestack synchronous inversion technology, including the P-wave velocity, S-wave velocity, P-wave impedance, and the hydrothermal dolomite paleokarst reservoir indicator factor. Finally, the hydrothermal dolomite paleokarst reservoirs were quantitatively predicted, and their distribution model was built. The 3D geophysical characterization approach improves our understanding of hydrothermal dolomite paleokarst reservoirs, and can also be applied to other similar heterogeneous reservoirs.

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Han, Yu, Peiru Wanyan, Haoli Wang, Mengfei Qu, Hanlie Cheng e Fahim Theon. "Effectiveness of Oil Filling in Tight Sandstone Reservoirs of Yancheng Formation in Ordos Basin". Journal of Chemistry 2022 (4 ottobre 2022): 1–8. http://dx.doi.org/10.1155/2022/9907772.

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Abstract (sommario):

The Ordos basin is one of the important oil-bearing basins in China, with abundant tight sandstone oil resources, wide distribution, and large thickness. It is the most realistic field of unconventional oil and gas exploration in China, and it is also an important oil and gas replacement resource at present. Oil accumulation in tight reservoirs is obviously different from conventional oil and gas accumulation, and the key lies in studying the effectiveness of oil filling in tight reservoirs. In order to solve this problem, this paper takes the tight sandstone reservoir of Member 7 of the Yancheng Formation in Ordos Basin as the research object, introduces the geological characteristics of this area after sorting out the previous research results, carries out the physical simulation experiment of oil filling, studies the relationship between the filling pressure and the lower limit of the filling throat, analyzes the effective accumulation space of the tight sandstone reservoir, defines the oil filling mechanism of the tight sandstone reservoir, and discusses the effectiveness and reservoir-forming effect of oil filling in different types of reservoirs. The results show that the rock types of tight sandstone reservoirs in the 7th member of the Yancheng Formation are mainly lithic feldspathic sandstone and feldspathic lithic sandstone, and the reservoirs have experienced strong compaction and carbonate cementation. The late iron-bearing carbonate cementation has further strengthened the degree of reservoir densification, and the reservoirs have been densified at the time of large-scale oil and gas filling. Through the simulation experiment of oil filling with natural cores with different physical properties, the relationship model between filling pressure and effective accumulation space of different types of tight sandstone reservoirs in Member 7 of the Yancheng Formation is established. With the change in filling pressure, the change trend and range of effective accumulation space of different types of tight sandstone reservoirs are obviously different. According to the relationship model between the filling pressure and the lower limit of the effective filling pore throat, the oil filling effectiveness of different types of tight sandstone reservoirs in the 7th member of the Yancheng Formation is determined. Class I and class II1 reservoirs are effective reservoirs for oil filling of tight sandstone reservoirs, which constitute the main oil-bearing section of tight sandstone reservoirs in member 7 of the Yancheng formation, while class II2 reservoirs are poor tight reservoirs, and class III reservoirs are basically oil-free, which are noneffective reservoirs for oil filling of tight sandstone reservoirs. The results provide theoretical data support for the next step of oil exploration and exploitation in tight sandstone reservoirs.

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Maju-Oyovwikowhe, E. G., e A. D. Osayande. "Hydrocarbon evaluation and distribution in Well-X and Well-Y in the Niger Delta Basin: Findings and validation through porosity comparison". Scientia Africana 22, n. 1 (14 giugno 2023): 255–78. http://dx.doi.org/10.4314/sa.v22i1.22.

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Abstract (sommario):

The aim of this study is to integrate well logs and core data to identify reservoir characteristics and determine the reservoir's petrophysical properties in order to improve the understanding of the reservoir and provide valuable information for reservoir management. Wells X and Y of the ‘SCOJAS’ Field in the Niger Delta Basin of Nigeria were analyzed using Gamma ray logs, Resistivity logs, Sonic, Neutron and Density Logs. The obtained results were compared with core data from the wells to verify their accuracy. Porosity values for Wells X and Y fall within the range typically observed in sedimentary rocks, with Well Y having higher values. Hydrocarbons were detected in all reservoirs except reservoir zone 1b in both Well-X (12 reservoirs) and Well-Y (7 reservoirs). In Well- X, oil was identified in 5 reservoir zones while in Well-Y, oil was present in 2 reservoir zones. The remaining zones in both wells contained gas. To validate the results further, a comparison was made with the porosity of selected fields in the Niger Delta Basin and the general porosity of the Basin. Well X has a porosity range of 2.7% to 20.8%, which is generally lower than the reported porosity range Well Y has a porosity range of 19.90% to 24.38%, which falls at the upper end of the reported porosity range. Comparing previous works and data from other fields provides important validation for the findings of the study, which is crucial in the oil and gas industry for making informed decisions about exploration and production.

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Ulseth, A. J., e R. O. Hall Jr. "Dam tailwaters compound the effects of reservoirs on the longitudinal transport of organic carbon in an arid river". Biogeosciences Discussions 12, n. 8 (24 aprile 2015): 6081–114. http://dx.doi.org/10.5194/bgd-12-6081-2015.

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Abstract (sommario):

Abstract. Reservoirs on rivers can disrupt organic carbon (OC) transport and transformation, but less is known how downstream river reaches directly below dams contribute to OC processing than reservoirs alone. We compared how reservoirs and their associated tailwaters affected OC quantity and quality by calculating particulate (P) OC and dissolved (D) OC fluxes, and measuring composition and bioavailability of DOC. We sampled the Yampa River near Maybell, Colorado, USA and the Green River above and below Fontenelle and Flaming Gorge reservoirs, and their respective tailwaters from early snowmelt to base flow hydrological conditions. In unregulated reaches (Yampa River, Green River above Fontenelle reservoir), DOC and POC concentrations increased with snowmelt discharge. POC and DOC concentrations also increased with stream discharge below Fontenelle reservoir, but there was no relationship between DOC and stream flow below Flaming Gorge reservoir. The annual load of POC was 3-fold lower below Fontenelle Reservoir and nearly 7-fold lower below Flaming Gorge reservoir, compared to their respective upstream sampling sites. DOC exported to downstream reaches from both reservoirs was less bioavailable, as measured with bioassays, than DOC upriver of the reservoirs. Lastly, tailwater reaches below the reservoirs generated OC, exporting 1.6–2.2 g C m−2 d−1 of OC to downstream ecosystems. Changes in total fluxes from upstream to downstream of reservoirs and their tailwaters do not represent the simultaneous transformation and production of OC, which may lead to the underestimation of the quantity of OC mineralized, transformed, or retained in coupled river-reservoir-tailwater ecosystems.

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Bai, Xiangwu, Zhiping Li e Fengpeng Lai. "Optimal Selection Method for Sweet Spots in Low-Permeability Multilayered Reservoirs". Geofluids 2021 (18 gennaio 2021): 1–10. http://dx.doi.org/10.1155/2021/6698010.

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Abstract (sommario):

Low-permeability oil reservoirs account for more than two-thirds of China’s proven reserves, and most of them are multilayered; the traditional sweet spots focus on single-layered reservoirs. The sweet spots of low-permeability reservoirs have two meanings: the geologically superior reservoir and the beneficial development of the reservoir. In this study, a concept of reservoir stratification coefficient is proposed to evaluate the characteristics of multilayered reservoirs, and three indicators are proposed, namely, reservoir stratification coefficient, energy storage coefficient, and stratigraphic coefficient, as the indicators of sweet spots of multilayered reservoirs. The three indicators are combined into a single indicator using a weighted approach, and the sweet spots can be identified based on the combined indicator. The Xiliu A area of the North China oilfield was selected for a case study. According to the structural, sedimentary, and reservoir characteristics of the block, combined with the development and production conditions, the Sha 3 Member I oil group was selected as the study object of sweet spots of the low-permeability reservoir. The results show that the reservoir stratification coefficient, energy storage coefficient, and stratigraphic coefficient proposed in this study are effective indicators for the preferential selection of sweet spots, which can reflect the longitudinal heterogeneity, energy storage size, and flow capacity of multilayered reservoirs. After a comparative analysis with actual blocks, it was found that the results obtained using the method are consistent with the actual capacity of the reservoir. The production capacity is high. The evaluation effect is ideal, and the applicability is good. Thus, this study provides a new technical method for the evaluation of similar multilayered reservoirs. The findings of this study can help for a better understanding of the development and production conditions and optimization basis of low-permeability reservoirs.

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Tashlykova, Tatiana G., Tamara G. Ryashchenko, Anna A. Dolgaya e Elena A. Lukyanova. "Induced seismicity: a geo-ecological problem of a technogenic nature". Environmental & Socio-economic Studies 4, n. 3 (1 settembre 2016): 21–25. http://dx.doi.org/10.1515/environ-2016-0014.

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Abstract (sommario):

Abstract A debatable problem of the display of induced seismicity and its causes during the construction of reservoirs (Reservoir Induced Seismicity - RIS) is considered on the basis of an analysis of various publications. This paper describes the history of the evolution of ideas about the possibility of the activation of seismic events in the zones of influence of artificial reservoirs and examples of such activation in aseismic areas, which is a medium geological response to technogenic interference (e.g. Shivajisagar reservoir in West India, Mead reservoir in the USA, Danjiangkou Reservoir in central China, Nurek reservoir in Central Asia, Chirkey reservoir in Dagestan and other). The problem and reasons of induced seismicity (RIS) are debatable. however, published examples demonstrate the existence of this process. For reservoirs with different amounts of water RIS is an inseparable component of the natural and man-made geological process. The world statistics knows cases of seismicity intensification in areas near small man-made reservoirs with low pressure levels (Belecha in former Yugoslavia, Marathon in Greece, Grandval in France). In addition, it was found that the number of local earthquakes increased after creating a cascade of three small water reservoirs (Studen Kladenets, Kardzhali and Ivaylovgrad) in the basin of The Arda river (Bulgaria). The RIS examples listed above allow us to think that it is not only the creation of large reservoirs that change (in some cases, intensifies) the local seismicity in the surrounding area. No reservoir, no matter what size it is, is insured from such geological process. At the present time there are more than 100 places in the world with displays of induced seismicity due to reservoir construction. In India there are up to eight reservoirs with these problems. Induced seismicity associated with the influence of man-made water reservoirs, causes a specific geo-ecological risks to the surrounding areas.

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Song, Yunlong. "Study on Water Quality and Trophic Status of Subtropical Cascade Reservoirs in Dongjiang River Basin in Dry Season". E3S Web of Conferences 406 (2023): 03022. http://dx.doi.org/10.1051/e3sconf/202340603022.

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Abstract (sommario):

The Dongjiang River Basin is an important water source for Guangdong Province, providing water for living, production and ecology for more than 40 million people. The three large reservoirs, Xinfengjiang Reservoir, Fengshuba Reservoir and Baipenzhu Reservoir, are the three largest reservoirs in the Dongjiang River Basin. The quality of the water environment in the three reservoirs plays an important role in ensuring the safety of drinking water and promoting the overall protection, systematic restoration and comprehensive management of the water ecosystem. 11 indicators, including water temperature, transparency, pH, DO, turbidity, conductivity, ammonia nitrogen, TN, TP, CODMn and chlorophyll a, were tested in October 2022 to study the water quality characteristics and trophic status of the three cascade reservoirs. The results of the single-factor evaluation of water quality showed that all three reservoirs reached the surface water class II level. TN is the primary pollutant in Fengshuba and Baipenzhu reservoirs. The concentration of Chla in Baekpongju Reservoir was 3.4 μg/L, with a mild risk of algal bloom. TLI (Σ) of the three cascade reservoirs were about 16.41~32.14.The results of the integrated nutrient status evaluation showed that Xinfengjiang Reservoir was in a depleted nutrient status, while Mapeshuba and Bailuanzhu Reservoirs were in a medium nutrient status. Factor analysis showed that 11 water quality factors can be classified into four categories. F1 represents the organic pollution. F2represents the phytoplankton biomass. F3 represents the concentration of nitrogen. F4 represents the suspended solids in water.

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Finecountry, S. C. P., e S. Inichinbia. "Lithology and Fluid discrimination of Sody field of the Nigerian Delta". Journal of Applied Sciences and Environmental Management 24, n. 8 (9 settembre 2020): 1321–27. http://dx.doi.org/10.4314/jasem.v24i8.3.

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Abstract (sommario):

The lithology and fluid discrimination of an onshore Sody field, of the Niger Delta was studied using gamma ray, resistivity and density logs from three wells in the field in order to evaluate the field’s reservoir properties. Two reservoir sands (RES 1 and RES 2) were delineated and identified as hydrocarbon bearing reservoirs. The petrophysical parameters calculated include total porosity, water saturation and volume of shale. The results obtained revealed that the average porosity of the reservoir sands, range from 21% to 39%, which is excellent indicator of a good quality reservoir and probably reflecting well sorted coarse grain sandstone reservoirs with minimal cementation. Water saturation is low in all the reservoirs, ranging from 2% to 32%, indicating that the proportion of void spaces occupied by water is low, and implying high hydrocarbon saturation. The crossplot discriminated the reservoirs lithologies as sand, shaly sand and shale sequences, except well Sody 2 which differentiated its lithologies as sand and shale sequences and distinguished the reservoirs’ litho-fluids into three, namely; gas, oil and brine. These results suggest that the reservoirs sand units of Sody field contain significant accumulations of hydrocarbon. Keywords: Reservoir, porosity, net-to-gross, impedance, lithology

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Chen, Mei Tao, Ning Yang e Shang Ming Yang. "Paleozoic Carbonate Hydrocarbon Accumulation Zones in Tahong Uplift Tarim Basin, Western China". Advanced Materials Research 403-408 (novembre 2011): 1511–16. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.1511.

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Abstract (sommario):

Analyzing the discovered carbonate reservoirs in the Tazhong area, Tarim Basin indicates that the development of a reservoir is controlled by subarial weathering and freshwater leaching processes, sedimentation, early diagenesis, and alteration by deep fluids. According to the origin and lateral distribution of reservoirs, the hydrocarbon accumulation zones in the Tazhong area are classified into four types: buried hill and palaeoweathering crust, organic buildup reef-bank, dolomite interior, and deep fluid alteration. Different types of carbonate hydrocarbon accumulation zones are distributed mainly in specific areas of the Tazhong uplift. Because of the different mechanisms of forming reservoirs in different carbonate hydrocarbon accumulation zones, the reservoir space, reservoir capability, type of reservoir and distribution of reservoirs are often different.

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40

Silva, Juliano Pilotto Abelardino da, Adriane Esquivel Muelbert, Elton Celton de Oliveira e Luís Fernando Fávaro. "Reproductive tactics used by the Lambari Astyanax aff. fasciatus in three water supply reservoirs in the same geographic region of the upper Iguaçu River". Neotropical Ichthyology 8, n. 4 (2010): 885–92. http://dx.doi.org/10.1590/s1679-62252010000400019.

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The species Astyanax aff. fasciatus was investigated as regards differences in reproductive tactics in three reservoirs with different ages (Iraí, Piraquara and Passaúna) located in the same geographic region. The biological material was obtained through monthly collections carried out from july/2006 to june/2007. The average value of the gonadosomatic index (GSI) in Passaúna reservoir was significantly higher in relation to the values obtained in the other reservoirs. Spawning was total in Iraí reservoir and partial in the others. Allometric growth of the species was negative in Iraí reservoir and positive in the others. The highest condition factor value was estimated in Iraí reservoir, followed by Piraquara and Passaúna reservoirs, respectively. Females predominated in all of the reservoirs during the study period. The sex ratio per length class showed, for the three reservoirs, the predominance of males in the smaller length classes. These results verified that the species uses distinct reproductive tactics in the analyzed reservoirs and that these tactics seem to reflect the degree of stabilization of each environment.

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Abeshu, Guta Wakbulcho, Fuqiang Tian, Thomas Wild, Mengqi Zhao, Sean Turner, A. F. M. Kamal Chowdhury, Chris R. Vernon et al. "Enhancing the representation of water management in global hydrological models". Geoscientific Model Development 16, n. 18 (22 settembre 2023): 5449–72. http://dx.doi.org/10.5194/gmd-16-5449-2023.

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Abstract. This study enhances an existing global hydrological model (GHM), Xanthos, by adding a new water management module that distinguishes between the operational characteristics of irrigation, hydropower, and flood control reservoirs. We remapped reservoirs in the Global Reservoir and Dam (GRanD) database to the 0.5∘ spatial resolution in Xanthos so that a single lumped reservoir exists per grid cell, which yielded 3790 large reservoirs. We implemented unique operation rules for each reservoir type, based on their primary purposes. In particular, hydropower reservoirs have been treated as flood control reservoirs in previous GHM studies, while here, we determined the operation rules for hydropower reservoirs via optimization that maximizes long-term hydropower production. We conducted global simulations using the enhanced Xanthos and validated monthly streamflow for 91 large river basins, where high-quality observed streamflow data were available. A total of 1878 (296 hydropower, 486 irrigation, and 1096 flood control and others) out of the 3790 reservoirs are located in the 91 basins and are part of our reported results. The Kling–Gupta efficiency (KGE) value (after adding the new water management) is ≥ 0.5 and ≥ 0.0 in 39 and 81 basins, respectively. After adding the new water management module, model performance improved for 75 out of 91 basins and worsened for only 7. To measure the relative difference between explicitly representing hydropower reservoirs and representing hydropower reservoirs as flood control reservoirs (as is commonly done in other GHMs), we use the normalized root mean square error (NRMSE) and the coefficient of determination (R2). Out of the 296 hydropower reservoirs, the NRMSE is > 0.25 (i.e., considering 0.25 to represent a moderate difference) for over 44 % of the 296 reservoirs when comparing both the simulated reservoir releases and storage time series between the two simulations. We suggest that correctly representing hydropower reservoirs in GHMs could have important implications for our understanding and management of freshwater resource challenges at regional-to-global scales. This enhanced global water management modeling framework will allow the analysis of future global reservoir development and management from a coupled human–earth system perspective.

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42

Li, Xinshuai, Xuesong Yang, Huilai Wang, Chenlin Wu, Jun Xie, Qiongyao Pu, Xuecai Zhang, Xiaofan Hao e Yan Li. "Accurate identification of traps and pinch-outs on a stratigraphic reservoir-A case from Hala’alate Mountain in the Junggar Basin, China". PLOS ONE 19, n. 5 (31 maggio 2024): e0303467. http://dx.doi.org/10.1371/journal.pone.0303467.

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In the investigation of stratigraphic reservoirs, a significant discrepancy frequently exists between the delineation of the formation pinch-out line as traced using the characteristics of seismic wave reflections and the actual location of the formation pinch-out line. This has been the main problem restricting further hydrocarbon exploration and development. In this study, Hala’alate Mountain on the northwestern margin of the Junggar Basin is taken as an example for carrying out the study of stratigraphic reservoirs by integrating logging, drilling, and 3D seismic data. On the one hand, in studies based on the identification of formation pinch-out points using seismic data, the identification error of reservoir pinch-out lines is reduced by the improved included angle extrapolation method by utilizing the half energy attribute. On the other hand, the Poisson’s ratio curve is reconstructed using acoustic curves and oil-gas sensitive logging, then the reservoir oil-bearing facies zone is predicted using Poisson’s ratio post-stack genetic inversion to comprehensively analyze the controlling factors of stratigraphic reservoirs. The study area mainly features structural lithologic reservoirs, structural stratigraphic reservoirs and stratigraphic overlaps that pinch out reservoirs. The boundary of a stratigraphic reservoir is affected by the dip angle of the unconformity surface, the formation dip angle, and other factors. The improved included angle extrapolation method improves the identification accuracy of stratigraphic overlap pinch-out reservoirs. The reservoir distribution then is calculated according to Poisson’s ratio inversion, improving the prediction accuracy for the reservoir. This method improves the predictive effect for stratigraphic reservoirs and provides a new idea for the exploration and development of similar reservoirs.

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Wang, Liang, Zhiqiang Mao, Zhongchun Sun, Xingping Luo, Yong Song e Zhen Liu. "Genesis Analysis of High-Gamma Ray Sandstone Reservoir and Its Log Evaluation Techniques: A Case Study from the Junggar Basin, Northwest China". Scientific World Journal 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/848201.

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In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs’ recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation’s high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation.

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44

Song, Chunqiao, Chenyu Fan, Jingying Zhu, Jida Wang, Yongwei Sheng, Kai Liu, Tan Chen et al. "A comprehensive geospatial database of nearly 100 000 reservoirs in China". Earth System Science Data 14, n. 9 (6 settembre 2022): 4017–34. http://dx.doi.org/10.5194/essd-14-4017-2022.

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Abstract. With rapid population growth and socioeconomic development over the last century, a great number of dams/reservoirs have been constructed globally to meet various needs. China has strong economical and societal demands for constructing dams and reservoirs. The official statistics reported more than 98 000 dams/reservoirs in China, including nearly 40 % of the world's largest dams. Despite the availability of several global-scale dam/reservoir databases (e.g., the Global Reservoir and Dam database (GRanD), the GlObal geOreferenced Database of Dams (GOODD), and the Georeferenced global Dams And Reservoirs (GeoDAR)), these databases have insufficient coverage of the reservoirs in China, especially for small or newly constructed ones. The lack of reservoir information impedes the estimation of water budgets and the evaluation of dam impacts on hydrologic and nutrient fluxes for China and its downstream countries. Therefore, we presented the China Reservoir Dataset (CRD), which contains 97 435 reservoir polygons and fundamental attribute information (e.g., name and storage capacity) based on existing dam/reservoir products, national basic geographic datasets, multi-source open map data, and multi-level governmental yearbooks and databases. The reservoirs compiled in the CRD have a total maximum water inundation area of 50 085.21 km2 and a total storage capacity of about 979.62 km3 (924.96–1060.59 km3). The quantity of reservoirs decreases from the southeast to the northwest, and the density hotspots mainly occur in hilly regions and large plains, with the Yangtze River basin dominating in reservoir count, area, and storage capacity. We found that these spatial accumulations of reservoirs are closely related to China's socioeconomic development and the implementation of major policies. Finally, we presented the comparison of the CRD with GOODD, GeoDAR, and GRanD databases. The CRD has significantly increased the reservoir count, area, and storage capacity in China, especially for reservoirs smaller than 1 km2. The CRD database provides more comprehensive reservoir spatial and attribute information and is expected to benefit water resources managements and the understanding of ecological and environmental impacts of dams across China and its affected transboundary basins. The CRD database is publicly available at https://doi.org/10.5281/zenodo.6984619 (Song et al., 2022).

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Liu, Xuan, Mingxiang Yang, Xianyong Meng, Fan Wen e Guangdong Sun. "Assessing the Impact of Reservoir Parameters on Runoff in the Yalong River Basin using the SWAT Model". Water 11, n. 4 (27 marzo 2019): 643. http://dx.doi.org/10.3390/w11040643.

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The construction and operation of cascade reservoirs has changed the natural hydrological cycle in the Yalong River Basin, and reduced the accuracy of hydrological forecasting. The impact of cascade reservoir operation on the runoff of the Yalong River Basin is assessed, providing a theoretical reference for the construction and joint operation of reservoirs. In this paper, eight scenarios were set up, by changing the reservoir capacity, operating location, and relative location in the case of two reservoirs. The aim of this study is to explore the impact of the capacity and location of a single reservoir on runoff processes, and the effect of the relative location in the case of joint operation of reservoirs. The results show that: (1) the reservoir has a delay and reduction effect on the flood during the flood season, and has a replenishment effect on the runoff during the dry season; (2) the impact of the reservoir on runoff processes and changes in runoff distribution during the year increases with the reservoir capacity; (3) the mitigation of flooding is more obvious at the river basin outlet control station when the reservoir is further downstream; (4) an arrangement with the smaller reservoir located upstream and the larger reservoir located downstream can maximize the benefits of the reservoirs in flood control.

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Campos, Jody, Iran Eduardo Lima Neto, Ticiana Marinho Studart e José Nilson Beserra Campos. "Influence of sediment distribution on the relationships among reservoir yield, spill, and evaporation losses". Engenharia Sanitaria e Ambiental 23, n. 5 (ottobre 2018): 849–56. http://dx.doi.org/10.1590/s1413-41522018177058.

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ABSTRACT This study shows how the sedimentation process in reservoirs affects the yield-spill-evaporation losses in reservoirs of Ceará State, Brazilian Northeast. Reservoirs are assumed to have, initially, inverted conical shape. Three forms of sedimentation were investigated: type 1, with deposition occurring parallel to the wetted perimeter; type 2, deposition distributed proportionally to the water depth; and, type 3, deposition concentrated in the reservoir bottom. These sedimentation patterns were found in many reservoirs in Ceará, with capacity ranging from about 0.5 to 100 hm3. Nevertheless, type 2 pattern was the most frequent. In this paper, five large reservoirs, over 100 hm3, were studied using Monte Carlo approach, and considering the silting over the time horizon. It was found that sediment distribution can significantly affect the yield-spill-evaporation trade-off on large reservoirs. Type 1 results have the lowest impact on reservoir yield, followed by type 2 and type 3. For Cedro reservoir, the yield would go to zero in 2115, assuming a type 3 deposition pattern. These results reinforce the need for monitoring sedimentation in large reservoirs in the Brazilian semiarid region. In addition, this study provides a relatively simple methodology to predict the impact of siltation on reservoir yield-spill-evaporation relationships, for the three most found patterns of sedimentation.

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Duka, Maurice Alfonso, Tetsuya Shintani e Katsuhide Yokoyama. "Mediating the Effects of Climate on the Temperature and Thermal Structure of a Monomictic Reservoir through Use of Hydraulic Facilities". Water 13, n. 8 (20 aprile 2021): 1128. http://dx.doi.org/10.3390/w13081128.

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Climate warming can alter the thermal conditions of reservoirs. However, some hydraulic interventions can be explored to mitigate this impact. This study investigates the long-term effects of climate on the temperature and thermal structure of a monomictic reservoir that has had varying operations from 1959 to 2016. Reservoir progressively operated through three distinct periods, namely, (A) deep penstock withdrawal (DPW; 1959–1991), (B) purely selective withdrawal (SW; 1992–2001), and (C) combination of SW and vertical curtain (VC; 2002–2016). Although annual air temperatures are increasing (+0.15 °C decade−1) in the long term, the reservoir’s surface water temperatures have been found to be decreasing (−0.06 °C decade−1). Periods B and C produced colder profiles and exhibited lower heat content and higher potential energy anomaly than Period A. Furthermore, stronger thermoclines, as indicated by Brunt–Vaisala frequency, were observed in the two latter periods. The results of this study show that varying operations bear a stronger influence on the reservoir’s temperature and thermal structure than climate change itself. Mitigating the thermal impacts of climate warming in reservoirs appears promising with the use of SW and VC.

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Yu, Yu, Yu Bai, Yingying Ni, Yi Luo e Shafique Junejo. "Water Quality Variation Law and Prediction Method of a Small Reservoir in China". Sustainability 14, n. 21 (24 ottobre 2022): 13755. http://dx.doi.org/10.3390/su142113755.

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Compared with the attention of large reservoirs, the water quality of small reservoirs also needs attention. In recent years, the problem of reservoir water quality has become increasingly serious. How to predict reservoir water quality may be an urgent problem to be solved. Taking the Yangmeiling reservoir as an example, this paper collects the hydrological and water quality data of the Yangmeiling reservoir in the last ten years, analyzes the relationship between hydrological and water quality data, and uses a machine learning method to simulate the relationship between water quality and hydrological data. The results show that the water quality of small reservoirs can be simply linked with hydrological data and can be predicted through hydrological data, and has high simulation accuracy. This method can be popularized in the simulation and prediction of the water quality of small reservoirs; it does not provide a theoretical basis for the water quality management of small reservoirs.

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Vanderkelen, Inne, Shervan Gharari, Naoki Mizukami, Martyn P. Clark, David M. Lawrence, Sean Swenson, Yadu Pokhrel, Naota Hanasaki, Ann van Griensven e Wim Thiery. "Evaluating a reservoir parametrization in the vector-based global routing model mizuRoute (v2.0.1) for Earth system model coupling". Geoscientific Model Development 15, n. 10 (1 giugno 2022): 4163–92. http://dx.doi.org/10.5194/gmd-15-4163-2022.

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Abstract. Human-controlled reservoirs have a large influence on the global water cycle. While global hydrological models use generic parameterizations to model dam operations, the representation of reservoir regulation is still lacking in many Earth system models. Here we implement and evaluate a widely used reservoir parametrization in the global river-routing model mizuRoute, which operates on a vector-based river network resolving individual lakes and reservoirs and is currently being coupled to an Earth system model. We develop an approach to determine the downstream area over which to aggregate irrigation water demand per reservoir. The implementation of managed reservoirs is evaluated by comparing them to simulations ignoring inland waters and simulations with reservoirs represented as natural lakes using (i) local simulations for 26 individual reservoirs driven by observed inflows and (ii) global-domain simulations driven by runoff from the Community Land Model. The local simulations show the clear added value of the reservoir parametrization, especially for simulating storage for large reservoirs with a multi-year storage capacity. In the global-domain application, the implementation of reservoirs shows an improvement in outflow and storage compared to the no-reservoir simulation, but a similar performance is found compared to the natural lake parametrization. The limited impact of reservoirs on skill statistics could be attributed to biases in simulated river discharge, mainly originating from biases in simulated runoff from the Community Land Model. Finally, the comparison of modelled monthly streamflow indices against observations highlights that including dam operations improves the streamflow simulation compared to ignoring lakes and reservoirs. This study overall underlines the need to further develop and test runoff simulations and water management parameterizations in order to improve the representation of anthropogenic interference of the terrestrial water cycle in Earth system models.

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Hidayat, Fahmi, Pitojo T. Juwono, Agus Suharyanto, Alwafi Pujiraharjo, Djoko Legono, Dian Sisinggih, David Neil, Masaharu Fujita e Tetsuya Sumi. "Assessment of Sedimentation in Wlingi and Lodoyo Reservoirs: A Secondary Disaster Following the 2014 Eruption of Mt. Kelud, Indonesia". Journal of Disaster Research 12, n. 3 (29 maggio 2017): 617–30. http://dx.doi.org/10.20965/jdr.2017.p0617.

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Wlingi and Lodoyo reservoirs in the Brantas River basin, Indonesia, provide numerous benefits including reliable irrigation water supply, flood control, power generation, fisheries and recreation. The function of both reservoirs particularly in relation to flood control has declined due to severe sedimentation that has reduced their storage capacities. The sedimentation in Wlingi and Lodoyo reservoirs is mainly caused by sediment inflow from the areas most affected by ejecta from eruptions of Mt. Kelud, one of the most active volcanoes in Indonesia. The main objective of this research is to assess the sedimentation problem in Wlingi and Lodoyo reservoirs, particularly as they are affected by eruptions of Mt Kelud. We performed reservoir bathymetric surveys and field surveys after the most recent eruption of Mt. Kelud in February 2014 and compared the results with surveys undertaken before the eruption. The assessment revealed that both reservoirs were severely affected by the 2014 eruption. The effective storage capacity of Wlingi reservoir in March 2013 was 2.01 Mm3and the survey in May 2015 indicated that the effective storage of Wlingi reservoir had decreased to 1.01 Mm3. Similarly, the effective storage capacity of Lodoyo reservoir in March 2013 was 2.72 Mm3, reduced to 1.33 Mm3in May 2015. These findings underpin the analysis of the impacts of the secondary disaster due to reservoir sedimentation following the volcanic eruption and the implications for mitigating and managing the risks for sustainable use of reservoirs to control floods, supply water, generate electricity, etc. To cope with the extreme sedimentation problem in Wlingi and Lodoyo reservoirs, diverse sediment management strategies have been applied in these reservoirs and their catchments. However sediment disaster management strategies for both reservoirs, an integral part of the Mt. Kelud Volcanic Disaster Mitigation Plan, require continuous maintenance and recurrent operations, and ongoing evaluation and improvement.

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