Sample records for evaluate reservoir dissolved

  1. Dissolved methane in Indian freshwater reservoirs

    Digital Repository Service at National Institute of Oceanography (India)

    Narvenkar, G.; Naqvi, S.W.A.; Kurian, S.; Shenoy, D.M.; Pratihary, A.K.; Naik, H.; Patil, S.; Sarkar, A.; Gauns, M.

    reservoirs in India, most of which experience seasonal anaerobic conditions and CH4 buildup in the hypolimnia. However, strong stratification prevents the CH4-rich subsurface layers to ventilate CH4 directly to the atmosphere, and surface water CH4...

  2. Artificial neural network modeling of dissolved oxygen in reservoir. (United States)

    Chen, Wei-Bo; Liu, Wen-Cheng


    The water quality of reservoirs is one of the key factors in the operation and water quality management of reservoirs. Dissolved oxygen (DO) in water column is essential for microorganisms and a significant indicator of the state of aquatic ecosystems. In this study, two artificial neural network (ANN) models including back propagation neural network (BPNN) and adaptive neural-based fuzzy inference system (ANFIS) approaches and multilinear regression (MLR) model were developed to estimate the DO concentration in the Feitsui Reservoir of northern Taiwan. The input variables of the neural network are determined as water temperature, pH, conductivity, turbidity, suspended solids, total hardness, total alkalinity, and ammonium nitrogen. The performance of the ANN models and MLR model was assessed through the mean absolute error, root mean square error, and correlation coefficient computed from the measured and model-simulated DO values. The results reveal that ANN estimation performances were superior to those of MLR. Comparing to the BPNN and ANFIS models through the performance criteria, the ANFIS model is better than the BPNN model for predicting the DO values. Study results show that the neural network particularly using ANFIS model is able to predict the DO concentrations with reasonable accuracy, suggesting that the neural network is a valuable tool for reservoir management in Taiwan.

  3. The effect of Sequoyah Nuclear Plant on dissolved oxygen in Chickamauga Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Butkus, S.R.; Shiao, M.C.; Yeager, B.L.


    During the summer of 1985, the Tennessee Division of Water Pollution Control and the Tennessee Wildlife Resources Agency measured dissolved oxygen (DO) concentrations downstream from the Sequoyah Nuclear Plant (SQN) discharge mixing zone that were below the state criterion for DO. The Tennessee General Water Quality Criteria'' specifies that DO should be a minimum of 5.0 mg/l measured at a depth of 5 feet for the protection of fish and aquatic life. The Tennessee Valley Authority developed the present study to answer general concerns about reservoir conditions and potential for adverse effects on aquatic biota. Four objectives were defined for this study: (1) to better define the extent and duration of the redistribution of DO in the reservoir, (2) to better understand DO dynamics within the mixing zone, (3) to determine whether DO is being lost (or added) as the condenser cooling water passes through the plant, and (4) to evaluate the potential for impact on aquatic life in the reservoir.

  4. Formation of trihalomethanes of dissolved organic matter fractions in reservoir and canal waters. (United States)

    Musikavong, Charongpun; Srimuang, Kanjanee; Tachapattaworakul Suksaroj, Thunwadee; Suksaroj, Chaisri


    The formation of trihalomethanes (THMs) of hydrophobic organic fraction (HPO), transphilic organic fraction (TPI), and hydrophilic organic fraction (HPI) of reservoir and canal waters from the U-Tapao River Basin, Songkhla, Thailand was investigated. Water samples were collected three times from two reservoirs, upstream, midstream, and downstream of the U-Tapao canal. The HPO was the major dissolved organic matter (DOM) fraction in reservoir and canal waters. On average, the HPO accounted for 53 and 45% of the DOM in reservoir and canal waters, respectively. The TPI of 19 and 23% in reservoir and canal waters were determined, respectively. The HPI of 29% of the reservoir water and HPI of 32% of the canal water were detected. For the reservoir water, the highest trihalomethane formation potential (THMFP)/dissolved organic carbon (DOC) was determined for the HPI, followed by the TPI and HPO, respectively. The average values of the THMFP/DOC of the HPI, TPI, and HPO of the reservoir water were 78, 52, and 49 µg THMs/mg C, respectively. The highest THMFP/DOC of the canal water was detected for the HPI, followed by HPO and TPI, respectively. Average values of the THMFP/DOC of HPI of water at upstream and midstream locations of 58 µg THMs/mg C and downstream location of 113 µg THMs/mg C were determined. Average values of THMFP/DOC of HPO of water at upstream and midstream and downstream locations were 48 and 93 µg THMs/mg C, respectively. For the lowest THMFP/DOC fraction, the average values of THMFP/DOC of TPI of water at upstream and midstream and downstream locations were 35 and 73 µg THMs/mg C, respectively.

  5. Slimholes for geothermal reservoir evaluation - An overview

    Energy Technology Data Exchange (ETDEWEB)

    Hickox, C.E.


    The topics covered in this session include: slimhole testing and data acquisition, theoretical and numerical models for slimholes, and an overview of the analysis of slimhole data acquired by the Japanese. The fundamental issues discussed are concerned with assessing the efficacy of slimhole testing for the evaluation of geothermal reservoirs. the term reservoir evaluation is here taken to mean the assessment of the potential of the geothermal reservoir for the profitable production of electrical power. As an introduction to the subsequent presentations and discussions, a brief summary of the more important aspects of the use of slimholes in reservoir evaluation is given.

  6. Seasonal variation in dissolved gaseous mercury and total mercury concentrations in Juam Reservoir, Korea. (United States)

    Park, Jong-Sung; Oh, Sehee; Shin, Mi-Yeon; Kim, Moon-Kyung; Yi, Seung-Muk; Zoh, Kyung-Duk


    Dissolved gaseous mercury (DGM) and total mercury (TM) concentrations were measured in Juam Reservoir, Korea. DGM concentrations were higher in spring (64+/-13pgL(-1)) and summer (109+/-15pgL(-1)), and lower in fall (20+/-2pgL(-1)) and winter (23+/-6pgL(-1)). In contrast, TM concentrations were higher in fall (3.2+/-0.1ngL(-1)) and winter (3.3+/-0.1ngL(-1)) than in spring (2.3+/-0.1ngL(-1)) and summer (2.2+/-0.4ngL(-1)). DGM concentrations were correlated with water temperature (pNorth American lakes (DGM=38+/-16pgL(-1); TM=1.0+/-1.2ngL(-1)), but lower than levels reported for Baihua Reservoir in China.

  7. Monitoring and evaluation of aquatic resource health and use suitability in Tennessee Valley Authority reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Dycus, D.L.; Meinert, D.L.


    TVA initiated a Reservoir Monitoring Program in 1990 with two objectives -- to evaluate the health of the reservoir ecosystem and to examine how well each reservoir meets the swimmable and fishable goals of the Clean Water Act. In 1990 reservoir health was evaluated subjectively using a weight-of-evidence approach (a reservoir was deemed healthy if most of the physical, chemical, and biological monitoring components appeared healthy). In the second year (1991) a more objective, quantitative approach was developed using information on five important indicators of reservoir health -- dissolved oxygen, chlorophyll, sediment quality, benthic macroinvertebrates, and fishes. The most recent information (1992) was evaluated with the same basic approach, modified to incorporate improvements based on comments from reviewers and additional data. Reservoirs were stratified into two groups for evaluation: run-of-the-river reservoirs and tributary storage reservoirs. Key locations are sampled in each reservoir (forebay, transition zone or midreservoir, inflow, and major embayments) for most or all of these five reservoir health indicators. For each indicator (or metric), scoring criteria have been developed that assign a score ranging from 1 to 5 representing poor to good conditions, respectively. Scores for the metrics at a location are summed and then the sums for all locations are totaled. Each reservoir has one to four sample locations depending on reservoir characteristics. The resultant total is divided by the maximum possible score (all metrics good at all locations) for the reservoir. Thus, the possible range of scores is from 20 percent (all metrics poor) to 100 percent (all metrics good). This reservoir ecological health evaluation method is proving to be a valuable tool for providing the public with information about the condition of the Valley`s reservoirs, for allowing meaningful comparisons among reservoirs, and for tracking changes in reservoir health with time.

  8. Low ratios of silica to dissolved nitrogen supplied to rivers arise from agriculture not reservoirs. (United States)

    Downing, John A; Cherrier, Christine T; Fulweiler, Robinson W


    Coastal marine systems are greatly altered by toxic marine algae, eutrophication and hypoxia. These problems have been linked to decreased ratios of dissolved silica to inorganic nitrogen (Si : DIN) delivered from land. Two mechanisms for this decline under consideration are enhanced nitrogen (N) fertiliser losses from agricultural lands or Si sequestration in reservoirs. Here we examine these mechanisms via nutrient concentrations in impoundments receiving water from 130 watersheds in a landscape representative of the agriculture that often dominates coastal nutrient inputs. Decreased Si : DIN was correlated with agriculture, not impoundment. Watersheds with > 60% agricultural land yielded highest DIN, whereas Si was uncorrelated with agricultural intensity. Furthermore, eutrophic lakes were dominated by Cyanobacteria that use little Si, so reservoirs did not diminish Si : DIN. Instead, Si : DIN increased slightly as reservoir residence time increased. These data suggest that impoundments in agricultural watersheds may enhance the water quality of coastal ecosystems, whereas fertiliser losses are detrimental. © 2016 John Wiley & Sons Ltd/CNRS.

  9. Occurrence of dissolved solids, nutrients, atrazine, and fecal coliform bacteria during low flow in the Cheney Reservoir watershed, south-central Kansas, 1996 (United States)

    Christensen, V.G.; Pope, L.M.


    A network of 34 stream sampling sites was established in the 1,005-square-mile Cheney Reservoir watershed, south-central Kansas, to evaluate spatial variability in concentrations of selected water-quality constituents during low flow. Land use in the Cheney Reservoir watershed is almost entirely agricultural, consisting of pasture and cropland. Cheney Reservoir provides 40 to 60 percent of the water needs for the city of Wichita, Kansas. Sampling sites were selected to determine the relative contribution of point and nonpoint sources of water-quality constituents to streams in the watershed and to identify areas of potential water-quality concern. Water-quality constituents of interest included dissolved solids and major ions, nitrogen and phosphorus nutrients, atrazine, and fecal coliform bacteria. Water from the 34 sampling sites was sampled once in June and once in September 1996 during Phase I of a two-phase study to evaluate water-quality constituent concentrations and loading characteristics in selected subbasins within the watershed and into and out of Cheney Reservoir. Information summarized in this report pertains to Phase I and was used in the selection of six long-term monitoring sites for Phase II of the study. The average low-flow constituent concentrations in water collected during Phase I from all sampling sites was 671 milligrams per liter for dissolved solids, 0.09 milligram per liter for dissolved ammonia as nitrogen, 0.85 milligram per liter for dissolved nitrite plus nitrate as nitrogen, 0.19 milligram per liter for total phosphorus, 0.20 microgram per liter for dissolved atrazine, and 543 colonies per 100 milliliters of water for fecal coliform bacteria. Generally, these constituents were of nonpoint-source origin and, with the exception of dissolved solids, probably were related to agricultural activities. Dissolved solids probably occur naturally as the result of the dissolution of rocks and ancient marine sediments containing large salt

  10. Forecasting of dissolved oxygen in the Guanting reservoir using an optimized NGBM (1,1) model. (United States)

    An, Yan; Zou, Zhihong; Zhao, Yanfei


    An optimized nonlinear grey Bernoulli model was proposed by using a particle swarm optimization algorithm to solve the parameter optimization problem. In addition, each item in the first-order accumulated generating sequence was set in turn as an initial condition to determine which alternative would yield the highest forecasting accuracy. To test the forecasting performance, the optimized models with different initial conditions were then used to simulate dissolved oxygen concentrations in the Guanting reservoir inlet and outlet (China). The empirical results show that the optimized model can remarkably improve forecasting accuracy, and the particle swarm optimization technique is a good tool to solve parameter optimization problems. What's more, the optimized model with an initial condition that performs well in in-sample simulation may not do as well as in out-of-sample forecasting. Copyright © 2015. Published by Elsevier B.V.

  11. Two-dimensional numerical modelling of dissolved and particulate pollutant transport in the Three Gorges Reservoir (United States)

    Hu, W.; Wang, L.-J.; Chen, H.; Holbach, A.; Zheng, B.-H.; Norra, S.; Westrich, B.


    After impoundment of the Three Gorges Reservoir (TGR) in 2003, hydrological regimes of the Yangtze River, upstream and downstream of the Three Gorges Dam, have been changed enormously, leading to significant environmental, ecological and social impacts. Nutrients and pollutants from agriculture, industry and municipalities are of concern due to their impact on the aquatic environment and hence, transport behavior of sediment associated pollutants must be modeled and analyzed to establish a sustainable water reservoir management. As part of the Chinese-German Yangtze-Project [1], two-dimensional numerical model TELEMAC is applied to study the dissolved and particulate pollutant transport at different locations of concern in the TGR. In-situ measurement campaigns for morphology and water quality data using mobile measuring device (MINIBAT) are carried out to provide detailed information for the different water bodies at different time. Additional morphological data are taken from cross-section profiles in the literature, the digital elevation model (DEM) of Shuttle Radar Topography Mission (SRTM) from CGIAR. Daily and hourly water level and discharge, suspended sediment concentration and pollutant loads are obtained from the authorities and extracted from literature. The model describes the spatial-temporal flow field, transport and dispersion of sediment associated pollutants with emphasis on the dynamic interaction and mutual influence of the river Yangtze, its major tributaries and adjacent lagoon-like dead water bodies due to the 30 meter annual reservoir water level fluctuation. Since algae bloom, especially in the tributaries and side arms of the mainstream, is one of the major issues occurred after 2003, the results of the numerical modeling together with the statistical analysis of the MINIBAT measurements are used for the eutrophication status analysis. Acknowledgments The Yangtze-Project is funded by the Federal Ministry of Education and Research (BMBF

  12. Occurrence and dominance of Cylindrospermopsis raciborskii and dissolved cylindrospermopsin in urban reservoirs used for drinking water supply, South China. (United States)

    Lei, Lamei; Peng, Liang; Huang, Xianghui; Han, Bo-Ping


    The tropical cyanobacterium Cylindrospermopsis raciborskii is of particular concern for its invasive characteristics and production of the toxin cylindrospermopsin (CYN). The present study represents the first attempt to determine the distribution of C. raciborskii and CYN in tropical China. The presence of C. raciborskii and CYN, as well as the composition of phytoplankton, was determined from a total of 86 samples from 25 urban reservoirs for drinking water supply in Dongguan City of South China. The presence of C. raciborskii was observed in 21 of the 25 reservoirs and confirmed that this species has been widely distributed in the investigated reservoirs. C. raciborskii accounted for between 0.1 and 90.3 % of the total phytoplankton biomass and contributed to the majority of the phytoplankton in some reservoirs such as Tangkengbian and Xiagongyan. Its biomass was negatively correlated with NO3 (-)-N concentration and Secchi depth. Dissolved CYN was detected in more than one-half of the reservoirs with concentrations up to 8.25 μg L(-1), and it positively correlated with C. raciborskii biomass. Dissolved microcystins (MCs) were detected in 12 of the 25 reservoirs with a maximum concentration 1.99 μg L(-1). Our data strongly suggest that C. raciborskii and CYN could be important health hazards in urban reservoirs of South China and that more data are needed for further assessment.

  13. New method for evaluating composite reservoir systems

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.M.; Lai, C.H.


    A simple new technique has been developed for evaluating interference test data in radially symmetric composite reservoirs. The technique is based on the realization that systematic variations in the apparent storage coefficient (calculated from semi-log analysis of the late-time data are indicative of a two-mobility (k/ reservoir. By analyzing variations in the apparent storage coefficient, both the mobility and size of the inner region can be calculated. The technique is particularly useful for evaluating heterogeneous geothermal systems where the intersection of several faults, or hydrothermal alteration has created a high permeability region in the center of the geothermal field. The technique is applied to an extensive interference test in the geothermal reservoir at Klamath Falls, Oregon. 7 refs., 7 figs.

  14. Evaluation of storm event inputs on levels of gross primary production and respiration in a drinking water reservoir

    DEFF Research Database (Denmark)

    Samal, Nihar; Stæhr, Peter A.; Pierson, Donald C.

    Weather related episodic events are typically unpredictable and the episodic inputs of dissolved and particulate material during storm events can have important effects on lake and reservoir ecosystem function and also impact reservoir drinking water quality.   We evaluate the impacts of storm...... events using vertical profiles of temperature, dissolved oxygen, turbidity and chlorophyll automatically collected at 6 hour intervals in West basin of Ashokan Reservoir, which is a part of the New York City drinking water supply. Using data from before, during and after storm events, we examine how...

  15. Dynamics and ecological risk assessment of chromophoric dissolved organic matter in the Yinma River Watershed: Rivers, reservoirs, and urban waters. (United States)

    Li, Sijia; Zhang, Jiquan; Guo, Enliang; Zhang, Feng; Ma, Qiyun; Mu, Guangyi


    The extensive use of a geographic information system (GIS) and remote sensing in ecological risk assessment from a spatiotemporal perspective complements ecological environment management. Chromophoric dissolved organic matter (CDOM), which is a complex mixture of organic matter that can be estimated via remote sensing, carries and produces carcinogenic disinfection by-products and organic pollutants in various aquatic environments. This paper reports the first ecological risk assessment, which was conducted in 2016, of CDOM in the Yinma River watershed including riverine waters, reservoir waters, and urban waters. Referring to the risk formation theory of natural disaster, the entropy evaluation method and DPSIR (driving force-pressure-state-impact-response) framework were coupled to establish a hazard and vulnerability index with multisource data, i.e., meteorological, remote sensing, experimental, and socioeconomic data, of this watershed. This ecological vulnerability assessment indicator system contains 23 indicators with respect to ecological sensitivity, ecological pressure, and self-resilience. The characteristics of CDOM absorption parameters from different waters showed higher aromatic content and molecular weights in May because of increased terrestrial inputs. The assessment results indicated that the overall ecosystem risk in the study area was focused in the extremely, heavily, and moderately vulnerable regions. The ecological risk assessment results objectively reflect the regional ecological environment and demonstrate the potential of ecological risk assessment of pollutants over traditional chemical measurements. Copyright © 2017. Published by Elsevier Inc.

  16. Identification of dissolved organic matter in raw water supply from reservoirs and canals as precursors to trihalomethanes formation. (United States)

    Musikavong, Charongpun; Wattanachira, Suraphong


    The characteristic and quantity of dissolved organic matter (DOM) as trihalomethanes precursors in water from the U-Tapao Basin, Songkhla, Thailand was investigated. The sources of water in the basin consisted of two reservoirs and the U-Tapao canal. The canal receives water discharge from reservoirs, treated and untreated wastewater from agricultural processes, communities and industries. Water downstream of the canal is utilized as a raw water supply. Water samples were collected from two reservoirs, upstream and midstream of the canal, and the raw water supply in the rainy season and summer. The DOM level in the canal water was higher than that of the reservoir water. The highest trihalomethane formation potential (THMFP) was formed in the raw water supply. Fourier-transform infrared peaks of the humic acid were detected in the reservoir and canal waters. Aliphatic hydrocarbon and organic nitrogen were the major chemical classes in the reservoir and canal water characterized by a pyrolysis gas chromatography mass spectrometer. The optimal condition of the poly aluminum chloride (PACl) coagulation was obtained at a dosage of 40 mg/L at pH 7. This condition could reduce the average UV-254 to 57%, DOC to 64%, and THMFP to 42%. In the coagulated water, peaks of O-H groups or H-bonded NH, C˭O of cyclic and acyclic compounds, ketones and quinines, aromatic C˭C, C-O of alcohols, ethers, and carbohydrates, deformation of COOH, and carboxylic acid salts were detected. The aliphatic hydrocarbon, organic nitrogen and aldehydes and ketones were the major chemical classes. These DOM could be considered as the prominent DOM for the water supply plant that utilized PACl as a coagulant.

  17. Reservoir evaluation: key to recovery success

    Energy Technology Data Exchange (ETDEWEB)

    Bachwald, R.W. Jr.; Neinast, G.S.


    Importance of detailed evaluation of the reservoir in determining the right type of secondary recovery technique to be used was reflected at the old Bull Bayou field of Red River Parish, Louisiana, where Sun Oil Co. has a successful waterflood program under way. To assure that an effective injection program is being conducted, it was recognized that a method of investigation, designing, and monitoring the program would be necessary. It was necessary to include such pertinent items as petro-physical properties, fluid saturation, well locations, and fluid injection and fluid withdrawals. This was accomplished by selecting a 2-dimensional mathematical model to track the position of the flood front as a function of time. Using the simulation model, it was possible to determine for any designated location of injectors and producers the progress of the front of the injected water.

  18. Gas reservoir evaluation for underbalanced horizontal drilling

    Directory of Open Access Journals (Sweden)

    Li Gao


    Full Text Available A set of surface equipment for monitoring the parameters of fluid and pressure while drilling was developed, and mathematical models for gas reservoir seepage and wellbore two-phase flow were established. Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling. Based on the monitored gas production along the well depth, the gas reservoir type could be identified.

  19. Gas reservoir evaluation for underbalanced horizontal drilling

    National Research Council Canada - National Science Library

    Li Gao; Meng Ying-Feng; Wei Na; Xu Zhao-Yang; Li Hong-Tao; Xiao Gui-Lin; Zhang Yu-Rui


    .... Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling...

  20. Petrophysical evaluation of reservoir sand bodies in Kwe Field ...

    African Journals Online (AJOL)

    Reservoir sand bodies in Kwe Field, coastal swamp depobelt, onshore eastern Niger Delta Basin were evaluated from a composite log suite comprising gamma ray, resistivity, density and neutron logs of five (5) wells with core photographs of one (1) reservoir of one well. The aim of the study was to evaluate the ...

  1. Formulation and Evaluation of Mouth Dissolving Tablets of Tramadol ...

    African Journals Online (AJOL)

    Purpose: To prepare, and evaluate in vitro and in vivo tramadol hydrochloride mouth dissolving tablets (MDT). Methods: Tramadol HCl MDT were prepared by direct compression using Pharmaburst as coprocessed excipient and compared with a reference product (Rybix ODT, 50 mg). Physicochemical parameters including ...

  2. Stable isotope mass balances versus concentration differences of dissolved inorganic carbon - implications for tracing carbon turnover in reservoirs. (United States)

    Barth, Johannes A C; Mader, Michael; Nenning, Franziska; van Geldern, Robert; Friese, Kurt


    The aim of this study was to identify sources of carbon turnover using stable isotope mass balances. For this purpose, two pre-reservoirs in the Harz Mountains (Germany) were investigated for their dissolved and particulate carbon contents (dissolved inorganic carbon (DIC), dissolved organic carbon, particulate organic carbon) together with their stable carbon isotope ratios. DIC concentration depth profiles from March 2012 had an average of 0.33 mmol L-1. Increases in DIC concentrations later on in the year often corresponded with decreases in its carbon isotope composition (δ13CDIC) with the most negative value of -18.4 ‰ in September. This led to a carbon isotope mass balance with carbon isotope inputs of -28.5 ‰ from DOC and -23.4, -31.8 and -30.7 ‰ from algae, terrestrial and sedimentary matter, respectively. Best matches between calculated and measured DIC gains were achieved when using the isotope composition of algae. This shows that this type of organic material is most likely responsible for carbon additions to the DIC pool when its concentrations and δ13CDIC values correlate negatively. The presented isotope mass balance is transferable to other surface water and groundwater systems for quantification of organic matter turnover.

  3. Evaluating Reservoir Risks and Their Influencing Factors during CO2 Injection into Multilayered Reservoirs

    Directory of Open Access Journals (Sweden)

    Lu Shi


    Full Text Available Wellbore and site safety must be ensured during CO2 injection into multiple reservoirs during carbon capture and storage projects. This study focuses on multireservoir injection and investigates the characteristics of the flow-rate distribution and reservoir-risk evaluation as well as their unique influences on multireservoir injection. The results show that more CO2 enters the upper layers than the lower layers. With the increase in injection pressure, the risks of the upper reservoirs increase more dramatically than those of the low reservoirs, which can cause the critical reservoir (CR to shift. The CO2 injection temperature has a similar effect on the injection flow rate but no effect on the CR’s location. Despite having no effect on the flow-rate distribution, the formation-fracturing pressures in the reservoirs determine which layer becomes the CR. As the thickness or permeability of a layer increases, the inflows exhibit upward and downward trends in this layer and the lower layers, respectively, whereas the inflows of the upper layers remain unchanged; meanwhile, the risks of the lower layer and those of the others decrease and remain constant, respectively. Compared to other parameters, the reservoir porosities have a negligible effect on the reservoir risks and flow-rate distributions.

  4. Geospatial analysis of dissolved nutrients dataset in the surface water of Karayar reservoir, Southern India. (United States)

    Magesh, N S; Chandrasekar, N; Krishnakumar, S


    Spatial dataset representing the nutrient distribution in Karayar reservoir during pre and post-monsoon season is presented. Random sampling method was used for data collection and the sample location were fixed using a handheld global positioning system (Garmin GPSMAP-76). The nutrients were estimated using the standard techniques as described in the American Public Health Association (APHA) manual. Physical parameters were estimated using a Hanna portable multi water quality probe (HI-9828, USA). The spatial distribution of physical and nutrient content in surface water is carried out using an inverse distance weighted technique.

  5. Geospatial analysis of dissolved nutrients dataset in the surface water of Karayar reservoir, Southern India

    Directory of Open Access Journals (Sweden)

    N.S. Magesh


    Full Text Available Spatial dataset representing the nutrient distribution in Karayar reservoir during pre and post-monsoon season is presented. Random sampling method was used for data collection and the sample location were fixed using a handheld global positioning system (Garmin GPSMAP-76. The nutrients were estimated using the standard techniques as described in the American Public Health Association (APHA manual. Physical parameters were estimated using a Hanna portable multi water quality probe (HI-9828, USA. The spatial distribution of physical and nutrient content in surface water is carried out using an inverse distance weighted technique.

  6. Evaluation of stochastic reservoir operation optimization models (United States)

    Celeste, Alcigeimes B.; Billib, Max


    This paper investigates the performance of seven stochastic models used to define optimal reservoir operating policies. The models are based on implicit (ISO) and explicit stochastic optimization (ESO) as well as on the parameterization-simulation-optimization (PSO) approach. The ISO models include multiple regression, two-dimensional surface modeling and a neuro-fuzzy strategy. The ESO model is the well-known and widely used stochastic dynamic programming (SDP) technique. The PSO models comprise a variant of the standard operating policy (SOP), reservoir zoning, and a two-dimensional hedging rule. The models are applied to the operation of a single reservoir damming an intermittent river in northeastern Brazil. The standard operating policy is also included in the comparison and operational results provided by deterministic optimization based on perfect forecasts are used as a benchmark. In general, the ISO and PSO models performed better than SDP and the SOP. In addition, the proposed ISO-based surface modeling procedure and the PSO-based two-dimensional hedging rule showed superior overall performance as compared with the neuro-fuzzy approach.

  7. Pharmacokinetic and pharmacodynamic evaluation of insulin dissolving microneedles in dogs. (United States)

    Fukushima, Keizo; Yamazaki, Takenao; Hasegawa, Ryo; Ito, Yukako; Sugioka, Nobuyuki; Takada, Kanji


    This study tested the hypothesis that dissolving microneedles are a useful transdermal drug delivery system (TDDS) for insulin. Insulin was loaded on a patch (1.0 cm2) that had 100 dissolving microneedles with chondroitin sulfate by microfabrication technology. Pharmacodynamic evaluation was performed by applying two or four patches to the shaved abdominal skin of dogs, and blood samples were collected for 360 min to measure plasma glucose and insulin levels. In diffusion experiment, microneedles containing fluorescein isothiocyanate-insulin and/or Evans blue were administered to the rat skin, and the diffusion rates of tracers were recorded. The mean length, diameter of basement, and drug-loaded space from the top of the microneedles were 492.6 +/- 2.4, 290.0 +/- 3.6, and 316.0 +/- 7.3 microm, respectively. The insulin content was 1.67 +/- 0.17 IU per patch. The time when the minimum plasma glucose level was obtained was 50.0 +/- 8.7 min for two-patch and 82.5 +/- 14.4 min for four-patch studies. A dose-dependent hypoglycemic effect was observed. By comparing the cumulative percentage change in the plasma glucose level between insulin microneedles and solution, the relative physiological availabilities were calculated to be 71.1 +/- 17.8% (for two patches) and 59.3 +/- 4.4% (for four patches). Bioavailabilities of insulin from microneedles were 72.1 +/- 11.6% (for two patches) and 72.4 +/- 8.3% (for four patches). High diffusion rates of fluorescein isothiocyanate-insulin and Evans blue were observed at the administered skin site and correlated well with the high absorption rate of insulin into the systemic circulation. Insulin was stable in dissolving microneedles for 1 month at 4 degrees C; the recovered percentage was 99.2 +/- 13.9%. Dissolving microneedles were demonstrated to be a useful TDDS as an immediate-acting insulin preparation.

  8. Evaluation, prediction, and protection of water quality in Danjiangkou Reservoir, China

    Directory of Open Access Journals (Sweden)

    Xiao-kang Xin


    Full Text Available The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project (SNWDP, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus (TP, permanganate index (CODMn, dissolved oxygen (DO, and five-day biochemical oxygen demand (BOD5, and the concentrations of TP, BOD5, ammonia nitrogen (NH3–N, CODMn, DO, and anionic surfactant (Surfa do not reach the specified standard levels in the tributaries. Seasonal Mann–Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis (CA results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.

  9. In vitro evaluation of domperidone mouth dissolving tablets. (United States)

    Patra, S; Sahoo, R; Panda, R K; Himasankar, K; Barik, B B


    In the present research work mouth dissolving tablets of domperidone were developed with superdisintegrants like crospovidone, croscarmellose sodium and sodium starch glycollate in various concentrations like 3%, 4% and 6% w/w by direct compression method. All formulations were evaluated for physical characteristics of compressed tablets such as weight variation, hardness, friability, content uniformity, in vitro disintegration time, wetting time and in vitro dissolution study. Among all, the formulation F3 (containing 6% w/w concentration of crospovidone) was considered to be the best formulation, having disintegration time of 9 s, wetting time of 15 s and in vitro drug release of 99.22% in 15 min.

  10. Formulation and evaluation of aceclofenac mouth-dissolving tablet

    Directory of Open Access Journals (Sweden)

    Shailendra Singh Solanki


    Full Text Available Aceclofenac has been shown to have potent analgesic and anti-inflammatory activities similar to indomethacin and diclofenac, and due to its preferential Cox-2 blockade, it has a better safety than conventional Non steroidal anti-inflammatory drug (NSAIDs with respect to adverse effect on gastrointestinal and cardiovascular systems. Aceclofenac is superior from other NSAIDs as it has selectivity for Cox-2, a beneficial Cox inhibitor is well tolerated, has better Gastrointestinal (GI tolerability and improved cardiovascular safety when compared with other selective Cox-2 inhibitor. To provide the patient with the most convenient mode of administration, there is need to develop a fast-disintegrating dosage form, particularly one that disintegrates and dissolves/disperses in saliva and can be administered without water, anywhere, any time. Such tablets are also called as "melt in mouth tablet." Direct compression, freeze drying, sublimation, spray drying, tablet molding, disintegrant addition, and use of sugar-based excipients are technologies available for mouth-dissolving tablet. Mouth-dissolving tablets of aceclofenac were prepared with two different techniques, wet granulation and direct compression, in which different formulations were prepared with varying concentration of excipients. These tablets were evaluated for their friability, hardness, wetting time, and disintegration time; the drug release profile was studied in buffer Phosphate buffered Saline (PBS pH 7.4. Direct compression batch C3 gave far better dissolution than the wet granulation Batch F2, which released only 75.37% drug, and C3, which released 89.69% drug in 90 minutes.

  11. Inorganic carbon loading as a primary driver of dissolved carbon dioxide concentrations in the lakes and reservoirs of the contiguous United States (United States)

    McDonald, Cory P.; Stets, Edward; Striegl, Robert G.; Butman, David


    Accurate quantification of CO2 flux across the air-water interface and identification of the mechanisms driving CO2 concentrations in lakes and reservoirs is critical to integrating aquatic systems into large-scale carbon budgets, and to predicting the response of these systems to changes in climate or terrestrial carbon cycling. Large-scale estimates of the role of lakes and reservoirs in the carbon cycle, however, typically must rely on aggregation of spatially and temporally inconsistent data from disparate sources. We performed a spatially comprehensive analysis of CO2 concentration and air-water fluxes in lakes and reservoirs of the contiguous United States using large, consistent data sets, and modeled the relative contribution of inorganic and organic carbon loading to vertical CO2 fluxes. Approximately 70% of lakes and reservoirs are supersaturated with respect to the atmosphere during the summer (June–September). Although there is considerable interregional and intraregional variability, lakes and reservoirs represent a net source of CO2 to the atmosphere of approximately 40 Gg C d–1 during the summer. While in-lake CO2 concentrations correlate with indicators of in-lake net ecosystem productivity, virtually no relationship exists between dissolved organic carbon and pCO2,aq. Modeling suggests that hydrologic dissolved inorganic carbon supports pCO2,aq in most supersaturated systems (to the extent that 12% of supersaturated systems simultaneously exhibit positive net ecosystem productivity), and also supports primary production in most CO2-undersaturated systems. Dissolved inorganic carbon loading appears to be an important determinant of CO2concentrations and fluxes across the air-water interface in the majority of lakes and reservoirs in the contiguous United States.

  12. Formulation and Evaluation of Mouth Dissolving Tablets of Cinnarizine (United States)

    Patel, B. P.; Patel, J. K.; Rajput, G. C.; Thakor, R. S.


    The purpose of this research was to develop mouth dissolve tablets of cinnarizine by effervescent, superdisintegrant addition and sublimation methods. All the three formulations were evaluated for disintegration time, hardness and friability, among these superdisintegrant addition method showed lowest disintegration time; hence it was selected for further studies. Further nine batches (B1-B9) were prepared by using crospovidone, croscarmellose sodium and L-HPC in different concentrations such as 5, 7.5 and 10%. All the formulations were evaluated for weight variation, hardness, friability, drug content, in vitro disintegration time, wetting time, in vitro dissolution. Formulation with 10% L-HPC showed the less disintegration time (25.3 s) and less wetting time (29.1 s). In vitro dissolution studies showed total drug release at the end of 6 min. PMID:21218071

  13. Sustainability evaluation of Mornos Lake/Reservoir, Greece. (United States)

    Rousakis, Grigoris; Panagiotopoulos, Ioannis P; Drakopoulou, Paraskevi; Georgiou, Panos; Nikolopoulos, Dimitrios; Mporompokas, Nikolaos; Kapsimalis, Vasilios; Livanos, Isidoros; Morfis, Ioannis A; Anagnostou, Christos; Koutra, Maria


    The modern climate trend and population growth have dramatically increased the need for maximization of the net benefit from the existing storage space in freshwater reservoirs. However, sedimentation in reservoirs through physical deposition and/or slope failures is a major threat to their productivity and life expectancy. In this context, the sedimentation impact on the sustainability of Mornos Lake/Reservoir, which is exceptionally vital for the ~ 3.1 million inhabitants of Athens, had to be evaluated. Therefore, a meticulous geophysical survey of the reservoir bed was conducted in 2015 for the very first time. Bathymetric, sidescan sonar, and seismic profiling datasets, all integrated with real-time kinematic (RTK) positioning, were analyzed for a realistic evaluation of the storage capacity loss. Approximately 18.2 × 106 m3 of lacustrine sediments derived through physical wedge-type deposition process and ~ 800,000 m3 of material produced by slope failures have covered the bottom since reservoir commissioning in 1981. This configures an average storage capacity loss of ~ 0.07% per year, which, however, is one of the lowest rates worldwide. Moreover, the 108-m-deep reservoir basin can presently accommodate a maximum active water volume of ~ 740 × 106 m3. The siltation pattern and sediment transport pathways in the reservoir are principally controlled by vigorous turbidity underflows, which deliver sediment mainly to the dam area (deposition thickness up to ~ 7 m) as well as to the pumping area (deposition thickness up to ~ 4 m) posing there a future risk; nevertheless, according to the predicted lake bathymetry, this risk will be negligible till 2045.

  14. Evaluation of Frasnian Shale reservoir, case studywell DAK-1, Ahnet ...

    African Journals Online (AJOL)

    The evaluation of unconventional reservoir in term of future exploration plan where the geochemical data are not unavailable making us different results from logging and Gas Data However this paper aim to define Potential zone throught the estimation of total organic carbon(TOC) using Δ log R Method and thermal ...

  15. Reservoir

    Directory of Open Access Journals (Sweden)

    M. Mokhtar


    Full Text Available Scarab field is an analog for the deep marine slope channels in Nile Delta of Egypt. It is one of the Pliocene reservoirs in West delta deep marine concession. Channel-1 and channel-2 are considered as main channels of Scarab field. FMI log is used for facies classification and description of the channel subsequences. Core data analysis is integrated with FMI to confirm the lithologic response and used as well for describing the reservoir with high resolution. A detailed description of four wells penetrated through both channels lead to define channel sequences. Some of these sequences are widely extended within the field under study exhibiting a good correlation between the wells. Other sequences were of local distribution. Lithologic sequences are characterized mainly by fining upward in Vshale logs. The repetition of these sequences reflects the stacking pattern and high heterogeneity of the sandstone reservoir. It also refers to the sea level fluctuation which has a direct influence to the facies change. In terms of integration of the previously described sequences with a high resolution seismic data a depositional model has been established. The model defines different stages of the channel using Scarab-2 well as an ideal analog.

  16. Organic matter turnover in reservoirs of the Harz Mountains (Germany): evidence from 13C/12C changes in dissolved inorganic carbon (United States)

    Barth, Johannes A. C.; Nenning, Franziska; van Geldern, Robert; Mader, Michael; Friese, Kurt


    The Harz Mountains in Germany host several reservoirs for drinking water and electricity supply, the largest of which is the Rappbode System with its two pre-reservoirs. They are the Hassel and the Rappbode pre-reservoirs that have about the same size. These pre-reservoirs were investigated in a comparative study in order to quantify turnover of dissolved organic carbon (DOC) as a representative for organic matter. The objective was to find out how organic matter turnover in these reservoirs may affect dissolved inorganic carbon (DIC) and related CO2 dynamics. Depth profiles of dissolved organic and inorganic carbon (DOC and DIC) were established together with their carbon stable isotope distributions (expressed as δ13CDIC and δ13CDOC). Our results showed up to 104 % increase of DIC contents by organic matter turnover when calculated via isotope mass balances. This contrasted observations of DIC concentration differences between waters collected at the surface and at 12 m depth. These concentration comparisons showed much less DIC increases, and in some cases even decreases, between surface and bottom waters. Such discrepancies could be explained by formation of CO2 at depths below the photic zone that reached calculated values above 7000 ppmV. Such high CO2 concentrations may have reduced the DIC pool by upwards migration. Despite such a concentration decrease, turnover of organic matter has likely incorporated its isotope signal into the DIC pool. While not all DOC present was transposed to DIC, other forms of organic matter from sediments may also have transferred their isotope ratio on the DIC pool. However, with its stable isotope ratio of -28.5 permille the measured DOC was representative of C3 plants and can be assumed as a proxy for other forms of sedimentary carbon including carbon from pore waters and particulate organic matter. Other carbon turnover, including DOC leaching, increased import to the reservoirs after precipitation events and

  17. Evaluation of field development plans using 3-D reservoir modelling

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, D.; Lewis, J.J.M. [Heriot-Watt Univ., Edinburgh (United Kingdom); Newbery, J.D.H. [Conoco, UK Ltd., Aberdeen (United Kingdom)] [and others


    Three-dimensional reservoir modelling has become an accepted tool in reservoir description and is used for various purposes, such as reservoir performance prediction or integration and visualisation of data. In this case study, a small Northern North Sea turbiditic reservoir was to be developed with a line drive strategy utilising a series of horizontal producer and injector pairs, oriented north-south. This development plan was to be evaluated and the expected outcome of the wells was to be assessed and risked. Detailed analyses of core, well log and analogue data has led to the development of two geological {open_quotes}end member{close_quotes} scenarios. Both scenarios have been stochastically modelled using the Sequential Indicator Simulation method. The resulting equiprobable realisations have been subjected to detailed statistical well placement optimisation techniques. Based upon bivariate statistical evaluation of more than 1000 numerical well trajectories for each of the two scenarios, it was found that the wells inclinations and lengths had a great impact on the wells success, whereas the azimuth was found to have only a minor impact. After integration of the above results, the actual well paths were redesigned to meet external drilling constraints, resulting in substantial reductions in drilling time and costs.

  18. Real Time Oil Reservoir Evaluation Using Nanotechnology (United States)

    Li, Jing (Inventor); Meyyappan, Meyya (Inventor)


    A method and system for evaluating status and response of a mineral-producing field (e.g., oil and/or gas) by monitoring selected chemical and physical properties in or adjacent to a wellsite headspace. Nanotechnology sensors and other sensors are provided for one or more underground (fluid) mineral-producing wellsites to determine presence/absence of each of two or more target molecules in the fluid, relative humidity, temperature and/or fluid pressure adjacent to the wellsite and flow direction and flow velocity for the fluid. A nanosensor measures an electrical parameter value and estimates a corresponding environmental parameter value, such as water content or hydrocarbon content. The system is small enough to be located down-hole in each mineral-producing horizon for the wellsite.

  19. Design and evaluation of fast dissolving tablets of clonazepam. (United States)

    Shirsand, S B; Suresh, Sarasija; Swamy, P V; Kumar, D Nagendra; Rampure, M V


    In the present work, fast dissolving tablets of clonazepam were prepared by direct compression method with a view to enhance patient compliance. Three super-disintegrants, viz., crospovidone, croscarmellose sodium and sodium starch glycolate in different ratios with microcrystalline cellulose (Avicel PH-102) along with directly compressible mannitol (Pearlitol SD 200) to enhance mouth feel. The prepared batches of tablets were evaluated for hardness, friability, drug content uniformity, wetting time, water absorption ratio and in vitro dispersion time. Based on in vitro dispersion time (approximately 13 s), three formulations were tested for the in vitro drug release pattern (in pH 6.8 phosphate buffer), short-term stability (at 40°/75% relative humidity for 6 mo) and drug-excipient interaction (IR spectroscopy). Among the three promising formulations, the formulation prepared by using 10% w/w of crospovidone and 35% w/w of microcrystalline cellulose emerged as the overall best formulation (t(50%) 1.8 min) based on the in vitro drug release characteristics compared to conventional commercial tablet formulation (t(50%) 16.4 min). Short-term stability studies on the formulations indicated that there were no significant changes in drug content and in vitro dispersion time (P<0.05).

  20. Evaluation of Gaussian approximations for data assimilation in reservoir models

    KAUST Repository

    Iglesias, Marco A.


    The Bayesian framework is the standard approach for data assimilation in reservoir modeling. This framework involves characterizing the posterior distribution of geological parameters in terms of a given prior distribution and data from the reservoir dynamics, together with a forward model connecting the space of geological parameters to the data space. Since the posterior distribution quantifies the uncertainty in the geologic parameters of the reservoir, the characterization of the posterior is fundamental for the optimal management of reservoirs. Unfortunately, due to the large-scale highly nonlinear properties of standard reservoir models, characterizing the posterior is computationally prohibitive. Instead, more affordable ad hoc techniques, based on Gaussian approximations, are often used for characterizing the posterior distribution. Evaluating the performance of those Gaussian approximations is typically conducted by assessing their ability at reproducing the truth within the confidence interval provided by the ad hoc technique under consideration. This has the disadvantage of mixing up the approximation properties of the history matching algorithm employed with the information content of the particular observations used, making it hard to evaluate the effect of the ad hoc approximations alone. In this paper, we avoid this disadvantage by comparing the ad hoc techniques with a fully resolved state-of-the-art probing of the Bayesian posterior distribution. The ad hoc techniques whose performance we assess are based on (1) linearization around the maximum a posteriori estimate, (2) randomized maximum likelihood, and (3) ensemble Kalman filter-type methods. In order to fully resolve the posterior distribution, we implement a state-of-the art Markov chain Monte Carlo (MCMC) method that scales well with respect to the dimension of the parameter space, enabling us to study realistic forward models, in two space dimensions, at a high level of grid refinement. Our

  1. Absorption and fluorescence properties of chromophoric dissolved organic matter: implications for the monitoring of water quality in a large subtropical reservoir. (United States)

    Liu, Xiaohan; Zhang, Yunlin; Shi, Kun; Zhu, Guangwei; Xu, Hai; Zhu, Mengyuan


    The development of techniques for real-time monitoring of water quality is of great importance for effectively managing inland water resources. In this study, we first analyzed the absorption and fluorescence properties in a large subtropical reservoir and then used a chromophoric dissolved organic matter (CDOM) fluorescence monitoring sensor to predict several water quality parameters including the total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), dissolved organic carbon (DOC), and CDOM fluorescence parallel factor analysis (PARAFAC) components in the reservoir. The CDOM absorption coefficient at 254 nm (a(254)), the humic-like component (C1), and the tryptophan-like component (C3) decreased significantly along a gradient from the northwest to the lake center, northeast, southwest, and southeast region in the reservoir. However, no significant spatial difference was found for the tyrosine-like component (C2), which contributed only four marked peaks. A highly significant linear correlation was found between the a(254) and CDOM concentration measured using the CDOM fluorescence sensor (r(2) = 0.865, n = 76, p water quality parameters and trace the humic-like fluorescence substance in clear aquatic ecosystems with DOC sensor is a useful tool for on-line water quality monitoring if the empirical relationship between the CDOM concentration measured using the CDOM fluorescence sensor and the water quality parameters is calibrated and validated.

  2. Program review: resource evaluation, reservoir confirmation, and exploration technology

    Energy Technology Data Exchange (ETDEWEB)

    Ward, S.H.


    The details of the program review are reported. A summary of the recommendations, means for their implementation, and a six year program of expenditures which would accomplish the objectives of the recommendations are presented. Included in appendices are the following: DOE/DGE consortia participants; program managers contacted for opinion; communications received from program managers; participants, program review panel; and program strategy for resource evaluation and reservoir confirmation. (MHR)


    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James


    We are now entering the final stages of our ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342). We have now developed several techniques to help distinguish economic hydrocarbon deposits from false ''Fizz'' gas signatures. These methods include using the proper in situ rock and fluid properties, evaluating interference effects on data, and doing better constrained inversions for saturations. We are testing these techniques now on seismic data from several locations in the Gulf of Mexico. In addition, we are examining the use of seismic attenuation as indicated by frequency shifts below potential reservoirs. During this quarter we have: Began our evaluation of our latest data set over the Neptune Field; Developed software for computing composite reflection coefficients; Designed and implemented stochastic turbidite reservoir models; Produced software & work flow to improve frequency-dependent AVO analysis; Developed improved AVO analysis for data with low signal-to-noise ratio; and Examined feasibility of detecting fizz gas using frequency attenuation. Our focus on technology transfer continues, both by generating numerous presentations for the upcoming SEG annual meeting, and by beginning our planning for our next DHI minisymposium next spring.

  4. The spatiotemporal distribution of dissolved inorganic and organic carbon in the main stem of the Changjiang (Yangtze) River and the effect of the Three Gorges Reservoir (United States)

    Zhang, Longjun; Xue, Ming; Wang, Min; Cai, Wei-Jun; Wang, Liang; Yu, Zhigang


    The Changjiang River supplies huge amounts of fresh water and dissolved and particulate substances to the East China Sea, thereby exerting a great influence on the coastal ecosystem. Meanwhile, the construction of the Three Gorges Reservoir (TGR) has reallocated the annual discharge, likely affecting the transportation of carbon in its various forms. The transport and transformation of carbon in Changjiang River and the effect of the TGR were discussed based on three field campaigns, a 1 year time series investigation, and historical data. Our results indicated the following: (1) Dissolved inorganic carbon (DIC) was derived from the upper stream and was significantly diluted downstream by the low-DIC waters from two large lakes. Dissolved organic carbon (DOC) was a product of anthropogenic input and showed no clear relationship with discharge. particulate organic carbon (POC) within total suspended matter (POC%) was below the global average. (2) The TGR has not measurably affected the transport of DOC downstream of the reservoir dam. However, downstream grain size has decreased and autochthonous processes have increased, resulting in a sharp increase in POC% since reservoir construction. (3) For the period 1997-2010, estimated annual DIC flux was 16.9 Tg yr-1. The regulation of river flow by the TGR has decreased the river DIC flux to the East China Sea in the autumn and increased it in the spring. Furthermore, the South-North Water Diversion will reduce the high-DIC water from the upper reach, thus affecting the biogeochemistry of the Changjiang estuary and the ecosystem of the nearby coastal ocean.

  5. Partitioning of chromium (VI) and chromium (III) between dissolved and colloidal forms in a stream and reservoir contaminated with tannery waste water (United States)

    Dominik, J.; Bas, B.; Bobrowski, A.; Dworak, T.; Koukal, B.; Niewiara, E.; Pereira de Abreu, M.-H.; Rossé, P.; Szalinska, E.; Vignati, D.


    Environmental fate of chromium rejected from tannery wastewater to the Dunajec River (southern Poland) was investigated using separation with tangential flow filtration followed by measurements with Cathodic Adsorptive Stripping Voltammetry (CAdSV) and ICP-MS. Virtually all Cr(VI) was found in the dissolved fraction (<1 kDa). Thus form was present at low concentrations. Cr(III) was rapidly transferred from dissolved and low molecular weight colloidal fractions to particles and high molecular weight colloids and thus scavenged from the water column of the Czorsztyn Reservoir to the sediments. The possibility of Cr remobilization via oxidation of Cr(III) in the presence of freshly precipitated Mn-oxides in water or at the water-sediment interface needs further investigation.

  6. Eutrophication trends inferred from hypolimnetic dissolved-oxygen dynamics within selected White River reservoirs, northern Arkansas-southern Missouri, 1974-94 (United States)

    Green, W.R.


    The White River Basin in northern Arkansas and southern Missouri contains four major reservoirs. Beaver, Table Rock, and Bull Shoals Lakes form a chain of reservoirs on the main stem of the White River. Norfork Lake is on the North Fork River, a tributary of the White River. Vertical water- column profiles of temperature and dissolved- oxygen concentrations have been collected monthly, in general, at sites near the dam of each reservoir since 1974. Hypolimnetic dissolved- oxygen dynamics of these reservoirs from 1974 through 1994 were examined based on the near-dam data and used to infer temporal changes in eutrophication. Regression models indicated that a positive relation existed between discharge through the dam during the stratification season and the areal hypolimnetic deficit. Temporal changes in the relative areal hypolimnetic oxygen deficit, a model that adjusts the areal hypolimnetic oxygen deficit to standard temperature and depth, showed a decreasing trend in Beaver Lake from 1974 through 1994, indicating that the level of eutrophication decreased. Little or no change in the relative areal hypolimnetic oxygen deficit occurred in Table Rock, Bull Shoals, or Norfork Lakes over the period of record. Temporal analysis of the residuals from the oxygen deficit-discharge model indicated that the oxygen deficit-discharge function changed over time in Beaver and Table Rock Lakes. There was little or no temporal trend in residuals of areal hypolimnetic oxygen deficit over the period of record for Bull Shoals and Norfork Lakes. Multiple regression using a time variable and discharge through the dam during the stratification season was examined for the four reservoirs. The slope coefficient of the time variable for both Beaver and Table Rock Lakes was negative, indicating that the temporal function driving the discharge related areal hypolimnetic oxygen deficit decreased over the period of record. This temporal function may be an expression of biological

  7. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle


    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

  8. Effect of a dam on the optical properties of different-sized fractions of dissolved organic matter in a mid-subtropical drinking water source reservoir. (United States)

    Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong


    The presence of a dam on a river is believed to have a key role in affecting changes in the components of the chromophoric dissolved organic matter (CDOM) in reservoirs. However, questions remain about the mechanisms that control these changes. In this study, we used tangential ultrafiltration, fluorescence spectrum and phytoplankton cell density detection to explore the impacts of a dam on the CDOM components in the Shanzai Reservoir, a source of drinking water. The results demonstrated each CDOM size fraction comprised two main components, namely C1 (protein-like substance) and C2 (humic-like substance). The C1 content had a higher value in areas with slow flow than in the normal river channel, while the C2 contents were generally stable in the flow direction. The topography of the reservoir site affected the structure of the CDOM components based on changes in the hydraulic conditions caused by the dam. The variations in the CDOM components, hydraulic parameters and fluorescence indices in the river flow direction indicated that the contribution of the phytoplankton to the CDOM content increased as the distance to the dam decreased, phytoplankton metabolism enhanced C1 content of the 1-10kDa molecular weights range fraction. Further, the contributions of different phytoplankton biomass to C1 proved that the dam changed the hydraulic conditions, had secondary effects on the metabolism of the phytoplankton, and resulted in changes in the structure of the CDOM components. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Analysing the correlations of long-term seasonal water quality parameters, suspended solids and total dissolved solids in a shallow reservoir with meteorological factors. (United States)

    Zhang, Chen; Zhang, Wenna; Huang, Yixuan; Gao, Xueping


    To explore the correlations among water quality parameters, suspended solids (SS) and total dissolved solids (TDS) with meteorological factors in a shallow reservoir in China, the long-term variations of water quality were considered. A non-parametric regression method, generalized additive models (GAM), was used to analyse the correlations among eleven physicochemical and biological parameters as well as three meteorological factors (wind speed, rainfall and solar radiation) which we collected from 2000 to 2011. The results indicate that the three meteorological factors may have positive effects on SS. Moreover, statistically significant correlations between many water quality parameters and SS or TDS were exhibited seasonally. The correlations between electrical conductivity (EC) and SS were opposite to correlations between EC and TDS. This finding reveals that TDS have a positive impact on EC, while EC negatively affects SS. The results indicated that many parameters, such as total nitrogen, total phosphorus, biological oxygen demand (BOD) and chemical oxygen demand (COD), were related to SS due to the adsorption of SS. Moreover, both positive and negative correlations between COD and TDS were observed in this freshwater reservoir. The positive correlation between chlorophyll a and SS suggested that the change of SS concentration in autumn was caused by the growth of algae. Meanwhile, significant correlations between SS and meteorological factors were also observed, indicating that meteorological factors had effects on SS dynamics. This study provides useful information regarding the correlations among water quality parameters, SS and TDS with meteorological factors in a freshwater reservoir.


    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James


    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  11. Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James


    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  12. Petrophysical Evaluation of Reservoir Sand Bodies in Kwe Field ...

    African Journals Online (AJOL)


    the field on the basis of their petrophysical properties and architecture. Reservoir A has an average NTG (61.4 %), Ø (27.50 %), K .... mottled with dark organic material. On the gamma-ray log (Fig. 3), this section shows a ... Reservoir Architecture and Depositional Model of. Reservoir 'C' in Kwe Field. As shown on Figure 6, ...

  13. Reservoir site evaluation through routing | Ogunlela | Journal of ...

    African Journals Online (AJOL)

    ... m3/s, and a relative attenuation of 41.10%. Also; the reservoir would not be overtopped since the 99.54 m water elevation for the 25-yr, 24-hr storm was below the reservoir embankment top elevation. Keywords:Reservoir routing. Journal of Modeling, Design and Management of Engineering Systems Vol. 3 (1) 2005: pp.

  14. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James


    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), our efforts have become focused on technology transfer. To this end, we completing our theoretical developments, generating recommended processing flows, and perfecting our rock and fluid properties interpretation techniques. Some minor additional data analysis and modeling will complete our case studies. During this quarter we have: Presented findings for the year at the DHI/FLUIDS meeting at UH in Houston; Presented and published eight papers to promote technology transfer; Shown how Rock and fluid properties are systematic and can be predicted; Shown Correct values must be used to properly calibrate deep-water seismic data; Quantified and examined the influence of deep water geometries in outcrop; Compared and evaluated hydrocarbon indicators for fluid sensitivity; Identified and documented inappropriate processing procedures; Developed inversion techniques to better distinguish hydrocarbons; Developed new processing work flows for frequency-dependent anomalies; and Evaluated and applied the effects of attenuation as an indicator. We have demonstrated that with careful calibration, direct hydrocarbon indicators can better distinguish between uneconomic ''Fizz'' gas and economic hydrocarbon reservoirs. Some of this progress comes from better characterization of fluid and rock properties. Other aspects include alternative techniques to invert surface seismic data for fluid types and saturations. We have also developed improved work flows for accurately measuring frequency dependent changes in seismic data that are predicted by seismic models, procedures that will help to more reliably identify anomalies associated with hydrocarbons. We have been prolific in publishing expanded abstracts and presenting results, particularly at the SEG. This year, we had eight such

  15. Reservoirs and human well being: new challenges for evaluating impacts and benefits in the neotropics

    Directory of Open Access Journals (Sweden)

    JG. Tundisi

    Full Text Available As in many other continents, neotropical ecosystems are impacted by the construction of reservoirs. These artificial ecosystems change considerably the natural terrestrial and aquatic ecosystems and their biodiversity. The multiple uses of reservoirs promote benefits for the human beings in terms of economic development, income, jobs and employment. Services of reservoirs are important assets for the regional ecosystem. Evaluation of ecosystem services produced by artificial reservoirs, are new challenges to the understanding of the cost/benefit relationships of reservoir construction in the neotropics. Regulating and other services promoted by reservoirs lead to new trends for "green technology" and the implementation of ecohydrological and ecotechnological developments. This approach can be utilized with better success as a substitute for the usual impact/benefit evaluation of the reservoirs. Better and diversified services can be achieved with "green technology" applied to the construction.

  16. Sources and sinks of sulphate dissolved in lake water of a dam reservoir: S and O isotopic approach

    Energy Technology Data Exchange (ETDEWEB)

    Lewicka-Szczebak, Dominika, E-mail: [Laboratory of Isotope Geology and Geoecology, Department of Applied Geology and Geochemistry, Institute of Geological Sciences, University of Wroclaw, ul. Cybulskiego 30, 50-205 Wroclaw (Poland); Trojanowska, Adriana; Drzewicki, Wojciech; Gorka, Maciej; Jedrysek, Mariusz-Orion; Jezierski, Piotr; Kurasiewicz, Marta; Krajniak, Janusz [Laboratory of Isotope Geology and Geoecology, Department of Applied Geology and Geochemistry, Institute of Geological Sciences, University of Wroclaw, ul. Cybulskiego 30, 50-205 Wroclaw (Poland)


    Understanding the cycling of biophilic elements is crucial for successful management of water quality in lowland dam reservoirs. This study aimed to determine the sources and sinks of SO{sub 4}{sup 2-} in lakewater using S and O stable isotope analysis. Water samples were collected from 5 sampling points along the Sulejow Reservoir (central Poland) on 5 separate sampling campaigns (spring 2005, summer 2005, winter 2006, spring 2006 and summer 2006) applying a diel sampling strategy. Pronounced spatial, seasonal and diurnal variations were found in SO{sub 4}{sup 2-} concentration (from 10.3 to 36.2 mg L{sup -1}) and in their S ({delta}{sup 34}S from 2.1 per mille to 5.4 per mille ) and O isotopic composition ({delta}{sup 18}O from 2.8 per mille to 10.6 per mille ). Sulphate isotopic signature has been applied to define the fluxes of SO{sub 4}{sup 2-} by means of the isotopic mass balance and thus identify 'missing' fluxes. A significant seasonal input of SO{sub 4}{sup 2-} from the direct catchment was found during the spring, whereas this input appeared to be fairly negligible in summer. Moreover, an additional SO{sub 4}{sup 2-} flux from mobilisation of reduced S compounds stored in the sediments was identified, especially during periods of elongated water retention time. Pronounced diurnal variation was observed for {delta}{sup 18}O(SO{sub 4}{sup 2-}) (up to 4 per mille ) in all seasons except winter, which is probably caused by dynamic biochemical red-ox reactions and intensive mixing processes of SO{sub 4}{sup 2-} originating from different sources.

  17. Experimental evaluation on the damages of different drilling modes to tight sandstone reservoirs

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    Gao Li


    Full Text Available The damages of different drilling modes to reservoirs are different in types and degrees. In this paper, the geologic characteristics and types of such damages were analyzed. Then, based on the relationship between reservoir pressure and bottom hole flowing pressure corresponding to different drilling modes, the experimental procedures on reservoir damages in three drilling modes (e.g. gas drilling, liquid-based underbalanced drilling and overbalanced drilling were designed. Finally, damage simulation experiments were conducted on the tight sandstone reservoir cores of the Jurassic Ahe Fm in the Tarim Basin and Triassic Xujiahe Fm in the central Sichuan Basin. It is shown that the underbalanced drilling is beneficial to reservoir protection because of its less damage on reservoir permeability, but it is, to some extent, sensitive to the stress and the empirical formula of stress sensitivity coefficient is obtained; and that the overbalanced drilling has more reservoir damages due to the invasion of solid and liquid phases. After the water saturation of cores rises to the irreducible water saturation, the decline of gas logging permeability speeds up and the damage degree of water lock increases. It is concluded that the laboratory experiment results of reservoir damage are accordant with the reservoir damage characteristics in actual drilling conditions. Therefore, this method reflects accurately the reservoir damage characteristics and can be used as a new experimental evaluation method on reservoir damage in different drilling modes.

  18. Research on Fluorescence Spectroscopy Characteristics of Dissolved Organic Matter of Landfill Leachate in the Rear Part of Three Gorges Reservoir

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    Zhigang Xie


    Full Text Available Three-dimensional fluorescence and infrared spectroscopy analysis of the leachate dissolved organic matter (DOM of the Three Gorges was reported in spring, summer, and autumn seasons, respectively. Studies show that, that organic matter of landfill leachate in Yongchuan, Dazu and Jiangjin is the class of fulvic-like acid and protein-like fluorescence. The study also found that the longer the time of the pile of garbage, the lower the content of class of protein-like concentration, and the higher the concentration of fulvic-like acid, indicating that the protein waste material in the humification process is easy degradation. However, the same source of DOM is similar in the functional group composition and molecular structure. Characteristic frequency area analysis showed that humic acids (HA, and fulvic acids (FA contain more than hydrophilic organic matter (HyI aromatic ring structure, and FA aromatic ring structure is the most. Because of Chung-amide NH deformation vibration, there are strong absorption peaks in the 1562~1572 cm−1 for various components; HyI contains many organic nitrogen compounds and fatty acids.


    Energy Technology Data Exchange (ETDEWEB)

    M. Batzle; D-h Han; R. Gibson; O. Djordjevic


    The ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' (Grant/Cooperative Agreement DE-FC26-02NT15342) began September 1, 2002. During this second quarter: A Direct Hydrocarbon Indicator (DHI) symposium was held at UH; Current DHI methods were presented and forecasts made on future techniques; Dr. Han moved his laboratory from HARC to the University of Houston; Subcontracts were re-initiated with UH and TAMU; Theoretical and numerical modeling work began at TAMU; Geophysical Development Corp. agreed to provide petrophysical data; Negotiations were begun with Veritas GDC to obtain limited seismic data; Software licensing and training schedules were arranged with Paradigm; and Data selection and acquisition continues. The broad industry symposium on Direct Hydrocarbon Indicators was held at the University of Houston as part of this project. This meeting was well attended and well received. A large amount of information was presented, not only on application of the current state of the art, but also on expected future trends. Although acquisition of appropriate seismic data was expected to be a significant problem, progress has been made. A 3-D seismic data set from the shelf has been installed at Texas A&M University and analysis begun. Veritas GDC has expressed a willingness to provide data in the deep Gulf of Mexico. Data may also be available from TGS.


    Directory of Open Access Journals (Sweden)

    Ewa Jachniak


    Full Text Available In this publication the trophy level of Wapienica dam reservoir, based on the composition species of planktonic algae and their biomass, and concentrations of chlorophyll a, was defined. The research was conducted during the vegetative season in 2013 year; the samples were taken from two research points (W1 – the part of river Wapienica inflow to reservoir and W2 – the part of the reservoir dam by using bathometer. The whole biomass of planktonic algae and concentration of chlorophyll a from two research areas were low and it allowed to classify water of this reservoir to oligo-/ mesotrophic. Only in the part of the reservoir dam, in summer season, an increased trophy level was observed (Heinonen 1980. A similar trophic character (oligo-/ mesotrophic of the water reservoir was also indicated by algae species: Achnanthes lanceolata (Bréb. Grun. in Cl. and Grun., Chrysoccoccus minutus (Fritsch Nygaard. For a temporary increase of the trophy level, the diatom Nitzschia acicularis (Kütz. W. Sm. could indicate, because it is a typical species in poorly eutrophic water. The green algae (Pediastrum and Coelastrum, which were observed in summer season could also indicate for a rise of the trophic state, because they are typical for eutrophic water.

  1. [Ultraviolet-visible (UV-Vis) and fluorescence spectral characteristics of soil dissolved organic matter (DOM) in typical agricultural watershed of Three Gorges Reservoir Region]. (United States)

    Wang, Qi-Lei; Jiang, Tao; Zhao, Zheng; Mu, Zhi-Jian; Wei, Shi-Qiang; Yan, Jin-Long; Liang, Jian


    As an important geo-factor to decide the environmental fate of pollutants in watershed, soil dissolved organic matter (DOM) sampled from a typical agricultural watershed in the Three Gorges Reservoir area was investigated using ultraviolet-visible (UV-Vis) and fluorescence spectroscopies, to analyze and discuss the effect of different land uses including forest, cropland, vegetable field and residence, on soil DOM geochemical characteristics. The results showed that significant differences in DOM samples amongst different land uses were observed, and DOM from forest had the highest aromaticity and humification degree, followed by DOM from cropland. Although DOM from vegetable field and residence showed the highest dissolved organic carbon (DOC) concentration (average values 0.81 g x kg(-1) and 0.89 g x kg(-1), respectively), but the aromaticity was lower indicating lower humification, which further suggested that the non-chromophoric component in these DOM samples contributed significantly to total DOM compositions. Additionally, in all DOM samples that were independent of land uses, fluorescence index (FI) values were between 1.4 (terrigenous) and 1.9 (authigenic) , evidently indicating both the allochthonous and autochthonous sources contributed to DOM characteristics. Meanwhile, r(T/C) values in most of samples were higher than 2.0, suggesting that soil DOM in this agricultural watershed was heavily affected by anthropogenic activities such as agricultural cultivation, especially, vegetable field was a good example. Additionally, sensitivities of different special spectral parameters for reflecting the differences of DOM characteristics amongst different land uses were not identical. For example, neither spectral slope ratio (S(R)) nor humification index (HIX) could clearly unveil the various geochemical characteristics of soil DOM from different sources. Thus, simple and single special spectral parameter cannot comprehensively provide the detailed information

  2. Dissolved oxygen stratification and response to thermal structure and long-term climate change in a large and deep subtropical reservoir (Lake Qiandaohu, China). (United States)

    Zhang, Yunlin; Wu, Zhixu; Liu, Mingliang; He, Jianbo; Shi, Kun; Zhou, Yongqiang; Wang, Mingzhu; Liu, Xiaohan


    From January 2010 to March 2014, detailed depth profiles of water temperature, dissolved oxygen (DO), and chromophoric dissolved organic matter (CDOM) were collected at three sites in Lake Qiandaohu, a large, deep subtropical reservoir in China. Additionally, we assessed the changes in DO stratification over the past 61 years (1953-2013) based on our empirical models and long-term air temperature and transparency data. The DO concentration never fell below 2 mg/L, the critical value for anoxia, and the DO depth profiles were closely linked to the water temperature depth profiles. In the stable stratification period in summer and autumn, the significant increase in CDOM in the metalimnion explained the decrease in DO due to the oxygen consumed by CDOM. Well-developed oxygen stratification was detected at the three sites in spring, summer and autumn and was associated with thermal stratification. Oxycline depth was significantly negatively correlated with daily air temperature and thermocline thickness but significantly positively correlated with thermocline depth during the stratification weakness period (July-February). However, there were no significant correlations among these parameters during the stratification formation period (March-June). The increase of 1.67 °C in yearly average daily air temperature between 1980 and 2013 and the decrease of 0.78 m in Secchi disk depth caused a decrease of 1.65 m and 2.78 m in oxycline depth, respectively, facilitating oxygen stratification and decreasing water quality. Therefore, climate warming has had a substantial effect on water quality through changing the DO regime in Lake Qiandaohu. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Migration depths of juvenile Chinook salmon and steelhead relative to total dissolved gas supersaturation in a Columbia River reservoir (United States)

    Beeman, J.W.; Maule, A.G.


    The in situ depths of juvenile salmonids Oncorhynchus spp. were studied to determine whether hydrostatic compensation was sufficient to protect them from gas bubble disease (GBD) during exposure to total dissolved gas (TDG) supersaturation from a regional program of spill at dams meant to improve salmonid passage survival. Yearling Chinook salmon O. tshawytscha and juvenile steelhead O. mykiss implanted with pressure-sensing radio transmitters were monitored from boats while they were migrating between the tailrace of Ice Harbor Dam on the Snake River and the forebay of McNary Dam on the Columbia River during 1997-1999. The TDG generally decreased with distance from the tailrace of the dam and was within levels known to cause GBD signs and mortality in laboratory bioassays. Results of repeated-measures analysis of variance indicated that the mean depths of juvenile steelhead were similar throughout the study area, ranging from 2.0 m in the Snake River to 2.3 m near the McNary Dam forebay. The mean depths of yearling Chinook salmon generally increased with distance from Ice Harbor Dam, ranging from 1.5 m in the Snake River to 3.2 m near the forebay. Juvenile steelhead were deeper at night than during the day, and yearling Chinook salmon were deeper during the day than at night. The TDG level was a significant covariate in models of the migration depth and rates of each species, but no effect of fish size was detected. Hydrostatic compensation, along with short exposure times in the area of greatest TDG, reduced the effects of TDG exposure below those generally shown to elicit GBD signs or mortality. Based on these factors, our results indicate that the TDG limits of the regional spill program were safe for these juvenile salmonids.

  4. Evaluation of reservoir properties using petrophysical and petrographical data of Ghar and Asmari reservoirs in north-west of Persian Gulf (United States)

    Naghavi Azad, Maral; Sabouhi, Mostafa; Jahani, Davood; Arbab, Bita


    Now a days, the evaluation of reservoir rocks has special importance in oil Industry. The ability of petrophysics and petrography methods as complement of each others in finding reservoir zones and studies of them in petroleum geology have the specific importance. In this study, reservoir properties such as porosity, water saturation, volume of shale and lithology has been evaluated using log data and combining of this information with petrography studies and microfacieses in thin sections attempted to evaluating Asmari Formations in Ahwaz sandstone member (Ghar) and the carbonate Asmari aspect of Development of reservoir properties. Based on petrophysical properties variations comparing and combining with thinsection from the cores and Lithology, five petrophysical zones for Ghar reservoir and six petrophysical zones in the Asmari reservoir described. The result of this studies show that based on petrophysical properties distribution the central area of field is the best area for drilling the developmental wells.

  5. Modeling Tools for Drilling, Reservoir Navigation, and Formation Evaluation

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    Sushant Dutta


    Full Text Available The oil and gas industry routinely uses borehole tools for measuring or logging rock and fluid properties of geologic formations to locate hydrocarbons and maximize their production. Pore fluids in formations of interest are usually hydrocarbons or water. Resistivity logging is based on the fact that oil and gas have a substantially higher resistivity than water. The first resistivity log was acquired in 1927, and resistivity logging is still the foremost measurement used for drilling and evaluation. However, the acquisition and interpretation of resistivity logging data has grown in complexity over the years. Resistivity logging tools operate in a wide range of frequencies (from DC to GHz and encounter extremely high (several orders of magnitude conductivity contrast between the metal mandrel of the tool and the geologic formation. Typical challenges include arbitrary angles of tool inclination, full tensor electric and magnetic field measurements, and interpretation of complicated anisotropic formation properties. These challenges combine to form some of the most intractable computational electromagnetic problems in the world. Reliable, fast, and convenient numerical modeling of logging tool responses is critical for tool design, sensor optimization, virtual prototyping, and log data inversion. This spectrum of applications necessitates both depth and breadth of modeling software—from blazing fast one-dimensional (1-D modeling codes to advanced threedimensional (3-D modeling software, and from in-house developed codes to commercial modeling packages. In this paper, with the help of several examples, we demonstrate our approach for using different modeling software to address different drilling and evaluation applications. In one example, fast 1-D modeling provides proactive geosteering information from a deep-reading azimuthal propagation resistivity measurement. In the second example, a 3-D model with multiple vertical resistive fractures

  6. Rising trends of dissolved organic matter in drinking-water reservoirs as a result of recovery from acidification in the Ore Mts., Czech Republic. (United States)

    Oulehle, Filip; Hruska, Jakub


    The concentration of chemical oxygen demand (COD), a common proxy for dissolved organic matter (DOM), was measured at seven drinking-water reservoirs and four streams between 1969 and 2006. Nine of them showed significant DOM increases (median COD change +0.08 mg L(-1) yr(-1)). Several potential drivers of these trends were considered, including air temperature, rainfall, land-use and water sulfate concentration. Temperature and precipitation influenced inter-annual variations, but not long-term trends. The long-term DOM increase was significantly associated with declines of acidic deposition, especially sulfur deposition. Surface water sulfate concentrations decreased from a median of 62 mg L(-1)-27 mg L(-1) since 1980. The magnitude of DOM increase was positively correlated with average DOM concentration (R(2) = 0.79, p < 0.001). Simultaneously, DOM concentration was positively correlated with the proportion of Histosols within the catchments (R(2) = 0.79, p < 0.001). A focus on the direct removal of DOM by water treatment procedures rather than catchment remediation is needed.

  7. Evaluating the fisheries potential of solar salt works reservoirs at ...

    African Journals Online (AJOL)

    Artisanal fisheries are important livelihoods for coastal communities in many developing countries, where uncontrolled fishing can easily lead to depleted stocks in nearshore waters. Man-made reservoirs associated with solar salt works along the coast of Ungwana Bay provide alternative fishing grounds for local fishers ...

  8. Evaluating the fisheries potential of solar salt works reservoirs at ...

    African Journals Online (AJOL)

    Prawn seine nets were the dominant fishing gear used in the three reservoirs, augmented by traps at Kurawa. A total weight of 4.02 tonnes consisting of 49 finfish and 9 crustacean species was sampled. Metapeneaus monoceros was the most abundant species at Gongoni and Marereni, and Oreochromis mossambicus ...


    This investigation evaluated the occurrence of Cryptosporidium oocysts and Giardia cysts at 17 sampling locations in Lake Texoma reservoir using method 1623 with standard Envirocheck™ capsule filters. The watershed serves rural agricultural communities active in cattle ranching, ...

  10. Petrophysical evaluation of low-resistivity sandstone reservoirs with nuclear magnetic resonance log

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, G.M.; Al-Blehed, M.S.; Al-Awad, M.N.; Al-Saddique, M.A. [Petroleum Engineering Department, College of Engineering, King Saud University, P.O. Box 800, 11421 Riyadh (Saudi Arabia)


    The combination of conventional logs, such as density, neutron and resistivity logs, is proven to be very effective in the evaluation of normal reservoirs. For low-resistivity reservoirs, however, an accurate determination of the petrophysical parameters with the conventional log reservoirs is very difficult. This paper presents two cases of low-resistivity reservoirs and low-contrast resistivity reservoirs, where conventional logs fail to determine the petrophysical properties of reservoirs, mainly, low-resistivity and low-contrast resistivity reservoirs. The problems of these reservoirs are that conventional logging interpretation shows high water saturation zones, but water-free hydrocarbon would be produced. In the case of low-resistivity contrast reservoirs, it is very hard to determine water hydrocarbon contact with resistivity logs. Nuclear magnetic resonance (NMR) has only been available as a supplementary tool to provide additional information on the producibility of the reservoir. The main limitations of NMR have been the cost and time of acquiring data. This paper shows that in the case of low-resistivity reservoirs, NMR is a very cost-effective tool and is of help in accurately determining the reservoir rock petrophysical properties. In the analysis of NMR data, several aspects of NMR technique have been used: (1) T1/T2 ratio for fluid identification, (2) the difference between NMR-derived porosity and total porosity to determine the types of clay minerals, (3) NMR relaxation properties to identify fluids composition and rock properties. This paper presents four examples of low-resistivity reservoirs. Analysis of the NMR data of low-resistivity reservoirs has helped identify the producibility of these zones, determine lithology-independent porosity and distinguish between bound and free water. For the case of low-contrast resistivity reservoir, where there was little resistivity contrast between water-bearing formation and oil-bearing formation, NMR has

  11. Evaluation on the effectiveness of natural fractures in Changxing Fm reef-flat facies reservoirs, Yuanba area, Sichuan Basin

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    Xiangyuan Zhao


    Full Text Available Study on the effectiveness of fractures is of great significance for understanding reservoir types and properties, identifying reservoir seepage mechanisms and delineating the reasonable development technologies and policies. In this paper, the Changxing reef-flat facies reservoirs in the Yuanba area, Sichuan Basin, was taken as an example. After the characteristics of natural fractures were evaluated, the effectiveness of different types of fractures was investigated by using core, thin section, imaging logging and production performance data. Then, the main geological factors that influence fracture effectiveness were analyzed, and the development significance of effective fractures was illustrated. The following results are obtained. (1 Structural fractures and diagenetic fractures are mainly developed in Changxing Fm carbonate reservoirs in Yuanba area. Structural fractures include shear fractures and extensional fractures, and diagenetic fractures include dissolution fractures, structural-dissolution fractures and pressure-solution fractures. (2 High-angle structural fractures are the most effective, followed by horizontal fractures and then oblique fractures, and pressure-solution fractures are the least effective. (3 Among structural fractures, those of NW–SE and nearly E–W oriented are more effective than those of the NE–SW oriented. (4 The earlier the fractures are formed, the more likely they are to be filled with calcite or dolomite and become invalid. (5 The fractures which are formed before or during the oil and gas charging tend to be filled with organic matters and become invalid. The late fractures which are formed after oil and gas charging are mostly effective and their contribution to the reservoir is the greatest. (6 The fractures nearly parallel to the maximum principal stress direction of current ground stress present good effectiveness with large opening. It is concluded that the opening and filling features of

  12. Design and Evaluation of Cefixime Fast Dissolving Tablets Using Super Disintegrating Agents

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    V L Narasaiah


    Full Text Available The aim of the present investigation was to formulate fast dissolving tablets of Cefixime by wet granulation using super disintegrants such as crospovidone, croscarmellose sodium, and sodium starch glycolate. The prepared tablets were evaluated for post compressional parameters like hardness, friability, weight variation, in-vitro disintegration time, in-vitro dispersion time, wetting time, in-vitro drug release studies. The drug-excipient interaction was studied by Fourier transform infrared spectroscopy (FTIR studies. No chemical interaction between drug and excipients was confirmed by FTIR studies. Amongst all formulations, formulation F12 prepared by 24 mg of crospovidone showed less disintegrating time of 18.4 sec and faster dissolution. Enhancement of oral Bioavailability of cefixime can be increased by formulating it as a Fast Dissolving Tablet using crospovidone as super disintegrating agent.

  13. On the evaluation of steam assisted gravity drainage in naturally fractured oil reservoirs

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    Seyed Morteza Tohidi Hosseini


    Full Text Available Steam Assisted Gravity Drainage (SAGD as a successful enhanced oil recovery (EOR process has been applied to extract heavy and extra heavy oils. Huge amount of global heavy oil resources exists in carbonate reservoirs which are mostly naturally fractured reservoirs. Unlike clastic reservoirs, few studies were carried out to determine the performance of SAGD in carbonate reservoirs. Even though SAGD is a highly promising technique, several uncertainties and unanswered questions still exist and they should be clarified for expansion of SAGD methods to world wide applications especially in naturally fractured reservoirs. In this communication, the effects of some operational and reservoir parameters on SAGD processes were investigated in a naturally fractured reservoir with oil wet rock using CMG-STARS thermal simulator. The purpose of this study was to investigate the role of fracture properties including fracture orientation, fracture spacing and fracture permeability on the SAGD performance in naturally fractured reservoirs. Moreover, one operational parameter was also studied; one new well configuration, staggered well pair was evaluated. Results indicated that fracture orientation influences steam expansion and oil production from the horizontal well pairs. It was also found that horizontal fractures have unfavorable effects on oil production, while vertical fractures increase the production rate for the horizontal well. Moreover, an increase in fracture spacing results in more oil production, because in higher fracture spacing model, steam will have more time to diffuse into matrices and heat up the entire reservoir. Furthermore, an increase in fracture permeability results in process enhancement and ultimate recovery improvement. Besides, diagonal change in the location of injection wells (staggered model increases the recovery efficiency in long-term production plan.

  14. Development and in vitro evaluation of fast-dissolving oral films of ondansetron hydrochloride

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    Shohreh Alipour


    Full Text Available Ondansetron hydrochloride, a selective 5-HT3 receptor blocker, is an effective antiemetic drug with oral bioavailability of 60% and half-life of 4-5 hours. The present study was carried out to prepare fast dissolving films of ondansetron hydrochloride to increase patient compliance and improve efficacy of this drug. Films were prepared by solvent casting method, using poly vinyl alcohol, poly vinyl pyrrolidone and konjac glucomannan as film formers and PEG400 as plasticizer. Natural and synthetic sweeteners were used for masking bitterness of the drug. Satisfactory results were obtained from evaluation of physical characteristics of fast dissolving films of ondansetron hydrochloride including: thickness (0.37-0.39 mm, surface pH (6.77, folding endurance (up to 300 times and tensile strength (35.75-50.93 g/cm². Films were also subjected to an in vitro dissolution and release studies. In vitro drug release studies indicated 93-95% release in 5 min. Fast dissolving films of ondansetron could be a potential alternative for the currently marketed oral formulation, parenteral form and suppository with better patient compliance and higher bioavailability for the rapid control of emesis.

  15. Formulation and in vitro evaluation of fast dissolving tablets of metoprolol tartrate

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    Mangesh Machhindranath Satpute


    Full Text Available The demand for fast dissolving tablets has been growing during the last decade, especially for elderly and children who have swallowing difficulties. In the present work, fast dissolving tablets of metoprolol tartrate, were prepared using sodium starch glycolate, sodium croscarmellose and crospovidone as superdisintegrants, by the direct compression method. The tablets prepared were evaluated for various parameters including weight variation, hardness, friability, in vitro dispersion time, drug-polymer interaction, drug content water absorption ratio, wetting time, in vitro drug release, FTIR and DSC studies. The tablets prepared by the direct compression method had a weight variation in the range of 145 mg to 152 mg, which is below ± 7.5%, a hardness of 3.6 kg/cm² to 4.5 kg/cm², percentage friability of 0.46% to 0.73%, in vitro dispersion time of 18 s to 125 s, drug content uniformity of between 98.12% and 100.03%, a water absorption ratio of 67% to 87%, wetting time of 32 sec. to 64 sec., and an in vitro drug release of 53.92% - 98.82% within 15 min. The IR spectral analysis and DSC study showed no drug interaction with formulation additives of the tablet, and the formulations indicated no significant changes in hardness, friability, drug content or in vitro drug release. Fast dissolving tablets of metoprolol tartrate have enhanced dissolution and will lead to improved bioavailability and more effective therapy.

  16. Distribution and health risk assessment of dissolved heavy metals in the Three Gorges Reservoir, China (section in the main urban area of Chongqing). (United States)

    Zhao, Xin; Li, Ting-Yong; Zhang, Tao-Tao; Luo, Wei-Jun; Li, Jun-Yun


    The Three Gorges Project (TGP) is the largest hydropower station ever built in the world. A better understanding of the concentrations of heavy metals in the aquatic environment of the Three Gorges Reservoir (TGR) is crucial for national drinking water security and sustainable ecosystem development. To thoroughly investigate the impact of heavy metals on water quality after the impoundment to the maximum level of 175 m in the TGR, the concentrations of the dissolved heavy metals (Cr, Cu, Zn, Cd, Pb, As) were measured in April and August 2015, by inductively coupled plasma mass spectrometry (ICP-MS). (1) Except Zn and Pb, most of the heavy metal concentrations in the water of the TGR reached the level of the National Surface Water Environmental Quality Standards (GB3838-2002) I of China, revealing that the water quality of the TGR was good overall. (2) There were significant positive correlations among the concentrations of Cu, As, and Cd, revealing that they may exhibit similar geochemical behaviors. (3) The spatial distribution of the heavy metal concentrations was diverse and complex. The Zn concentration obviously increased in the rainy season from upstream to downstream in the Yangtze River, while the other heavy metals exhibited no significant changes in their concentrations. The distribution characteristics of the heavy metal concentrations on both sides and the middle of the river were different at different sites. (4) The health risk of the six elements was assessed through a human health risk assessment (HHRA), and the assessment results were lower than the maximum acceptable risk level designed by the US EPA and International Commission on Radiological Protection (ICRP). The HHRA model in the aquatic environment revealed that the risk of non-carcinogenic heavy metals (Cu, Zn, and Pb) was at a negligible risk level of 10-11∼10-9 a-1. At all the study sites, the risk of carcinogenic heavy metals (Cr, Cd, and As) was higher than the risk of non

  17. Development and evaluation of a reservoir model for the Chain of Lakes in Illinois (United States)

    Domanski, Marian M.


    Forecasts of flows entering and leaving the Chain of Lakes reservoir on the Fox River in northeastern Illinois are critical information to water-resource managers who determine the optimal operation of the dam at McHenry, Illinois, to help minimize damages to property and loss of life because of flooding on the Fox River. In 2014, the U.S. Geological Survey; the Illinois Department of Natural Resources, Office of Water Resources; and National Weather Service, North Central River Forecast Center began a cooperative study to develop a system to enable engineers and planners to simulate and communicate flows and to prepare proactively for precipitation events in near real time in the upper Fox River watershed. The purpose of this report is to document the development and evaluation of the Chain of Lakes reservoir model developed in this study.The reservoir model for the Chain of Lakes was developed using the Hydrologic Engineering Center–Reservoir System Simulation program. Because of the complex relation between the dam headwater and reservoir pool elevations, the reservoir model uses a linear regression model that relates dam headwater elevation to reservoir pool elevation. The linear regression model was developed using 17 U.S. Geological Survey streamflow measurements, along with the gage height in the reservoir pool and the gage height at the dam headwater. The Nash-Sutcliffe model efficiency coefficients for all three linear regression model variables ranged from 0.90 to 0.98.The reservoir model performance was evaluated by graphically comparing simulated and observed reservoir pool elevation time series during nine periods of high pool elevation. In addition, the peak elevations during these time periods were graphically compared to the closest-in-time observed pool elevation peak. The mean difference in the simulated and observed peak elevations was -0.03 feet, with a standard deviation of 0.19 feet. The Nash-Sutcliffe coefficient for peak prediction was

  18. Evaluation of flow regime of turbidity currents entering Dez Reservoir using extended shallow water model

    Directory of Open Access Journals (Sweden)

    Valery Ivanovich ELFIMOV


    Full Text Available In this study, the performance of the extended shallow water model (ESWM in evaluation of the flow regime of turbidity currents entering the Dez Reservoir was investigated. The continuity equations for fluid and particles and the Navier-Stokes equations govern the entire flow of turbidity currents. The shallow water equations governing the flow of the depositing phase of turbidity currents are derived from these equations. A case study was conducted on the flow regime of turbidity currents entering the Dez Reservoir in Iran from January 2002 to July 2003. Facing a serious sedimentation problem, the dead storage of the Dez Reservoir will be full in the coming 10 years, and the inflowing water in the hydropower conduit system is now becoming turbid. Based on the values of the dimensionless friction number ( and dimensionless entrainment number ( of turbidity currents, and the coefficient of determination between the observed and predicted deposit depths (R2 = 0.86 for the flow regime of negligible friction and negligible entrainment (NFNE, the flow regime of turbidity currents coming into the Dez Reservoir is considered to be NFNE. The results suggest that the ESWM is an appropriate approach for evaluation of the flow regime of turbidity currents in dam reservoirs where the characteristics of turbidity currents, such as the deposit depth, must be evaluated.

  19. Suspended-sediment transport and storage: A demonstration of acoustic methods in the evaluation of reservoir management strategies for a small water-supply reservoir in western Colorado (United States)

    Williams, Cory A.; Richards, Rodney J.; Collins, Kent L.


    The U.S. Bureau of Reclamation (USBR) and local stakeholder groups are evaluating reservoir-management strategies within Paonia Reservoir. This small reservoir fills to capacity each spring and requires approximately half of the snowmelt-runoff volume from its sediment-laden source waters, Muddy Creek. The U.S. Geological Survey is currently conducting high-resolution (15-minute data-recording interval) sediment monitoring to characterize incoming and outgoing sediment flux during reservoir operations at two sites on Muddy Creek. The high-resolution monitoring is being used to establish current rates of reservoir sedimentation, support USBR sediment transport and storage models, and assess the viability of water-storage recovery in Paonia Reservoir. These sites are equipped with in situ, single-frequency, side-looking acoustic Doppler current meters in conjunction with turbidity sensors to monitor sediment flux. This project serves as a demonstration of the capability of using surrogate techniques to predict suspended-sediment concentrations in small streams (less than 20 meters in width and 2 meters in depth). These two sites provide the ability to report near real-time suspended-sediment concentrations through the U.S. Geological Survey National Water Information System (NWIS) web interface and National Real-Time Water Quality websites (NRTWQ) to aid in reservoir operations and assessments.

  20. Simulation studies to evaluate the effect of fracture closure on the performance of fractured reservoirs; Final report

    Energy Technology Data Exchange (ETDEWEB)

    Howrie, I.; Dauben, D.


    A three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The overall objectives of the study were to: (1) evaluate the reservoir conditions for which fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. The evaluations of reservoir performance were made by a modern dual porosity simulator, TETRAD. This simulator treats both porosity and permeability as functions of pore pressure. The Austin Chalk in the Pearsall Field in of South Texas was selected as the prototype fractured reservoir for this work. During the first year, simulations of vertical and horizontal well performance were made assuming that fracture permeability was insensitive to pressure change. Sensitivity runs indicated that the simulator was predicting the effects of critical reservoir parameters in a logical and consistent manner. The results confirmed that horizontal wells could increase both rate of oil recovery and total oil recovery from naturally fractured reservoirs. In the second year, the performance of the same vertical and horizontal wells was reevaluated with fracture permeability treated as a function of reservoir pressure. To investigate sensitivity to in situ stress, differing loading conditions were assumed. Simulated natural depletions confirm that pressure sensitive fractures degrade well performance. The severity of degradation worsens when the initial reservoir pressure approaches the average stress condition of the reservoir, such as occurs in over pressured reservoirs. Simulations with water injection indicate that degradation of permeability can be counteracted when reservoir pressure is maintained and oil recovery can be increased when reservoir properties are favorable.

  1. Sanitary impact evaluation of drinking water in storage reservoirs in Moroccan rural area. (United States)

    Aziz, Faissal; Parrado Rubio, Juan; Ouazzani, Naaila; Dary, Mohammed; Manyani, Hamid; Rodríguez Morgado, Bruno; Mandi, Laila


    In Morocco, storage reservoirs are particular systems of water supply in rural areas. These reservoirs are fed with rainwater and/or directly from the river, which are very contaminated by several pathogenic bacteria. They are used without any treatment as a drinking water by the surrounding population. In this context, the aim of this study is to evaluate the impact of consuming contaminated water stored in reservoirs on health status for six rural communities located in Assif El Mal, Southern East of Marrakech. This was investigated using a classical methodology based on population survey and by molecular approach using PCR-DGGE technique to determine the intestinal bacterial diversity of consumers. The survey showed that, the residents of the studied area suffered from numerous health problems (diarrheal diseases, vomiting or hepatitis A) due to the lack of waste management infrastructures. The consumer's stool analysis by molecular approach revealed that numbers of Escherichia coli, Aeromonas hydrophila and Clostridia, were significantly higher in the diarrheal feces. In addition, PCR-DGGE study of the prevalence and distribution of bacteria causing human diseases, confirmed that, there is a relationship between water bacterial contaminations of storage reservoirs and microbial disease related health status. Therefore, water reservoir consumption is assumed to be the mean way of exposure for this population. It's clear that this approach gives a very helpful tool to confirm without any doubt the relationship between water bacterial contamination and health status.

  2. The contribution of component variation and phytoplankton growth to the distribution variation of chromophoric dissolved organic matter content in a mid-latitude subtropical drinking water source reservoir for two different seasons. (United States)

    Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong


    The distribution variation in chromophoric dissolved organic matter (CDOM) content in mid-latitude subtropical drinking water source reservoirs (MDWSRs) has great significance in the security of aquatic environments and human health. CDOM distribution is heavily influenced by biogeochemical processes and anthropogenic activity. However, little is known regarding the impact of component variation and phytoplankton growth on CDOM distribution variation in MDWSR. Therefore, samples were collected from a representative MDWSR (the Shanzai Reservoir) for analysis. CDOM absorption and fluorescence coupling with parallel factor analysis were measured and calculated. The results indicated that only two CDOM components were found in the surface water of Shanzai Reservoir, fulvic acid, and high-excitation tryptophan, originating from terrestrial and autochthonous sources, respectively. The types of components did not change with the season. The average molecular weight of CDOM increased in proportion to its fulvic acid content. The distribution variation in CDOM content mainly resulted from the variation in two CDOM components in summer and from high-excitation tryptophan in winter. Phytoplankton growth strongly influenced the distribution variation of CDOM content in summer; the metabolic processes of Cyanobacteria and Bacillariophyta consumed fulvic acid, while that of Cryptophyta produced high-excitation tryptophan.

  3. A discussion on the interrelationships between five properties in reservoir evaluation

    Directory of Open Access Journals (Sweden)

    Liangxiao Zhao


    Full Text Available Reservoir pore spaces (incl. pores, fractures and vugs are too complex to be predicted by use of the traditional interrelationships between the four properties of reservoirs, thus more and more contradictions occur in reservoir evaluation. A great number of case studies were made to reveal the causes of these contradictions and the corresponding solutions were also proposed. For the reservoirs with complex pore spaces, we found four common types of contradictions between porosity and permeability, porosity and water saturation, absolute permeability and effective permeability, and electrical property and hydrocarbon property. These contradictions are mainly caused by variation of pore types, pore-throat sizes and fracture occurrence. On this basis, the concept of geometrical property was presented and methods were discussed for qualitatively or quantitatively describing the geometrical properties of pores, fractures and vugs. The following findings were achieved. (1 For pores, two relationships were established between pores & throat sizes and rock textures, physical property & fluid property, and between pore types and fluid property & logging responses. (2 For fractures, five relationships were established between occurrence and pore texture index (m, radial extension and deep/shallow borehole resistivity, openness and fracture permeability, occurrence and matrix water saturation, and between development index and lithology. (3 For vugs, two relationships were established between size & connectivity and m value & three porosities derived from logging responses (neutron, density and sonic wave, and filling degree and logging responses. The interrelationships between geometrical property, lithology, physical property, fluid property and electrical property can significantly improve the evaluation of complex reservoirs such as carbonates.

  4. Development and Evaluation of Mouth Dissolving Films of Amlodipine Besylate for Enhanced Therapeutic Efficacy

    Directory of Open Access Journals (Sweden)

    K. M. Maheswari


    Full Text Available The present investigation was undertaken with an objective of formulating mouth dissolving films (MDFs of Amlodipine Besylate (AMLO to enhance convenience and compliance of the elderly and pediatric patients for better therapeutic efficacy. Film formers like hydroxy propyl methyl cellulose (HPMC and methyl cellulose (MC along with film modifiers like poly vinyl pyrrolidone K30 (PVP K30, and sodium lauryl sulphate (SLS as solubilizing agents were evaluated. The prepared MDFs were evaluated for in vitro dissolution characteristics, in vitro disintegration time, and their physicomechanical properties. All the prepared MDFs showed good mechanical properties like tensile strength, folding endurance, and % elongation. MDFs were evaluated by means of FTIR, SEM, and X-RD studies. MDFs with 7.5% (w/w of HPMC E3 gave better dissolution properties when compared to HPMC E5, HPMC E15, and MC. MDFs with PVP K30 and SLS gave superior dissolution properties when compared to MDFs without PVP K30 and SLS. The dissolution properties of MDFs with PVP K30 were superior when compared to MDFs with SLS. In the case of F3 containing 7.5% of HPMC E3 and 0.04% of PVP K30, complete and faster release was observed within 60 sec when compared to other formulations. Release kinetics data reveals diffusion is the release mechanism.

  5. Fast techniques for the evaluation of reservoirs capacity; Metodos de evaluacion rapida de capacidad de yacimentos

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly del Carmen [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)


    Fast techniques for the evaluation of geothermal reservoirs allow us to have an approach of its electrical potential. Based on the laws of conservation of mass and energy, considering infinite permeability, this paper presents techniques for fast reservoir evaluation. These techniques let us calculate in a very practical way, the electric power that can be obtained from a geothermal field. These techniques can be an important tool to solve practical problems, and are useful during the preliminary development of geothermal sources. [Espanol] Los metodos de evaluacion rapida de yacimientos permiten estimar de manera aproximada la potencia electrica maxima y minima de los mismos. Se presentan tecnicas de evaluacion basadas en las leyes de conservacion de masa y energia, considerando permeabilidad infinita. Las tecnicas utilizadas pueden ser una herramienta importante para la solucion de problemas practicos y para la toma de decisiones en etapas de prefactibilidad.

  6. Evaluation of flow regime of turbidity currents entering Dez Reservoir using extended shallow water model


    Valery Ivanovich ELFIMOV; Hamid KHAKZAD


    In this study, the performance of the extended shallow water model (ESWM) in evaluation of the flow regime of turbidity currents entering the Dez Reservoir was investigated. The continuity equations for fluid and particles and the Navier-Stokes equations govern the entire flow of turbidity currents. The shallow water equations governing the flow of the depositing phase of turbidity currents are derived from these equations. A case study was conducted on the flow regime of turbidity currents e...

  7. Evaluating the effect of dissolved oxygen on simultaneous nitrification and denitrification in polyurethane foam contact oxidation reactors. (United States)

    Tan, Chong; Ma, Fang; Li, Ang; Qiu, Shan; Li, Jianzheng


    The effects of dissolved oxygen on simultaneous nitrification and denitrification were evaluated in polyurethane foam contact oxidation reactors in a municipal wastewater treatment process. It was observed that nitrate could be removed at low dissolved oxygen levels, but the removal rate was gradually reduced as the dissolved oxygen concentration increased to a higher level of 6.0 mg/L. Nitrogen removal remained optimal within the dissolved oxygen range of 0.5 to 1.0 mg/L. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that the diversity of the microbial community changed accompanying dissolved oxygen values of 0.5 to 1.0 mg/L, 2.5 to 3.5 mg/L, 6.0 to 6.5 mg/L, and 10.0 to 12.0 mg/L, in turn, which was supported by the Shannon-Wiener index of 1.56, 1.71, 1.43, and 1.56, accordingly. Both DGGE profiling and phylogenetic analysis confirmed that the nitrifiers in reactors that are responsible for nitrification during the experiment include Nitrosospira sp., Nitrosomonas sp., and Nitrospira sp.

  8. Formulation and evaluation of fast dissolving tablets of cinnarizine using superdisintegrant blends and subliming material

    Directory of Open Access Journals (Sweden)

    Biswajit Basu


    Full Text Available The aim of this investigation was to develop fast dissolving tablet of cinnarizine. A combination of super disintegrants, i.e., sodium starch glycolate (SSG and crosscarmellose sodium (CCS were used along with camphor as a subliming material. An optimized concentration of camphor was added to aid the porosity of the tablet. A 3 2 full factorial design was applied to investigate the combined effect of two formulation variables: Amount of SSG and CCS. Infrared (IR spectroscopy was performed to identify the physicochemical interaction between drug and polymer. IR spectroscopy showed that there is no interaction of drug with polymer. In the present study, direct compression was used to prepare the tablets. The powder mixtures were compressed into tablet using flat face multi punch tablet machine. Camphor was sublimed from the tablet by exposing the tablet to vacuum drier at 60°C for 12 hours. All the formulations were evaluated for their characteristics such as average weight, hardness, wetting time, friability, content uniformity, dispersion time (DT, and dissolution rate. An optimized tablet formulation (F 9 was found to have good hardness of 3.30 ± 0.10 kg/cm 2 , wetting time of 42.33 ± 4.04 seconds, DT of 34.67 ± 1.53 seconds, and cumulative drug release of not less than 99% in 16 minutes.

  9. Evaluation of sediment management strategies on reservoir storage depletion rate: a case study

    NARCIS (Netherlands)

    Ali, M.; Sterk, G.


    Sedimentation aspects have a major role during the design of new reservoir projects because life of the reservoir mainly depends upon sediment handling during reservoir operation. Therefore, proper sediment management strategies should be adopted to enhance the life span of reservoirs. Basha

  10. [Distribution Characteristics and Pollution Status Evaluation of Sediments Nutrients in a Drinking Water Reservoir]. (United States)

    Huang, Ting-lin; Liu, Fei; Shi, Jian-chao


    The main purpose of this paper is to illustrate the influence of nutrients distribution in sediments on the eutrophication of drinking water reservoir. The sediments of three representative locations were field-sampled and analyzed in laboratory in March 2015. The distribution characteristics of TOC, TN and TP were measured, and the pollution status of sediments was evaluated by the comprehensive pollution index and the manual for sediment quality assessment. The content of TOC in sediments decreased with depth, and there was an increasing trend of the nitrogen content. The TP was enriched in surface sediment, implying the nutrients load in Zhoucun Reservoir was aggravating as the result of human activities. Regression analysis indicated that the content of TOC in sediments was positively correlated with contents of TN and TP in sediments. The TOC/TN values reflected that the vascular land plants, which contain cellulose, were the main source of organic matter in sediments. The comprehensive pollution index analysis result showed that the surface sediments in all three sampling sites were heavily polluted. The contents of TN and TP of surface sediments in three sampling sites were 3273-4870 mg x kg(-1) and 653-2969 mg x kg(-1), and the content of TOC was 45.65-83.00 mg x g(-1). According to the manual for sediment quality assessment, the TN, TP and TOC contents in sediments exceed the standard values for the lowest level of ecotoxicity, so there is a risk of eutrophication in Zhoucun Reservoir.

  11. Evaluating Geothermal Potential in Germany by Numerical Reservoir Modeling of Engineered Geothermal Systems (United States)

    Jain, Charitra; Vogt, Christian; Clauser, Christoph


    We model hypothetical Engineered Geothermal System (EGS) reservoirs by solving coupled partial differential equations governing fluid flow and heat transport. Building on EGS's strengths of inherent modularity and storage capability, it is possible to implement multiple wells in the reservoir to extend the rock volume accessible for circulating water in order to increase the heat yield. By varying parameters like flow rates and well-separations in the subsurface, this study looks at their long-term impacts on the reservoir development. This approach allows us to experiment with different placements of the engineered fractures and propose several EGS layouts for achieving optimized heat extraction. Considering the available crystalline area and accounting for the competing land uses, this study evaluates the overall EGS potential and compares it with those of other used renewables in Germany. There is enough area to support 13450 EGS plants, each with six reversed-triplets (18 wells) and an average electric power of 35.3MWe. When operated at full capacity, these systems can collectively supply 4155TWh of electric energy in one year which would be roughly six times the electric energy produced in Germany in the year 2011. Engineered Geothermal Systems make a compelling case for contributing towards national power production in a future powered by a sustainable, decentralized energy system.

  12. Simulation studies to evaluate the effect of fracture closure on the performance of naturally fractured reservoirs. Annual report

    Energy Technology Data Exchange (ETDEWEB)


    The first of a three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The objectives of the study are to (1) evaluate the reservoir conditions where fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. Simulation studies were conducted with a dual porosity simulator capable of simulating the performance of vertical and horizontal wells. Each simulator was initialized using properties typical of the Austin Chalk reservoir in Pearsall Field, Texas. Simulations of both vertical and horizontal well performance were made assuming that fracture permeability was insensitive to pressure change. Sensitivity runs indicate that the simulator is predicting the effects of critical reservoir parameters in a logical and consistent manner. The results to-date confirm that horizontal wells can increase both oil recovery rate and total oil recovery from naturally fractured reservoirs. The year one simulation results will provide the baseline for the ongoing study which will evaluate the performance degradation caused by the sensitivity of fracture permeability to pressure change, and investigate fluid injection pressure maintenance as a means to improve oil recovery performance. The study is likely to conclude that fracture closure decreases oil recovery and that pressure support achieved through fluid injection could be beneficial in improving recovery.

  13. Modeling evaluation of integrated strategies to meet proposed dissolved oxygen standards for the Chicago waterway system. (United States)

    Melching, Charles S; Ao, Yaping; Alp, Emre


    The Chicago Waterway System (CWS) is a 113.8 km branching network of navigable waterways controlled by hydraulic structures in which the majority of flow is treated sewage effluent and there are periods of substantial combined sewer overflow. The Illinois Pollution Control Board (IPCB) designated the majority of the CWS as Secondary Contact and Indigenous Aquatic Life Use waters in the 1970s and made small alterations to these designations in 1988. Between 1988 and 2002 substantial improvements in the pollution control and water-quality management facilities were made in the Chicago area. The results of a Use Attainability Analysis led the Illinois Environmental Protection Agency (IEPA) to propose the division of the CWS into two new aquatic life use classes with appropriate dissolved oxygen (DO) standards. To aid the IPCB in their deliberations regarding the appropriate water use classifications and DO standards for the CWS, the DUFLOW model that is capable of simulating hydraulics and water-quality processes under unsteady-flow conditions was used to evaluate integrated strategies of water-quality improvement facilities that could meet the proposed DO standards during representative wet (2001) and dry (2003) years. A total of 28 new supplementary aeration stations with a maximum DO load of 80 or 100 g/s and aerated flow transfers at three locations in the CWS would be needed to achieve the IEPA proposed DO standards 100% of the time for both years. A much simpler and less costly (≈one tenth of the cost) system of facilities would be needed to meet the IEPA proposed DO standards 90% of the time. In theory, the combinations of flow augmentation and new supplemental aeration stations can achieve 100% compliance with the IEPA proposed DO standards, however, 100% compliance will be hard to achieve in practice because of-(1) difficulties in determining when to turn on the aeration stations and (2) localized heavy loads of pollutants during storms that may yield

  14. [Planktonic Algae's Distribution and Correlation with Dissolved Organic Matters' Fluorescence in the End of the Three Gorges Reservoir's Back Water Zone]. (United States)

    Fan, Lei-lei; Li, Si; Yu, Dan-ni; He, Qiang; Ji, Fang-ying; Jiang, Zhong-yuan; Gao, Zhi-xi; Ao, Ke-hou


    For researching the community structure, composition, and distribution of the planktonic algae in the Three Gorges Reservoir (TRG), especially, within TRG water levels' fluctuating, mpacting to water quality with the algae's growing, 6 sampling cites in the end of the TGR's back water zone, from Chaotianmen to Taihonggang Town, are chosen to monitor, at the sensitive stages time of algal bloom between March to May 2012, namely, water levels lowing from the highest impounding. The community's structure, composition, and distribution of the planktonic algae in the TGR, and the correlation of water quality parameters and DOM's fluorescence features with algae density, are obtained. According to the experimental results, blue algae fibre, chlorella, melosira, navicula are the dominated algae in the end of the TGR's back water zone, from Chaotianmen to Taihonggang Town, algae density are 0.40~0.56 × 10(6), 1.9~0.8 × 10(6), 0.36~0.25 × 10(6), 0.42~0.15 × 10(6) cells · L(-1) respectively. Besides, anabaena, phormidium, cladophora, feather, ovate algae are existing in only limited 2 sections. The fitting results reveal obvious linear correlation of the EEM characteristics of DOM with the 4 kinds of dominated algal density, which could be useful conference for the algae bloom monitor, conveniently and effectively.

  15. Prospect evaluation of shallow I-35 reservoir of NE Malay Basin offshore, Terengganu, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Janjua, Osama Akhtar, E-mail:; Wahid, Ali, E-mail:; Salim, Ahmed Mohamed Ahmed, E-mail: [Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 32610 Tronoh, Perak (Malaysia); Rahman, M. Nasir B. A., E-mail: [Petroleum Engineering Division, PETRONAS Carigali Sdn Bhd, Kuala Lumpur (Malaysia)


    A potential accumulation of hydrocarbon that describes significant and conceivable drilling target is related to prospect. Possibility of success estimation, assuming discovery of hydrocarbons and the potential recoverable quantities range under a commercial development program are the basis of Prospect evaluation activities. The objective was to find the new shallow prospects in reservoir sandstone of I –Formation in Malay basin. The prospects in the study area are mostly consisting of faulted structures and stratigraphic channels. The methodology follows seismic interpretation and mapping, attribute analysis, evaluation of nearby well data i.e., based on well – log correlation. The petrophysical parameters analogue to nearby wells was used as an input parameter for volumetric assessment. Based on analysis of presence and effectiveness, the prospect has a complete petroleum system. Two wells have been proposed to be drilled near the major fault and stratigraphic channel in I-35 reservoir that is O-1 and O-2 prospects respectively. The probability of geological success of prospect O-1 is at 35% while for O-2 is 24%. Finally, for hydrocarbon in place volumes were calculated which concluded the best estimate volume for oil in O-1 prospect is 4.99 MMSTB and O-2 prospect is 28.70 MMSTB while for gas is 29.27 BSCF and 25.59 BSCF respectively.

  16. The suitability evaluation of dredged soil from reservoirs as embankment material. (United States)

    Park, Jaesung; Son, Younghwan; Noh, Sookack; Bong, Taeho


    We assessed the suitability of soil dredged from reservoirs as embankment material and investigated its physical and geochemical properties and strength parameters, as well as its environmental stability. The dredged soil samples were taken from the Ansung, Jechon, and Mulwang Reservoirs in Korea. To evaluate their environmental stability and geochemical properties, we examined their levels of heavy metal contamination, pH, and electrical conductivity. We also conducted X-ray fluorescence and X-ray diffraction analyses. Furthermore, we determined the geotechnical characteristics, such as the compaction characteristics, and permeability coefficient, and we performed consolidated undrained triaxial compression tests to evaluate the recycling potential of dredged soil as embankment material. The concentrations of heavy metals in the sediment samples were lower than those of the standard samples. The pH value of the soil samples ranged from 4.25 to 5.39, and the electrical conductivity ranged between 83.3 and 265.0 μS/cm, indicating suitability for use as construction material with steel and concrete. Based on the values of the mechanical properties of the dredged soil, analysis of slope stability was performed for various cases and water level conditions. Our results indicate that the dredged soil has sufficient stability for substitution of embankment material and also as new embankment material for expansion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Clinical evaluation of fullerene-C60 dissolved in squalane for anti-wrinkle cosmetics. (United States)

    Kato, Shinya; Taira, Hikaru; Aoshima, Hisae; Saitoh, Yasukazu; Miwa, Nobuhiko


    Highly purified and organic solvent-free fullerene-C60 was dissolved, at nearly saturated concentration of 278 ppm, in squalane prepared from olive oil, which is designated as LipoFullerene (LF-SQ) and was examined for usage as a cosmetic ingredient with antioxidant ability. The aim of this study was to assess the anti-wrinkle formation efficacy of LF-SQ in subjects. A total of 23 Japanese women (group I: age 38.9 +/- 3.8, n = 11, group II; age 39.4 +/- 4.3, n = 12) were enrolled in an 8-week trial of LF-SQ blended cream in a randomized, matched pair double-blind study. The LF-SQ cream was applied twice daily on the right or left half of the face, and squalane blended cream (without fullerene-C60) was applied as the placebo on another half of the face. As clinical evaluations of wrinkle grades, visual observation and photographs, and silicone replicas of both crow's feet areas were taken at baseline (0 week) and at 4th and 8th weeks. Skin replicas were analyzed using an optical profilometry technique. The wrinkle and skin-surface roughness features were calculated and statistically analyzed. Subsequently, trans-epidermal water loss (TEWL), moisture levels of the stratum corneum, and visco-elasticity (suppleness: RO and elasticity: R7) were measured on cheeks by instrumental analysis. LF-SQ cream enhanced the skin moisture and the anti-wrinkle formation. LF-SQ cream that was applied on a face twice daily was not effective at 4th week, but significantly more effective than the placebo at 8th week (p < 0.05) without severe side effects. The roughness-area ratio showed significant improvement (p < 0.05) at 8th week with LF-SQ cream as compared to 0 week with LF-SQ cream, but no significant difference was detected between LF-SQ cream and the placebo. We suggest that LF-SQ could be used as an active ingredient for wrinkle-care cosmetics.

  18. An integrated workflow to characterize and evaluate low resistivity pay and its phenomenon in a sandstone reservoir (United States)

    Pratama, Edo; Suhaili Ismail, Mohd; Ridha, Syahrir


    The identification, characterization and evaluation of low resistivity pay is very challenging and important for the development of oil and gas fields. Proper identification and characterization of these reservoirs is essential for recovering their reserves. There are many reasons for low resistivity pay zones. It is crucial to identify the origin of this phenomenon. This paper deals with the identification, characterization and evaluation of low resistivity hydrocarbon-bearing sand reservoirs in order to understand the low resistivity phenomenon in a sandstone reservoir, the characterization of the rock types and how to conduct petrophysical analysis to accurately obtain petrophysical properties. An integrated workflow based on petrographical, rock typing and petrophysical methods is conducted and applied. From the integrated analysis that was performed, the presence of illite and a mixed layer of illite-smectite clay minerals in sandstone formation and pyrite-siderite conductive minerals was identified as one of the main reasons for low resistivity occurence in sandstone reservoirs. These clay minerals are distributed as a laminated-dispersed shale distribution model in sandstone reservoirs. The dual water method is recommended to calculate water saturation in low resistivity hydrocarbon-bearing sand reservoirs as this method is more accurate and does not result in an over estimation in water saturation calculation.


    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E.; Hansen, E. K.; Shehee, T. C.


    This report includes the literature review, hydrogen off-gas calculations, and hydrogen generation tests to determine that H-Canyon can safely dissolve the Sodium Reactor Experiment (SRE; thorium fuel), Ford Nuclear Reactor (FNR; aluminum alloy fuel), and Denmark Reactor (DR-3; silicide fuel, aluminum alloy fuel, and aluminum oxide fuel) assemblies in the L-Bundles with respect to the hydrogen levels in the projected peak off-gas rates. This is provided that the number of L-Bundles charged to the dissolver is controlled. Examination of SRE dissolution for potential issues has aided in predicting the optimal batching scenario. The calculations detailed in this report demonstrate that the FNR, SRE, and DR-3 used nuclear fuel (UNF) are bounded by MURR UNF and may be charged using the controls outlined for MURR dissolution in a prior report.

  20. Evaluation of the return periods of water crises and evaporation in Monte Cotugno reservoir (Southern Italy) (United States)

    Copertino, Vito; Lo Vecchio, Giuseppina; Marotta, Lucia; Pastore, Vittoria; Ponzio, Giuseppe; Scavone, Giuseppina; Telesca, Vito; Vita, Michele


    In the past water resources management has been dealt and solved increasing water availabilities; today such opportunities have been considerably reduced and the technical-scientific perspectives are addressed above all to improve water system effectiveness and to promote an use of water resources that holds account of the droughts frequency and based on a correct estimate of the hydrologic balance. In this work a study on the water stored in Monte Cotugno reservoir in Sinni river - Basilicata (Southern Italy) - is proposed, estimating water crises return periods and reservoir evaporation. For such purpose the runs method was applied, based on the comparison between the temporal series of the "water volume" hydrological variable and a threshold representative of the "normal" conditions regarding which the availability in excess or defect was estimated. This allowed to individualize the beginning and the end of a water crisis event and to characterize the droughts in terms of duration, sum deficit and intensity. Therefore the return period was evaluated by means of the methodology proposed by Shiau and Shen in 2001, turned out equal approximately to 6 years. Such value was then verified with a frequency analysis of the "water volume" random variable, using the Weibull's distribution. Subsequently, the Fourier's analysis in the last twenty years was carried out, obtaining the same result of the previous methods. Moreover, in proximity of the Monte Cotugno reservoir the weather station of Senise is located, managed by ALSIA (Agenzia Lucana di Sviluppo e Innovazione in Agricultura), that provides in continuous measurements of air temperature and humidity, wind speed and direction, and global solar radiation since 2000. Such parameters allowed to apply five methods for reservoir evaporation estimate selected from those proposed in the literature, of which the first three, the Jensen-Haise's method, Makkink's method and Stephens-Stewart's one are based on solar radiation

  1. Simulation studies to evaluate the effect of fracture closure on the performance of naturally fractured reservoirs. Annual report

    Energy Technology Data Exchange (ETDEWEB)


    The second year of this three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The overall objectives of the study are to: (1) evaluate the reservoir conditions where fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. Simulation studies have been conducted with a dual porosity simulator capable of simulating the performance of vertical and horizontal wells. Each simulation model has been initialized with properties typical of the Austin Chalk reservoir in Pearsall Field, Texas. During year one, simulations of both vertical and horizontal well performance were made assuming that fracture permeability was insensitive to pressure charge. The results confirmed that horizontal wells could increase both rate of oil recovery and total oil recovery from naturally fractured reservoirs. During the second year the performances of the same vertical and horizontal wells were evaluated with the assumption that fracture permeability was a function of reservoir pressure. This required repetition of most of the natural depletion cases simulated in year one while invoking the pressure-sensitive fracture permeability option. To investigate sensitivity to in situ stress, two stress conditions were simulated for each primary variable. The water injection cases, begun in year one, were extended to include most of the reservoir parameters investigated for natural depletion, including fracture permeability as a function of net stress and the use of horizontal wells. The results thus far confirm that pressure-sensitive fractures degrade well performance and that the degradation is reduced by water injection pressure maintenance. Furthermore, oil recovery can be significantly increased by water injection pressure maintenance.

  2. Applying the Back-Propagation Neural Network model and fuzzy classification to evaluate the trophic status of a reservoir system. (United States)

    Chang, C L; Liu, H C


    The trophic state index, and in particular, the Carlson Trophic State Index (CTSI), is critical for evaluating reservoir water quality. Despite its common use in evaluating static water quality, the reliability of the CTSI may decrease when water turbidity is high. Therefore, this study examines the reliability of the CTSI and uses the Back-Propagation Neural Network (BPNN) model to create a new trophic state index. Fuzzy theory, rather than binary logic, is implemented to classify the trophic status into its three grades. The results show that compared to the CTSI with traditional classification, the new index with fuzzy classification can improve trophic status evaluation with high water turbidity. A reliable trophic state index can correctly describe reservoir water quality and allow relevant agencies to address proper water quality management strategies for a reservoir system.

  3. Studies on jackfruit seed starch as a novel natural superdisintegrant for the design and evaluation of irbesartan fast dissolving tablets. (United States)

    Suryadevara, Vidyadhara; Lankapalli, Sasidhar Reddyvallam; Danda, Lakshmi Harika; Pendyala, Vijetha; Katta, Vijetha


    In the present investigation, an attempt was made to isolate starch from jackfruit seed powder and utilize it as a superdisintegrant to design fast dissolving tablets of irbesartan. Starch was isolated from jackfruit seeds via aqueous and alkali extraction processes and evaluated for its physicochemical properties, for phytochemical tests, and for acute toxicity studies. Irbesartan fast dissolving formulations were prepared using the wet granulation technique. Acute toxicity studies for the extract indicated that all rats were healthy with no physiological changes in their behavior. The prepared irbesartan tablet formulations were found to be stable according to the Indian Pharmacopoeia-specified limits for postcompression parameters. From in vitro dissolution studies, it was observed that formulations F5 and F8 containing 5% w/w of alkali extracted starch and 5% w/w of croscarmellose sodium showed faster disintegration and improved dissolution rate compared with the other formulations. Fourier transfer infrared spectroscopic and differential scanning colorimetric analysis performed on optimized formulations indicated that there were no major interactions between the drug and excipients. Accelerated stability studies carried out on optimized formulations showed all tablets to be stable. The tablets prepared from jackfruit seed starch as superdisintegrant were found to be suitable for preparation of fast dissolving tablets.

  4. Evaluation of trends for iron and manganese concentrations in wells, reservoirs, and water distribution networks, Qom city, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Fahiminia


    Full Text Available Background: This study aimed to evaluated trends for iron and manganese concentrations in wells, reservoirs, and water distribution networks in Qom city during the summer of 2012. Methods: This was a cross-sectional study. The studied scopes consisted of groundwater (60 wells, reservoirs (10 tanks, and water distribution network (33 points. One sample was taken from each source monthly. Statistical tests used included post hoc tests (Tukey HSD. Finally, the results were compared with drinking water standards. Results: The average concentrations of iron in groundwater, reservoirs, and distribution networks were 0.09, 0.07, and 0.07 mg/l, respectively. The average concentrations of manganese in groundwater, reservoirs, and distribution networks were 0.15, 0.09, and 0.1 mg/l, respectively. The turbidity averages in groundwater, reservoirs, and distribution networks were 0.58, 0.6, and 0.52 NTU, respectively. The average concentrations of free chlorine residual in water reservoirs and distribution networks were 1.74 and 1.06 mg/l, respectively. The pH averages in groundwater, reservoirs, and distribution networks were 7.4, 7.7, and 7.5, respectively. The amounts of iron, manganese, turbidity, free chlorine residual, and pH in the investigated resources had no significant differences (P > 0.05. Conclusion: The amounts of iron, manganese, turbidity, free chlorine residual and pH in groundwater, reservoirs, and water distribution networks of Qom are within permissible limits of national standards and EPA guidelines. Only the amount of manganese was higher than the Environmental Protection Agency (EPA permissible limit.

  5. Research on the physical properties of supercritical CO2 and the log evaluation of CO2-bearing volcanic reservoirs (United States)

    Pan, Baozhi; Lei, Jian; Zhang, Lihua; Guo, Yuhang


    CO2-bearing reservoirs are difficult to distinguish from other natural gas reservoirs during gas explorations. Due to the lack of physical parameters for supercritical CO2, particularly neutron porosity, at present a hydrocarbon gas log evaluation method is used to evaluate CO2-bearing reservoirs. The differences in the physical properties of hydrocarbon and CO2 gases have led to serious errors. In this study, the deep volcanic rock of the Songliao Basin was the research area. In accordance with the relationship between the density and acoustic velocity of supercritical CO2 and temperature and pressure, the regularity between the CO2 density and acoustic velocity, and the depth of the area was established. A neutron logging simulation was completed based on a Monte Carlo method. Through the simulation of the wet limestone neutron logging, the relationship between the count rate ratio of short and long space detectors and the neutron porosity was acquired. Then, the nature of the supercritical CO2 neutron moderation was obtained. With consideration given to the complexity of the volcanic rock mineral composition, a volcanic rock volume model was established, and the matrix neutron and density parameters were acquired using the ECS log. The properties of CO2 were applied in the log evaluation of the CO2-bearing volcanic reservoirs in the southern Songliao Basin. The porosity and saturation of CO2 were obtained, and a reasonable application was achieved in the CO2-bearing reservoir.

  6. Evaluation of different flooding scenarios as enhanced oil recovery method in a fractured reservoir: a case study

    Energy Technology Data Exchange (ETDEWEB)

    Shahvaranfard, A. [Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Moradi, B. [Iranian Central Oil Fields Company (Iran, Islamic Republic of)], E-mail:; Tahami, S.A.; Gholami, A. [Petropars Oil and Gas Institute (POGI), Tehran (Iran, Islamic Republic of)


    Because of technological complexity and financial requirements to initiate a gas flooding project, a thorough evaluation is necessary before it is performed. In this paper, a reservoir modeling approach was used to evaluate different flooding processes (miscible and immiscible) in a fractured oil reservoir. This study included: (1) equation of state (EOS) modeling of experimental PVT data, (2) determination of MMP for different gas compositions using a slim-tube model and study of the effect of grid number on the results (numerical dispersion), (3) study of the effect of completion pattern and injection rate on recovery performance, and (4) comparison of the recovery performance in different flooding scenarios. (author)

  7. Evaluating National Weather Service Seasonal Forecast Products in Reservoir Operation Case Studies (United States)

    Nielson, A.; Guihan, R.; Polebistki, A.; Palmer, R. N.; Werner, K.; Wood, A. W.


    Forecasts of future weather and streamflow can provide valuable information for reservoir operations and water management. A challenge confronting reservoir operators today is how to incorporate both climate and streamflow products into their operations and which of these forecast products are most informative and useful for optimized water management. This study incorporates several reforecast products provided by the Colorado Basin River Forecast Center (CBRFC) which allows a complete retrospective analysis of climate forecasts, resulting in an evaluation of each product's skill in the context of water resources management. The accuracy and value of forecasts generated from the Climate Forecast System version 2 (CFSv2) are compared to the accuracy and value of using an Ensemble Streamflow Predictions (ESP) approach. Using the CFSv2 may offer more insight when responding to climate driven extremes than the ESP approach because the CFSv2 incorporates a fully coupled climate model into its forecasts rather than using all of the historic climate record as being equally probable. The role of forecast updating frequency will also be explored. Decision support systems (DSS) for both Salt Lake City Parley's System and the Snohomish County Public Utility Department's (SnoPUD) Jackson project will be used to illustrate the utility of forecasts. Both DSS include a coupled simulation and optimization model that will incorporate system constraints, operating policies, and environmental flow requirements. To determine the value of the reforecast products, performance metrics meaningful to the managers of each system are to be identified and quantified. Without such metrics and awareness of seasonal operational nuances, it is difficult to identify forecast improvements in meaningful ways. These metrics of system performance are compared using the different forecast products to evaluate the potential benefits of using CFSv2 seasonal forecasts in systems decision making.

  8. Evaluation of leachate dissolved organic nitrogen discharge effect on wastewater effluent quality. (United States)

    Bolyard, Stephanie C; Reinhart, Debra R


    Nitrogen is limited more and more frequently in wastewater treatment plant (WWTP) effluents because of the concern of causing eutrophication in discharge waters. Twelve leachates from eight landfills in Florida and California were characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was approximately 1146mg/L and 40mg/L, respectively. Solid-phase extraction was used to fractionate the DON based on hydrophobic (recalcitrant fraction) and hydrophilic (bioavailable fraction) chemical properties. The average leachate concentrations of bioavailable (bDON) and recalcitrant (rDON) DON were 16.5mg/L and 18.4mg/L, respectively. The rDON fraction was positively correlated, but with a low R2, with total leachate apparent color dissolved UV254, chemical oxygen demand (COD), and humic acid (R2 equals 0.38, 0.49, and 0.40, respectively). The hydrophobic fraction of DON (rDON) was highly colored. This fraction was also associated with over 60% of the total leachate COD. Multiple leachate and wastewater co-treatment simulations were carried out to assess the effects of leachate on total nitrogen wastewater effluent quality using removals for four WWTPs under different scenarios. The calculated pass through of DON suggests that leachate could contribute to significant amounts of nitrogen discharged to aquatic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Evaluation of the anti-wrinkle effect of an ascorbic acid-loaded dissolving microneedle patch via a double-blind, placebo-controlled clinical study. (United States)

    Lee, C; Yang, H; Kim, S; Kim, M; Kang, H; Kim, N; An, S; Koh, J; Jung, H


    Although an ascorbic acid-loaded dissolving microneedle patch has been developed to improve anti-wrinkle effects, an efficacy evaluation with a control group has not yet been performed. In this study, the anti-wrinkle effect of an ascorbic acid-loaded dissolving microneedle patch was evaluated in a double-blind clinical study with a control group. In addition, a cumulative skin irritation and sensitization potential of the ascorbic acid-loaded dissolving microneedle patch was performed. Twenty-three subjects were selected for anti-wrinkle effect evaluation in a double-blind clinical study. Subjects were divided into two groups. Group I subjects applied an ascorbic acid-loaded dissolving microneedle patch on a crow's feet area on the left side of the face and a control sample on a crow's feet area on the right side of the face every 4 days. Group II subjects placed the same patches on opposite sides of the face. Global Photodamage Score and skin replica analysis were conducted by visual inspection and skin visiometer, respectively. A skin irritation and sensitization assessment was performed on 51 subjects using the modified Shelanski & Shelanski procedure. Cumulative skin irritation potential and skin sensitization of the ascorbic acid-loaded dissolving microneedle patch and control sample were evaluated. Skin treated with the ascorbic acid-loaded dissolving microneedle patch showed a statistically significant improvement in both the Global Photodamage Score and visiometer R values (P skin irritation and sensitization assessment demonstrated that the ascorbic acid-loaded dissolving microneedle patch did not induce any cumulative skin irritation potential or skin sensitization. An ascorbic acid-loaded dissolving microneedle patch produced a significant anti-wrinkle effect without skin irritation and sensitization problems. This cosmetic dissolving microneedle patch can be used efficiently in the anti-wrinkle cosmetic field with patient convenience. © 2015 Society

  10. Fabrication and evaluation of a reservoir tillage machine to reduce runoff from farms with sprinkler irrigation systems

    Directory of Open Access Journals (Sweden)

    M. A Rostami


    Full Text Available Introduction Nowadays, in a lot of farm land due to reasons such as high density, heavy textured soils, steep terrain and a large body of water at each irrigation, rapid and complete absorption of water in the soil does not happen and runoff will be accrued. Improvement of infiltration reduces runoff and thus increases available water capacity. The main methods used to increase the infiltration area: The use of soil amendments, soil management by tillage and conservation farming. These methods may be used separately or together. Reservoir tillage is the process by which small holes or depressions are punched in the soil to prevent runoff of water from irrigation or rainfall. The objective of this study was to develop and evaluate a new reservoir tillage machine for runoff control in the fields. Materials and Methods Fabricated machine has four main units include three-point hitch, toolbar, frame and tillage unit. Tillage unit was a spider wheel with 6 arms that has 6 Wedge-shaped blades, mounted on them. Each tillage unit mounted on a frame and the frame is attached to the toolbar with a yoke. The toolbar was attached to the tractor by three-point hitch. The movement of tractor caused blades impact soil and spider wheel was rotating. Spider wheel rotation speed was depended on the forward speed of the tractor. Blades were created mini-reservoirs on the soil surface for "In situ" irrigation water or rainwater harvesting. Theoretically distance between basins, created by reservoir tillage machine, fabricated in this study was 57 and 68 cm for Arm's length of 30 and 40 cm respectively. For the construction of machine, first the plan was drawn with SolidWorks software and then the parts of the machine were built based on technical drawings. First tillage unit was constructed and its shaft was based in two bearings. Six of the arms were positioned at 60 degrees from each other around tillage units and connected by welding. For evaluation of machine

  11. The water-quality monitoring program for the Baltimore reservoir system, 1981-2007—Description, review and evaluation, and framework integration for enhanced monitoring (United States)

    Koterba, Michael T.; Waldron, Marcus C.; Kraus, Tamara E.C.


    The City of Baltimore, Maryland, and parts of five surrounding counties obtain their water from Loch Raven and Liberty Reservoirs. A third reservoir, Prettyboy, is used to resupply Loch Raven Reservoir. Management of the watershed conditions for each reservoir is a shared responsibility by agreement among City, County, and State jurisdictions. The most recent (2005) Baltimore Reservoir Watershed Management Agreement (RWMA) called for continued and improved water-quality monitoring in the reservoirs and selected watershed tributaries. The U.S. Geological Survey (USGS) conducted a retrospective review of the effectiveness of monitoring data obtained and analyzed by the RWMA jurisdictions from 1981 through 2007 to help identify possible improvements in the monitoring program to address RWMA water-quality concerns. Long-term water-quality concerns include eutrophication and sedimentation in the reservoirs, and elevated concentrations of (a) nutrients (nitrogen and phosphorus) being transported from the major tributaries to the reservoirs, (b) iron and manganese released from reservoir bed sediments during periods of deep-water anoxia, (c) mercury in higher trophic order game fish in the reservoirs, and (d) bacteria in selected reservoir watershed tributaries. Emerging concerns include elevated concentrations of sodium, chloride, and disinfection by-products (DBPs) in the drinking water from both supply reservoirs. Climate change and variability also could be emerging concerns, affecting seasonal patterns, annual trends, and drought occurrence, which historically have led to declines in reservoir water quality. Monitoring data increasingly have been used to support the development of water-quality models. The most recent (2006) modeling helped establish an annual sediment Total Maximum Daily Load to Loch Raven Reservoir, and instantaneous and 30-day moving average water-quality endpoints for chlorophyll-a (chl-a) and dissolved oxygen (DO) in Loch Raven and Prettyboy

  12. Building technical capacity in formation evaluation, petrophysics, borehole geophysics, and reservoir geophysics: challenges and the road ahead (United States)

    Torres-Verdin, C.


    This presentation considers the challenges involved in the development of instruction and research facilities in the areas of formation evaluation, well logging, petrophysics, rock physics, and integrated reservoir characterization, both at the Master's and Ph.D. level. It also considers the interplay between industry and academia to design research programs that are aligned with short- and long-term industry needs.

  13. Reservoir evaluation of “T-X” field (Onshore, Niger delta) from well ...

    African Journals Online (AJOL)

    A well log data from this field have been examined and analyzed. The logs include gamma ray (used for the identification of lithology), resistivity and porosity logs (used for delineating hydrocarbon bearing reservoirs). Wireline log analysis was employed in the characterization of the reservoirs in the well studied; the ...

  14. Evaluation of Management of Water Release for Painted Rocks Reservoir, Bitterroot River, Montana, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lere, Mark E. (Montana Department of Fish, Wildlife and Parks, Missoula, MT)


    Baseline fisheries and habitat data were gathered during 1983 and 1984 to evaluate the effectiveness of supplemental water releases from Painted Rocks Reservoir in improving the fisheries resource in the Bitterroot River. Discharge relationships among main stem gaging stations varied annually and seasonally. Flow relationships in the river were dependent upon rainfall events and the timing and duration of the irrigation season. Daily discharge monitored during the summers of 1983 and 1984 was greater than median values derived at the U.S.G.S. station near Darby. Supplemental water released from Painted Rocks Reservoir totaled 14,476 acre feet in 1983 and 13,958 acre feet in 1984. Approximately 63% of a 5.66 m{sup 3}/sec test release of supplemental water conducted during April, 1984 was lost to irrigation withdrawals and natural phenomena before passing Bell Crossing. A similar loss occurred during a 5.66 m{sup 3}/sec test release conducted in August, 1984. Daily maximum temperature monitored during 1984 in the Bitterroot River averaged 11.0, 12.5, 13.9 and 13.6 C at the Darby, Hamilton, Bell and McClay stations, respectively. Chemical parameters measured in the Bitterroot River were favorable to aquatic life. Population estimates conducted in the Fall, 1983 indicated densities of I+ and older rainbow trout (Salmo gairdneri) were significantly greater in a control section than in a dewatered section (p < 0.20). Numbers of I+ and older brown trout (Salmo trutta) were not significantly different between the control and dewatered sections (p > 0.20). Population and biomass estimates for trout in the control section were 631/km and 154.4 kg/km. In the dewatered section, population and biomass estimates for trout were 253/km and 122.8 kg/km. The growth increments of back-calculated length for rainbow trout averaged 75.6 mm in the control section and 66.9mm in the dewatered section. The growth increments of back-calculated length for brown trout averaged 79.5 mm in the

  15. Dissolved oxygen

    National Research Council Canada - National Science Library


    Dissolved oxygen concentrations in the waters of Botany Bay and Georges and Cooks Rivers vary mainly as a result of tidal water movements, algal and macrophytic growth and decay, and effects of storms...

  16. Formulation and Evaluation of Taste Masked Mouth Dissolving Tablets of Levocetirizine Hydrochloride (United States)

    Sharma, Vijay; Chopra, Himansu


    Aim of this research work was to develop mouth dissolving tablet that disintegrates rapidly in mouth by using tasteless complex of Levocetirizine and Tulsion-335. Effect of different parameters such as swelling time, resin activation, drug resin ratio as well as stirring time was optimized by taste and percentage drug loading. Formulated DRC (Drug Resin Complex) was characterized by infrared spectroscopy, thermal analysis and X-ray diffraction pattern. Tablets were formulated by wet granulation with PVP as binder, Sodium Starch Glycolate (SSG) and Crospovidone as super disintegrants. In these batches optimum hardness was achieved but disintegration time was found to be very high as ≥ 70 second, so further trials were planned by using different superdisintegrants such as Croscarmellose sodium, Sodium Starch Glycolate (SSG) as well as Crospovidone by wet granulation method. Tablets formulated with 7.5% crospovidone showed comparatively low disintegration time (25 sec), wetting time (20 sec) and friability (0.60 %) than the other batches. In present study we optimized the conditions required for maximum drug loading of Levocetirizine with Tulsion-335. Among different superdisintergants, crospovidone was found suitable with drug-resin complex to get the low disintegration time, wetting time and friability of tablets. PMID:24250469

  17. Quantitative evaluation of noncovalent interactions between glyphosate and dissolved humic substances by NMR spectroscopy. (United States)

    Mazzei, Pierluigi; Piccolo, Alessandro


    Interactions of glyphosate (N-phosphonomethylglycine) herbicide (GLY) with soluble fulvic acids (FAs) and humic acids (HAs) at pH 5.2 and 7 were studied by (1)H and (31)P NMR spectroscopy. Increasing concentrations of soluble humic matter determined broadening and chemical shift drifts of proton and phosphorus GLY signals, thereby indicating the occurrence of weak interactions between GLY and humic superstructures. Binding was larger for FAs and pH 5.2 than for HAs and pH 7, thus suggesting formation of hydrogen bonds between GLY carboxyl and phosphonate groups and protonated oxygen functions in humic matter. Changes in relaxation and correlation times of (1)H and (31)P signals and saturation transfer difference NMR experiments confirmed the noncovalent nature of GLY-humic interactions. Diffusion-ordered NMR spectra allowed calculation of the glyphosate fraction bound to humic superstructures and association constants (K(a)) and Gibbs free energies of transfer for GLY-humic complex formation at both pH values. These values showed that noncovalent interactions occurred most effectively with FAs and at pH 5.2. Our findings indicated that glyphosate may spontaneously and significantly bind to soluble humic matter by noncovalent interactions at slightly acidic pH and, thus, potentially pollute natural water bodies by moving through soil profiles in complexes with dissolved humus.

  18. Investigation of Fault Permeability in Sands with Different Mineral Compositions (Evaluation of Gas Hydrate Reservoir

    Directory of Open Access Journals (Sweden)

    Sho Kimura


    Full Text Available We used a ring-shear apparatus to examine the perpendicular permeability of sands with different mineral compositions to evaluate fault behavior around gas hydrate reservoirs. The effect of effective normal stress on the permeability of two sand types was investigated under constant effective normal stresses of 0.5–8.0 MPa. Although Toyoura sand and silica sand No. 7 mainly comprise quartz, silica sand No. 7 contains small amounts of feldspar. For Toyoura sand, the permeability after ring-shearing dramatically decreased with increasing effective normal stress up to 3.0 MPa, then gradually decreased for stresses over 3.0 MPa, whereas the permeability after ring-shearing of silica sand No. 7 rapidly decreased with increasing effective normal stress up to 2.0 MPa. Although the relationships between the permeability after ring-shearing and effective normal stress for both sands could be expressed by exponential equations up to 3.0 MPa, a more gradual change in slope was shown for Toyoura sand. The permeabilities of both sands were almost equal for effective normal stresses over 3.0 MPa. The mineralogical properties of the small amount of feldspar in the sample indicate that both mineralogy and original grain size distribution affect the fault permeability and shear zone formation.

  19. Bioenergetic evaluation of diel vertical migration by bull trout (Salvelinus confluentus) in a thermally stratified reservoir (United States)

    Eckmann, Madeleine; Dunham, Jason; Connor, Edward J.; Welch, Carmen A.


    Many species living in deeper lentic ecosystems exhibit daily movements that cycle through the water column, generally referred to as diel vertical migration (DVM). In this study, we applied bioenergetics modelling to evaluate growth as a hypothesis to explain DVM by bull trout (Salvelinus confluentus) in a thermally stratified reservoir (Ross Lake, WA, USA) during the peak of thermal stratification in July and August. Bioenergetics model parameters were derived from observed vertical distributions of temperature, prey and bull trout. Field sampling confirmed that bull trout prey almost exclusively on recently introduced redside shiner (Richardsonius balteatus). Model predictions revealed that deeper (>25 m) DVMs commonly exhibited by bull trout during peak thermal stratification cannot be explained by maximising growth. Survival, another common explanation for DVM, may have influenced bull trout depth use, but observations suggest there may be additional drivers of DVM. We propose these deeper summertime excursions may be partly explained by an alternative hypothesis: the importance of colder water for gametogenesis. In Ross Lake, reliance of bull trout on warm water prey (redside shiner) for consumption and growth poses a potential trade-off with the need for colder water for gametogenesis.

  20. Petrophysical properties evaluation of tight gas sand reservoirs using NMR and conventional openhole logs

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, G.M. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)


    Three petrophysical parameters of tight gas sand reservoirs were determined in this study. These complex reservoirs have low porosity and low permeability and are often enhanced by natural fracturing. Clay minerals such as illite, kaolin and micas are present in the pores. The complicity of tight reservoirs can also be attributed to heterogeneity in vertical and lateral directions. Conventional logs alone cannot determine the petrophysical properties of such complex tight gas reservoirs. Therefore, NMR was used on an individual basis as well as in combination with conventional open hole logs such as density magnetic resonance porosity (DMR) and bulk gas magnetic resonance permeability (KBGMR) to determine density porosity, permeability, capillary pressure, gas movement and bulk gas volume. The result were encouraging and significantly reduced the uncertainties in petrophysical parameters. 18 refs., 18 figs.

  1. Inland dissolved salt chemistry: statistical evaluation of bivariate and ternary diagram models for surface and subsurface waters

    Directory of Open Access Journals (Sweden)

    Stephen T. THRELKELD


    Full Text Available We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models even if large water bodies were evaluated separate from small water bodies. Atmospheric precipitation effects were identified using ternary diagrams in water with total dissolved salts (TDS 1000 mg l-1. A principal components analysis showed that the variability in the relative proportions of the major ions was related to atmospheric precipitation, weathering, and evaporation. About half of the variation in the distribution of inorganic ions was related to rock weathering. By considering most of the important inorganic ions, ternary diagrams are able to distinguish the contributions of atmospheric precipitation, rock weathering, and evaporation to inland water chemistry.

  2. Identification and evaluation of fluvial-dominated deltaic (Class I oil) reservoirs in Oklahoma. Final report, August 1998

    Energy Technology Data Exchange (ETDEWEB)

    Banken, M.K.


    The Oklahoma Geological Survey (OGS), the Geo Information Systems department, and the School of Petroleum and Geological Engineering at the University of Oklahoma have engaged in a five-year program to identify and address Oklahoma`s oil recovery opportunities in fluvial-dominated deltaic (FDD) reservoirs. This program included a systematic and comprehensive collection and evaluation of information on all FDD oil reservoirs in Oklahoma and the recovery technologies that have been (or could be) applied to those reservoirs with commercial success. The execution of this project was approached in phases. The first phase began in January, 1993 and consisted of planning, play identification and analysis, data acquisition, database development, and computer systems design. By the middle of 1994, many of these tasks were completed or nearly finished including the identification of all FDD reservoirs in Oklahoma, data collection, and defining play boundaries. By early 1995, a preliminary workshop schedule had been developed for project implementation and technology transfer activities. Later in 1995, the play workshop and publication series was initiated with the Morrow and the Booch plays. Concurrent with the initiation of the workshop series was the opening of a computer user lab that was developed for use by the petroleum industry. Industry response to the facility initially was slow, but after the first year lab usage began to increase and is sustaining. The remaining six play workshops were completed through 1996 and 1997, with the project ending on December 31, 1997.

  3. Laboratory and simulation approach to the polymer EOR evaluation in German reservoir characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, S.; Hincapie-Reina, R.; Ganzer, L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE


    Nowadays, polymer flooding is widely used as it enhances oil recovery. As polymer has relatively higher viscosity than water, which leads to better mobility ratio compared to it, and thus better sweep efficiency. However, this technique is limited by some factors. As normal polymers are not tolerant to high temperature or salinity or hardness, which lead to lose of most their viscosity, and thus lost their function in enhanced oil recovery. Therefore, new polymers which are resistant to high temperature, high salinity or other factors which may happen in the reservoir should be employed. In that direction, the present work focus in characterize two different polymers, Flopaam AN 125 and ZLPAM 22051, how they would be influenced by polymer concentration, salinity, shear rate and temperature, and to predict how they would work in the reservoir. A synthetic brine from a German reservoir (Valendis, Suderbruch Field) is used to analyze the polymer. In many different previous experiments is observed the divalent and monovalent effect of salt in polymers was carried out. Rheology characterization was done under the reservoir conditions to get the best approximation related to concentration, shear rate and temperature effect; filtration ratio and filterability plot are used as a quality check for the solutions. Finally, all the data is used into the Polymer Flood Predictive Model (PFPM), to figure out how polymer acted in German typical reservoir conditions, and the specific incremental in oil recovery and effect due the possible polymer application, which might provide information for future polymer flooding application decisions. (orig.)

  4. Composition of dissolved organic matter (DOM) from periodically submerged soils in the Three Gorges Reservoir areas as determined by elemental and optical analysis, infrared spectroscopy, pyrolysis-GC-MS and thermally assisted hydrolysis and methylation. (United States)

    Jiang, Tao; Kaal, Joeri; Liang, Jian; Zhang, Yaoling; Wei, Shiqiang; Wang, Dingyong; Green, Nelson W


    Soil-derived dissolved organic matter (DOM) has a major influence in biogeochemical processes related to contaminant dynamics and greenhouse gas emissions, due to its reactivity and its bridging role between the soil and aquatic systems. Within the Three Gorges Reservoir (TGR, China) area, an extensive water-fluctuation zone periodically submerges the surrounding soils. Here we report a characterization study of soil-derived DOM across the TGR areas, using elemental and optical analysis, infrared spectroscopy (FTIR), pyrolysis-GC-MS (Py-GC-MS) and thermally assisted hydrolysis and methylation (THM-GC-MS). The results showed that the soil DOM from the TGR area is a mixture of "allochthonous" (i.e., plant-derived/terrigenous) and "autochthonous" (i.e., microbial) origins. The terrigenous DOM is composed primarily of phenolic and aliphatic structures from lignin and aliphatic biopolymers (i.e. cutin, suberin), respectively. Multivariate statistics differentiated between two fractions of the microbial DOM, i.e. chitin-derived, perhaps from fungi and arthropods in soil, and protein-derived, partially sourced from algal or aquatic organisms. Molecular proxies of source and degradation state were in good agreement with optical parameters such as SUVA254, the fluorescence index (FI) and the humification index (HIX). The combined use of elemental analysis, fluorescence spectroscopy, and Py-GC-MS provides rigorous and detailed DOM characterization, whereas THM-GC-MS is useful for more precise but qualitative identification of the different phenolic (cinnamyl, p-hydroxyphenyl, guaiacyl, syringyl and tannin-derived) and aliphatic materials. With the multi-methodological approach used in this study, FTIR was the least informative, in part, because of the interference of inorganic matter in the soil DOM samples. The soil DOM from the TGR's water fluctuation zone exhibited considerable compositional diversity, mainly related to the balance between DOM source (microbial- or plant

  5. Spatio-temporal variability of solid, total dissolved and labile metal: passive vs. discrete sampling evaluation in river metal monitoring. (United States)

    Priadi, Cindy; Bourgeault, Adeline; Ayrault, Sophie; Gourlay-Francé, Catherine; Tusseau-Vuillemin, Marie-Hélène; Bonté, Philippe; Mouchel, Jean-Marie


    In order to obtain representative dissolved and solid samples from the aquatic environment, a spectrum of sampling methods are available, each one with different advantages and drawbacks. This article evaluates the use of discrete sampling and time-integrated sampling in illustrating medium-term spatial and temporal variation. Discrete concentration index (CI) calculated as the ratio between dissolved and solid metal concentrations in grab samples are compared with time-integrated concentration index (CI) calculated from suspended particulate matter (SPM) collected in sediment traps and labile metals measured by the diffusive gel in thin films (DGT) method, collected once a month during one year at the Seine River, upstream and downstream of the Greater Paris Region. Discrete CI at Bougival was found to be significantly higher than at Triel for Co, Cu, Mn, Ni and Zn, while discrete metal partitioning at Marnay was found to be similar to Bougival and Triel. However, when using time-integrated CI, not only was Bougival CI significantly higher than Triel CI, CI at Marnay was also found to be significantly higher than CI at Triel which was not observed for discrete CI values. Since values are time-averaged, dramatic fluctuations were smoothed out and significant medium-term trends were enhanced. As a result, time-integrated concentration index (CI) was able to better illustrate urbanization impact between sites when compared to discrete CI. The impact of significant seasonal phenomenon such as winter flood, low flow and redox cycles was also, to a certain extent, visible in time-integrated CI values at the upstream site. The use of time-integrated concentration index may be useful for medium- to long-term metal studies in the aquatic environment.

  6. Reservoir evaluation tests on RRGE 1 and RRGE 2, Raft River Geothermal Project, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, T.N.; Witherspoon, P.A.


    Results of the production and interference tests conducted on the geothermal wells RRGE 1 and RRGE 2 in Raft River Valley, Idaho during September--November, 1975 are presented. In all, three tests were conducted, two of them being short-duration production tests and one, a long duration interference test. In addition to providing estimates on the permeability and storage parameters of the geothermal reservoir, the tests also indicated the possible existence of barrier boundaries. The data collected during the tests also indicated that the reservoir pressure varies systematically in response to the changes in the Earth's gravitational field caused by the passage of the sun and the moon. Overall, the results of the tests indicate that the geothermal reservoir in southern Raft River valley is fairly extensive and significantly permeable and merits further exploration.

  7. Design and evaluation of fast dissolving tablets containing diclofenac sodium using fenugreek gum as a natural superdisintegrant. (United States)

    Kumar, M Uday; Babu, M Kishore


    To formulate diclofenac sodium as fast dissolving tablets (FDTs) using fenugreek gum as a natural superdisintegrant which also possess anti-inflammatory activity. An attempt was made to extract the fenugreek gum and evaluated it for various physicochemical characterizations. The swelling index and viscosity of fenugreek gum was 221% and 293.4 mpa.s respectively. FDTs of diclofenac sodium was formulated by direct compression technique using different concentrations (1%-6%, w/w) of fenugreek gum as a natural superdisintegrant and compared with renowned synthetic superdisintegrants like sodium starch glycolate and croscarmellose sodium. The anti-inflammatory activity of a formulation was evaluated with carrageenan induced experimental rats. The formulated tablets were evaluated for various physical tests like weight variation, friability, hardness and results complied with the limits. The drug release from all the formulations ascertained first order kinetics. Among all the formulations F3 containing fenugreek gum with the concentration of 6% produced least disintegrating time 21 seconds resulting in higher drug release rate 93.74% at the end of 25 min. Hence, it was considered as optimized formulation. The present study revealed that the fenugreek gum as a natural superdisintegrant showed better disintegrating property than the most widely used synthetic superdisintegrants like sodium starch glycolate and croscarmellose sodium in the formulations of FDTs. The results suggested that the fenugreek gum act as a good super disintegrating agent and it showed promising additive anti-inflammatory activity with diclofenac sodium.

  8. Evaluation of microbial transformations of dissolved organic matter - what information can be extracted from high-field FTICR-MS elemental formula data sets? (United States)

    Herzsprung, Peter; von Tümpling, Wolf; Harir, Mourad; Hertkorn, Norbert; Schmitt-Kopplin, Philippe; Norf, Helge; Weitere, Markus; Kamjunke, Norbert


    ). They were highly saturated and oxygen-poor (lipid-like). As a conclusion components of biogeochemical groups (specified by their H/C and O/C coordinates in Van Krevelen diagrams) can be allocated to DOM transformation processes by their tendency of intensity change. References 1) Lechtenfeld, O.J., Kattner, G., Flerus, R., McCallister, S.L., Schmitt-Kopplin, P., Koch, B.P., 2014. Molecular transformation and degradation of refractory dissolved organic matter in the Atlantic and Southern Ocean. Geochim. Cosmochim. Acta 126, 321-337. 2) Morling, K., Herzsprung, P., Kamjunke, N., 2017. Discharge determines production of, decomposition of and quality changes in dissolved organic carbon in pre-dams of drinking water reservoirs. Sci. Tot. Environ. 577, 329-339. 3) Ohno, T., Parr, T.B., Gruselle, M.C.I., Fernandez, I.J., Sleighter, R.L., Hatcher, P.G., 2014. Molecular Composition and Biodegradability of Soil Organic Matter: A Case Study Comparing Two New England Forest Types. Environ. Sci. Technol. 48, 7229 - 7236.

  9. Geothermal reservoir technology

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J.


    A status report on Lawrence Berkeley Laboratory's Reservoir Technology projects under DOE's Hydrothermal Research Subprogram is presented. During FY 1985 significant accomplishments were made in developing and evaluating methods for (1) describing geothermal systems and processes; (2) predicting reservoir changes; (3) mapping faults and fractures; and (4) field data analysis. In addition, LBL assisted DOE in establishing the research needs of the geothermal industry in the area of Reservoir Technology. 15 refs., 5 figs.

  10. Evaluation of linear solvers for oil reservoir simulation problems. Part 2: The fully implicit case

    Energy Technology Data Exchange (ETDEWEB)

    Joubert, W.; Janardhan, R.


    A previous paper [Joubert/Biswas 1997] contained investigations of linear solver performance for matrices arising from Amoco`s Falcon parallel oil reservoir simulation code using the IMPES formulation (implicit pressure, explicit saturation). In this companion paper, similar issues are explored for linear solvers applied to matrices arising from more difficult fully implicit problems. The results of numerical experiments are given.

  11. Evaluating changes to reservoir rule curves using historical water-level data (United States)

    Mower, Ethan; Miranda, Leandro E.


    Flood control reservoirs are typically managed through rule curves (i.e. target water levels) which control the storage and release timing of flood waters. Changes to rule curves are often contemplated and requested by various user groups and management agencies with no information available about the actual flood risk of such requests. Methods of estimating flood risk in reservoirs are not easily available to those unfamiliar with hydrological models that track water movement through a river basin. We developed a quantile regression model that uses readily available daily water-level data to estimate risk of spilling. Our model provided a relatively simple process for estimating the maximum applicable water level under a specific flood risk for any day of the year. This water level represents an upper-limit umbrella under which water levels can be operated in a variety of ways. Our model allows the visualization of water-level management under a user-specified flood risk and provides a framework for incorporating the effect of a changing environment on water-level management in reservoirs, but is not designed to replace existing hydrological models. The model can improve communication and collaboration among agencies responsible for managing natural resources dependent on reservoir water levels.

  12. The methods of evaluating storage volume for single-chamber reservoir in urban catchments

    Directory of Open Access Journals (Sweden)

    Szeląg Bartosz


    Full Text Available The article presents a method of designing single-chamber rectangular detention reservoirs based on nomographs connecting the parameters and the shape of the inflow with the reservoir hydrograph (triangular, described by the power function and described by the gamma distribution as well as the hydraulic characteristics of the accumulation chamber and the orifice. The preparation of nomographs involved using the SWMM (Storm Water Management Model program with the application of numerical calculations’ results of a differential equation for the stormwater volume balance. The performed analyses confirm a high level of similarity between the results of calculating the reservoir volume obtained by using the above mentioned program and using the developed nomographs. The examples of calculations presented in the paper confirm the application aspects of the discussed method of designing the detention reservoir. Moreover, based on the conducted analyses it was concluded that the inflow hydrograph described by the gamma distribution has the greatest impact on the reservoir’s storage volume, whereas the hydrograph whose shape in the rise and recession phases is described by the power function has the smallest effect.

  13. New Approach for Evaluation of a Watershed Ecosystem Service for Avoiding Reservoir Sedimentation and Its Economic Value: A Case Study from Ertan Reservoir in Yalong River, China

    Directory of Open Access Journals (Sweden)

    Bilige Sude


    Full Text Available A model was established to simulate an ecosystem service of avoiding reservoir sedimentation and its economic value based on the process of sediment delivery in a watershed. The model included fabricating the watershed of the study reservoir. The sediment retention coefficient of different land cover types were used to simulate the spatial patterns of the annual quantity of the sediment that were prevented from entering the reservoir by the vegetation in each cell followed the flow path in watershed. The economic value of the ecosystem service in this model was determined by the marginal cost of reservoir desilting. This study took the Ertan reservoir as an example. The results showed that most eroded soil was intercepted by different types of ecosystems in the process of sediment delivery in a watershed. The region with a higher quantity of sediment retention was around the reservoir. The absolute quantity of average sediment retention in forestland was lower, so the sediment retention ability of forestland failed to be brought into fullest play in watershed.

  14. The effect of question order on evaluations of test performance: Can the bias dissolve? (United States)

    Bard, Gabriele; Weinstein, Yana


    Question difficulty order has been shown to affect students' global postdictions of test performance. We attempted to eliminate the bias by letting participants experience the question order manipulation multiple times. In all three experiments, participants answered general knowledge questions and self-evaluated their performance. In Experiment 1, participants studied questions and answers in easy-hard or hard-easy question order prior to taking a test in the same order. In Experiment 2, participants took the same test twice in the opposite question order (easy-hard then hard-easy, or hard-easy then easy-hard). In Experiment 3, participants took two different tests in the opposite question order (easy-hard then hard-easy, or hard-easy then easy-hard). In all three experiments, we were unable to eliminate the bias, which suggests that repeated exposure is insufficient to overcome a strong initial anchor.

  15. Monitoring water quality in reservoirs for human supply through multi-biomarker evaluation in tropical fish. (United States)

    de Andrade Brito, Izabella; Arruda Freire, Carolina; Yamamoto, Flávia Yoshie; Silva de Assis, Helena Cristina; Rodrigues Souza-Bastos, Luciana; Cestari, Marta Margarete; de Castilhos Ghisi, Nédia; Prodocimo, Viviane; Filipak Neto, Francisco; de Oliveira Ribeiro, Ciro Alberto


    Paraíba do Sul River is located at a very densely inhabited region of Brazil crossing the three most industrialized states of the country (São Paulo, Minas Gerais and Rio de Janeiro states). As a result, industrial and farming residues as well as urban sewage are frequently disposed without appropriate treatment. The current study aimed at investigating the water quality in three reservoirs along the Paraíba do Sul River (Ilha dos Pombos, Santa Cecília and Santa Branca), through physiological, morphological, biochemical, and genetic biomarkers. The bioindicator chosen was the catfish Pimelodus maculatus, sampled during the dry (June 2008) and rainy (February 2009) seasons. Also, some water physicochemical parameters were analyzed from the sampling sites, but displayed no alterations according to the Brazilian Agency for Water Quality Legislation. Branchial carbonic anhydrase activity was inhibited in the dry season, while renal carbonic anhydrase activity was inhibited in the rainy season in the Santa Branca reservoir, indicating disturbance of osmoregulatory and acid-base regulation processes. Histopathological alterations were observed in the gills (neoplasic and tissue hyperplasia processes) and liver (necrosis), indicating serious damage to the functional integrity of these organs. A high incidence of melanomacrophage centers was observed in the liver, suggesting an intense immune response in all reservoirs. Acetylcholinesterase and catalase activity showed also differences corroborating some morphological results. Likewise, the induction of the micronucleus and DNA damage indicate genotoxicity, but mainly in the Santa Branca reservoir. Thus, the health status of P. maculatus warrants caution in the use of the water from the 3 reservoirs for direct human consumption, particularly after the accidental spill of endosulfan in November 2008, three months before the rainy season sampling.

  16. Seismic and well logging interpretation for evaluation of the lower Bahariya reservoir, southwest Qarun (SWQ) Field, Gindi Basin, Egypt (United States)

    Sarhan, Mohammad Abdelfattah; Basal, A. M. K.; Ibrahim, Ibrahim Mohamed


    This paper focuses on seismic and well log interpretations for evaluating the sandstones of the Cenomanian Bahariya Formation in the southwest Qarun Field, Gindi Basin, northern Western Desert of Egypt. The seismic profiles display a clear anticlinal structure intersected by reverse faults in the study area. This faulted anticline has been interpreted to be one of the Syrian arc system folds formed by Upper Cretaceous tectonic inversion, which resulted from the NW movement of the African Plate relative to Laurasia. This anticline has been recommended as a target for exploration by the present work as it may represent a structural trap for hydrocarbon accumulation. The sandstones of the Lower Bahariya Formation in the southwest Qarun Field display good reservoir characteristics. The interpretation of the available well log data for the SWQ-21 and SWQ-25 wells for the Lower Bahariya Formation reflects a good reservoir quality for oil production in its topmost part. This reservoir possesses low SW (<50%), high porosity (16%), low SW/SXO and low BVW (<0.09) which all reflect a high potential for oil production.

  17. Modeling energy flow in a large Neotropical reservoir: a tool do evaluate fishing and stability

    Directory of Open Access Journals (Sweden)

    Ronaldo Angelini

    Full Text Available Recently, there is an increasing perception that the ecosystem approach gives important insights to support fisheries stock assessment and management. This paper aims to quantify energy flows in the Itaipu Reservoir (Brazil and to simulate increase of the fishing effort of some species, using Ecopath with Ecosim software, which could allow inferences on stability. Therefore, two steady-state Itaipu models were built (1983-87 and 1988-92. Results showed that: a there are no differences between models, and results on aging trends do not vary over time indicating that fishery does not alter the ecosystem as a whole; b results of fisheries simulations are approximate to mono-specific stock assessment for the same species and periods; c many authors believe that tropical ecosystems are environments where biotic and abiotic oscillations are annual and sometimes unexpected, but the results found for the Itaipu Reservoir indicate that stability was met after 16 years.

  18. Reservoir volume optimization and performance evaluation of rooftop catchment systems in arid regions: A case study of Birjand, Iran

    Directory of Open Access Journals (Sweden)

    Zinat Komeh


    Full Text Available This study evaluated the performance of rooftop catchment systems in securing non-potable water supply in Birjand, located in an arid area in southeastern Iran. The rooftop catchment systems at seven study sites of different residential buildings were simulated for dry, normal, and wet water years, using 31-year rainfall records. The trial and error approach and mass diagram method were employed to optimize the volume of reservoirs in five different operation scenarios. Results showed that, during the dry water year from 2000 to 2001, for reservoirs with volumes of 200–20000 L, the proportion of days that could be secured for non-portable water supply was on average computed to be 16.4%–32.6% across all study sites. During the normal water year from 2009 to 2010 and the wet water year from 1995 to 1996, for reservoirs with volumes of 200–20000 L, the proportions were 20.8%–69.6% and 26.8%–80.3%, respectively. Therefore, a rooftop catchment system showed a high potential to meet a significant portion of non-potable water demand in the Birjand climatic region. Reservoir volume optimization using the mass diagram method produced results consistent with those obtained with the trial and error approach, except at sites #1, #2, and #5. At these sites, the trial and error approach performed better than the mass diagram method due to relatively high water consumption. It is concluded that the rooftop catchment system is applicable under the same climatic conditions as the study area, and it can be used as a drought mitigation strategy as well.

  19. Evaluation of using Smart Water to enhance oil recovery from Norwegian Continental Shelf sandstone reservoirs.


    Piotrowska, Natalia


    Master's thesis in Petroleum engineering. Recently, the scale of studies on smart water – one of EOR method - has increased. From decades, water flooding is one of the most used methods to increase oil recovery. However, more effective in sandstone reservoirs is injecting low salinity brine. Due to changing wettability, improved oil mobility in pores can be reached. The studies show, that the significant increase of oil recovery might be achieved. Main objective of the thesis is to answ...

  20. Fast Dissolving Sublingual Films Containing Sumatriptan Alone and Combined with Methoclopramide: Evaluation in Vitro Drug Release and Mucosal Permeation

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi, Mahdieh Rahmani, Hamed Ghavimi, Seyed Hassan Montazam, Saieede Soltani, Mitra Alami, Sara Salatin, Mitra Jelvehgari


    Full Text Available ackground: Sumatriptan succinate is a 5-HT1 receptor agonist which is used in the treatment of migraine. It shows low bioavailability (15% due to high hepatic first pass metabolism. The present work intended to formulate mucoadhesive sublingual films of sumatriptan combined with metoclopramide and sumatriptan alone with the objective of improving the therapeutic efficacy, patient compliance, and bioavailability. Methods: The sublingual films were formulated by solvent casting technique using mucoadhesive polymer of hydroxypropyl methylcellulose and propylene glycol as plasticizers. This study was also designed to evaluate the physicochemical and mucoadhesive characteristics of the films. The films were evaluated for their mechanical strength, folding endurance, drug content uniformity, swelling, in vitro residence time, in vitro release, in vitro bioadhesion, and in vivo mucoadhesion. Results: They showed good appearance and elasticity. The best drugs of polymer ratio were S3 (1:2 and SM2 (2.7:1:8. The film of S3 and SM2 showed 10.6 and 11.01 mg weight, 2.2 and 22.5 µm thickness, 300 folding endurance, 55.9 and 100% content uniformity, respectively. The Differential Scanning Calorimetry (DSC showed no stable sample of sumatriptan and metoclopramide in the drug loaded films and revealed amorphous form and transition of hydrate to anhydrous form for metoclopramide. The results showed that the films prepared were fast dissolving. The films (sumatriptan combined with metoclopramide and sumatriptan alone exhibited very good mucoadhesive properties and shorter retention time (15-30 s. Conclusion: The formulations were found to be suitable candidates for the development of sublingual films for therapeutic uses.

  1. Evaluation of Management of Water Releases for Painted Rocks Reservoir, Bitterroot River, Montana, 1983-1986, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Spoon, Ronald L. (Montana Department of Fish, Wildlife and Parks, Missoula, MT)


    This study was initiated in July, 1983 to develop a water management plan for the release of water purchased from Painted Rocks Reservoir. Releases were designed to provide optimum benefits to the Bitterroot River fishery. Fisheries, habitat, and stream flow information was gathered to evaluate the effectiveness of these supplemental releases in improving trout populations in the Bitterroot River. The study was part of the Northwest Power Planning Council's Fish and Wildlife Program and was funded by the Bonneville Power Administration. This report presents data collected from 1983 through 1986.

  2. Silurian "Clinton" Sandstone Reservoir Characterization for Evaluation of CO2-EOR Potential in the East Canton Oil Field, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Riley; John Wicks; Christopher Perry


    The purpose of this study was to evaluate the efficacy of using CO2-enhanced oil recovery (EOR) in the East Canton oil field (ECOF). Discovered in 1947, the ECOF in northeastern Ohio has produced approximately 95 million barrels (MMbbl) of oil from the Silurian 'Clinton' sandstone. The original oil-in-place (OOIP) for this field was approximately 1.5 billion bbl and this study estimates by modeling known reservoir parameters, that between 76 and 279 MMbbl of additional oil could be produced through secondary recovery in this field, depending on the fluid and formation response to CO2 injection. A CO2 cyclic test ('Huff-n-Puff') was conducted on a well in Stark County to test the injectivity in a 'Clinton'-producing oil well in the ECOF and estimate the dispersion or potential breakthrough of the CO2 to surrounding wells. Eighty-one tons of CO2 (1.39 MMCF) were injected over a 20-hour period, after which the well was shut in for a 32-day 'soak' period before production was resumed. Results demonstrated injection rates of 1.67 MMCF of gas per day, which was much higher than anticipated and no CO2 was detected in gas samples taken from eight immediately offsetting observation wells. All data collected during this test was analyzed, interpreted, and incorporated into the reservoir characterization study and used to develop the geologic model. The geologic model was used as input into a reservoir simulation performed by Fekete Associates, Inc., to estimate the behavior of reservoir fluids when large quantities of CO2 are injected into the 'Clinton' sandstone. Results strongly suggest that the majority of the injected CO2 entered the matrix porosity of the reservoir pay zones, where it diffused into the oil. Evidence includes: (A) the volume of injected CO2 greatly exceeded the estimated capacity of the hydraulic fracture and natural fractures; (B) there was a gradual injection and pressure rate build-up during the test

  3. Silurian "Clinton" Sandstone Reservoir Characterization for Evaluation of CO2-EOR Potential in the East Canton Oil Field, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Ronald; Wicks, John; Perry, Christopher


    The purpose of this study was to evaluate the efficacy of using CO2-enhanced oil recovery (EOR) in the East Canton oil field (ECOF). Discovered in 1947, the ECOF in northeastern Ohio has produced approximately 95 million barrels (MMbbl) of oil from the Silurian “Clinton” sandstone. The original oil-in-place (OOIP) for this field was approximately 1.5 billion bbl and this study estimates by modeling known reservoir parameters, that between 76 and 279 MMbbl of additional oil could be produced through secondary recovery in this field, depending on the fluid and formation response to CO2 injection. A CO2 cyclic test (“Huff-n-Puff”) was conducted on a well in Stark County to test the injectivity in a “Clinton”-producing oil well in the ECOF and estimate the dispersion or potential breakthrough of the CO2 to surrounding wells. Eighty-one tons of CO2 (1.39 MMCF) were injected over a 20-hour period, after which the well was shut in for a 32-day “soak” period before production was resumed. Results demonstrated injection rates of 1.67 MMCF of gas per day, which was much higher than anticipated and no CO2 was detected in gas samples taken from eight immediately offsetting observation wells. All data collected during this test was analyzed, interpreted, and incorporated into the reservoir characterization study and used to develop the geologic model. The geologic model was used as input into a reservoir simulation performed by Fekete Associates, Inc., to estimate the behavior of reservoir fluids when large quantities of CO2 are injected into the “Clinton” sandstone. Results strongly suggest that the majority of the injected CO2 entered the matrix porosity of the reservoir pay zones, where it diffused into the oil. Evidence includes: (A) the volume of injected CO2 greatly exceeded the estimated capacity of the hydraulic fracture and natural fractures; (B) there was a gradual injection and pressure rate build-up during the test; (C) there was a subsequent

  4. A methodology to evaluate regional hydraulic controls on flow from hydrocarbon reservoirs into overlying aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Fryar, A.E.; Kreitler, C.W.; Akhter, M.C. [Bureau of Economic Geology, Austin, TX (United States)] [and others


    Because drilling, completion, and abandonment practices for oil and gas wells have improved over the past century, some older abandoned wells may be mechanically deficient or inadequately plugged, thus posing a risk of contamination to underground sources of drinking water. The risk of saltwater contamination of freshwater aquifers through inadequately plugged, abandoned wells increases if the hydraulic potential of the oil- and-gas-bearing brine formations is higher than that in the overlying freshwater aquifers. First, average regional potentiometric surfaces of aquifers and reservoirs are generated from aquifer water-level measurements and the conversion of bottom-hole pressure measurements from oil and gas reservoirs to hydraulic heads. Next, differences in hydraulic heads between aquifers and reservoirs are calculated to delineate regional residual areas of upward (positive) or downward (negative) hydraulic gradients. Third, locations of abandoned wells and class II injection wells are plotted relative to residuals to examine where water flooding, pressure maintenance, and saltwater disposal may cause or exacerbate the potential for upward flow. Three areas were used as case studies for testing the method. Positive residuals in the South Texas basin (informally defined to include the Val Verde basin, Maverick basin, part of the Rio Grande Salt basin, and the Austin Chalk trend) result from natural geopressuring in formations deeper than 6000 ft, which are negligibly affected by class II injection wells. Positive residuals in the greater Permian basin (including the northwestern shelf, Delaware basin, part of the Palo Duro basin, Central Basin platform, Midland basin, southern shelf, and Fort Worth basin) may reflect injection for enhanced recovery in the west and natural hydrologic processes in the eastern shelf region. Residual surfaces for the San Juan basin indicate several areas with a natural potential for upward migration of brine.

  5. Evaluation of reagentless pH modification for in situ ocean analysis: determination of dissolved inorganic carbon using mass spectrometry. (United States)

    Cardenas-Valencia, Andres M; Adornato, Lori R; Bell, Ryan J; Byrne, Robert H; Short, R Timothy


    In situ analytical techniques that require the storage and delivery of reagents (e.g., acidic or basic solutions) have inherent durability limitations. The reagentless electrolytic technique for pH modification presented here was developed primarily to ease and to extend the longevity of dissolved inorganic carbon (DIC) determinations in seawater, but can also be used for other analytical methods. DIC, a primary carbon dioxide (CO(2)) system variable along with alkalinity, controls seawater pH, carbonate saturation state, and CO(2) fugacity. Determinations of these parameters are central to an understanding of ocean acidification and global climate change. Electrodes fabricated with electroactive materials, including manganese(III) oxide (Mn(2)O(3)) and palladium (Pd), were examined for potential use in electrolytic acidification. In-line acidification techniques were evaluated using a bench-top membrane introduction mass spectrometry (MIMS) setup to determine the DIC content of artificial seawater. Linear least-squares (LLSQ) calibrations for DIC concentration determinations over a range between 1650 and 2400 µmol kg(-1) were obtained, using both the novel electrolytic and conventional acid addition techniques. At sample rates of 4.5 mL min(-1), electrodes clad with Mn(2)O(3) and Pd were able to change seawater pH from 7.6 to 2.8 with a power consumption of less than 3 W. Although calibration curves were influenced by sampling rates at a flow of 4.5 mL min(-1), the 1σ measurement precision for DIC was of the order of ±20 µmol kg(-1). Calibrations obtained with the novel reagentless technique and the in-line addition of strong acid showed similar capabilities for DIC quantification. However, calculations of power savings for the reagentless technique relative to the mechanical delivery of stored acid demonstrated substantial advantages of the electrolytic technique for long-term deployments (>1 year). Copyright © 2013 John Wiley & Sons, Ltd.

  6. Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs

    Directory of Open Access Journals (Sweden)

    Jinzhi Zhu


    Full Text Available In order to explore the damage mechanisms and improve the method to evaluate and optimize the performance of formation damage control of oil-based drill-in fluids, this paper took an ultra-deep fractured tight gas reservoir in piedmont configuration, located in the Cretaceous Bashijiqike Fm of the Tarim Basin, as an example. First, evaluation experiments were conducted on the filtrate invasion, the dynamic damage of oil-based drill-in fluids and the loading capacity of filter cakes. Meanwhile, the evaluating methods were optimized for the formation damage control effect of oil-based drill-in fluids in laboratory: pre-processing drill-in fluids before grading analysis; using the dynamic damage method to simulate the damage process for evaluating the percentage of regained permeability; and evaluating the loading capacity of filter cakes. The experimental results show that (1 oil phase trapping damage and solid phase invasion are the main formation damage types; (2 the damage degree of filtrate is the strongest on the matrix; and (3 the dynamic damage degree of oil-based drill-in fluids reaches medium strong to strong on fractures and filter cakes show a good sealing capacity for the fractures less than 100 μm. In conclusion, the filter cakes' loading capacity should be first guaranteed, and both percentage of regained permeability and liquid trapping damage degree should be both considered in the oil-based drill-in fluids prepared for those ultra-deep fractured tight sandstone gas reservoirs.

  7. Evaluation of the Theoretical Geothermal Potential of Inferred Geothermal Reservoirs within the Vicano–Cimino and the Sabatini Volcanic Districts (Central Italy by the Application of the Volume Method

    Directory of Open Access Journals (Sweden)

    Daniele Cinti


    Full Text Available The evaluation of the theoretical geothermal potential of identified unexploited hydrothermal reservoirs within the Vicano–Cimino and Sabatini volcanic districts (Latium region, Italy has been made on the basis of a revised version of the classical volume method. This method is based on the distribution of the partial pressure of CO2 (pCO2 in shallow and deep aquifers to delimit areas of geothermal interest, according to the hypothesis that zones of high CO2 flux, either from soil degassing and dissolved into aquifers, are spatially related to deep hydrothermal reservoirs. On the whole, 664 fluid discharges (cold waters, thermal waters, and bubbling pools have been collected from shallow and deep aquifers in the Vicano–Cimino Volcanic District and the Sabatini Volcanic District for chemical and isotopic composition, in an area of approximately 2800 km2. From this large hydro-geochemical dataset the pCO2 values have been computed and then processed to obtain a contour map of its spatial distribution by using geostatistical techniques (kriging. The map of pCO2 has been used to draw up the boundaries of potentially exploitable geothermal systems within the two volcanic districts, corresponding to the areas where endogenous CO2 raise up to the surface from the deep hydrothermal reservoirs. The overall estimated potential productivities and theoretical minimum and maximum thermal power of the two volcanic districts are of about 45 × 103 t/h and 3681–5594 MWt, respectively. This makes the Vicano–Cimino Volcanic District and the Sabatini Volcanic District very suitable for both direct and indirect exploitation of the geothermal resources, in view of the target to reduce electricity generation from conventional and poorly sustainable energy sources.

  8. Evaluation of optimal reservoir prospectivity using acoustic-impedance model inversion: A case study of an offshore field, western Niger Delta, Nigeria (United States)

    Oyeyemi, Kehinde D.; Olowokere, Mary T.; Aizebeokhai, Ahzegbobor P.


    The evaluation of economic potential of any hydrocarbon field involves the understanding of the reservoir lithofacies and porosity variations. This in turns contributes immensely towards subsequent reservoir management and field development. In this study, integrated 3D seismic data and well log data were employed to assess the quality and prospectivity of the delineated reservoirs (H1-H5) within the OPO field, western Niger Delta using a model-based seismic inversion technique. The model inversion results revealed four distinct sedimentary packages based on the subsurface acoustic impedance properties and shale contents. Low acoustic impedance model values were associated with the delineated hydrocarbon bearing units, denoting their high porosity and good quality. Application of model-based inverted velocity, density and acoustic impedance properties on the generated time slices of reservoirs also revealed a regional fault and prospects within the field.

  9. Development and in vitro evaluation of mesalamine delayed release pellets and tableted reservoir-type pellets. (United States)

    Bendas, Ehab R; Christensen, J Mark; Ayres, James W


    The basic objective of this study was to develop a novel technique that aids in compaction of coated pellets into tablets and obtain a release pattern from compressed pellets resembling the same pattern before compression. Multi-unit dosage forms of mesalamine targeted to the colon were formulated by extrusion-spheronization, and then coated with Eudragit S (30%). These pellets were filled into gelatin capsules or further formulated and compressed into tablets. Tablets for colonic delivery of mesalamine were prepared by mixing the coated beads with cushioning agents like stearic acid and Explotab, or by applying an additional coat of gelatin (4% weight gain) onto the Eudragit S coated pellets, and then compressing into tablets (tableted reservoir-type pellets). Then additional coating of the tablets prepared by the coating technique was applied utilizing Eudragit L 100-55 (5% weight gain). This technique provides additive protection for the coated beads to withstand the compression force during tableting. Excellent in vitro dissolution results were obtained, which were comparable to the results of the release of mesalamine from uncompressed beads filled in capsules. Mesalamine release from the capsules was 0.3% after 2 hours in gastric pH, 0.37% was released after an additional 1 hour in pH 6, and 89% was released after 1.5 hours in colonic pH 7.2. Various formulation and process parameters have to be optimized in order to obtain tableted reservoir-type pellets having the same release properties as the uncompressed pellets. The coating technique delays the release of mesalamine until the beads reach the terminal ileum and colon. Once released in the colon, mesalamine is minimally absorbed and can act locally to treat ulcerative colitis.

  10. Application of nuclear magnetic resonance logs for evaluating low-resistivity reservoirs: a case study from the Cambay basin, India (United States)

    Chatterjee, Rima; Datta Gupta, Saurabh; Farooqui, M. Y.


    Low-resistivity pay sands have been identified in four wells, namely: AM-7, AM-8, TA-1 and TA-5, which penetrate the Eocene pay-IV (EP-IV) sand unit of the Kalol formation in the Cambay basin. These wells are located near the Dholka and Kanwara oilfields in the Cambay basin. The main objective of this paper is to evaluate nuclear magnetic resonance (NMR) logs of the low-resistivity reservoirs from these four wells and to determine the petrophysical properties more accurately than conventional logs have done. The thickness of low-resistivity sand varies from 5 to 17 m in the wells under the study area. The formation has been characterized by a high surface area; thus irreducible water saturation (Swi) is high. The resistivity of these pay zones varies from 1 to 8 Ωm and the total NMR porosity ranges from 15% to 50%. The free fluid porosity ranges from 2% to 5% in wells TA-1 and TA-5 and 12-20% in wells AM-7 and AM-8. The Timur-Coates/SDR model derived that the permeability of the low-resistivity reservoir ranges from 0.8 to 1.5 md in wells TA-1 and TA-5 and 10-110 md in wells AM-7 and AM-8.

  11. Evaluation and use of a diffusion-controlled sampler for determining chemical and dissolved oxygen gradients at the sediment-water interface (United States)

    Simon, N.S.; Kennedy, M.M.; Massoni, C.S.


    Field and laboratory evaluations were made of a simple, inexpensive diffusion-controlled sampler with ports on two sides at each interval which incorporates 0.2-??m polycarbonate membrane to filter samples in situ. Monovalent and divalent ions reached 90% of equilibrium between sampler contents and the external solution within 3 and 6 hours, respectively. Sediment interstitial water chemical gradients to depths of tens of centimeters were obtained within several days after placement. Gradients were consistent with those determined from interstitial water obtained by centrifugation of adjacent sediment. Ten milliliter sample volumes were collected at 1-cm intervals to determine chemical gradients and dissolved oxygen profiles at depth and at the interface between the sediment and water column. The flux of dissolved species, including oxygen, across the sediment-water interface can be assessed more accurately using this sampler than by using data collected from benthic cores. ?? 1985 Dr W. Junk Publishers.

  12. Drainage-system development in consecutive melt seasons at a polythermal, Arctic glacier, evaluated by flow-recession analysis and linear-reservoir simulation. (United States)

    Hodgkins, Richard; Cooper, Richard; Tranter, Martyn; Wadham, Jemma


    [1] The drainage systems of polythermal glaciers play an important role in high-latitude hydrology, and are determinants of ice flow rate. Flow-recession analysis and linear-reservoir simulation of runoff time series are here used to evaluate seasonal and inter-annual variability in the drainage system of the polythermal Finsterwalderbreen, Svalbard, in 1999 and 2000. Linear-flow recessions are pervasive, with mean coefficients of a fast reservoir varying from 16 (1999) to 41 h (2000), and mean coefficients of an intermittent, slow reservoir varying from 54 (1999) to 114 h (2000). Drainage-system efficiency is greater overall in the first of the two seasons, the simplest explanation of which is more rapid depletion of the snow cover. Reservoir coefficients generally decline during each season (at 0.22 h d(-1) in 1999 and 0.52 h d(-1) in 2000), denoting an increase in drainage efficiency. However, coefficients do not exhibit a consistent relationship with discharge. Finsterwalderbreen therefore appears to behave as an intermediate case between temperate glaciers and other polythermal glaciers with smaller proportions of temperate ice. Linear-reservoir runoff simulations exhibit limited sensitivity to a relatively wide range of reservoir coefficients, although the use of fixed coefficients in a spatially lumped model can generate significant subseasonal error. At Finsterwalderbreen, an ice-marginal channel with the characteristics of a fast reservoir, and a subglacial upwelling with the characteristics of a slow reservoir, both route meltwater to the terminus. This suggests that drainage-system components of significantly contrasting efficiencies can coexist spatially and temporally at polythermal glaciers.

  13. Data for "Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin" (United States)

    U.S. Environmental Protection Agency — Dissolved oxygen, dissolved nitrous oxide, and water temperature in reservoirs. This dataset is associated with the following publication: Beaulieu , J., C. Nietch ,...

  14. Advanced Reservoir Characterization and Evaluation of C02 Gravity Drainage in the Naturally Fractured Sprayberry Trend Area

    Energy Technology Data Exchange (ETDEWEB)

    David S. Schechter


    The objective is to assess the economic feasibility of CO2 flooding of the naturally fractured Straberry Trend Area in west Texas. Research is being conducted in the extensive characterization of the reservoirs, the experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, the analytical and numerical simulation of Spraberry reservoirs, and the experimental investigations on CO2 gravity drainage in Spraberry whole cores.

  15. Evaluation of a Ferrozine Based Autonomous in Situ Lab-on-Chip Analyzer for Dissolved Iron Species in Coastal Waters

    Directory of Open Access Journals (Sweden)

    Felix Geißler


    Full Text Available The trace metal iron (Fe is an essential micronutrient for phytoplankton growth and limits, or co-limits primary production across much of the world's surface ocean. Iron is a redox sensitive element, with Fe(II and Fe(III co-existing in natural waters. Whilst Fe(II is the most soluble form, it is also transient with rapid oxidation rates in oxic seawater. Measurements of Fe(II are therefore preferably undertaken in situ. For this purpose an autonomous wet chemical analyzer based on lab-on-chip technology was developed for the in situ determination of the concentration of dissolved (<0.45 μm Fe species (Fe(II and labile Fe suitable for deployments in a wide range of aquatic environments. The spectrophotometric approach utilizes a buffered ferrozine solution and a ferrozine/ascorbic acid mixture for Fe(II and labile Fe(III analyses, respectively. Diffusive mixing, color development and spectrophotometric detection take place in three separate flow cells with different lengths such that the analyzer can measure a broad concentration range from low nM to several μM of Fe, depending on the desired application. A detection limit of 1.9 nM Fe was found. The microfluidic analyzer was tested in situ for nine days in shallow waters in the Kiel Fjord (Germany along with other sensors as a part of the SenseOCEAN EU-project. The analyzer's performance under natural conditions was assessed with discrete samples collected and processed according to GEOTRACES protocol [acidified to pH < 2 and analyzed via inductively coupled plasma mass spectrometry (ICP-MS]. The mechanical performance of the analyzer over the nine day period was good (consistent high precision of Fe(II and Fe(III standards with a standard deviation of 2.7% (n = 214 and 1.9% (n = 217, respectively, and successful completion of every programmed data point. However, total dissolved Fe was consistently low compared to ICP-MS data. Recoveries between 16 and 75% were observed, indicating that the

  16. Evaluation of polyacrylamide gels with accelerator ammonium salts for water shutoff in ultralow temperature reservoirs: Gelation performance and application recommendations

    Directory of Open Access Journals (Sweden)

    Hu Jia


    Full Text Available Water shutoff in ultralow temperature reservoirs has received great attention in recent years. In previous study, we reported a phenol-formaldehyde-based gel formula with ammonium salt which can provide a gelation time between 2 hrs and 2 days at 25 °C. However, systematic evaluation and field recommendations of this gel formula when encountering complex reservoirs environment are not addressed. In this paper, how and why such practical considerations as water composition, temperature, pH, weight ratio of formaldehyde to resorcinol and contaminant Fe3+ to affect the gelation performance are examined. Brookfield DV-III and scanning electron microscopy (SEM are employed respectively for viscosity measurement and microstructure analysis. SEM results further illustrate the mechanism of the effect of salinity on gelation performance. It reveals that crosslinking done by covalent bond has great advantage for gel stability under high salinity environment. The target gel formula can provide desirable gelation time below 60 °C, perfect for 15–45 °C, while it is unfeasible to use high salinity to delay gelation at 60 °C. We summarized the effect of salinity on gelation performance of different gel formulas from the present study and published literature. The summarized data can provide important guideline for gel formula design before conducting any kinds of experiments. The variation of gelation performance at different salinity may be dominated by the interaction between crosslinker-salt-polymer, not only limited to “charge-screening effect” and “ion association” proposed by several authors. We hope the analysis encouraging further investigations. Some recommendations for field application of this gel are given in the end of this paper.

  17. Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans (United States)

    Pohlman, John; Waite, William F.; Bauer, James E.; Osburn, Christopher L.; Chapman, N. Ross


    Marine sediments contain about 500–10,000 Gt of methane carbon1, 2, 3, primarily in gas hydrate. This reservoir is comparable in size to the amount of organic carbon in land biota, terrestrial soils, the atmosphere and sea water combined1, 4, but it releases relatively little methane to the ocean and atmosphere5. Sedimentary microbes convert most of the dissolved methane to carbon dioxide6, 7. Here we show that a significant additional product associated with microbial methane consumption is methane-derived dissolved organic carbon. We use Δ14C and δ13C measurements and isotopic mass-balance calculations to evaluate the contribution of methane-derived carbon to seawater dissolved organic carbon overlying gas hydrate-bearing seeps in the northeastern Pacific Ocean. We show that carbon derived from fossil methane accounts for up to 28% of the dissolved organic carbon. This methane-derived material is much older, and more depleted in 13C, than background dissolved organic carbon. We suggest that fossil methane-derived carbon may contribute significantly to the estimated 4,000–6,000 year age of dissolved organic carbon in the deep ocean8, and provide reduced organic matter and energy to deep-ocean microbial communities.

  18. [Using ultraviolet-visible ( UV-Vis) absorption spectrum to estimate the dissolved organic matter (DOM) concentration in water, soils and sediments of typical water-level fluctuation zones of the Three Gorges Reservoir areas]. (United States)

    Li, Lu-lu; Jiang, Tao; Lu, Song; Yan, Jin-long; Gao, Jie; Wei, Shi-qiang; Wang, Ding-yong; Guo, Nian; Zhao, Zhena


    Dissolved organic matter (DOM) is a very important component in terrestrial ecosystem. Chromophoric dissolved organic matter (CDOM) is a significant constituent of DOM, which can be measured by ultraviolet-visible (UV-Vis) absorption spectrum. Thus the relationship between CDOM and DOM was investigated and established by several types of models including single-wavelength model, double-wavelength model, absorption spectrum slope (S value) model and three-wavelength model, based on the UV-Vis absorption coefficients of soil and sediment samples (sampled in July of 2012) and water samples (sampled in November of 2012) respectively. The results suggested that the three-wavelength model was the best for fitting, and the determination coefficients of water, soil and sediment data were 0. 788, 0. 933 and 0. 856, respectively. Meanwhile, the nominal best model was validated with the UV-Vis data of 32 soil samples and 36 water samples randomly collected in 2013, showing the RRMSE and MRE were 16. 5% and 16. 9% respectively for soil DOM samples, 10. 32% and 9. 06% respectively for water DOM samples, which further suggested the prediction accuracy was higher in water DOM samples as compared with that in soil DOM samples.

  19. Assessing threshold values for eutrophication management using Bayesian method in Yuqiao Reservoir, North China. (United States)

    Li, Xue; Xu, Yuan; Zhao, Gang; Shi, Chunli; Wang, Zhong-Liang; Wang, Yuqiu


    The eutrophication problem of drinking water source is directly related to the security of urban water supplication, and phosphorus has been proved as an important element to the water quality of the most northern hemisphere lakes and reservoirs. In the paper, 15-year monitoring records (1990∼2004) of Yuqiao Reservoir were used to model the changing trend of the total phosphorus (TP), analyze the uncertainty of nutrient parameters, and estimate the threshold of eutrophication management at a specific water quality goal by the application of Bayesian method through chemical material balance (CMB) model. The results revealed that Yuqiao Reservoir was a P-controlled water ecosystem, and the inner concentration of TP in the reservoir was significantly correlated with TP loading concentration, hydraulic retention coefficient, and bottom water dissolved oxygen concentration. In the case, the goal of water quality for TP in the reservoir was set to be 0.05 mg L(-1) (the third level of national surface water standard for reservoirs according to GB3838-2002), management measures could be taken to improve water quality in reservoir through controlling the highest inflow phosphorus concentration (0.15∼0.21 mg L(-1)) and the lowest DO concentration (3.76∼5.59 mg L(-1)) to the threshold. Inverse method was applied to evaluate the joint manage measures, and the results revealed that it was a valuable measure to avoid eutrophication by controlling lowest dissolved oxygen concentration and adjusting the inflow and outflow of reservoir.

  20. Evaluation of the TRMM multisatellite precipitation analysis and its applicability in supporting reservoir operation and water resources management in Hanjiang basin, China (United States)

    Yang, Na; Zhang, Ke; Hong, Yang; Zhao, Qiaohua; Huang, Qin; Xu, Yinshan; Xue, Xianwu; Chen, Sheng


    In this study, we first evaluated a satellite-based precipitation product (3B42V7) using gauge observations and then investigated its utility in supporting reservoir operation and water resources management in Hanjiang basin from January 1998 to December 2013. Direct comparison of 3B42V7 with gauge observations shows that it can well capture the spatial and temporal characteristics of precipitation over the study basin. However, the 3B42V7 estimates generally show slight underestimation of precipitation, especially for extreme precipitation events, which need be considered in the future algorithm development. Next, we conducted the long-term (2008-2013) hydrologic evaluation of the 3B42V7 product using a calibrated monthly hydrologic model. The results show that the performance of the monthly hydrologic model driven by 3B42V7 is compatible to the results driven by gauge-based simulations according to high values of Nash-Sutcliffe coefficients (0.83 and 0.66 for observation-driven and 3B47V7 driven simulations, respectively) and small values of biases (-8.16% and -3.98%). We further evaluated the applicability of 3B42V7 in reservoir operation through a set of operation experiments, in which modeled inflow series were used to make decisions. The results indicate that reservoir operations based on modeled streamflow using the 3B42V7 estimates perform well in water allocation decision-making and strongly agree with actual inflow based operations. Despite that 3B42V7 tends to slightly underestimate precipitation, the resultant operations do not impact the functions and benefits of reservoir operation much. This suggests that the 3B42V7 precipitation estimates are valuable and useful for monthly streamflow simulation and long-term reservoir operation in Hanjiang basin. This study provides a new insight on the evaluation and utility of the remote sensing based precipitation estimates.

  1. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Yutian Luo


    Full Text Available This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.

  2. Advanced Reservoir Characterization and Evaluation of CO{sub 2} Gravity Drainage in the Naturally Fractured Spraberry Trend Area

    Energy Technology Data Exchange (ETDEWEB)

    Schechter, D.S.


    The overall goal of this project is to assess the economic feasibility of CO{sub 2} flooding the naturally fractured Spraberry Trend Area in West Texas. This objective is being accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interactions in the reservoirs, (3) reservoir performance analysis, and, (4) experimental investigations on CO2 gravity drainage in Spraberry whole cores. This report provides results of the third year of the five-year project for each of the four areas including a status report of field activities leading up to injection of CO2.

  3. Advanced Reservoir Characterization and Evaluation of CO2 Gravity Drainage in the Naturally Fractured Spraberry Trend Area, Class III

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Bill; Schechter, David S.


    The goal of this project was to assess the economic feasibility of CO2 flooding the naturally fractured Spraberry Trend Area in west Texas. This objective was accomplished through research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interactions in the reservoirs, (3) reservoir performance analysis, and (4) experimental investigations on CO2 gravity drainage in Spraberry whole cores. This provides results of the final year of the six-year project for each of the four areas.

  4. Lithological and petrophysical evaluation of the caprock keybeds, Asmari Reservoir of Pazanan Oil Field, Zagros, Iran


    Bahman Soleimani; Amir Sasan Zarvani


    The Pazanan oil field is located 150 km SE of ahvaz city in SW of Iran and measures 60 km long, 4-6 km wide. The caprock of this oil field were evaluated using well logs (gamma-ray and sonic logs) SEM and petrographical microscopy data. The cap rock consist of mudstone, interlayers of anhydrite and bitumens shale. Therefore, it can be classified as mudstone type. On the basis of our investigations, the Caprock can be divided in to 6 keybeds: A(Anhydrite), B(Bitumenshale & some times bitumen m...

  5. Chickamauga reservoir embayment study - 1990

    Energy Technology Data Exchange (ETDEWEB)

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.


    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.

  6. Comparisons of Simulated Hydrodynamics and Water Quality for Projected Demands in 2046, Pueblo Reservoir, Southeastern Colorado (United States)

    Ortiz, Roderick F.; Galloway, Joel M.; Miller, Lisa D.; Mau, David P.


    2002) were compared to the No Action scenario (projected demands in 2046) to assess changes in water quality over time. All scenario modeling used an external nutrient-decay model to simulate degradation and assimilation of nutrients along the riverine reach upstream from Pueblo Reservoir. Reservoir modeling was conducted using the U.S. Army Corps of Engineers CE-QUAL-W2 two-dimensional water-quality model. Lake hydrodynamics, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, algal biomass, and total iron were simulated. Two reservoir site locations were selected for comparison. Results of simulations at site 3B were characteristic of a riverine environment in the reservoir while results at site 7B (near the dam) were characteristic of the main body of the reservoir. Simulation results for the epilimnion and hypolimnion at these two sites also were evaluated and compared. The simulation results in the hypolimnion at site 7B were indicative of the water quality leaving the reservoir. Comparisons of the different scenario results were conducted to assess if substantial differences were observed between selected scenarios. Each of the scenarios was simulated for three contiguous years representing a wet, average, and dry annual hydrologic cycle (water years 2000 through 2002). Additionally, each selected simulation scenario was evaluated for differences in direct- and cumulative-effects on a particular scenario. Direct effects are intended to isolate the future effects of the scenarios. Cumulative effects are intended to evaluate the effects of the scenarios in conjunction with all reasonably foreseeable future activities in the study area. Comparisons between the direct- and cumulative-effects analyses indicated that there were not large differences in the results between most of the simulation scenarios and, as such, the focus of this report was on results for the direct-effects analysis. Addi

  7. Evaluation of potential geothermal reservoirs in central and western New York State. Volume 3. Final report

    Energy Technology Data Exchange (ETDEWEB)


    Computer processed geophysical well logs from central and western New York State were analysed to evaluate the potential of subsurface formations as a source for low-temperature geothermal water. The analysis indicated that porous sandstone sections at the top of the Ordovician Theresa Formation and at the base of the Cambrian Potsdam Formation have the required depth, porosity, and permeability to act as a source for geothermal fluids over a relatively large area in the central part of the state. The fluid potential plus an advantageous geothermal gradient and the results of the test well drilled in the city of Auburn in Cayuga County suggest that low temperature geothermal energy may ba a viable alternative to other more conventional forms of energy that not indigenous to New York State.

  8. Determination of dissolved oxygen in the cryosphere: a comprehensive laboratory and field evaluation of fiber optic sensors. (United States)

    Bagshaw, E A; Wadham, J L; Mowlem, M; Tranter, M; Eveness, J; Fountain, A G; Telling, J


    Recent advances in the Cryospheric Sciences have shown that icy environments are host to consortia of microbial communities, whose function and dynamics are often controlled by the concentrations of dissolved oxygen (DO) in solution. To date, only limited spot determinations of DO have been possible in these environments. They reveal the potential for rates of change that exceed realistic manual sampling rates, highlighting the need to explore methods for the continuous measurement of DO concentrations. We report the first comprehensive field and laboratory performance tests of fiber-optic sensors (PreSens, Regensburg, Germany) for measuring DO in icy ecosystems. A series of laboratory tests performed at low and standard temperatures (-5 to 20 °C) demonstrates high precision (0.3% at 50 μmol/kg and 1.3% at 300 μmol/kg), rapid response times (sensor film was mechanically fixed to the fiber and protected by a stainless steel sheath. Results of two field deployments of sensors to the Swiss Alps and Antarctica largely demonstrate a performance consistent with laboratory tests and superior to traditional methods.

  9. Development and evaluation of fast-dissolving tablets of meloxicam-β-cyclodextrin complex prepared by direct compression. (United States)

    Obaidat, Aiman A; Obaidat, Rana M


    The aim of this study was to prepare fast-dissolving tablets of meloxicam after its complexation with β-cyclodextrin (β-CD) and to investigate the effect of using different superdisintegrants on the disintegration and release of meloxicam from the tablets. A complex of meloxicam with β-CD was prepared by spray drying and then compressed in the form of tablets utilizing the direct compression technique. Three superdisintegrants were employed at various levels - sodium starch glycolate, croscarmellose sodium, and crospovidone. Co-spray dried micro-crystalline cellulose and mannitol (Avicel HFE-102) were used as diluents in the tablets. Prior to compression, the pre-compression parameters showed satisfactory flow properties. Post-compression parameters showed that all tablet formulations had acceptable mechanical properties. Wetting and disintegration times were prolonged by increasing the level of sodium starch glycolate in the tablets. This was attributed to the formation of a viscous gel layer around the tablets by sodium starch glycolate whereas this effect was not observed with croscarmellose sodium and crospovidone. Dissolution studies showed fast release of meloxicam except in tablets containing a high level of sodium starch glycolate. Complexation of meloxicam with β-CD significantly improved the solubility of the drug and improved the mechanical properties of tablets produced by direct compression.

  10. Lithological and petrophysical evaluation of the caprock keybeds, Asmari Reservoir of Pazanan Oil Field, Zagros, Iran

    Directory of Open Access Journals (Sweden)

    Bahman Soleimani


    Full Text Available The Pazanan oil field is located 150 km SE of ahvaz city in SW of Iran and measures 60 km long, 4-6 km wide. The caprock of this oil field were evaluated using well logs (gamma-ray and sonic logs SEM and petrographical microscopy data. The cap rock consist of mudstone, interlayers of anhydrite and bitumens shale. Therefore, it can be classified as mudstone type. On the basis of our investigations, the Caprock can be divided in to 6 keybeds: A(Anhydrite, B(Bitumenshale & some times bitumen marls, C (mudstone with interlayers of shale & anhydrite, D (mudstone & anhydrite, E (mudstone& F(mudstone & packstone, almost all of these units coverd by salt. Anhydrite beds show the following textures: microlitic, spherolite, porphyroblast, and granular. Anhydrite crystals indicate the occurrence of processes such as emplacement and calcitization. Sonic and gamma-ray well logs were used to determine lithological changes. The highest peak is correlated with mudstone units. Caprock depth varies from 2580m(min-2717m(max [northern part], 1704(min. - 2444(max. [central part],And 2050 (min.- 2490 (max. [southern part] using well drilling data. It seems that that the thickness in the southern part is less than is other part. Comparing the thicknesses of different keybeds. The maximum occurs in the c-keybeds. The sedimentar : sequence of Caprock started by mudstone, packstone and interlayers of anhydrite, followed by mudstone, anhydrite, shale-marl, as well as bitumen shale, mudstone and anhydrite and finally was overlaid by salt. Lithological variation indicate a sabkha-lacustrine environment. Therefore, the hot-wet and hot-dry climate was dominated. In some cases, Caprock thickness decreases to 6m without any gap. This thinning is related to structural deformation. Unfavorable lithologyconditions resulted is well collaps.

  11. Avaliação do estado de assoreamento do reservatório de Cachoeira Dourada (GO/MG / Evaluation of Sedimentation State in Cachoeira Dourada Reservoir (GO/MG, Brazil

    Directory of Open Access Journals (Sweden)

    João Batista Pereira Cabral


    Full Text Available This research analyzed the degree of sedimentation in Cachoeira Dourada reservoir Brazil, belongingto the Paranaíba hydrologic catchment basin. Were evaluated bottom sediments of the lake, in an areaof 74 km2. Were considered particle and bathymetric parameters. The results, presented on the maps,showed the distribution of the particles chacteristics and allowed to estimate the volume of sediments.The bottom deposits are essentially constituted of silt and clay in the portion near the dike; of fine andvery fine sandy material in the middle sector of the reservoir and, in the beginning of the reservoir, wehave since silt just large sand. By comparison of topographic data, since the construction of the reservoir,with present measured bathymetric data, the Cachoeira Dourada reservoir lost 38.5 % of its originalstoring capacity. The expected reservoir useful life, estimated in this research, is of about 145 years,following this deposition rhythm.

  12. A flexible model of HIV-1 latency permitting evaluation of many primary CD4 T-cell reservoirs. (United States)

    Lassen, Kara G; Hebbeler, Andrew M; Bhattacharyya, Darshana; Lobritz, Michael A; Greene, Warner C


    Latently infected cells form the major obstacle to HIV eradication. Studies of HIV latency have been generally hindered by the lack of a robust and rapidly deployable cell model that involves primary human CD4 T lymphocytes. Latently infected cell lines have proven useful, but it is unclear how closely these proliferating cells recapitulate the conditions of viral latency in non-dividing CD4 T lymphocytes in vivo. Current primary lymphocyte models more closely reflect the in vivo state of HIV latency, but they are limited by protracted culture periods and often low cell yields. Additionally, these models are always established in a single latently infected cell type that may not reflect the heterogeneous nature of the latent reservoir. Here we describe a rapid, sensitive, and quantitative primary cell model of HIV-1 latency with replication competent proviruses and multiple reporters to enhance the flexibility of the system. In this model, post-integration HIV-1 latency can be established in all populations of CD4 T cells, and reactivation of latent provirus assessed within 7 days. The kinetics and magnitude of reactivation were evaluated after stimulation with various cytokines, small molecules, and T-cell receptor agonists. Reactivation of latent HIV proviruses was readily detected in the presence of strong activators of NF-κB. Latently infected transitional memory CD4 T cells proved more responsive to these T-cell activators than latently infected central memory cells. These findings reveal potentially important biological differences within the latently infected pool of memory CD4 T cells and describe a flexible primary CD4 T-cell system to evaluate novel antagonists of HIV latency.

  13. An interpretation of core and wireline logs for the Petrophysical evaluation of Upper Shallow Marine sandstone reservoirs of the Bredasdorp Basin, offshore South Africa (United States)

    Magoba, Moses; Opuwari, Mimonitu


    This paper embodies a study carried out to assess the Petrophysical evaluation of upper shallow marine sandstone reservoir of 10 selected wells in the Bredasdorp basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine formation with the purpose of conducting a regional study to assess the difference in reservoir properties across the formation. The data sets used in this study were geophysical wireline logs, Conventional core analysis and geological well completion report. The physical rock properties, for example, lithology, fluid type, and hydrocarbon bearing zone were qualitatively characterized while different parameters such as volume of clay, porosity, permeability, water saturation ,hydrocarbon saturation, storage and flow capacity were quantitatively estimated. The quantitative results were calibrated with the core data. The upper shallow marine reservoirs were penetrated at different depth ranging from shallow depth of about 2442m to 3715m. The average volume of clay, average effective porosity, average water saturation, hydrocarbon saturation and permeability range from 8.6%- 43%, 9%- 16%, 12%- 68% , 32%- 87.8% and 0.093mD -151.8mD respectively. The estimated rock properties indicate a good reservoir quality. Storage and flow capacity results presented a fair to good distribution of hydrocarbon flow.

  14. Laboratory Experiments to Evaluate Matrix Diffusion of Dissolved Organic Carbon Carbon-14 in Southern Nevada Fractured-rock Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyatt [Nevada University, Reno, NV (United States). Desert Research Institute


    Dissolved inorganic carbon (DIC) carbon-14 (14C) is used to estimate groundwater ages by comparing the DIC 14C content in groundwater in the recharge area to the DIC 14C content in the downgradient sampling point. However, because of chemical reactions and physical processes between groundwater and aquifer rocks, the amount of DIC 14C in groundwater can change and result in 14C loss that is not because of radioactive decay. This loss of DIC 14C results in groundwater ages that are older than the actual groundwater ages. Alternatively, dissolved organic carbon (DOC) 14C in groundwater does not react chemically with aquifer rocks, so DOC 14C ages are generally younger than DIC 14C ages. In addition to chemical reactions, 14C ages may also be altered by the physical process of matrix diffusion. The net effect of a continuous loss of 14C to the aquifer matrix by matrix diffusion and then radioactive decay is that groundwater appears to be older than it actually is. Laboratory experiments were conducted to measure matrix diffusion coefficients for DOC 14C in volcanic and carbonate aquifer rocks from southern Nevada. Experiments were conducted using bromide (Br-) as a conservative tracer and 14C-labeled trimesic acid (TMA) as a surrogate for groundwater DOC. Outcrop samples from six volcanic aquifers and five carbonate aquifers in southern Nevada were used. The average DOC 14C matrix diffusion coefficient for volcanic rocks was 2.9 x 10-7 cm2/s, whereas the average for carbonate rocks was approximately the same at 1.7 x 10-7 cm2/s. The average Br- matrix diffusion coefficient for volcanic rocks was 10.4 x 10-7 cm2/s, whereas the average for carbonate rocks was less at 6.5 x 10-7 cm2/s. Carbonate rocks exhibited greater variability in

  15. Aeration optimization through operation at low dissolved oxygen concentrations: Evaluation of oxygen mass transfer dynamics in different activated sludge systems. (United States)

    Fan, Haitao; Qi, Lu; Liu, Guoqiang; Zhang, Yuankai; Fan, Qiang; Wang, Hongchen


    In wastewater treatment plants (WWTPs) using the activated sludge process, two methods are widely used to improve aeration efficiency - use of high-efficiency aeration devices and optimizing the aeration control strategy. Aeration efficiency is closely linked to sludge characteristics (such as concentrations of mixed liquor suspended solids (MLSS) and microbial communities) and operating conditions (such as air flow rate and operational dissolved oxygen (DO) concentrations). Moreover, operational DO is closely linked to effluent quality. This study, which is in reference to WWTP discharge class A Chinese standard effluent criteria, determined the growth kinetics parameters of nitrifiers at different DO levels in small-scale tests. Results showed that the activated sludge system could meet effluent criteria when DO was as low as 0.3mg/L, and that nitrifier communities cultivated under low DO conditions had higher oxygen affinity than those cultivated under high DO conditions, as indicated by the oxygen half-saturation constant and nitrification ability. Based on nitrifier growth kinetics and on the oxygen mass transfer dynamic model (determined using different air flow rate (Q' air ) and mixed liquor volatile suspended solids (MLVSS) values), theoretical analysis indicated limited potential for energy saving by improving aeration diffuser performance when the activated sludge system had low oxygen consumption; however, operating at low DO and low MLVSS could significantly reduce energy consumption. Finally, a control strategy coupling sludge retention time and MLVSS to minimize the DO level was discussed, which is critical to appropriate setting of the oxygen point and to the operation of low DO treatment technology. Copyright © 2016. Published by Elsevier B.V.

  16. Bench-scale evaluation of ferrous iron oxidation kinetics in drinking water: effect of corrosion control and dissolved organic matter. (United States)

    Rahman, Safiur; Gagnon, Graham A


    Corrosion control strategies are important for many utilities in maintaining water quality from the water treatment plant to the customers' tap. In drinking water with low alkalinity, water quality can become significantly degraded in iron-based pipes if water utilities are not diligent in maintaining proper corrosion control. This article reports on experiments conducted in bicarbonate buffered (5 mg-C/L) synthetic water to determine the effects of corrosion control (pH and phosphate) and dissolved organic matter (DOM) on the rate constants of the Fe(II) oxidation process. A factorial design approach elucidated that pH (P = 0.007, contribution: 42.5%) and phosphate (P = 0.025, contribution: 22.7%) were the statistically significant factors in the Fe(II) oxidation process at a 95% confidence level. The comprehensive study revealed a significant dependency relationship between the Fe(II) oxidation rate constants (k) and phosphate-to- Fe(II) mole ratio. At pH 6.5, the optimum mole ratio was found to be 0.3 to reduce the k values. Conversely, the k values were observed to increase for the phosphate-to- Fe(II) mole ratio > 1. The factorial design approach revealed that chlorine and DOM for the designated dosages did not cause a statistically significant (α = 0.05, P > 0.05)change in rate constants. However, an increment of the chlorine to ferrous iron mole ratio by a factor of ∼ 2.5 resulted in an increase k values by a factor of ∼ 10. This study conclusively demonstrated that the lowest Fe(II) oxidation rate constant was obtained under low pH conditions (pH ≤ 6.5), with chlorine doses less than 2.2 mg/L and with a phosphate-to-Fe(II) mole ratio ≈ 0.3 in the iron water systems.

  17. Evaluation of starch-based flocculants for the flocculation of dissolved organic matter from textile dyeing secondary wastewater. (United States)

    Wu, Hu; Liu, Zhouzhou; Li, Aimin; Yang, Hu


    China is a major textile manufacturer in the world; as a result, large quantities of dyeing effluents are generated every year in the country. In this study, the performances of two cationic starch-based flocculants with different chain architectures, i.e., starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] (STC-g-PDMC) and starch-3-chloro-2-hydroxypropyl trimethyl ammonium chloride (STC-CTA), in flocculating dissolved organic matter (DOM) in dyeing secondary effluents were investigated and compared with that of polyaluminum chloride (PAC). In the exploration of the flocculation mechanisms, humic acid (HA) and bovine serum albumin (BSA) were selected as main representatives of DOM in textile dyeing secondary effluents, which were humic/fulvic acid-like and protein-like extracellular matters according to the studied wastewater's characteristics based on its three-dimensional excitation-emission matrix spectrum. According to experimental results of the flocculation of both the real and synthetic wastewaters, STC-g-PDMC with cationic branches had remarkable advantages over STC-CTA and PAC because of the more efficient charge neutralization and bridging flocculation effects of STC-g-PDMC. Another interesting finding in this study was the reaggregation phenomenon after restabilization at an overdose during the flocculation of BSA effluents by STC-g-PDMC at a very narrow pH range under a nearly neutral condition. This phenomenon might be ascribed to the formation of STC-g-PDMC/BSA complexes induced by some local charge interactions between starch-based flocculant and the amino acid fragments of protein due to charge patch effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Freshwater reservoir effect variability in Northern Germany


    Philippsen, Bente; Heinemeier, Jan


    The freshwater reservoir effect is a potential problem when radiocarbon dating fishbones, shells, human bones or food crusts on pottery from sites next to rivers or lakes. The reservoir age in rivers containing considerable amounts of dissolved 14C-free carbonates can be up to several thousand years and may be highly variable. For accurate radiocarbon dating of freshwater-based samples, the order of magnitude of the reservoir effect as well as the degree of variability has to be known.The ini...

  19. Flood protection effect of the existing and projected reservoirs in the Amur River basin: evaluation by the hydrological modeling system

    Directory of Open Access Journals (Sweden)

    Y. Motovilov


    Full Text Available Hydrological modeling system was developed as a tool addressed supporting flood risk management by the existing and projected reservoirs in the Amur River basin. The system includes the physically-based semi-distributed model of runoff generation ECOMAG coupled with a hydrodynamic MIKE-11 model to simulate channel flow in the main river. The case study was carried out for the middle part of the Amur River where large reservoirs are located on the Zeya and Bureya Rivers. The models were calibrated and validated using streamflow measuruments at the different gauges of the main river and its tributaries. Numerical experiments were carried out to assess the effect of the existing Zeya and Bureya reservoirs regulation on 850 km stretch of the middle Amur River stage. It was shown that in the absence of the reservoirs, the water levels downstream of the Zeya and Bureya Rivers would be 0.5–1.5 m higher than the levels measured during the disastrous flood of 2013. Similar experiments were carried out to assess possible flood protection effect of new projected reservoirs on the Zeya and Bureya Rivers.

  20. Flood protection effect of the existing and projected reservoirs in the Amur River basin: evaluation by the hydrological modeling system (United States)

    Motovilov, Y.; Danilov-Danilyan, V.; Dod, E.; Kalugin, A.


    Hydrological modeling system was developed as a tool addressed supporting flood risk management by the existing and projected reservoirs in the Amur River basin. The system includes the physically-based semi-distributed model of runoff generation ECOMAG coupled with a hydrodynamic MIKE-11 model to simulate channel flow in the main river. The case study was carried out for the middle part of the Amur River where large reservoirs are located on the Zeya and Bureya Rivers. The models were calibrated and validated using streamflow measuruments at the different gauges of the main river and its tributaries. Numerical experiments were carried out to assess the effect of the existing Zeya and Bureya reservoirs regulation on 850 km stretch of the middle Amur River stage. It was shown that in the absence of the reservoirs, the water levels downstream of the Zeya and Bureya Rivers would be 0.5-1.5 m higher than the levels measured during the disastrous flood of 2013. Similar experiments were carried out to assess possible flood protection effect of new projected reservoirs on the Zeya and Bureya Rivers.

  1. Evaluation of Bee Diversity within Different Sweet Cherry Orchards in the Sultandaği Reservoir (Turkey

    Directory of Open Access Journals (Sweden)

    Güler Yasemin


    Full Text Available Many varieties of sweet cherry are self-incompatible. Therefore, sweet cherry orchards require a huge population of pollinator bees to carry out an adequate amount of pollen transfer between the different varieties. Our study was conducted to evaluate the differences in the richness and diversity of these pollinators within very closely located sweet cherry orchards, and to understand the underlying effects causing these differences. The study was conducted in the Sultandağı Reservoir (Turkey which covers the towns of Sultandağı (Afyonkarahisar and Akşehir (Konya. In order to avoid a sampling bias, Malaise traps were used to collect bee samples. Sampling collections were repeated for three years; from 2007 to 2009, between April and May. The traps were set in the bud-swell period and lifted in the green-fruit period. Climatic data were taken from meteorology stations near the orchards. Vegetation in the surrounding areas was also inspected. The composition of pollinator bee species was determined and compared between orchards. In total, 83 bee species and 38 plant species were recorded. It was found that Halictidae is the most abundant and richest group among the pollinator bees. The effects of the quantity of the Malaise traps on bee sampling success were also tested. It was found that one trap per 325 trees is enough for an adequate sampling. Apart from the annual fluctuations of bee richness in the orchards, general differences in the bee diversity among orchards might be affected by the surrounding vegetation and especially from different agricultural practices such as tilling the ground.

  2. Evaluation of the long term monitoring of phytoplankton assemblages in a canyon-shape reservoir using multivariate statistical methods

    Czech Academy of Sciences Publication Activity Database

    Komárková, Jaroslava; Komárek, O.; Hejzlar, Josef


    Roč. 504, - (2003), s. 143-157 ISSN 0018-8158. [Reservoir Limnology and Water Quality /4./. České Budějovice, 12.08.2002-16.08.2002] R&D Projects: GA AV ČR IBS6017004; GA AV ČR KSK3046108; GA ČR GA206/99/P062 Institutional research plan: CEZ:MSM 123100004 Keywords : reservoirs * phytoplankton * Canoco Subject RIV: DJ - Water Pollution ; Quality Impact factor: 0.720, year: 2003

  3. Impact of environmental factors on maintaining water quality of Bakreswar reservoir, India

    Directory of Open Access Journals (Sweden)

    Moitreyee Banerjee


    Full Text Available Reservoirs and dams are engineered systems designed to serve purposes like supply of drinking water as well as other commercial and industrial use. A thorough assessment of water quality for these systems is thus necessary. The present study is carried out at Bakreswar reservoir, in Birbhum district, which was created by the dam, built on Bakreswar River. The major purpose of the reservoir is the supply of drinking water to the surrounding villages and Bakreswar Thermal Power Station. Water samples were collected fortnightly from three different stations of the reservoir. Physical and chemical factors like dissolved oxygen, atmospheric temperature, pH, conductivity, salinity, solar radiation, water temperature, alkalinity, hardness, chloride, productivity etc. were analysed using standard procedure. Abundance data is calculated for four major groups of zooplanktons (Cladocera, Copepoda, Ostracoda, and Rotifera with the software PAST 2.1. Multivariate statistical analysis like PCA, hierarchical cluster and CCA are performed in order to predict the temporal variation in the water quality factors using SPSS 20. Distinct seasonal variation was found for environmental factors and zooplankton groups. Bakreswar reservoir has good assemblage of zooplankton and distinct temporal variation of environmental factors and its association with zooplankton predicts water quality condition. These results could help in formulating proper strategies for advanced water quality management and conservation of reservoir ecosystem. Key elements for growth and sustenance of the system can then be evaluated and this knowledge can be further applied for management purposes.

  4. Tenth workshop on geothermal reservoir engineering: proceedings

    Energy Technology Data Exchange (ETDEWEB)


    The workshop contains presentations in the following areas: (1) reservoir engineering research; (2) field development; (3) vapor-dominated systems; (4) the Geysers thermal area; (5) well test analysis; (6) production engineering; (7) reservoir evaluation; (8) geochemistry and injection; (9) numerical simulation; and (10) reservoir physics. (ACR)

  5. Evaluation of Very Low Pressure Sprinkler Irrigation and Reservoir Tillage for Efficient Use of Water and Energy : Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Kincaid, Dennis C.


    Two types of very low pressure devices were tested, spray nozzles and furrow drops (bubblers). For minimizing spray loss and maintaining uniformity, optimum conditions for spray heads are elevation about 6 feet, spacing 8 to 9 feet and pressure 15 to 20 psi. Use of furrow bubblers is not recommended for most regional conditions. Reservoir tillage with very low pressure systems reduces runoff on sloping fields while maintaining or slightly increasing yield. The total amount of water applied is slightly less because of reduction in spray loss. Effectiveness of reservoir tillage depends on the reservoir storing water until it infiltrates. Failure of the reservoirs during the season may result in increased runoff and erosion. Pressure regulators tested are adequate for their intended use. The uniformity of application using low pressure components was comparable to that of high pressure systems. Energy saving scan result from both low operating pressure and better application efficiency, but the relative importance of these two factors depends on individual circumstances. Payback times for some example systems are four years or less.

  6. Seasonal variation of Legionella in Taiwan's reservoir and its relationships with environmental factors. (United States)

    Kao, Po-Min; Hsu, Bing-Mu; Chang, Tien-Yu; Hsu, Tsui-Kang; Tzeng, Kai-Jiun; Huang, Yu-Li


    In this study, the presence of Legionella in major water reservoirs of Taiwan was examined with respect to seasonal variation, geographical variation, and water quality parameters using TaqMan real-time qPCR. Water samples were collected quarterly at 19 reservoirs in Taiwan between November 2012 and August 2013. The detection rate for Legionella was 35.5% (27/76), and Legionella was detected in all seasons. The Legionella concentration was relatively high in spring and summer, reaching 3.86 × 10(8) and 7.35 × 10(8) cells/L, respectively. By sampling the area, Legionella was detected at a higher proportion in reservoirs in the northern and southern areas, and the difference was consistent in all seasons. Significant association was found between detection of Legionella and various water quality parameters, including conductivity, chlorophyll a, and dissolved oxygen (Mann-Whitney U test, P Legionella detection with pH (P = 0.030, R = -0.497) and dissolved oxygen (P = 0.007, R = -0.596) in fall and positive correlation with Carlson's trophic state index (P = 0.049, R = 0.457) in spring. The identified species included Legionella pneumophila and Legionella drancourtii. The detection of Legionella in reservoirs was indicative of a potential public health risk and should be further evaluated.

  7. DHI evaluation by combining rock physics simulation and statistical techniques for fluid identification of Cambrian-to-Cretaceous clastic reservoirs in Pakistan (United States)

    Ahmed, Nisar; Khalid, Perveiz; Shafi, Hafiz Muhammad Bilal; Connolly, Patrick


    The use of seismic direct hydrocarbon indicators is very common in exploration and reservoir development to minimise exploration risk and to optimise the location of production wells. DHIs can be enhanced using AVO methods to calculate seismic attributes that approximate relative elastic properties. In this study, we analyse the sensitivity to pore fluid changes of a range of elastic properties by combining rock physics studies and statistical techniques and determine which provide the best basis for DHIs. Gassmann fluid substitution is applied to the well log data and various elastic properties are evaluated by measuring the degree of separation that they achieve between gas sands and wet sands. The method has been applied successfully to well log data from proven reservoirs in three different siliciclastic environments of Cambrian, Jurassic, and Cretaceous ages. We have quantified the sensitivity of various elastic properties such as acoustic and extended elastic (EEI) impedances, elastic moduli (K sat and K sat-μ), lambda-mu-rho method (λρ and μρ), P-to-S-wave velocity ratio (V P/V S), and Poisson's ratio (σ) at fully gas/water saturation scenarios. The results are strongly dependent on the local geological settings and our modeling demonstrates that for Cambrian and Cretaceous reservoirs, K sat-μ, EEI, V P/V S, and σ are more sensitive to pore fluids (gas/water). For the Jurassic reservoir, the sensitivity of all elastic and seismic properties to pore fluid reduces due to high overburden pressure and the resultant low porosity. Fluid indicators are evaluated using two metrics: a fluid indicator coefficient based on a Gaussian model and an overlap coefficient which makes no assumptions about a distribution model. This study will provide a potential way to identify gas sand zones in future exploration.

  8. A comparison of four porewater sampling methods for metal mixtures and dissolved organic carbon and the implications for sediment toxicity evaluations (United States)

    Cleveland, Danielle; Brumbaugh, William G.; MacDonald, Donald D.


    Evaluations of sediment quality conditions are commonly conducted using whole-sediment chemistry analyses but can be enhanced by evaluating multiple lines of evidence, including measures of the bioavailable forms of contaminants. In particular, porewater chemistry data provide information that is directly relevant for interpreting sediment toxicity data. Various methods for sampling porewater for trace metals and dissolved organic carbon (DOC), which is an important moderator of metal bioavailability, have been employed. The present study compares the peeper, push point, centrifugation, and diffusive gradients in thin films (DGT) methods for the quantification of 6 metals and DOC. The methods were evaluated at low and high concentrations of metals in 3 sediments having different concentrations of total organic carbon and acid volatile sulfide and different particle-size distributions. At low metal concentrations, centrifugation and push point sampling resulted in up to 100 times higher concentrations of metals and DOC in porewater compared with peepers and DGTs. At elevated metal levels, the measured concentrations were in better agreement among the 4 sampling techniques. The results indicate that there can be marked differences among operationally different porewater sampling methods, and it is unclear if there is a definitive best method for sampling metals and DOC in porewater.

  9. Revised Comparisons of Simulated Hydrodynamics and Water Quality for Projected Demands in 2046, Pueblo Reservoir, Southeastern Colorado (United States)

    Ortiz, Roderick F.; Miller, Lisa D.


    2046) to assess changes in water quality over time. All scenario modeling used an external nutrient-decay model to simulate degradation and assimilation of nutrients along the riverine reach upstream from Pueblo Reservoir. Reservoir modeling was conducted using the U.S. Army Corps of Engineers CE-QUAL-W2 two-dimensional water-quality model. Lake hydrodynamics, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, algal biomass, and total iron were simulated. Two reservoir site locations were selected for comparison. Results of simulations at site 3B were characteristic of a riverine environment in the reservoir, whereas results at site 7B (near the dam) were characteristic of the main body of the reservoir. Simulation results for the epilimnion and hypolimnion at these two sites also were evaluated and compared. The simulation results in the hypolimnion at site 7B were indicative of the water quality leaving the reservoir. Comparisons of the different scenario results were conducted to assess if substantial differences were observed between selected scenarios. Each of the scenarios was simulated for three contiguous years representing a wet, average, and dry annual hydrologic cycle (water years 2000 through 2002). Additionally, each selected simulation scenario was evaluated for differences in direct and cumulative effects on a particular scenario. Direct effects are intended to isolate the future effects of the scenarios. Cumulative effects are intended to evaluate the effects of the scenarios in conjunction with all reasonably foreseeable future activities in the study area. Comparisons between the direct- and cumulative-effects analyses indicated that there were not large differences in the results between most of the simulation scenarios, and, as such, the focus of this report was on results for the direct-effects analysis. Additionally, the differences between simulation results generally were

  10. Quantification of Libby Reservoir Levels Needed to Maintain or Enhance Reservoir Fisheries, Appendices, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, Bradley B.


    The appendices include: (1) stream habitat inventory procedures; (2) lengths and volumes across hydroacoustic transects in Libby Reservoir; (3) temperature, pH, dissolved oxygen, and conductivity profiles in Libby Reservoir; (4) habitat survey information by reach; (5) gill net catches by species; (6) annual catches of fish in floating gill nets; (7) vertical distributions of fish and zooplankton; (8) timing of juvenile and adult movement through traps; (9) food habits information for collected fish; (10) estimated densities and composition of zooplankton by genera; (11) seasonal catch of macroinvertebrates; and (12) initial modeling effort on the Libby Reservoir fishery. (ACR)

  11. Paleozoic stratigraphy and petroleum reservoir potential in the Hudson Bay Basin, Northern Canada; re-evaluation of offshore well data

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Kezhen; Dietrich, James; Dewing, Keith [Geological Survey of Canada, 3303 33St. NW, Calgary, AB, T2L 2A7 (Canada)], email:; Zhang, Shunxin [Canada-Nunavut Geoscience Office, PO Box 2319, 626 Tumit Plaza, Iqaluit, NU, X0A 0H0 (Canada); Asselin, Esther (Geological Survey of Canada (Canada))


    The Paleozoic Hudson Bay Basin underlies Hudson Bay and neighbouring land areas in northern Manitoba, Ontario and southern Nunavut. Upper Ordovician to Devonian strata, unconformably overlain by erosional remnants of Mesozoic strata, are part of the sedimentary succession. New stratigraphic correlations for the five offshore wells drilled in the Hudson Bay Basin give an understanding of basin depositional and erosional features, which include a major unconformity in Lower Devonian strata and a Lower Devonian evaporite section whose thickness is highly variable. Petrophysical analyses of the five wells, combined with core data, give valuable information on lithology and porosity, permeability, and water saturation in Paleozoic strata. The petrophysical data shows that many limestone, dolomite and sandstone units are sufficiently porous and permeable to form good quality reservoirs, and possible hydrocarbon-bearing zones are identified in some intervals. This new stratigraphic and reservoir framework will provide a basis for future studies on the Hudson Bay basin and the surrounding Hudson platform as a possible site for petroleum reservoirs.

  12. Use of a two-dimensional hydrodynamic model to evaluate extreme flooding and transport of dissolved solids through Devils Lake and Stump Lake, North Dakota, 2006 (United States)

    Nustad, Rochelle A.; Wood, Tamara M.; Bales, Jerad D.


    The U.S. Geological Survey in cooperation with the North Dakota Department of Transportation, North Dakota State Water Commission, and U.S. Army Corps of Engineers, developed a two-dimensional hydrodynamic model of Devils Lake and Stump Lake, North Dakota to be used as a hydrologic tool for evaluating the effects of different inflow scenarios on water levels, circulation, and the transport of dissolved solids through the lake. The numerical model, UnTRIM, and data primarily collected during 2006 were used to develop and calibrate the Devils Lake model. Performance of the Devils Lake model was tested using 2009 data. The Devils Lake model was applied to evaluate the effects of an extreme flooding event on water levels and hydrological modifications within the lake on the transport of dissolved solids through Devils Lake and Stump Lake. For the 2006 calibration, simulated water levels in Devils Lake compared well with measured water levels. The maximum simulated water level at site 1 was within 0.13 feet of the maximum measured water level in the calibration, which gives reasonable confidence that the Devils Lake model is able to accurately simulate the maximum water level at site 1 for the extreme flooding scenario. The timing and direction of winddriven fluctuations in water levels on a short time scale (a few hours to a day) were reproduced well by the Devils Lake model. For this application, the Devils Lake model was not optimized for simulation of the current speed through bridge openings. In future applications, simulation of current speed through bridge openings could be improved by more accurate definition of the bathymetry and geometry of select areas in the model grid. As a test of the performance of the Devils Lake model, a simulation of 2009 conditions from April 1 through September 30, 2009 was performed. Overall, errors in inflow estimates affected the results for the 2009 simulation; however, for the rising phase of the lakes, the Devils Lake model

  13. Duck Valley Reservoirs Fish Stocking and O&M, Annual Progress Report 2007-2008.

    Energy Technology Data Exchange (ETDEWEB)

    Sellman, Jake; Perugini, Carol [Department of Fish, Wildlife, and Parks, Shoshone-Paiute Tribes


    The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance Project (DV Fisheries) is an ongoing resident fish program that serves to partially mitigate the loss of anadromous fish that resulted from downstream construction of the federal hydropower system. The project's goals are to enhance subsistence fishing and educational opportunities for Tribal members of the Shoshone-Paiute Tribes and provide fishing opportunities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View (MVR), Lake Billy Shaw (LBS), and Sheep Creek Reservoirs (SCR), the program is also designed to: maintain healthy aquatic conditions for fish growth and survival, provide superior facilities with wilderness qualities to attract non-Tribal angler use, and offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period fall into three categories: operations and maintenance, monitoring and evaluation, and public outreach. Operation and maintenance of the three reservoirs include maintaining fences, roads, dams and all reservoir structures, feeder canals, water troughs, stock ponds, educational signs, vehicles, equipment, and restroom facilities. Monitoring and evaluation activities include creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, and control of encroaching exotic vegetation. Public outreach activities include providing environmental education to school children, providing fishing reports to local newspapers and vendors, updating the website, hosting community environmental events, and fielding numerous phone calls from anglers. The reservoir monitoring program focuses on water quality and fishery success. Sheep Creek Reservoir and Lake Billy Shaw had less than productive trout growth due to water

  14. New approaches to screening infrastructure investments in multi-reservoir systems- Evaluating proposed dams in Ethiopia and Kenya (United States)

    Harou, J. J.; Geressu, R. T.; Hurford, A. P.


    Two approaches have been used traditionally to screen infrastructure investments in multi-reservoir systems: scenario analysis of a few simulated designs and deterministic optimization, sometimes using hydro-economic models or screening optimization models. Simulation models realistically represent proposed water systems and can easily include multiple performance metrics; however each prospective system operating rules need to be formulated and simulated for each proposed design (time consuming. Optimization models have been used to overcome this burden. Screening optimization models use integer or non-linear programming and can be challenging to apply to large and/or multi-objective systems. Hydro-economic models that use deterministic (implicit stochastic) optimization must be modified to examine each different plan and they cannot always reproduce realistic or politically acceptable system operations. In this presentation we demonstrate the application of a new screening approach to multi-reservoir systems where operating rules and new assets (dams) are simultaneously optimized in a multi-criteria context. Results are not least cost investment plans that satisfy reliability or other engineering constraints, but rather Pareto-optimal sets of asset portfolios that work well under historical and/or future scenarios. This is achieved by using stakeholder-built simulation models linked to multi-criteria search algorithms (e.g. many objective evolutionary algorithms, MOEA). Typical output is demonstrated through two case-studies on the Tana and Blue Nile rivers where operating rules and reservoir assets are efficiently screened together considering stakeholder-defined metrics. The focus on the Tana system is how reservoir operating rules and new irrigation schemes should be co-managed to limit ecological damages. On the Nile system, we identify Blue Nile river reservoir capacities that least negatively impact downstream Nile nations. Limitations and new directions of

  15. Flow heterogeneity in reservoir rocks

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, A.; Simon, R.


    A study by Chevron Oil Field Research Co. shows that microscopic flow heterogeneity values are essential for interpreting laboratory displacement data and properly evaluating field displacement projects. Chevron discusses microscopic flow heterogeneity in reservoir rocks: a measuring method, results of some measurements, and several applications to reservoir engineering problems. Heterogeneity is expressed in terms of both breakthrough recovery and the Dykstra-Parsons permeability variation. Microscopic flow heterogeneity in a reservoir rock is related to pore size, pore shape, and location of the different pore sizes that determine flow paths of various permeabilities. This flow heterogeneity affects secondary recovery displacement efficiency, residual oil and water saturations, and capillary pressure measurements.

  16. Dilution limits dissolved organic carbon utilization in the deep ocean

    NARCIS (Netherlands)

    Arrieta, J.M.; Mayol, E.; Hansman, R.L.; Herndl, G.J.; Dittmar, T.; Duarte, C.M.


    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An

  17. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)


    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  18. Duck Valley Reservoirs Fish Stocking and Operation and Maintenance, 2006-2007 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sellman, Jake; Dykstra, Tim [Shoshone-Paiute Tribes


    The Duck Valley Reservoirs Fish Stocking and Operations and Maintenance (DV Fisheries) project is an ongoing resident fish program that serves to partially mitigate the loss of anadromous fish that resulted from downstream construction of the hydropower system. The project's goals are to enhance subsistence fishing and educational opportunities for Tribal members of the Shoshone-Paiute Tribes and provide resident fishing opportunities for non-Tribal members. In addition to stocking rainbow trout (Oncorhynchus mykiss) in Mountain View, Lake Billy Shaw, and Sheep Creek Reservoirs, the program is also designed to maintain healthy aquatic conditions for fish growth and survival, to provide superior facilities with wilderness qualities to attract non-Tribal angler use, and to offer clear, consistent communication with the Tribal community about this project as well as outreach and education within the region and the local community. Tasks for this performance period are divided into operations and maintenance plus monitoring and evaluation. Operation and maintenance of the three reservoirs include fences, roads, dams and all reservoir structures, feeder canals, water troughs and stock ponds, educational signs, vehicles and equipment, and outhouses. Monitoring and evaluation activities included creel, gillnet, wildlife, and bird surveys, water quality and reservoir structures monitoring, native vegetation planting, photo point documentation, control of encroaching exotic vegetation, and community outreach and education. The three reservoirs are monitored in terms of water quality and fishery success. Sheep Creek Reservoir was very unproductive this year as a fishery. Fish morphometric and water quality data indicate that the turbidity is severely impacting trout survival. Lake Billy Shaw was very productive as a fishery and received good ratings from anglers. Mountain View was also productive and anglers reported a high number of quality sized fish. Water quality

  19. Changes to the Bakomi Reservoir

    Directory of Open Access Journals (Sweden)

    Kubinský Daniel


    Full Text Available This article is focused on the analysis and evaluation of the changes of the bottom of the Bakomi reservoir, the total volume of the reservoir, ecosystems, as well as changes in the riparian zone of the Bakomi reservoir (situated in the central Slovakia. Changes of the water component of the reservoir were subject to the deposition by erosion-sedimentation processes, and were identifed on the basis of a comparison of the present relief of the bottom of reservoir obtained from feld measurements (in 2011 with the relief measurements of the bottom obtained from the 1971 historical maps, (i.e. over a period of 40 years. Changes of landscape structures of the riparian zone have been mapped for the time period of 1949–2013; these changes have been identifed with the analysis of ortophotomaps and the feld survey. There has been a signifcant rise of disturbed shores with low herb grassland. Over a period of 40 years, there has been a deposition of 667 m3 of sediments. The results showed that there were no signifcant changes in the local ecosystems of the Bakomi reservoir in comparison to the other reservoirs in the vicinity of Banská Štiavnica.

  20. Forming mechanism of the Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin


    Heng Fu; Jianhui Han; Wanbin Meng; Mingshi Feng; Lei Hao; Yanfei Gao; Yueshan Guan


    The Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin are important oil and gas exploration targets in the basin, but their dissolution mechanisms are in controversy. In this paper, based on the integrated study of sedimentation, sequence and reservoir, together with microscopic analysis and macroscopic seismic data analysis, the carbonate karst reservoirs in the study area were divided into three types: dissolved pore-cavity limestone reservoir, pore-cavity d...

  1. A new approach for evaluating transformations of dissolved organic matter (DOM) via high-resolution mass spectrometry and relating it to bacterial activity. (United States)

    Kamjunke, Norbert; von Tümpling, Wolf; Hertkorn, Norbert; Harir, Mourad; Schmitt-Kopplin, Philippe; Norf, Helge; Weitere, Markus; Herzsprung, Peter


    Streams are important sites of transformation of dissolved organic matter (DOM). The molecular characterization of DOM-quality changes requires sophisticated analytical evaluation techniques. The goal of our study was to link molecular DOM transformation with bacterial activity. We measured the degradation of leaf leachate over a gradient of bacterial production obtained by different rates of percolation of sediments in seven experimental flumes on five sampling dates. We developed a new strategy for evaluating molecular formula data sets obtained by ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS), in which the time-dependent change of component abundance was fitted by a linear regression model after normalization of mass peak intensities. All components were categorized by calculating the slope (change of percent intensity per day) in each of the seven flumes. These slopes were then related to cumulative bacterial production. The concentration of DOM decreased quickly in all flumes. Bacterial activity was higher in flumes with percolated sediment than in those without percolation, whereas plankton bacterial activity was higher in flumes without percolation or without sediment. There were no differences in molecular-DOM characteristics between flumes, but there were distinct changes over time. Positive slopes, i.e. increasing intensities over time, were found for small molecules (MW < 450 Da) and high O/C ratios, whereas decreasing intensities were observed less often and only for large molecules and low O/C ratios. The positive slopes of produced components showed a positive relationship to bacterial production for small and for oxygen-rich components. The negative slopes of degraded components were negatively related to bacterial production for large and for oxygen-deficient molecules. Overall, the approach provided new insights into the transformation of specific molecular DOM components. Copyright © 2017 Elsevier

  2. Rock core-based pre-stress evaluation experimental validation: A case study on Yutengping Sandstone as CO2 storage reservoir rock

    Directory of Open Access Journals (Sweden)

    Jian-Hong Wu


    Full Text Available Yutengping Sandstone in Tieh-chan-shan, Taiwan is a potential reservoir for geological CO2 storage. Cyclic loadings were applied to rock samples taken from an outcrop to create artificial pre-stress. The pre-stress evaluation accuracies using two core-based techniques, acoustic emission (AE and deformation rate analysis (DRA, were investigated under different pre-stresses, delay times and curing temperatures. The experimental results validate the pre-stress evaluations using AE and DRA. The delay time and curing temperature were shown to have minor impacts on the measurement accuracy. However, although both axial strain and lateral strain can be used in DRA, the stress memory fades as the delay time increases. Therefore, delay time, which represents the time from the borehole drilling to the DRA test, must be carefully considered when applying these techniques to evaluate the in situ stress of Yutengping sandstone.

  3. The evaluation of RADARSAT images for the period following the ice breakup of hydro-electric reservoirs in the Saguenay-Lac-Saint-Jean area, spring 1997; Evaluation d`images RADARSAT pour le suivi du degel des grands reservoirs hydro-electriques de la region du Saguenay-Lac-Saint-Jean, printemps 1977

    Energy Technology Data Exchange (ETDEWEB)

    Lemieux, G.H.; Carrier, A.; Begin, D.; Begin, R. [Quebec Univ., Chicoutimi, PQ (Canada)


    The results of a study to evaluate the use of RADARSAT images for the period following the progress of the 1997 spring ice breakup on several hydro-electric reservoirs of the Saguenay - Lac Saint-Jean region were presented. Following the catastrophic floods of 1996, the remote sensing laboratory of the Universite du Quebec at Chicoutimi acquired six RADARSAT images of the Saguenay - Lac Saint-Jean region. Three of the images were in high-resolution mode, the others were in wide-angle mode. The images were used to evaluate the evolution of the spring ice breakup on the region`s numerous hydro-electric reservoirs, in particular the Lac Saint-Jean, Kenogami, Pipmuacan and Manouane reservoirs. Image filtering and compression methods were described. The results indicate that ice breakup which starts first in the west of the region, occurs initially at the mouths of rivers, followed by the beds of ancient rivers. Multi-date images show very high potential for evaluating and monitoring spring breakup.

  4. Reservoir Engineering for Unconventional Gas Reservoirs: What Do We Have to Consider?

    Energy Technology Data Exchange (ETDEWEB)

    Clarkson, Christopher R [ORNL


    The reservoir engineer involved in the development of unconventional gas reservoirs (UGRs) is required to integrate a vast amount of data from disparate sources, and to be familiar with the data collection and assessment. There has been a rapid evolution of technology used to characterize UGR reservoir and hydraulic fracture properties, and there currently are few standardized procedures to be used as guidance. Therefore, more than ever, the reservoir engineer is required to question data sources and have an intimate knowledge of evaluation procedures. We propose a workflow for the optimization of UGR field development to guide discussion of the reservoir engineer's role in the process. Critical issues related to reservoir sample and log analysis, rate-transient and production data analysis, hydraulic and reservoir modeling and economic analysis are raised. Further, we have provided illustrations of each step of the workflow using tight gas examples. Our intent is to provide some guidance for best practices. In addition to reviewing existing methods for reservoir characterization, we introduce new methods for measuring pore size distribution (small-angle neutron scattering), evaluating core-scale heterogeneity, log-core calibration, evaluating core/log data trends to assist with scale-up of core data, and modeling flow-back of reservoir fluids immediately after well stimulation. Our focus in this manuscript is on tight and shale gas reservoirs; reservoir characterization methods for coalbed methane reservoirs have recently been discussed.

  5. Dissolving microneedles for transdermal drug delivery. (United States)

    Lee, Jeong W; Park, Jung-Hwan; Prausnitz, Mark R


    Microfabrication technology has been adapted to produce micron-scale needles as a safer and painless alternative to hypodermic needle injection, especially for protein biotherapeutics and vaccines. This study presents a design that encapsulates molecules within microneedles that dissolve within the skin for bolus or sustained delivery and leave behind no biohazardous sharp medical waste. A fabrication process was developed based on casting a viscous aqueous solution during centrifugation to fill a micro-fabricated mold with biocompatible carboxymethylcellulose or amylopectin formulations. This process encapsulated sulforhodamine B, bovine serum albumin, and lysozyme; lysozyme was shown to retain full enzymatic activity after encapsulation and to remain 96% active after storage for 2 months at room temperature. Microneedles were also shown to be strong enough to insert into cadaver skin and then to dissolve within minutes. Bolus delivery was achieved by encapsulating molecules just within microneedle shafts. For the first time, sustained delivery over hours to days was achieved by encapsulating molecules within the microneedle backing, which served as a controlled release reservoir that delivered molecules by a combination of swelling the backing with interstitial fluid drawn out of the skin and molecule diffusion into the skin via channels formed by dissolved microneedles. We conclude that dissolving microneedles can be designed to gently encapsulate molecules, insert into skin, and enable bolus or sustained release delivery.

  6. Dissolved organic materials in the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Myklestad, S.; Boersheim, K.Y. (Institutt for Bioteknologi (Norway). UNIT/NTH)


    Dissolved organic matter (DOC) is one of the largest reservoirs of organic matter on our globe. DOC is intimately connected with the fluxes of CO[sub 2] through photosynthetic planktonic microalgae. A recently developed method for the measurement of organic matter utilises combustion at high temperature and a catalyst consisting of platinum and aluminium oxide. Because the new method has revealed concentrations of organic matter in the upper 100 m of oceanic water that exceed previous estimates 3-5 times, DOC is now regarded as a far more important component of carbon cycling than previously believed. 2 figs.

  7. Evaluating factorial kriging for seismic attributes filtering: a geostatistical filter applied to reservoir characterization; Avaliacao da krigagem fatorial na filtragem de atributos sismicos: um filtro geoestatistico aplicado a caracterizacao de reservatorios

    Energy Technology Data Exchange (ETDEWEB)

    Mundim, Evaldo Cesario


    In this dissertation the Factorial Kriging analysis for the filtering of seismic attributes applied to reservoir characterization is considered. Factorial Kriging works in the spatial, domain in a similar way to the Spectral Analysis in the frequency domain. The incorporation of filtered attributes via External Drift Kriging and Collocated Cokriging in the estimate of reservoir characterization is discussed. Its relevance for the reservoir porous volume calculation is also evaluated based on comparative analysis of the volume risk curves derived from stochastic conditional simulations with collocated variable and stochastic conditional simulations with collocated variable and stochastic conditional simulations with external drift. results prove Factorial Kriging as an efficient technique for the filtering of seismic attributes images, of which geologic features are enhanced. The attribute filtering improves the correlation between the attributes and the well data and the estimates of the reservoir properties. The differences between the estimates obtained by External Drift Kriging and Collocated Cokriging are also reduced. (author)

  8. Dissolved Fe(II) in a river-estuary system rich in dissolved organic matter (United States)

    Hopwood, Mark J.; Statham, Peter J.; Milani, Ambra


    Reduced iron, Fe(II), accounts for a significant fraction of dissolved Fe across many natural surface waters despite its rapid oxidation under oxic conditions. Here we investigate the temporal and spatial variation in dissolved Fe redox state in a high dissolved organic matter (DOM) estuarine system, the River Beaulieu. We couple manual sample collection with the deployment of an autonomous in situ analyser, designed to simultaneously measure dissolved Fe(II) and total dissolved Fe, in order to investigate processes operating on the diurnal timescale and to evaluate the performance of the analyser in a high DOM environment. Concentrations of dissolved Fe available to the ligand ferrozine are elevated throughout the estuary (up to 21 μM in freshwater) and notably higher than those previously reported likely due to seasonal variation. Fe(II) is observed to account for a large, varying fraction of the dissolved Fe available to ferrozine (25.5 ± 12.5%) and this fraction decreases with increasing salinity. We demonstrate that the very high DOM concentration in this environment and association of this DOM with dissolved Fe, prevents the accurate measurement of dissolved Fe concentrations in situ using a sensor reliant on rapid competitive ligand exchange.

  9. Evaluating Chlorophyll-a Changes During Algal Bloom in Three Gorges Reservoir Using an Extended WASP Model

    Directory of Open Access Journals (Sweden)

    Jian Li


    Full Text Available Algal bloom in Three Gorges Reservoir (TGR and one of its tributaries, Xiangxi River (XR, have become major concerns and the dynamic changes of such events were investigated using the hydrodynamic model SELFE and the extended Water Quality Analysis Simulation Program (WASP model to address nutrient and biomass dynamics. The model has taken into consideration the surface wind, heat fluxes, oxygen exchanges, solar radiations and boundary conditions from main river channel and tributaries. As an extension to our previous work, this study aimed to report in more detailed the result of chlorophyll-a simulations, where the field observed data of algal blooms in TGR in 2007 was used for calibration and the horizontal and vertical distributions of phytoplankton biomass (based on chlorophyll-a were presented. It was found that the chlorophyll-a concentration characterized as algal biomass was influenced by many complex factors. Further study results are yet to be reported.

  10. Processes Affecting Phosphorus and Copper Concentrations and Their Relation to Algal Growth in Two Supply Reservoirs in the Lower Coastal Plain of Virginia, 2002-2003, and Implications for Alternative Management Strategies (United States)

    Speiran, Gary K.; Simon, Nancy S.; Mood-Brown, Maria L.


    Elevated phosphorus concentrations commonly promote excessive growth of algae in waters nationwide. When such waters are used for public supply, the algae can plug filters during treatment and impart tastes and odors to the finished water. This increases treatment costs and results in finished water that may not be of the quality desired for public supply. Consequently, copper sulfate is routinely applied to many reservoirs to control algal growth but only is a 'temporary fix' and must be reapplied at intervals that can range from more than 30 days in the winter to less than 7 days in the summer. Because copper has a maximum allowable concentration in public drinking water and can be toxic to aquatic life, water suppliers commonly seek to develop alternative, long-term strategies for managing reservoirs. Because these are nationwide issues and part of the mission of the U.S. Geological Survey (USGS) is to define and protect the quality of the Nation's water resources and better understand the physical, chemical, and biological processes in wetlands, lakes, reservoirs, and estuaries, investigations into these issues are important to the fulfillment of the mission of the USGS. The City of Newport News, Virginia, provides 50 million gallons per day of treated water for public supply from Lee Hall and Harwoods Mill Reservoirs (terminal reservoirs) to communities on the lower York-James Peninsula. About 3,500 pounds of copper sulfate are applied to each reservoir at 3- to 99-day intervals to control algal growth. Consequently, the USGS, in cooperation with the City of Newport News, investigated the effects of management practices and natural processes on phosphorus (the apparent growth-limiting nutrient), copper, and algal concentrations in the terminal reservoirs to provide information that can be used to develop alternative management strategies for the terminal reservoirs. Initial parts of the research evaluated circulation and stratification in the reservoirs

  11. Characterization of hydraulic fractures and reservoir properties of shale using natural tracers (United States)

    Heath, J. E.; Gardner, P.; Kuhlman, K. L.; Malama, B.


    Hydraulic fracturing plays a major role in the economic production of hydrocarbon from shale. Current fracture characterization techniques are limited in diagnosing the transport properties of the fractures on the near wellbore scale to that of the entire stimulated reservoir volume. Microseismic reveals information on fracture geometries, but not transport properties. Production analysis (e.g., rate transient analysis using produced fluids) estimates fracture and reservoir flow characteristics, but often relies on simplified models in terms of fracture geometries and fluid storage and transport. We present the approach and potential benefits of incorporating natural tracers with production data analysis for fracture and reservoir characterization. Hydraulic fracturing releases omnipresent natural tracers that accumulate in low permeability rocks over geologic time (e.g., radiogenic 4He and 40Ar). Key reservoir characteristics govern the tracer release, which include: the number, connectivity, and geometry of fractures; the distribution of fracture-surface-area to matrix-block-volume; and the nature of hydrocarbon phases within the reservoir (e.g., methane dissolved in groundwater or present as a separate gas phase). We explore natural tracer systematics using numerical techniques under relevant shale-reservoir conditions. We evaluate the impact on natural tracer transport due to a variety of conceptual models of reservoir-transport properties and boundary conditions. Favorable attributes for analysis of natural tracers include the following: tracer concentrations start with a well-defined initial condition (i.e., equilibrium between matrix and any natural fractures); there is a large suite of tracers that cover a range of at least 7x in diffusion coefficients; and diffusive mass-transfer out of the matrix into hydraulic fractures will cause elemental and isotopic fractionation. Sandia National Laboratories is a multi-program laboratory managed and operated by

  12. Fluids acidity in Los Humeros geothermal reservoir, Puebla, Mexico: Mineralogical evaluation; Acidez de los fluidos del yacimiento geotermico de Los Humeros, Puebla, Mexico: Evaluacion mineralogica

    Energy Technology Data Exchange (ETDEWEB)

    Izquierdo M, Georgina; Arellano G, Victor Manuel; Portugal M, Enrique; Aragon A, Alfonso [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Martinez, Ignasio [Comision Federal de Electricidad (Mexico)


    The occurrence of the acidity in fluids from Los Humeros geothermal reservoir has been noticeable due to the accelerated corrosion of pipes lines of wells located mainly in the area known as Collapse Central and wells along the East direction of the field. On the base of the evaluation of all available chemical and mineralogical information for Los Humeros geothermal field the main objective of this work was to recognize evidences on the origin of geothermal fluids acidity. Considering the occurrence of HCl in other geothermal systems, no relation to the available information from Los Humeros was found. It is possible that the geothermal fluids acidity would be recent. It could be generated when the deep reservoir was reached by drilling wells. However, the occurrence of H{sub 2}SO{sub 4} is evident due to the advance argillic alteration of surface rocks in some areas of the field. It is probable that the model proposed by D' Amore, may be valid for the geothermal field of Los Humeros. Considering that the origin of the vapor phase from the deep reservoir would be a fluid (of very high salinity) that favored the formation of the HCl gas; which moved to the vapor zone when exploitation began being transported in the vapor phase toward the upper reservoir forming aqueous HCl. [Spanish] La presencia de acidez en los fluidos producidos por el yacimiento geotermico de Los Humeros se ha evidenciado por la acelerada corrosion de las tuberias de algunos pozos localizados principalmente en la zona conocida como Colapso central y en direccion Este del campo. Con el objeto de identificar evidencias que permitan establecer el origen de la acidez en los fluidos geotermicos, se llevo a cabo la evaluacion de la informacion quimica y mineralogica existente para el campo geotermico de Los Humeros. Empleando los criterios conocidos sobre la presencia de HCl en otros sistemas geotermicos no se encontro relacion con la informacion evaluada. Por lo que se sugiere que la acidez en

  13. Dissolved air flotation and me. (United States)

    Edzwald, James K


    This paper is mainly a critical review of the literature and an assessment of what we know about dissolved air flotation (DAF). A few remarks are made at the outset about the author's personal journey in DAF research, his start and its progression. DAF has been used for several decades in drinking water treatment as an alternative clarification method to sedimentation. DAF is particularly effective in treating reservoir water supplies; those supplies containing algae, natural color or natural organic matter; and those with low mineral turbidity. It is more efficient than sedimentation in removing turbidity and particles for these type supplies. Furthermore, it is more efficient in removing Giardia cysts and Cryptosporidium oocysts. In the last 20 years, fundamental models were developed that provide a basis for understanding the process, optimizing it, and integrating it into water treatment plants. The theories were tested through laboratory and pilot-plant studies. Consequently, there have been trends in which DAF pretreatment has been optimized resulting in better coagulation and a decrease in the size of flocculation tanks. In addition, the hydraulic loading rates have increased reducing the size of DAF processes. While DAF has been used mainly in conventional type water plants, there is now interest in the technology as a pretreatment step in ultrafiltration membrane plants and in desalination reverse osmosis plants. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Evaluation of Water Treatment Plant Performance of Parsabad City in Ardabil Province in Removal of Total Dissolved Solids, Turbidity Phosphate and Calcium

    Directory of Open Access Journals (Sweden)

    Mohsen Rezaei


    Full Text Available Background: The determination of influent and effluent water quality of water treatment plants is important to increase standards of water quality for users. Parsabad city situated in north of Ardabil province and is the biggest city of province Ardabil. So, this study was accomplished due to lack of substantial studies for Parsabad water treatment plant. In the study, some of the important parameters of water was investigated for 7 years and was presented solutions for improvement treatment plant performance. Methods: This study was accomplished since 1384 to 1390 and four parameters total dissolved solids, turbidity, phosphate and calcium with 192 samples (96 samples collected from treatment plant influent and 96 samples collected from effluent were analyzed according to standard methods for the examination of water and wastewater. Results: Maximum removal performance of turbidity, total dissolved solids, phosphate and calcium were 99.8, 6.1, 92.67 and 28.45 respectively, during 7 years operation of treatment plant. Conclusions: The results of this study showed that Parsabad water treatment plant with having a rapid sand filter, enable to remove turbidity up 85% when maximum turbidity at treatment plant influent was 700 NTU. But, significant difference statistically was not observed between influent and effluent samples of total dissolved solids and calcium (Pvalue˃0.05 and removal performance were trivial for total dissolved solids and calcium. Also, this treatment plant has not good performance (mean %38 for phosphate removal.

  15. Multiobjective reservoir operating rules based on cascade reservoir input variable selection method (United States)

    Yang, Guang; Guo, Shenglian; Liu, Pan; Li, Liping; Xu, Chongyu


    The input variable selection in multiobjective cascade reservoir operation is an important and difficult task. To address this problem, this study proposes the cascade reservoir input variable selection (CIS) method that searches for the most valuable input variables for decision making in multiple-objectivity cascade reservoir operations. From a case study of Hanjiang cascade reservoirs in China, we derive reservoir operating rules based on the combination of CIS and Gaussian radial basis functions (RBFs) methods and optimize the rules through Pareto-archived dynamically dimensioned search (PA-DDS) with two objectives: to maximize both power generation and water supply. We select the most effective input variables and evaluate their impacts on cascade reservoir operations. From the simulated trajectories of reservoir water level, power generation, and water supply, we analyze the multiobjective operating rules with several input variables. The results demonstrate that the CIS method performs well in the selection of input variables for the cascade reservoir operation, and the RBFs method can fully express the nonlinear operating rules for cascade reservoirs. We conclude that the CIS method is an effective and stable approach to identifying the most valuable information from a large number of candidate input variables. While the reservoir storage state is the most valuable information for the Hanjiang cascade reservoir multiobjective operation, the reservoir inflow is the most effective input variable for the single-objective operation of Danjiangkou.

  16. Evaluation of gas condensate reservoir behavior using velocity dependent relative permeability during the numerical well test analysis

    Directory of Open Access Journals (Sweden)

    Arash Azamifard


    Full Text Available Gas condensate is one of the most different fluids in reservoir simulation due to retrograde condensation in case of pressure reduction. In this kind of fluids, two phenomena named negative inertia and positive coupling, become significant in the high velocity zone around the wellbore. In this study, a modified black oil simulator is developed that take into account the velocity dependent relative permeability. Against the industrial simulator that assumes linear variation of transmissibilities by pressure, modified black oil nonlinear equations are solved directly without linearization. The developed code is validated by ECLIPSE simulator. The behavior of two real gas condensate fluids, a lean and a rich one, are compared with each other. For each fluid, simulations of PVT experiments are carried out to calculate black oil property applying Coats approach for gas condensate fluids. For both fluids, the proposed models for gas condensate velocity dependent relative permeability show different influence of velocity on relative permeability in the same conditions. Moreover, it is observed that higher flow rate of gas production leads to more condensate production during constant rate well testing.

  17. Altering Reservoir Withdrawal: a modeling approach to tail-water eutrophication on the South Fork Humboldt Reservoir, NV USA (United States)

    Smith, D. W.; Warwick, J. J.; Fritsen, C. H.; Davis, C.; Memmott, J.; Wirthlin, E.


    The South Fork Humboldt Reservoir (south of Elko, Nevada) represents an arid, hypolimnetic release dam with tail-water eutrophication exceeding 300mg Chla per m2. The USEPA model AQUATOX 3 has been used to simulate reservoir nutrient loadings on tail-water periphyton and to predict changes in stream response to top release conditions. From April to September of 2009, an investigation characterized reservoir stratified nutrient profiles and downstream riverine algal dynamics due to reservoir bottom withdrawal. The 2009 period represents calibration with exceptional downstream diel dissolved oxygen swings (3.76 to 19.75 mg/L) and gross primary productivity (30.7 g C m2 d¬-1) for model prediction. The observed period was additionally simulated with exclusively top release conditions to investigate potential best management practices. The results predict potential changes of attached algal communities and associated dissolved oxygen conditions based on varied release nutrient loadings.

  18. Freshwater reservoir effect variability in Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, Bente; Heinemeier, Jan


    The freshwater reservoir effect is a potential problem when radiocarbon dating fishbones, shells, human bones or food crusts on pottery from sites next to rivers or lakes. The reservoir age in rivers containing considerable amounts of dissolved 14C-free carbonates can be up to several thousand...... years and may be highly variable. For accurate radiocarbon dating of freshwater-based samples, the order of magnitude of the reservoir effect as well as the degree of variability has to be known. The initial problem in this case was the accurate dating of food crusts on pottery from the Mesolithic sites...... and variability that can also be expected for the past. Water DIC from different seasons, and from the same season in different years, has been dated because it is the carbon source in photosynthesis and thus at the basis of the rivers’ food webs. The radiocarbon ages of underwater plants and different parts...

  19. Status of Norris Reservoir

    Energy Technology Data Exchange (ETDEWEB)


    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Norris Reservoir summarizes reservoir and watershed characteristics, reservoir uses, conditions that impair reservoir uses, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most up-to-date publications and data available, and from interviews with water resource professionals in various federal, state, and local agencies, and in public and private water supply and wastewater treatment facilities. 14 refs., 3 figs.

  20. Indicators: Dissolved Oxygen (United States)

    Dissolved oxygen (DO) is the amount of oxygen that is present in water. It is an important measure of water quality as it indicates a water body's ability to support aquatic life. Water bodies receive oxygen from the atmosphere and from aquatic plants.

  1. Optimizing withdrawal from drinking water reservoirs to reduce downstream temperature pollution and reservoir hypoxia. (United States)

    Weber, M; Rinke, K; Hipsey, M R; Boehrer, B


    Sustainable management of drinking water reservoirs requires balancing the demands of water supply whilst minimizing environmental impact. This study numerically simulates the effect of an improved withdrawal scheme designed to alleviate the temperature pollution downstream of a reservoir. The aim was to identify an optimal withdrawal strategy such that water of a desirable discharge temperature can be supplied downstream without leading to unacceptably low oxygen concentrations within the reservoir. First, we calibrated a one-dimensional numerical model for hydrodynamics and oxygen dynamics (GLM-AED2), verifying that the model reproduced water temperatures and hypolimnetic dissolved oxygen concentrations accurately over a 5 year period. Second, the model was extended to include an adaptive withdrawal functionality, allowing for a prescribed withdrawal temperature to be found, with the potential constraint of hypolimnetic oxygen concentration. Scenario simulations on epi-/metalimnetic withdrawal demonstrate that the model is able to autonomously determine the best withdrawal height depending on the thermal structure and the hypolimnetic oxygen concentration thereby optimizing the ability to supply a desirable discharge temperature to the downstream river during summer. This new withdrawal strategy also increased the hypolimnetic raw water volume to be used for drinking water supply, but reduced the dissolved oxygen concentrations in the deep and cold water layers (hypolimnion). Implications of the results for reservoir management are discussed and the numerical model is provided for operators as a simple and efficient tool for optimizing the withdrawal strategy within different reservoir contexts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97 (United States)

    Feaster, Toby D.; Conrads, Paul; Guimaraes, Wladmir B.; Sanders, Curtis L.; Bales, Jerad D.


    Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3

  3. Large reservoirs: Chapter 17 (United States)

    Miranda, Leandro E.; Bettoli, Phillip William


    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  4. Evaluation of the dynamic mobilization of vanadium in tributary sediments of the Three Gorges Reservoir after water impoundment (United States)

    Gao, Bo; Gao, Li; Zhou, Yang; Xu, Dongyu; Zhao, Xingjuan


    The Three Gorges Reservoir (TGR) is the largest water resource protection zone in China, and environmental safety is crucial to its operation. For both aqueous and sediment phases, diffusive gradients in thin films (DGT), total vanadium (V) concentration (CTotal-V), and community Bureau of Reference (BCR) sequential extraction data were used to measure the pollution characteristics, horizontal and vertical distributions of DGT-labile V, and the dynamic mobilization of V in a typical tributary (the Meixi River) of the TGR. The results showed that CTotal-V in the surface sediments were obviously higher than the background values in sediment and soil, indicating a potential anthropogenic input of V in this area. A positive relationship was found between total organic carbon (TOC) and CTotal-V in the sediments, indicating that the pollution characteristics of V were associated with TOC. In addition, horizontal and vertical distributions of the fluxes of DGT-labile V (FDGT-V) varied among the four DGT probes. In the same DGT probe, the horizontal distributions (0-6 mm, 6-12 mm and 12-18 mm) of FDGT-V were similar in the overlying water; however, the values showed a poor coincidence with those recorded in the sediment. The vertical distribution of FDGT-V in the same DGT probe showed similar tendencies. In fact, CDGT-V is significantly negatively correlated with CDGT-Fe, demonstrating that V had an inversely diffusive tendency with Fe. Moreover, diffusion fluxes of V at the sediment-water interface illustrated that the release characteristics of V varied among the sampling sites. In addition, the BCR fraction of V in the surface sediments of the four sampling sites showed that V mainly existed in the residual fraction (88.04-88.57%). The concentrations of DGT-labile V (CDGT-V) were considerably lower than the non-residual fractions (the sum of exchangeable, reducible, and oxidizable fractions) measured by BCR sequential extraction. Correlation analysis showed that CDGT

  5. An Integrated Modeling Approach for Describing Fate and Transport of Perfluorinated Compounds (PFCs) in Estuarine Reservoir (United States)

    Zhang, J.; Nguyen Viet, T.; Wang, X.; Chen, H.; Gin, K. Y. H.


    The fate and transport processes of emerging contaminants in aquatic ecosystems are complex, which are not only determined by their own properties but also influenced by the environmental setting, physical, chemical and biological processes. A 3D-emerging contaminant model has been developed based on Delft3D water quality model and coupled with a hydrodynamic model and a catchment-scale 1D- hydrological and hydraulic model to study the possible fate and transport mechanisms of perfluorinated compounds (PFCs) in Marina Reservoir in Singapore. The main processes in the contaminant model include partitioning (among detritus, dissolved organic matter and phytoplankton), settling, resuspension and degradation. We used the integrated model to quantify the distribution of the total PFCs and two major components, namely perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in the water, sediments and organisms in the reservoir. The model yielded good agreement with the field measurements when evaluated based on the datasets in 2009 and 2010 as well as recent observations in 2013 and 2014. Our results elucidate that the model can be a useful tool to characterize the occurrence, sources, sinks and trends of PFCs both in the water column and in the sediments in the reservoir. Thisapproach provides a better understanding of mechanisms that influence the fate and transport of emerging contaminants and lays down a framework for future experiments to further explore how the dominant environmental factors change towards mitigation of emerging contaminants in the reservoirs.

  6. Phytoplankton biodiversity changes in a shallow tropical reservoir during the hypertrophication process

    Directory of Open Access Journals (Sweden)

    LO. Crossetti

    Full Text Available Study aimed at evaluating phytoplankton biodiversity changes in a shallow tropical reservoir during its hypertrophication process. Samplings were carried out monthly during 8 consecutive years (1997-2004 in 5 depths. Conspicuous limnological changes in the reservoir derived from the presence and/or removal of the water hyacinth, characterized 3 different phases. Over the time series, reservoir changed from a typical polymictic eutrophic system to hypertrophic one, leading to a reduction of approximately 70 species (average 37%. Chlorophyceae accounted for the highest species richness (46% among all algal classes and strictly followed total species richness variation. Internal feedback mechanisms intensification over phase III clearly promoted the sharp decrease in biodiversity. Highest decreases, mainly during springs, occurred simultaneously to the highest Cyanobacteria blooms. Increased turbidity due to heavy phytoplankton blooms suppressed all other algal groups, so that at the end of the present study even Cyanobacteria species richness decreased. Total dissolved phosphorous was included in most of the best selected models used to analyze the temporal patterns in species richness loss. Present data show that biodiversity loss following trophic change was not a single dimension of a single factor but, rather, a template of factors (e.g. light, stability co-varying in consequence of the larger levels of biomass supported in the reservoir.

  7. Methods for evaluating temporal groundwater quality data and results of decadal-scale changes in chloride, dissolved solids, and nitrate concentrations in groundwater in the United States, 1988-2010 (United States)

    Lindsey, Bruce D.; Rupert, Michael G.


    Decadal-scale changes in groundwater quality were evaluated by the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Samples of groundwater collected from wells during 1988-2000 - a first sampling event representing the decade ending the 20th century - were compared on a pair-wise basis to samples from the same wells collected during 2001-2010 - a second sampling event representing the decade beginning the 21st century. The data set consists of samples from 1,236 wells in 56 well networks, representing major aquifers and urban and agricultural land-use areas, with analytical results for chloride, dissolved solids, and nitrate. Statistical analysis was done on a network basis rather than by individual wells. Although spanning slightly more or less than a 10-year period, the two-sample comparison between the first and second sampling events is referred to as an analysis of decadal-scale change based on a step-trend analysis. The 22 principal aquifers represented by these 56 networks account for nearly 80 percent of the estimated withdrawals of groundwater used for drinking-water supply in the Nation. Well networks where decadal-scale changes in concentrations were statistically significant were identified using the Wilcoxon-Pratt signed-rank test. For the statistical analysis of chloride, dissolved solids, and nitrate concentrations at the network level, more than half revealed no statistically significant change over the decadal period. However, for networks that had statistically significant changes, increased concentrations outnumbered decreased concentrations by a large margin. Statistically significant increases of chloride concentrations were identified for 43 percent of 56 networks. Dissolved solids concentrations increased significantly in 41 percent of the 54 networks with dissolved solids data, and nitrate concentrations increased significantly in 23 percent of 56 networks. At least one of the three - chloride, dissolved solids, or

  8. Fast Dissolving Tablets of Aloe Vera Gel | Madan | Tropical Journal ...

    African Journals Online (AJOL)

    Purpose: The objective of this work was to prepare and evaluate fast dissolving tablets of the nutraceutical, freeze dried Aloe vera gel. Methods: Fast dissolving tablets of the nutraceutical, freeze-dried Aloe vera gel, were prepared by dry granulation method. The tablets were evaluated for crushing strength, disintegration ...

  9. Reconnaissance of water quality of Pueblo Reservoir, Colorado: May through December 1985 (United States)

    Edelmann, Patrick


    Pueblo Reservoir is the farthest upstream, main-stream reservoir constructed on the Arkansas River and is located in Pueblo County approximately 6 miles upstream from the city of Pueblo, Colorado. During the 1985 sampling period, the reservoir was stratified, and underflow from the Arkansas River occurred that resulted in stratification with respect to specific conductance. Concentrations of dissolved solids decreased markedly below the thermocline during June. Later in the summer, dissolved-solids concentrations increased substantially below the thermocline. Substantial depletion of dissolved oxygen occurred near the bottom of the reservoir. The dissolved oxygen minimum of 0.1 mg/L occurred during August near the reservoir bottom at transect 7 (near the dam). The average total-inorganic-nitrogen concentration near the reservoir surface was about 0.2 mg/L; near the reservoir bottom, the average concentration was about 0.3 mg/L. Concentrations of total phosphorus ranged from less than 0.01 to 0.05 mg/L near the reservoir surface, and from less than 0.01 to 0.22 mg/L near the reservoir bottom. At transect 2 (about 7 miles upstream from the dam) near the bottom of the reservoir, concentrations of total iron exceeded aquatic-life standards, and dissolved-manganese concentrations exceeded standards for public water supply. Diatoms, green algae, blue-green algae, and cryptomonads comprised the majority of phytoplankton in Pueblo Reservoir in 1985. The maximum average of 41,000 cells/ml occurred in July. Blue-green algae dominated from June to September; diatoms were the dominant group of algae in October. The average concentrations of phytoplankton decreased from July to October. (USGS)

  10. Microbial Food-Web Drivers in Tropical Reservoirs. (United States)

    Domingues, Carolina Davila; da Silva, Lucia Helena Sampaio; Rangel, Luciana Machado; de Magalhães, Leonardo; de Melo Rocha, Adriana; Lobão, Lúcia Meirelles; Paiva, Rafael; Roland, Fábio; Sarmento, Hugo


    Element cycling in aquatic systems is driven chiefly by planktonic processes, and the structure of the planktonic food web determines the efficiency of carbon transfer through trophic levels. However, few studies have comprehensively evaluated all planktonic food-web components in tropical regions. The aim of this study was to unravel the top-down controls (metazooplankton community structure), bottom-up controls (resource availability), and hydrologic (water residence time) and physical (temperature) variables that affect different components of the microbial food web (MFW) carbon stock in tropical reservoirs, through structural equation models (SEM). We conducted a field study in four deep Brazilian reservoirs (Balbina, Tucuruí, Três Marias, and Funil) with different trophic states (oligo-, meso-, and eutrophic). We found evidence of a high contribution of the MFW (up to 50% of total planktonic carbon), especially in the less-eutrophic reservoirs (Balbina and Tucuruí). Bottom-up and top-down effects assessed through SEM indicated negative interactions between soluble reactive phosphorus and phototrophic picoplankton (PPP), dissolved inorganic nitrogen, and heterotrophic nanoflagellates (HNF). Copepods positively affected ciliates, and cladocerans positively affected heterotrophic bacteria (HB) and PPP. Higher copepod/cladoceran ratios and an indirect positive effect of copepods on HB might strengthen HB-HNF coupling. We also found low values for the degree of uncoupling (D) and a low HNF/HB ratio compared with literature data (mostly from temperate regions). This study demonstrates the importance of evaluating the whole size spectrum (including microbial compartments) of the different planktonic compartments, in order to capture the complex carbon dynamics of tropical aquatic ecosystems.

  11. Seasonal variability of water quality and metazooplankton community structure in Xiaowan Reservoir of the upper Mekong River

    Directory of Open Access Journals (Sweden)

    Xiaodong Wu


    Full Text Available Water quality problems in the Xiaowan Reservoir due to a recently built dam of upper Mekong River have became major ecological and economic concerns. The main goal of this work was thus to describe the present water quality and metazooplankton dynamics and to evaluate the effects of damming on aquatic ecosystem in the super reservoir. The water quality including conductivity, turbidity, Chlorophyll a, dissolved oxygen, total nitrogen, total phosphorus and metazooplankton communities were surveyed along the 30 km away from the dam in the reservoir from 2011 to 2012. Throughout our study, most of the water quality parameters showed clear temporal changes. The total nitrogen and phosphorus showed mean values of 0.9 and 0.04 mg L–1 at different sites. The dominated species of zooplankton showed typical seasonal succession. The most important factor in the determination of zooplankton throughout the year is water temperature and Chlorophyll a. The spatial distribution of water quality parameters and zooplankton communities fluctuated considerably among different sites. However, it is difficult to explain these spatial changes which may relate to the unstable water conditions. Our results showed that the area along the 30 km away from the dam of Xiaowan Reservoir belonged to lake-type environment. More attention should be paid on the aquatic ecosystems of the reservoirs which belong to the gorge area with high mountains and steep valleys.

  12. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund


    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...... leachates showed different Cd speciation patterns as expected. Some leachates were dominated by free divalent Cd (1-70%), some by inorganic complexes (1-87%), and some by organic complexes (7-98%)....

  13. Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

    Directory of Open Access Journals (Sweden)

    Haibo Zhang


    Full Text Available Recycling irrigation reservoirs (RIRs are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA and Maryland (MD. Surface water temperature (T and oxidation-reduction potential (ORP were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO, pH and chlorophyll a (Chla. The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC, total dissolved solids (TDS and turbidity (TUR. Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality

  14. Status of Cherokee Reservoir

    Energy Technology Data Exchange (ETDEWEB)


    This is the first in a series of reports prepared by Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overviews of Cherokee Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports, publications, and data available, and interviews with water resource professionals in various Federal, state, and local agencies and in public and private water supply and wastewater treatment facilities. 11 refs., 4 figs., 1 tab.

  15. Status of Wheeler Reservoir

    Energy Technology Data Exchange (ETDEWEB)


    This is one in a series of status reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Wheeler Reservoir summarizes reservoir purposes and operation, reservoir and watershed characteristics, reservoir uses and use impairments, and water quality and aquatic biological conditions. The information presented here is from the most recent reports, publications, and original data available. If no recent data were available, historical data were summarized. If data were completely lacking, environmental professionals with special knowledge of the resource were interviewed. 12 refs., 2 figs.

  16. Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

    KAUST Repository

    Yutkin, Maxim P.


    Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of

  17. Forming mechanism of the Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin

    Directory of Open Access Journals (Sweden)

    Heng Fu


    Full Text Available The Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin are important oil and gas exploration targets in the basin, but their dissolution mechanisms are in controversy. In this paper, based on the integrated study of sedimentation, sequence and reservoir, together with microscopic analysis and macroscopic seismic data analysis, the carbonate karst reservoirs in the study area were divided into three types: dissolved pore-cavity limestone reservoir, pore-cavity dolomite reservoir and fracture-cavity siliceous reservoir, and their forming mechanisms were discussed respectively. Some findings were obtained. First, dissolved pore-cavity limestone reservoirs are distributed in the upper Yingshan Fm and Yijianfang Fm of the Ordovician vertically, while pore-cavity dolomite reservoirs are mainly developed in the Penglai Fm and lower Yingshan Fm of the Ordovician with great thickness. Second, dissolved pore-cavity limestone reservoirs were formed by karstification on the third-order sequence boundary (lowstand tract, while pore-cavity dolomite reservoirs were formed by deep burial dolomitization controlled by karstification on the third-order sequence boundary, both of which are distributed in the highstand tract below the third-order sequence boundary. Third, siliceous reservoirs are developed under the control of faulting, as a result of reworking of deep hydrothermal fluids along faults to the limestone, and the siliceous reservoirs and their hydrothermal solution fracture-cavity systems are distributed near faults. It is further predicted that, in addition to the three types of reservoir above, platform-margin reef-flat reservoirs are developed in the Ordovician on the northern slope of central Tarim Basin.

  18. CO2 emissions from German drinking water reservoirs. (United States)

    Saidi, Helmi; Koschorreck, Matthias


    Globally, reservoirs are a significant source of atmospheric CO2. However, precise quantification of greenhouse gas emissions from drinking water reservoirs on the regional or national scale is still challenging. We calculated CO2 fluxes for 39 German drinking water reservoirs during a period of 22years (1991-2013) using routine monitoring data in order to quantify total emission of CO2 from drinking water reservoirs in Germany and to identify major drivers. All reservoirs were a net CO2 source with a median flux of 167gCm-2y-1, which makes gaseous emissions a relevant process for the carbon budget of each reservoir. Fluxes varied seasonally with median fluxes of 13, 48, and 201gCm-2y-1 in spring, summer, and autumn respectively. Differences between reservoirs appeared to be primarily caused by the concentration of CO2 in the surface water rather than by the physical gas transfer coefficient. Consideration of short term fluctuations of the gas transfer coefficient due to varying wind speed had only a minor effect on the annual budgets. High CO2 emissions only occurred in reservoirs with pHemissions correlated exponentially with pH but not with dissolved organic carbon (DOC). There was significant correlation between land use in the catchment and CO2 emissions. In total, German drinking water reservoirs emit 44000t of CO2 annually, which makes them a negligible CO2 source (emissions) in Germany. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Evaluation of the hydraulic and biological performance of the portable floating fish collector at Cougar Reservoir and Dam, Oregon, 2014 (United States)

    Beeman, John W.; Evans, Scott D.; Haner, Philip V.; Hansel, Hal C.; Hansen, Amy C.; Hansen, Gabriel S.; Hatton, Tyson W.; Sprando, Jamie M.; Smith, Collin D.; Adams, Noah S.


    The biological and hydraulic performance of a new portable floating fish collector (PFFC) located in a cul-de-sac within the forebay of Cougar Dam, Oregon, was evaluated during 2014. The purpose of the PFFC was to explore surface collection as a means to capture juvenile salmonids at one or more sites using a small, cost-effective, pilot-scale device. The PFFC used internal pumps to draw attraction flow over an inclined plane about 3 meters (m) deep, through a flume at a design velocity of as much as 6 feet per second (ft/s), and to empty a small amount of water and any entrained fish into a collection box. Performance of the PFFC was evaluated at 64 cubic feet per second (ft3/s) (Low) and 109 ft3/s (High) inflow rates alternated using a randomized-block schedule from May 27 to December 16, 2014. The evaluation of the biological performance was based on trap catch; behaviors, locations, and collection of juvenile Chinook salmon (Oncorhynchus tshawytscha) tagged with acoustic transmitters plus passive integrated transponder (PIT) tags; collection of juvenile Chinook salmon implanted with only PIT tags; and untagged fish monitored near and within the PFFC using acoustic cameras. The evaluation of hydraulic performance was based on measurements of water velocity and direction of flow in the PFFC.

  20. Advanced reservoir characterization and evaluation of CO2 gravity drainage in the naturally fractured Spraberry Trend Area. Annual report, September 1, 1996--August 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, P.


    The objective of the Spraberry CO{sub 2} pilot project is to determine the technical and economic feasibility of continuous CO{sub 2} injection in the naturally fractured reservoirs of the Spraberry Trend. In order to describe, understand, and model CO{sub 2} flooding in the naturally fractured Spraberry reservoirs, characterization of the fracture system is a must. Additional reservoir characterization was based on horizontal coring in the second year of the project. In addition to characterization of natural fractures, horizontal coring has confirmed a previously developed rock model for describing the Spraberry Trend shaly sands. A better method for identifying Spraberry pay zones has been verified. The authors have completed the reservoir characterization, which includes matrix description and detection (from core-log integration) and fracture characterization. This information is found in Section 1. The authors have completed extensive imbibition experiments that strongly indicate that the weakly water-wet behavior of the reservoir rock may be responsible for poor waterflood response observed in many Spraberry fields. The authors have also made significant progress in analytical and numerical simulation of performance in Spraberry reservoirs as seen in Section 3. They have completed several suites of CO{sub 2} gravity drainage in Spraberry and Berea whole cores at reservoir conditions and reported in Section 4. The results of these experiments have been useful in developing a model for free-fall gravity drainage and have validated the premise that CO{sub 2} will recover oil from tight, unconfined Spraberry matrix.

  1. Modeling Lake Turkana Hydrology: Evaluating the potential hydrological impact of Gibe III reservoir on the Lake Turkana water levels using multi-source satellite data (United States)

    Velpuri, N.; Senay, G. B.


    Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies >80% of the inflows to Lake Turkana, Kenya. On completion, the Gibe III dam will be the tallest dam in Africa (height of 241 m) with a storage capacity of 14.5 billion m3. Arguably, this is one of the most controversial hydro-power projects in the region because the nature of interactions and potential impacts of the dam regulated flows on Lake Turkana are not well understood due to its remote location and unavailability of reliable in situ hydrological datasets. In this research, we used a calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account 12 years (1998-2009) of satellite rainfall, model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model was used to evaluate the impact of the Gibe III dam using three different simple but robust approaches - a historical approach; a rainfall based sampling approach; and a non-parametric bootstrap resampling approach to generate rainfall-runoff scenarios. Modelling results indicate that, on average, the reservoir would take up to 8-10 months to reach minimum operation level of 201 m (initial impoundment period). During this period, the dam would regulate the lake inflows up to 50% and as a result the lake level would drop up to 2 m. However, after the initial impoundment period, due to releases from the dam, the rate of lake inflows would be around 10 m3/s less when compared to the rate without Gibe III (650 m3/s). Due to this, the lake levels will decline on average 1.5 m (3 m). Over the entire modeling period including the initial period of impoundment, the average rate of lake inflows due to Gibe III dam was estimated to be 500 m3/s. Results indicated that dam would also moderate the seasonal fluctuations in the lake. Areas along the Lake Turkana shoreline that are vulnerable to

  2. Advanced reservoir characterization and evaluation of CO{sub 2} gravity drainage in the naturally fractured Spraberry Trend Area. Annual report, September 1, 1995--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Schechter, D.S.


    The overall goal of this project is to assess the economic feasibility of CO{sub 2} flooding in the naturally fractured Spraberry Trend Area in West Texas. This objective is being accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, (3) analytical and numerical simulation of Spraberry reservoirs, and, (4) experimental investigations on CO{sub 2} gravity drainage in Spraberry whole cores. This report provides results of the first year of the five-year project for each of the four areas.

  3. Advanced reservoir characterization and evaluation of CO{sub 2} gravity drainage in the naturally fractured Spraberry Trend Area. Quarterly technical report

    Energy Technology Data Exchange (ETDEWEB)

    Schechter, David S.


    The overall goal of this project is to assess the economic feasibility of CO{sub 2} flooding the naturally fractured Spraberry Trend Area in West Texas. This objective is being accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, (3) analytical and numerical simulation of Spraberry reservoirs, and, (4) experimental investigations on CO{sub 2} gravity drainage in Spraberry whole cores. This report provides results of the fourth quarter of 1997 in the fourth area.

  4. Incorporating surface indicators of reservoir permeability into reservoir volume calculations: Application to the Colli Albani caldera and the Central Italy Geothermal Province (United States)

    Giordano, Guido; De Benedetti, Arnaldo Angelo; Bonamico, Andrea; Ramazzotti, Paolo; Mattei, Massimo


    The Quaternary Roman Volcanic Province extends for over 200 km along the Tyrrhenian margin of the Italian peninsula and is composed of several caldera complexes with significant associated geothermal potential. In spite of the massive programs of explorations conducted by the then state-owned ENEL and AGIP companies between the 1970s and 1990s, and the identification of several high enthalpy fields, this resource remains so far unexploited, although it occurs right below the densely populated metropolitan area of Roma capital city. The main reason for this failure is that deep geothermal reservoirs are associated with fractured rocks, the secondary permeability of which has been difficult to predict making the identification of the most productive volumes of the reservoirs and the localisation of productive wells uncertain. As a consequence, almost half of the many exploration deep bore-holes drilled in the area reached a dry target. This work reviews available data and re-assesses the geothermal potential of caldera-related systems in Central Italy, by analysing in detail the case of the Colli Albani caldera system, the closest to Roma capital city. A GIS based approach identifies the most promising reservoir volumes for geothermal exploitation and uses an improved volume method approach for the evaluation of geothermal potential. The approach is based on a three dimensional matrix of georeferenced spatial data; the A axis accounts for the modelling of the depth of the top of the reservoirs based on geophysical and direct data; the B axis accounts for the thermal modelling of the crust (i.e. T with depth) based on measured thermal gradients. Both A and B data are necessary but not sufficient to identify rock volumes actually permeated by geothermal fluids in fractured reservoirs. We discuss the implementation of a C axis that evaluates all surface data indicating permeability in the reservoir and actual geothermal fluid circulation. We consider datasets on: i

  5. Application of Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres for evaluating the sorption of organophosphate esters to dissolved organic matter (DOM). (United States)

    Pang, Long; Yang, Peijie; Yang, Huiqiang; Ge, Liming; Xiao, Jingwen; Zhou, Yifan


    Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in many products and materials. Because of the potential biologic toxicity on human beings, OPEs are regarded as a class of emerging pollutants. Dissolved organic matters (DOM) have significant effects on the bioavailability and toxicity of the pollutants in the environment. Negligible-depletion solid-phase microextraction (nd-SPME) is an efficient way for measuring the freely dissolved pollutants but suffers from long equilibrium time. Metal-organic frameworks (MOFs) are a class of porous crystalline materials with unique properties such as high pore volume, regular porosity, and tunable pore size, being widely used for the extraction of various organic compounds. Here we developed a novel method for quick determination the sorption coefficients of OPEs to DOM in aquatic phase using Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres. The mesoporous structures of the as-synthesized microspheres hindered the extraction of OPEs which associated with humic acid due to the volume exclusion effect. However, the freely dissolved OPEs can access into the mesoporous and then were extracted by MIL-100 (Fe). Due to the small pore size (4.81 nm), large surface area (141 m2 g-1), high pore volume (0.17 g3 g-1), and ultra-thin MOFs layers, Fe3O4@MIL-100 (Fe) core-shell magnetic microspheres have large contact area for the analytes in aqueous phase and therefore the diffusion distance was largely shortened. Besides, the microspheres can be collected conveniently after the extraction process by applying a magnetic field. Compared to the nd-SPME method with 35 h equilibration time (t90%), the proposed method for these studied OPEs only need 24 min to achieve equilibration. The sorption coefficients (logKDOC) of the OPEs to humic acid were ranged from 3.84-5.28, which were highly consistent with the results by using polyacrylate-coated fiber and polydimethylsiloxane-coated fiber with

  6. Understanding Your Watershed Fact Sheet: Dissolved Oxygen


    Mesner, Nancy; Geiger, John


    Dissolved oxygen describes oxygen molecules which have actually dissolved in water. Sometimes people confuse bubbles in water with dissolved oxygen, but in reality the dissolved form of oxygen cannot be seen.

  7. A Bayesian approach for evaluation of the effect of water quality model parameter uncertainty on TMDLs: A case study of Miyun Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shidong, E-mail: [School of Environment, Tsinghua University, 1 Qinghuayuan, Haidian District, Beijing 100084 (China); Jia, Haifeng, E-mail: [School of Environment, Tsinghua University, 1 Qinghuayuan, Haidian District, Beijing 100084 (China); Xu, Changqing, E-mail: [School of Environment, Tsinghua University, 1 Qinghuayuan, Haidian District, Beijing 100084 (China); Xu, Te, E-mail: [School of Environment, Tsinghua University, 1 Qinghuayuan, Haidian District, Beijing 100084 (China); Melching, Charles, E-mail: [Melching Water Solutions, 4030 W. Edgerton Avenue, Greenfield, WI 53221 (United States)


    ) determination. The sources of uncertainty are discussed and ways to reduce the uncertainties are proposed. - Highlights: • Effect of water quality model parameter uncertainty on TMDLs was evaluated. • A Bayesian approach was used for the model parameter uncertainty analysis. • DREAM algorithm, a multi-chain MCMC, was used as the Bayesian approach. • Miyun Reservoir, the most important drinking water source for Beijing, was studied. • Wide ranges of allowable loads were obtained through uncertainty propagation.

  8. Whitefly population dynamics and evaluation of whitefly-transmitted Tomato yellow leaf curl virus (TYLCV)-resistant tomato genotypes as whitefly and TYLCV reservoirs (United States)

    Tomato yellow leaf curl virus resistant tomato cultivars are a major tool for management of this economically important virus. Results presented emphasize that such resistant tomatoes can serve as virus and whitefly reservoirs and potentially influence virus epidemics....

  9. Dissolved oxygen: Chapter 6 (United States)

    Senn, David; Downing-Kunz, Maureen; Novick, Emily


    Dissolved oxygen (DO) concentration serves as an important indicator of estuarine habitat condition, because all aquatic macro-organisms require some minimum DO level to survive and prosper. The instantaneous DO concentration, measured at a specific location in the water column, results from a balance between multiple processes that add or remove oxygen (Figure 6.1): primary production produces O2; aerobic respiration in the water column and sediments consumes O2; abiotic or microbially-mediated biogeochemical reactions utilize O2 as an oxidant (e.g., oxidation of ammonium, sulfide, and ferrous iron); O2 exchange occurs across the air:water interface in response to under- or oversaturated DO concentrations in the water column; and water currents and turbulent mixing transport DO into and out of zones in the water column. If the oxygen loss rate exceeds the oxygen production or input rate, DO concentration decreases. When DO losses exceed production or input over a prolonged enough period of time, hypoxia ((<2-3 mg/L) or anoxia can develop. Persistent hypoxia or anoxia causes stress or death in aquatic organism populations, or for organisms that can escape a hypoxic or anoxic area, the loss of habitat. In addition, sulfide, which is toxic to aquatic organisms and causes odor problems, escapes from sediments under low oxygen conditions. Low dissolved oxygen is a common aquatic ecosystem response to elevated organic

  10. Evaluation of the biological and hydraulic performance of the portable floating fish collector at Cougar Reservoir and Dam, Oregon, September 2015–January 2016 (United States)

    Beeman, John W.; Evans, Scott D.; Haner, Philip V.; Hansel, Hal C.; Hansen, Amy C.; Hansen, Gabriel S.; Hatton, Tyson W.; Kofoot, Eric E.; Sprando, Jamie M.


    The biological and hydraulic performance of a portable floating fish collector (PFFC) located in the cul-de-sac of Cougar Dam and Reservoir, Oregon, was evaluated during 2015–16. The PFFC, first commissioned in May 2014, was modified during winter 2014–15 to address several deficiencies identified during operation and testing in 2014. These modifications included raising the water inflow structures to reduce the depth and volume of inflow to improve the internal hydraulic profiles, and moving the anchors so the PFFC could be positioned closer to the existing reservoir outlet, a water temperature control tower. The PFFC was positioned about 18 meters (m) upstream of the intake of the water temperature control tower and faced into the prevailing water current. Like several floating surface collectors operating in the Pacific Northwest at the time, the PFFC used pumps to draw water and fish over an inclined plane, past dewatering screens, and into a collection area. The portable and experimental nature of the PFFC required a smaller size, shallower entrance (about 2.5-m deep), and smaller inflow rate (72 cubic feet per second [ft3/s] inflow during the Low treatment, 122 ft3/s during the High treatment) than other collectors in the region.The collection of the target species, juvenile Chinook salmon (Oncorhynchus tshawytscha), during 2015–16 was an order of magnitude larger than in 2014. Subyearling-age Chinook salmon comprised most of the catch (2,616 subyearling compared to 258 yearling) and was greatest during the spring during the High inflow treatment. Bycatch consisted predominantly of cyprinids and centrarchids. Trap mortality (fish found dead in the trap) of juvenile Chinook salmon, at 9.2 percent of the subyearlings and 5.0 percent of yearlings, was about 30 percent of the level in 2014. Fish mortality from handling the live catch was about 1 percent.Data from fish tagged with passive integrated transponder (PIT) tags and those with acoustic+PIT tags

  11. An Evaluation of Common Cleaning Methodologies on the Persistence of a Clinical Isolate of Escherichia coli in Personal Hydration System Water-Reservoirs (United States)


    limited sunlight for two weeks. It was found that only the distilled water reservoir maintained viable organisms. No organisms could be recovered from...Douglas D. Lancaster, COL, DC Army Post Graduate Dental School 3 August 2016 Pages: 4 Words : 1950...Isolate of Escherichia coli in Personal Hydration System Water -Reservoirs CPT Stephanie Helmus DDS*, Jauchia Blythe PhD**, COL Peter Guevara DMD, MAGD

  12. The Alphabet Soup of HIV Reservoir Markers. (United States)

    Sharaf, Radwa R; Li, Jonathan Z


    Despite the success of antiretroviral therapy in suppressing HIV, life-long therapy is required to avoid HIV reactivation from long-lived viral reservoirs. Currently, there is intense interest in searching for therapeutic interventions that can purge the viral reservoir to achieve complete remission in HIV patients off antiretroviral therapy. The evaluation of such interventions relies on our ability to accurately and precisely measure the true size of the viral reservoir. In this review, we assess the most commonly used HIV reservoir assays, as a clear understanding of the strengths and weaknesses of each is vital for the accurate interpretation of results and for the development of improved assays. The quantification of intracellular or plasma HIV RNA or DNA levels remains the most commonly used tests for the characterization of the viral reservoir. While cost-effective and high-throughput, these assays are not able to differentiate between replication-competent or defective fractions or quantify the number of infected cells. Viral outgrowth assays provide a lower bound for the fraction of cells that can produce infectious virus, but these assays are laborious, expensive and substantially underestimate the potential reservoir of replication-competent provirus. Newer assays are now available that seek to overcome some of these problems, including full-length proviral sequencing, inducible HIV RNA assays, ultrasensitive p24 assays and murine adoptive transfer techniques. The development and evaluation of strategies for HIV remission rely upon our ability to accurately and precisely quantify the size of the remaining viral reservoir. At this time, all current HIV reservoir assays have drawbacks such that combinations of assays are generally needed to gain a more comprehensive view of the viral reservoir. The development of novel, rapid, high-throughput assays that can sensitively quantify the levels of the replication-competent HIV reservoir is still needed.

  13. Water resources review: Wheeler Reservoir, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Wallus, R.; Cox, J.P.


    Protection and enhancement of water quality is essential for attaining the full complement of beneficial uses of TVA reservoirs. The responsibility for improving and protecting TVA reservoir water quality is shared by various federal, state, and local agencies, as well as the thousands of corporations and property owners whose individual decisions affect water quality. TVA's role in this shared responsibility includes collecting and evaluating water resources data, disseminating water resources information, and acting as a catalyst to bring together agencies and individuals that have a responsibility or vested interest in correcting problems that have been identified. This report is one in a series of status reports that will be prepared for each of TVA's reservoirs. The purpose of this status report is to provide an up-to-date overview of the characteristics and conditions of Wheeler Reservoir, including: reservoir purposes and operation; physical characteristics of the reservoir and the watershed; water quality conditions: aquatic biological conditions: designated, actual, and potential uses of the reservoir and impairments of those uses; ongoing or planned reservoir management activities. Information and data presented here are form the most recent reports, publications, and original data available. 21 refs., 8 figs., 29 tabs.

  14. Three dimensional heat transport modeling in Vossoroca reservoir (United States)

    Arcie Polli, Bruna; Yoshioka Bernardo, Julio Werner; Hilgert, Stephan; Bleninger, Tobias


    Freshwater reservoirs are used for many purposes as hydropower generation, water supply and irrigation. In Brazil, according to the National Energy Balance of 2013, hydropower energy corresponds to 70.1% of the Brazilian demand. Superficial waters (which include rivers, lakes and reservoirs) are the most used source for drinking water supply - 56% of the municipalities use superficial waters as a source of water. The last two years have shown that the Brazilian water and electricity supply is highly vulnerable and that improved management is urgently needed. The construction of reservoirs affects physical, chemical and biological characteristics of the water body, e.g. stratification, temperature, residence time and turbulence reduction. Some water quality issues related to reservoirs are eutrophication, greenhouse gas emission to the atmosphere and dissolved oxygen depletion in the hypolimnion. The understanding of the physical processes in the water body is fundamental to reservoir management. Lakes and reservoirs may present a seasonal behavior and stratify due to hydrological and meteorological conditions, and especially its vertical distribution may be related to water quality. Stratification can control heat and dissolved substances transport. It has been also reported the importance of horizontal temperature gradients, e.g. inflows and its density and processes of mass transfer from shallow to deeper regions of the reservoir, that also may impact water quality. Three dimensional modeling of the heat transport in lakes and reservoirs is an important tool to the understanding and management of these systems. It is possible to estimate periods of large vertical temperature gradients, inhibiting vertical transport and horizontal gradients, which could be responsible for horizontal transport of heat and substances (e.g. differential cooling or inflows). Vossoroca reservoir was constructed in 1949 by the impoundment of São João River and is located near to

  15. Nanofiltration fouling propensity caused by wastewater effluent organic matters and surface-water dissolved organic matters. (United States)

    Shang, Wentao; Sun, Feiyun; Chen, Lichun


    Rejection of dissolved organic matters (DOMs) from wastewater treatment plant effluent (EfOM) and surface reservoir water (RW-DOM) by nanofiltration (NF) was comparatively studied to evaluate their influence on membrane fouling and to unveil the major causations. EfOM and RW-DOM were fractionated to determine the major components that preferentially form fouling layer and initiate biofouling. The results indicated that EfOM induced a rapid membrane permeability loss and a more complicated biofilm diversity than RW-DOM did. Hydrophilic components with small molecular weight (50 kDa) resulted in initially quick membrane fouling. The complex biofouling resulted from EfOM closely related with significant retention of SMP on the non-porous NF membrane surface, where the Proteobacteria phylum dominated the biofouling formed by microbial community growth and accumulation that gave rise to serious irreversible membrane fouling.

  16. Assessment of Reservoir Water Quality Using Multivariate Statistical Techniques: A Case Study of Qiandao Lake, China

    Directory of Open Access Journals (Sweden)

    Qing Gu


    Full Text Available Qiandao Lake (Xin’an Jiang reservoir plays a significant role in drinking water supply for eastern China, and it is an attractive tourist destination. Three multivariate statistical methods were comprehensively applied to assess the spatial and temporal variations in water quality as well as potential pollution sources in Qiandao Lake. Data sets of nine parameters from 12 monitoring sites during 2010–2013 were obtained for analysis. Cluster analysis (CA was applied to classify the 12 sampling sites into three groups (Groups A, B and C and the 12 monitoring months into two clusters (April-July, and the remaining months. Discriminant analysis (DA identified Secchi disc depth, dissolved oxygen, permanganate index and total phosphorus as the significant variables for distinguishing variations of different years, with 79.9% correct assignments. Dissolved oxygen, pH and chlorophyll-a were determined to discriminate between the two sampling periods classified by CA, with 87.8% correct assignments. For spatial variation, DA identified Secchi disc depth and ammonia nitrogen as the significant discriminating parameters, with 81.6% correct assignments. Principal component analysis (PCA identified organic pollution, nutrient pollution, domestic sewage, and agricultural and surface runoff as the primary pollution sources, explaining 84.58%, 81.61% and 78.68% of the total variance in Groups A, B and C, respectively. These results demonstrate the effectiveness of integrated use of CA, DA and PCA for reservoir water quality evaluation and could assist managers in improving water resources management.

  17. Are bogs reservoirs for emerging disease vectors? Evaluation of culicoides populations in the Hautes Fagnes Nature Reserve (Belgium). (United States)

    Zimmer, Jean-Yves; Smeets, François; Simonon, Grégory; Fagot, Jean; Haubruge, Eric; Francis, Frédéric; Losson, Bertrand


    Several species of Culicoides (Diptera: Ceratopogonidae) biting midges serve as biological vectors for the bluetongue virus (BTV) and the recently described Schmallenberg virus (SBV) in northern Europe. Since their recent emergence in this part of the continent, these diseases have caused considerable economic losses to the sheep and cattle industries. Much data is now available that describe the distribution, population dynamics, and feeding habits of these insects. However, little is known regarding the presence of Culicoides in unusual habitats such as peaty marshes, nor their potential vector capacity. This study evaluated Culicoides biting midges present in the bogs of a Belgian nature reserve compared to those residing at a nearby cattle farm. Culicoides were trapped in 2011 at four different sites (broadleaved and coniferous forested areas, open environments, and at a scientific station) located in the Hautes Fagnes Nature Reserve (Belgium). An additional light trap was operated on a nearby cattle farm. Very high numbers of biting midges were captured in the marshy area and most of them (70 to 95%) were Culicoides impunctatus, a potential vector of BTV and other pathogens. In addition, fewer numbers of C. obsoletus/C. scoticus species, C. chiopterus, and C. dewulfi were observed in the bogs compared to the farm. The wet environment and oligotrophic nature of the soil were probably responsible for these changes in the respective populations. A total of 297,808 Culicoides midges belonging to 27 species were identified during this study and 3 of these species (C. sphagnumensis, C. clintoni and C. comosioculatus) were described in Belgium for the first time.

  18. Optimising reservoir operation

    DEFF Research Database (Denmark)

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af res...

  19. Dynamic reservoir well interaction

    NARCIS (Netherlands)

    Sturm, W.L.; Belfroid, S.P.C.; Wolfswinkel, O. van; Peters, M.C.A.M.; Verhelst, F.J.P.C.M.


    In order to develop smart well control systems for unstable oil wells, realistic modeling of the dynamics of the well is essential. Most dynamic well models use a semi-steady state inflow model to describe the inflow of oil and gas from the reservoir. On the other hand, reservoir models use steady

  20. Natural and human drivers of salinity in reservoirs and their implications in water supply operation through a Decision Support System (United States)

    Contreras, Eva; Gómez-Beas, Raquel; Linares-Sáez, Antonio


    Salt can be a problem when is originally in aquifers or when it dissolves in groundwater and comes to the ground surface or flows into streams. The problem increases in lakes hydraulically connected with aquifers affecting water quality. This issue is even more alarming when water resources are used for urban and irrigation supply and water quantity and quality restrict that water demand. This work shows a data based and physical modeling approach in the Guadalhorce reservoir, located in southern Spain. This water body receives salt contribution from mainly groundwater flow, getting salinity values in the reservoir from 3500 to 5500 μScm-1. Moreover, Guadalhorce reservoir is part of a complex system of reservoirs fed from the Guadalhorce River that supplies all urban, irrigation, tourism, energy and ecology water uses, which makes that implementation and validation of methods and tools for smart water management is required. Meteorological, hydrological and water quality data from several monitoring networks and data sources, with both historical and real time data during a 40-years period, were used to analyze the impact salinity. On the other hand, variables that mainly depend on the dam operation, such as reservoir water level and water outflow, were also analyzed to understand how they affect to salinity in depth and time. Finally surface and groundwater inflows to the reservoir were evaluated through a physically based hydrological model to forecast when the major contributions take place. Reservoir water level and surface and groundwater inflows were found to be the main drivers of salinity in the reservoir. When reservoir water level is high, daily water inflow around 0.4 hm3 causes changes in salinity (both drop and rise) up to 500 μScm-1, but no significant changes are found when water level falls 2-3 m. However the gradual water outflows due to dam operation and consequent decrease in reservoir water levels makes that, after dry periods, salinity

  1. Evaluation of the Theoretical Geothermal Potential of Inferred Geothermal Reservoirs within the Vicano–Cimino and the Sabatini Volcanic Districts (Central Italy) by the Application of the Volume Method


    Daniele Cinti; Monia Procesi; Pier Paolo Poncia


    The evaluation of the theoretical geothermal potential of identified unexploited hydrothermal reservoirs within the Vicano–Cimino and Sabatini volcanic districts (Latium region, Italy) has been made on the basis of a revised version of the classical volume method. This method is based on the distribution of the partial pressure of CO2 (pCO2) in shallow and deep aquifers to delimit areas of geothermal interest, according to the hypothesis that zones of high CO2 flux, either from soil degassing...

  2. Advanced reservoir characterization and evaluation of CO{sub 2} gravity drainage in the naturally fractured Spraberry Trend Area, Class III

    Energy Technology Data Exchange (ETDEWEB)

    Heckman, Tracy; Schechter, David S.


    The overall goal of this project was to assess the economic feasibility of CO{sub 2} flooding the naturally fractured Spraberry Trend Area in West Texas. This objective was accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, (3) analytical and numerical simulation of Spraberry reservoirs, and, (4) experimental investigations on CO{sub 2} gravity drainage in Spraberry whole cores. This report provides results of the fourth year of the five-year project for each of the four areas including a status report of field activities leading up to injection of CO{sub 2}.

  3. Improved Petrophysical Evaluation of a Thinly Bedded Oil and Gas Bearing Reservoir, Using Triaxial Resistivity and Nuclear Magnetic Resonance Well Logging Measurements


    Olsen, Susanne Gryte


    The aim of this thesis was to conduct a petrophysical analysis on a laminated thin bedded reservoir from well 7220/8-1, containing gas in the upper section. A conventional analysis was done in advance, in order to create a basic zonation and an analysis of the logs available. The well was in addition compared with log data from two wells from the same area, 7220/7-1 and 7220/5-1, in order to see similarities and differences and correct for zonation within the two main reservoir formations, St...

  4. Evaluating dissolved organic carbon-water partitioning using polyparameter linear free energy relationships: Implications for the fate of disinfection by-products. (United States)

    Neale, Peta A; Escher, Beate I; Goss, Kai-Uwe; Endo, Satoshi


    The partitioning of micropollutants to dissolved organic carbon (DOC) can influence their toxicity, degradation, and transport in aquatic systems. In this study carbon-normalized DOC-water partition coefficients (K(DOC-w)) were measured for a range of non-polar and polar compounds with Suwannee River fulvic acid (FA) using headspace and solid-phase microextraction (SPME) methods. The studied chemicals were selected to represent a range of properties including van der Waal forces, cavity formation and hydrogen bonding interactions. The K(DOC-w) values were used to calibrate a polyparameter linear free energy relationship (pp-LFER). The difference between experimental and pp-LFER calculated K(DOC-w) values was generally less than 0.3 log units, indicating that the calibrated pp-LFER could provide a good indication of micropollutant interaction with FA, though statistical analysis suggested that more data would improve the predictive capacity of the model. A pp-LFER was also calibrated for Aldrich humic acid (HA) using K(DOC-w) values collected from the literature. Both experimental and pp-LFER calculated K(DOC-w) values for Aldrich HA were around one order of magnitude greater than Suwannee River FA. This difference can be explained by the higher cavity formation energy in Suwannee River FA. Experimental and pp-LFER calculated K(DOC-w) values were compared for halogenated alkanes and alkenes, including trihalomethane disinfection by-products, with good agreement between the two approaches. Experimental and calculated values show that DOC-water partitioning is generally low; indicating that sorption to DOC is not an important fate process for these chemicals in the environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Insight into dissolved organic matter fractions in Lake Wivenhoe during and after a major flood. (United States)

    Aryal, Rupak; Grinham, Alistair; Beecham, Simon


    Dissolved organic matter is an important component of biogeochemical processes in aquatic environments. Dissolved organic matter may consist of a myriad of different fractions and resultant processing pathways. In early January 2011, heavy rainfall occurred across South East Queensland, Australia causing significant catchment inflow into Lake Wivenhoe, which is the largest water supply reservoir for the city of Brisbane, Australia. The horizontal and vertical distributions of dissolved organic matter fractions in the lake during the flood period were investigated and then compared with stratified conditions with no catchment inflows. The results clearly demonstrate a large variation in dissolved organic matter fractions associated with inflow conditions compared with stratified conditions. During inflows, dissolved organic matter concentrations in the reservoir were fivefold lower than during stratified conditions. Within the dissolved organic matter fractions during inflow, the hydrophobic and humic acid fractions were almost half those recorded during the stratified period whilst low molecular weight neutrals were higher during the flood period compared to during the stratified period. Information on dissolved organic matter and the spatial and vertical variations in its constituents' concentrations across the lake can be very useful for catchment and lake management and for selecting appropriate water treatment processes.

  6. Extractable and dissolved soil organic nitrogen - A quantitative assessment

    NARCIS (Netherlands)

    Ros, G.H.; Hoffland, E.; Kessel, van C.; Temminghoff, E.J.M.


    Extractable Organic N (EON) or Dissolved Organic Nitrogen (DON) pools are often analyzed to predict N mineralisation, N leaching, and to evaluate agricultural (nutrient) management practices. Size and characteristics of both pools, however, are strongly influenced by methodology. Quantifying the

  7. Application of multi-agent simulation to evaluate the influence of reservoir operation strategies on the distribution of water availability in the semi-arid Jaguaribe basin, Brazil

    NARCIS (Netherlands)

    van Oel, P.R.; Krol, Martinus S.; Hoekstra, Arjen Ysbert


    Studying the processes responsible for the distribution of water resources in a river basin over space and time is of great importance for spatial planning. In this study a multi-agent simulation approach is applied for exploring the influence of alternative reservoir operation strategies on water

  8. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

    NARCIS (Netherlands)

    Wang, J.; Bovee, T.F.H.; Bi, Y.; Bernhöft, S.; Schramm, K.W.


    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated

  9. Avaliação da vulnerabilidade ambiental de reservatórios à eutrofização Evaluation of reservoirs environmental vulnerability to eutrophication

    Directory of Open Access Journals (Sweden)

    Maria Cléa Brito de Figueirêdo


    Full Text Available Esse trabalho apresenta uma ferramenta de análise da vulnerabilidade de reservatórios à eutrofização, visando subsidiar ações de controle e remediação desse processo. Foram analisadas três subbacias de açudes - Araras, Edson Queiroz e Jaibaras, da bacia do Acaraú, CE, Brasil. A análise multiatributo usada na definição de indicadores ambientais de vulnerabilidade dos açudes à eutrofização, considerou sua sensibilidade e fatores de pressão nas suas sub-bacias que acarretam o transporte de sedimentos e nutrientes para os reservatórios. Foi utilizado um Sistema de Informações Geográficas (SIG com a ferramenta álgebra de mapas para manipular dados de uso e ocupação do solo, declividade do terreno e erodibilidade do solo. Foi identificada alta vulnerabilidade à eutrofização nos três açudes pelas susceptibilidades à erosão, alta carga poluidora principalmente pela pecuária extensiva na região e baixa profundidade relativa dos reservatórios.This work presents a tool to analyze the vulnerability of reservoirs to eutrophication, aiming to subsidize control and remediation actions related with this process. It was analyzed the water basins of Araras, Edson Queiroz and Jaibaras reservoirs, located in the Acaraú watershed, Ceará, Brazil. The multi-criteria analyses methodology used, in order to define environmental vulnerability indicators to reservoir eutrophication, considered reservoir sensibility and pressure factors in the water basin responsible for the transport of sediments and nutrients to the reservoir. A Geographic Information System (GIS with map algebra as major tool was applied to soil use and occupation, declivity and erosion indicators. It was identified high vulnerability to eutrophication in the three mentioned reservoirs because of the waterbasins susceptibility to erosion, high phosphorous load mainly from the extensive cattle raising and low relative depth of the reservoirs.

  10. Advanced reservoir characterization and evaluation of CO{sub 2} gravity drainage in the naturally fractured Spraberry Trend Area. Annual report, September 1, 1996--August 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Schechter, D.S.


    The overall goal of this project is to assess the economic feasibility of CO{sub 2} flooding the naturally fractured Spraberry Trend Area in West Texas. This objective is being accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, (3) reservoir performance analysis, and (4) experimental investigations on CO{sub 2} gravity drainage in Spraberry whole cores. This report provides results of the second year of the five-year project for each of the four areas. In the first area, the author has completed the reservoir characterization, which includes matrix description and detection (from core-log integration) and fracture characterization. This information is found in Section 1. In the second area, the author has completed extensive inhibition experiments that strongly indicate that the weakly water-wet behavior of the reservoir rock may be responsible for poor waterflood response observed in many Spraberry fields. In the third area, the author has made significant progress in analytical and numerical simulation of performance in Spraberry reservoirs as seen in Section 3. In the fourth area, the author has completed several suites of CO{sub 2} gravity drainage in Spraberry and Berea whole cores at reservoir conditions and reported in Section 4. The results of these experiments have been useful in developing a model for free-fall gravity drainage and have validated the premise that CO{sub 2} will recover oil from tight, unconfined Spraberry matrix. The final three years of this project involves implementation of the CO{sub 2} pilot. Up to twelve new wells are planned in the pilot area; water injection wells to contain the CO{sub 2}, three production wells to monitor performance of CO{sub 2}, CO{sub 2} injection wells including one horizontal injection well and logging observation wells to monitor CO{sub 2} flood fronts. Results of drilling

  11. PENDEKATAN MULTI DIMENSIONAL SCALING UNTUK EVALUASI KEBERLANJUTAN WADUK CIRATA - PROPINSI JAWA BARAT (Multidimensional Scaling Approach to Evaluate Sustainability of Cirata Reservoir – West Java Province

    Directory of Open Access Journals (Sweden)

    Kholil Kholil


    Full Text Available ABSTRAK Waduk Cirata merupakan salah satu waduk di Indonesia yang memiliki peran sangat besar bagi pembangunan ekonomi, sebagai Pembangkit Listrik Tenaga Air (PLTA. Pertumbuhan Keramba Jaring Apung (KJA dan perkembangan permukiman di sekitar waduk, serta perubahan tataruang di DAS Citarum untuk kegiatan permukiman, industri, pertanian, dan peternakan menyebabkan peningkatan sedimentasi dan penurunan kualitas air waduk, sehingga berpengaruh terhadap kinerja dan keberlajutan waduk. Kajian ini bertujuan untuk mengetahui tingkat keberlanjutan waduk dengan menggunakan metode Multidimesional Scaling berdasarkan 5 dimensi yaitu ekologi dan tata ruang, ekonomi, sosial dan budaya, peraturan dan kelembagaan, dan infrastruktur dan teknologi. Hasil analisis MDS menunjukkan bahwa dimensi ekologi dan tataruang, dan peraturan dan kelembagaan kurang berlanjut dengan nilai indeks keberlanjutan masing-masing 45,76 dan 42,24. Sementara untuk dimensi ekonomi, sosial dan budaya, dan infrastruktur dan teknologi memiliki nilai indeks keberlanjutan masing-masing 63,12; 64,42 dan 68,64 yang berarti hanya masuk kategori cukup berlanjut. Atribut yang paling sensitif yang mempengaruhi indeks keberlanjutan ekologi dan tataruang adalah laju sedimentasi, jumlah KJA dan kualitas air waduk. Pada dimensi peraturan dan kelembagaan adalah lemahnya koordinasi, perijinan dan penegakan hukum. Untuk menjamin keberlanjutan kinerja Waduk Cirata perlu dilakukan pengendalian penggunaan lahan di DAS Citarum dan permukiman di sekitar waduk, pengetatan perijinan, dan penegakan hukum. ABSTRACT Cirata reservoir is one of the reservoirs in Indonesia, that plays an important role for economic development as a Hydroelectric Power Plant. The development of settlement around the dam, and land use change of Citarum’s watershed for industrial activities, agriculture, and animal husbandry have increased the erosion, sedimentation and degradation water quality of reservoir. This paper will discuss

  12. Evaluation of high-frequency mean streamwater transit-time estimates using groundwater age and dissolved silica concentrations in a small forested watershed (United States)

    Peters, Norman E.; Burns, Douglas A.; Aulenbach, Brent T.


    Many previous investigations of mean streamwater transit times (MTT) have been limited by an inability to quantify the MTT dynamics. Here, we draw on (1) a linear relation (r 2 = 0.97) between groundwater 3H/3He ages and dissolved silica (Si) concentrations, combined with (2) predicted streamwater Si concentrations from a multiple-regression relation (R 2 = 0.87) to estimate MTT at 5-min intervals for a 23-year time series of streamflow [water year (WY) 1986 through 2008] at the Panola Mountain Research Watershed, Georgia. The time-based average MTT derived from the 5-min data was ~8.4 ± 2.9 years and the volume-weighted (VW) MTT was ~4.7 years for the study period, reflecting the importance of younger runoff water during high flow. The 5-min MTTs are normally distributed and ranged from 0 to 15 years. Monthly VW MTTs averaged 7.0 ± 3.3 years and ranged from 4 to 6 years during winter and 8–10 years during summer. The annual VW MTTs averaged 5.6 ± 2.0 years and ranged from ~5 years during wet years (2003 and 2005) to >10 years during dry years (2002 and 2008). Stormflows are composed of much younger water than baseflows, and although stormflow only occurs ~17 % of the time, this runoff fraction contributed 39 % of the runoff during the 23-year study period. Combining the 23-year VW MTT (including stormflow) with the annual average baseflow for the period (~212 mm) indicates that active groundwater storage is ~1,000 mm. However, the groundwater storage ranged from 1,040 to 1,950 mm using WY baseflow and WY VW MTT. The approach described herein may be applicable to other watersheds underlain by granitoid bedrock, where weathering is the dominant control on Si concentrations in soils, groundwater, and streamwater.

  13. Turnover time of fluorescent dissolved organic matter in the dark global ocean

    DEFF Research Database (Denmark)

    Catalá, Teresa Serrano; Reche, Isabel; Fuentes-Lema, Antonio


    Marine dissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on Earth. In the dark ocean (>200 m), most of this carbon is refractory DOM. This refractory DOM, largely produced during microbial mineralization of organic matter, includes humic-like substances generated i...

  14. Chemical and physical characteristics of water and sediment in Scofield Reservoir, Carbon County, Utah (United States)

    Waddell, Kidd M.; Darby, D.W.; Theobald, S.M.


    Evaluations based on the nutrient content of the inflow, outflow, water in storage, and the dissolved-oxygen depletion during the summer indicate that the trophic state of Scofield Reservoir is borderline between mesotrophic and eutrophic and may become highly eutrophic unless corrective measures are taken to limit nutrient inflow.Sediment deposition in Scofield Reservoir during 1943-79 is estimated to be 3,000 acre-feet, and has decreased the original storage capacity of the reservoir by 4 percent. The sediment contains some coal, and age dating of those sediments (based on the radioisotope lead-210) indicates that most of the coal was deposited prior to about 1950.Scofield Reservoir is dimictic, with turnovers occurring in the spring and autumn. Water in the reservoir circulates completely to the bottom during turnovers. The concentration of dissolved oxygen decreases with depth except during parts of the turnover periods. Below an altitude of about 7,590 feet, where 20 percent of the water is stored, the concentration of dissolved oxygen was less than 2 milligrams per liter during most of the year. During the summer stratification period, the depletion of dissolved oxygen in the deeper layers is coincident with supersaturated conditions in the shallow layers; this is attributed to plant photosynthesis and bacterial respiration in the reservoir.During October 1,1979-August 31,1980, thedischargeweighted average concentrations of dissolved solids was 195 milligrams per liter in the combined inflow from Fish, Pondtown, and Mud Creeks, and was 175 milligrams per liter in the outflow (and to the Price River). The smaller concentration in the outflow was due primarily to precipitation of calcium carbonate in the reservoir about 80 percent of the decrease can be accounted for through loss as calcium carbonate.The estimated discharge-weighted average concentration of total nitrogen (dissolved plus suspended) in the combined inflow of Fish, Pondtown, and Mud Creeks was 1

  15. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.


    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  16. Multi-data reservoir history matching for enhanced reservoir forecasting and uncertainty quantification

    KAUST Repository

    Katterbauer, Klemens


    Reservoir simulations and history matching are critical for fine-tuning reservoir production strategies, improving understanding of the subsurface formation, and forecasting remaining reserves. Production data have long been incorporated for adjusting reservoir parameters. However, the sparse spatial sampling of this data set has posed a significant challenge for efficiently reducing uncertainty of reservoir parameters. Seismic, electromagnetic, gravity and InSAR techniques have found widespread applications in enhancing exploration for oil and gas and monitoring reservoirs. These data have however been interpreted and analyzed mostly separately, rarely exploiting the synergy effects that could result from combining them. We present a multi-data ensemble Kalman filter-based history matching framework for the simultaneous incorporation of various reservoir data such as seismic, electromagnetics, gravimetry and InSAR for best possible characterization of the reservoir formation. We apply an ensemble-based sensitivity method to evaluate the impact of each observation on the estimated reservoir parameters. Numerical experiments for different test cases demonstrate considerable matching enhancements when integrating all data sets in the history matching process. Results from the sensitivity analysis further suggest that electromagnetic data exhibit the strongest impact on the matching enhancements due to their strong differentiation between water fronts and hydrocarbons in the test cases.

  17. Global monitoring of large reservoir storage from satellite remote sensing (United States)

    Gao, Huilin; Birkett, Charon; Lettenmaier, Dennis P.


    We studied 34 global reservoirs for which good quality surface elevation data could be obtained from a combination of five satellite altimeters for the period from 1992 to 2010. For each of these reservoirs, we used an unsupervised classification approach using the Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day 250 m vegetation product to estimate the surface water areas over the MODIS period of record (2000 to 2010). We then derived elevation-area relationships for each of the reservoirs by combining the MODIS-based estimates with satellite altimeter-based estimates of reservoir water elevations. Through a combination of direct observations of elevation and surface area along with documented reservoir configurations at capacity, we estimated storage time histories for each reservoir from 1992 to 2010. We evaluated these satellite-based data products in comparison with gauge observations for the five largest reservoirs in the United States (Lakes Mead, Powell, Sakakawea, Oahe, and Fort Peck Reservoir). The storage estimates were highly correlated with observations (R = 0.92 to 0.99), with values for the normalized root mean square error (NRMSE) ranging from 3% to 15%. The storage mean absolute error (expressed as a percentage of reservoir capacity) for the reservoirs in this study was 4%. The multidecadal reconstructed reservoir storage variations are in accordance with known droughts and high flow periods on each of the five continents represented in the data set.

  18. Simulation of California's Major Reservoirs Outflow Using Data Mining Technique (United States)

    Yang, T.; Gao, X.; Sorooshian, S.


    The reservoir's outflow is controlled by reservoir operators, which is different from the upstream inflow. The outflow is more important than the reservoir's inflow for the downstream water users. In order to simulate the complicated reservoir operation and extract the outflow decision making patterns for California's 12 major reservoirs, we build a data-driven, computer-based ("artificial intelligent") reservoir decision making tool, using decision regression and classification tree approach. This is a well-developed statistical and graphical modeling methodology in the field of data mining. A shuffled cross validation approach is also employed to extract the outflow decision making patterns and rules based on the selected decision variables (inflow amount, precipitation, timing, water type year etc.). To show the accuracy of the model, a verification study is carried out comparing the model-generated outflow decisions ("artificial intelligent" decisions) with that made by reservoir operators (human decisions). The simulation results show that the machine-generated outflow decisions are very similar to the real reservoir operators' decisions. This conclusion is based on statistical evaluations using the Nash-Sutcliffe test. The proposed model is able to detect the most influential variables and their weights when the reservoir operators make an outflow decision. While the proposed approach was firstly applied and tested on California's 12 major reservoirs, the method is universally adaptable to other reservoir systems.

  19. The Calculation Of Ngancar Batuwarna Reservoir, Wonogiri, Central Java

    Directory of Open Access Journals (Sweden)

    Azura Ulfa


    Full Text Available Evaluation of reservoir capacity is needed to find out how big the effective volume change of Ngancar Reservoir from the beginning of measurement until 2016. The purpose of this research is measuring volume of Ngancar Reservoir using bathymetry method with echosounder and calculating the remaining relative age of Ngancar Reservoir. Measurement topography of Ngancar Reservoir is done by bathymetry method of aquatic systematic random sampling method through certain path using echosounder. Analysis of reservoir capacity is done by calculating the volumes of Ngancar Reservoir and calculating the residual life of the reservoir relative. Fluctuation analysis of volume change was done by calculating the effective volume of reservoirs 1946-2016 and graphs. The calculation of the volume of the Ngancar Reservoir from the topographic map produces an effective volume value of 2016 is 1269905 m3 and the effective puddle area is 1393416 m2. An increase in sedimentation volume from 2011-2016 amounted to 296119.75 m3 with sedimentation rate was 59223.95 / year. With the assumption that the same landuse and sedimentation rate tend to be stable then the remaining age of Ngancar Reservoir is 21 years and 95 years old.

  20. The Measurement of Dissolved Oxygen (United States)

    Thistlethwayte, D.; And Others


    Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)

  1. Quantification of Libby Reservoir Levels Needed to Maintain or Enhance Reservoir Fisheries, 1985 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Ian


    The goal was to quantify seasonal water levels needed to maintain or enhance the reservoir fishery in Libby. This report summarizes data collected from July 1984 through July 1985, and, where appropriate, presents data collected since 1983. The Canada, Rexford, and Tenmile areas of the reservoir are differentially affected by drawdown. Relative changes in water volume and surface area are greatest in the Canada area and smallest in the Tenmile area. Reservoir morphology and hydraulics probably play a major role in fish distribution through their influence on water temperature. Greatest areas of habitat with optimum water temperature for Salmo spp. and kokanee occurred during the spring and fall months. Dissolved oxygen, pH and conductivity levels were not limiting during any sampling period. Habitat enhancement work was largely unsuccessful. Littoral zone vegetation plantings did not survive well, primarily the result of extreme water level fluctuations. Relative abundances of fish species varied seasonally within and between the three areas. Water temperature is thought to be the major influence in fish distribution patterns. Other factors, such as food availability and turbidity, may mitigate its influence. Sampling since 1975 illustrates a continued increase in kokanee numbers and a dramatic decline in redside shiners. Salmo spp., bull trout, and burbot abundances are relatively low while peamouth and coarsescale sucker numbers remain high. A thermal dynamics model and a trophic level components model will be used to quantify the impact of reservoir operation on the reservoir habitat, primary production, secondary production and fish populations. Particulate carbon will be used to track energy flow through trophic levels. A growth-driven population dynamics simulation model that will estimate the impacts of reservoir operation on fish population dynamics is also being considered.

  2. Spatial and seasonal distribution of macroinvertebrates in high altitude reservoir (Beyler Reservoir, Turkey) (United States)

    Findik, Özlem


    A highland reservoir in the West Black Sea region of Turkey which belongs to the Mediterranean climatic zone was examined. Both littoral and profundal zones were sampled from October 2009 to September 2010, to determine taxonomic composition, biodiversity and abundance of benthic invertebrates as well as the seasonal variation of these measures. A total of 35 taxa were identified, of which 12 belong to Chironomidae and 10 to Oligochaeta groups. The highest diversity and abundance of benthic macroinvertebrates were found at the littoral stations. Macroinvertebrates showed significant positive correlations with water temperature and NO2 and NO3 concentrations, and negative correlation with dissolved oxygen.

  3. Evaluation of mercury in rainbow trout collected from Duck Valley Indian Reservation reservoirs, southwestern Idaho and northern Nevada, 2007, 2009, and 2013 (United States)

    Williams, Marshall L.; MacCoy, Dorene E.; Maret, Terry R.


    The U.S. Geological Survey, in cooperation with the Shoshone-Paiute Tribes of the Duck Valley Indian Reservation, analyzed mercury (Hg) concentration in rainbow trout (Oncorhynchus mykiss) collected from three reservoirs on the reservation (Mountain View, Lake Billy Shaw, and Sheep Creek) during sampling events in 2007, 2009, and 2013, to determine the risk of Hg exposure to Tribal members and the general public.

  4. Pre- and post-reservoir ground-water conditions and assessment of artificial recharge at Sand Hollow, Washington County, Utah, 1995-2005 (United States)

    Heilweil, Victor M.; Susong, David D.; Gardner, Philip M.; Watt, Dennis E.


    Sand Hollow, Utah, is the site of a surface-water reservoir completed in March 2002, which is being operated by the Washington County Water Conservancy District primarily as an aquifer storage and recovery project. The reservoir is an off-channel facility receiving water from the Virgin River, diverted near the town of Virgin, Utah. It is being operated conjunctively, providing both surface-water storage and artificial recharge to the underlying Navajo aquifer. The U.S. Geological Survey and the Bureau of Reclamation conducted a study to document baseline ground-water conditions at Sand Hollow prior to the operation of the reservoir and to evaluate changes in ground-water conditions caused by the reservoir.Pre-reservoir age dating using tritium/helium, chlorofluorocarbons, and carbon-14 shows that shallow ground water in the Navajo Sandstone in some areas of Sand Hollow entered the aquifer from 2 to 25 years before sample collection. Ground water in low-recharge areas and deeper within the aquifer may have entered the aquifer more than 8,000 years ago. Ground-water levels in the immediate vicinity of Sand Hollow Reservoir have risen by as much as 80 feet since initial filling began in March 2002. In 2005, ground water was moving laterally away from the reservoir in all directions, whereas the pre-reservoir direction of ground-water flow was predominantly toward the north.Tracers, or attributes, of artificial recharge include higher specific conductance, higher dissolved-solids concentrations, higher chloride-to-bromide ratios, more-depleted stable isotopes (2H and 18O), and higher total-dissolved gas pressures. These tracers have been detected at observation and production wells close to the reservoir. About 15,000 tons of naturally occurring salts that previously accumulated in the vadose zone beneath the reservoir are being flushed into the aquifer. Except for the shallowest parts of the aquifer, this is generally not affecting water quality, largely because of

  5. Evaluation of Three Evaporation Estimation Techniques In A Semi-Arid Region (Omar El Mukhtar Reservoir Sluge, Libya- As a case Study

    Directory of Open Access Journals (Sweden)

    Lubna s. Ben Taher


    Full Text Available In many semi-arid countries in the world like Libya, drinking water supply is dependent on reservoirs water storage. Since the evaporation rate is very high in semi-arid countries, estimates and forecasts of reservoir evaporation rate can be useful in the management of major water source. Many researchers have been investigating the suitability of estimates evaporation rates methods in many climatic settings, infrequently of which were in an arid setting. This paper presents the modeling results of evaporation from Omar El Mukhtar Reservoir, Libya. Three techniques namely (artificial neural networks (ANN, Multiple linear regression (MLR and response surface methods (RSM were developed, to assess the estimation of monthly evaporation records from 2001 to 2009; their relative performance were compared using the coefficient of determination(E, mean absolute percentage error (MAPE%, and 95% confidence interval. The key variables used to develop and validate the models were: monthly (precipitation Rf., average temperature Temp., relative humidity Rh., sunshine hours Sh., atmospheric pressure Pa. and wind speed Ws.. The encouraging results approved that the models with more inputs generally had better accuracies and the ANN model performed superior to the other models in predicting monthly Evp with high E=0.86 and low MAPE%= 13.9 and the predicted mean within the range of observed 95CI%. In summary, it is revealed in this study that the ANN and RSM models are appropriate for predicting Evp using climatic inputs in semi-arid climate.

  6. Conowingo Reservoir Sedimentation and Chesapeake Bay: State of the Science. (United States)

    Cerco, Carl F


    The Conowingo Reservoir is situated on the Susquehanna River, immediately upstream of Chesapeake Bay, the largest estuary in the United States. Sedimentation in the reservoir provides an unintended benefit to the bay by preventing sediments, organic matter, and nutrients from entering the bay. The sediment storage capacity of the reservoir is nearly exhausted, however, and the resulting increase in loading of sediments and associated materials is a potential threat to Chesapeake Bay water quality. In response to this threat, the Lower Susquehanna River Watershed Assessment was conducted. The assessment indicates the reservoir is in a state of "dynamic equilibrium" in which sediment loads from the upstream watershed to the reservoir are balanced by sediments leaving the reservoir. Increased sediment loads are not a threat to bay water quality. Increased loads of associated organic matter and nutrients are, however, detrimental. Bottom-water dissolved oxygen declines of 0.1 to 0.2 g m are projected as a result of organic matter oxidation and enhanced eutrophication. The decline is small relative to normal variations but results in violations of standards enforced in a recently enacted total maximum daily load. Enhanced reductions in nutrient loads from the watershed are recommended to offset the decline in water quality caused by diminished retention in the reservoir. The assessment exposed several knowledge gaps that require additional investigation, including the potential for increased loading at flows below the threshold for reservoir scour and the nature and reactivity of organic matter and nutrients scoured from the reservoir bottom. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  7. Simulation of Hydrodynamics and Water Quality in Pueblo Reservoir, Southeastern Colorado, for 1985 through 1987 and 1999 through 2002 (United States)

    Galloway, Joel M.; Ortiz, Roderick F.; Bales, Jerad D.; Mau, David P.


    Pueblo Reservoir is west of Pueblo, Colorado, and is an important water resource for southeastern Colorado. The reservoir provides irrigation, municipal, and industrial water to various entities throughout the region. In anticipation of increased population growth, the cities of Colorado Springs, Fountain, Security, and Pueblo West have proposed building a pipeline that would be capable of conveying 78 million gallons of raw water per day (240 acre-feet) from Pueblo Reservoir. The U.S. Geological Survey, in cooperation with Colorado Springs Utilities and the Bureau of Reclamation, developed, calibrated, and verified a hydrodynamic and water-quality model of Pueblo Reservoir to describe the hydrologic, chemical, and biological processes in Pueblo Reservoir that can be used to assess environmental effects in the reservoir. Hydrodynamics and water-quality characteristics in Pueblo Reservoir were simulated using a laterally averaged, two-dimensional model that was calibrated using data collected from October 1985 through September 1987. The Pueblo Reservoir model was calibrated based on vertical profiles of water temperature and dissolved-oxygen concentration, and water-quality constituent concentrations collected in the epilimnion and hypolimnion at four sites in the reservoir. The calibrated model was verified with data from October 1999 through September 2002, which included a relatively wet year (water year 2000), an average year (water year 2001), and a dry year (water year 2002). Simulated water temperatures compared well to measured water temperatures in Pueblo Reservoir from October 1985 through September 1987. Spatially, simulated water temperatures compared better to measured water temperatures in the downstream part of the reservoir than in the upstream part of the reservoir. Differences between simulated and measured water temperatures also varied through time. Simulated water temperatures were slightly less than measured water temperatures from March to

  8. Richness and distribution of aquatic macrophytes in a subtropical reservoir in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Carolina Pavão


    Full Text Available Abstract Aims: to evaluate the richness, biomass and distribution of aquatic macrophytes in a subtropical reservoir in the dry and rainy seasons. Methods this study was carried out in the Itupararanga Reservoir, an important water source in São Paulo State, undergoing a continuous process of eutrophication. Samples of macrophytes were collected at 12 sampling sites in the summer and at 9 sampling sites in the winter in the Itupararanga Reservoir using the quadrat method (0.25 m2. In the laboratory, the plants were washed to remove the coarse material and then were dried (60 °C for biomass determination (gDW. m-2. All the species in the sampling sites in both periods were identified using the specific literature. In each sampling site, the water temperature, pH, electrical conductivity and dissolved oxygen were measured using a probe. The temporal and spatial differences were analyzed using t-test and a Cluster Analysis was performed. Results The checklist showed sixteen species, 75% of them were emergent. From the 16 species, 15 were present in the summer and 10 in the winter. Eichhornia crassipes, Polygonum sp., and Urochloa sp. were the frequent taxa and had the highest biomass in both periods. The winter showed the highest biomass mainly due to the growth of free-floating species. The headwaters of the reservoir, the most eutrophic region, showed that the highest macrophyte richness and the sampling sites of this area were clustered in both the summer and winter. Conclusions There was no significant spatial variation among the measured variables. E. crassipes, Salvinia sp. and Urochloa sp. showed a significant variation of biomass between two periods. Urochloa sp. is a nuisance species occurring in up to 60% of the sampling sites having implications for the whole catchment. Continuous macrophyte monitoring is important due to the increasing trophic status of this ecosystem.

  9. Mrica Reservoir Sedimentation: Current Situation and Future Necessary Management

    Directory of Open Access Journals (Sweden)

    Puji Utomo


    Full Text Available Mrica Reservoir is one of many reservoirs located in Central Java that experienced a considerably high sedimentation during the last ten years. This condition has caused a rapid decrease in reservoir capacity. Various countermeasures have been introduced to reduce the rate of the reservoir sedimentation through catchment management and reservoir operation by means of flushing and/or dredging. However, the sedimentation remains intensive so that the fulfillment of water demand for electrical power generation was seriously affected. This paper presents the results of evaluation on the dynamics of the purpose of this research is to evaluate the sediment balance of the Mrica Reservoir based on two different scenarios, i.e. the existing condition and another certain type of reservoir management. The study on sediment balance was carried out by estimating the sediment inflow applying sheet erosion method in combination with the analysis of sediment rating curve. The measurement of the deposited sediment rate in the reservoir was conducted through the periodic echo sounding, whereas identification of the number of sediment that has been released from the reservoir was carried out through the observation on both flushing and dredging activities. The results show that during the last decade, the rate of the sediment inflow was approximately 5.869 MCM/year, whereas the released sediment from the reservoir was 4.097 MCM/year. In order to maintain the reservoir capacity, therefore, at least 1.772 MCM/year should be released from the reservoir by means of either flushing or dredging. Sedimentation management may prolong the reservoir’s service life to exceed the design life. Without sediment management, the lifetime of the reservoir would have finished by 2016, whereas with the proper management the lifetime may be extended to 2025.

  10. Population dynamics: seasonal variation of phytoplankton functional groups in brazilian reservoirs (Billings and Guarapiranga, São Paulo). (United States)

    Gemelgo, M C P; Mucci, J L N; Navas-Pereira, D


    Phytoplankton may function as a 'sensor' of changes in aquatic environment and responds rapidly to such changes. In freshwaters, coexistence of species that have similar ecological requirements and show the same environmental requirements frequently occurs; such species groups are named functional groups. The use of phytoplankton functional groups to evaluate these changes has proven to be very useful and effective. Thus, the aim of this study was to evaluate the occurrence of functional groups of phytoplankton in two reservoirs (Billings and Guarapiranga) that supply water to millions of people in São Paulo city Metropolitan Area, southeastern Brazil. Surface water samples were collected monthly and physical, chemical and biological (quantitative and qualitative analyses of the phytoplankton) were performed. The highest biovolume (mm(3).L-1) of the descriptor species and functional groups were represented respectively by Anabaena circinalis Rabenh. (H1), Microcystis aeruginosa (Kützing) Kützing (L M/M) and Mougeotia sp. (T) in the Guarapiranga reservoir and Cylindrospermopsis raciborskii (Wolosz.) Seen. and Subba Raju (S N), Microcystis aeruginosa and M. panniformis Komárek et al. (L M/M), Planktothrix agardhii (Gom.) Anagn. and Komárek and P. cf. clathrata (Skuja) Anagn. and Komárek (S1) in the Billings reservoir. The environmental factors that most influenced the phytoplankton dynamics were water temperature, euphotic zone, turbidity, conductivity, pH, dissolved oxygen, nitrate and total phosphorous.

  11. Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters. (United States)

    Turner, Geraldine S C; Mills, Graham A; Burnett, Jonathan L; Amos, Sean; Fones, Gary R


    Commercially available Diphonix(®) resin (TrisKem International) was evaluated as a receiving phase for use with the diffusive gradients in thin-films (DGT) passive sampler for measuring uranium. This resin has a high partition coefficient for actinides and is used in the nuclear industry. Other resins used as receiving phases with DGT for measuring uranium have been prone to saturation and significant chemical interferences. The performance of the device was evaluated in the laboratory and in field trials. In laboratory experiments uptake of uranium (all 100% efficiency) by the resin was unaffected by varying pH (4-9), ionic strength (0.01-1.00 M, as NaNO3) and varying aqueous concentrations of Ca(2+) (100-500 mg L(-1)) and HCO3(-) (100-500 mg L(-1)). Due to the high partition coefficient of Diphonex(®), several elution techniques for uranium were evaluated. The optimal eluent mixture was 1M NaOH/1M H2O2, eluting 90% of the uranium from the resin. Uptake of uranium was linear (R(2)=0.99) over time (5 days) in laboratory experiments using artificial freshwater showing no saturation effects of the resin. In field deployments (River Lambourn, UK) the devices quantitatively accumulated uranium for up to 7 days. In both studies uptake of uranium matched that theoretically predicted for the DGT. Similar experiments in seawater did not follow the DGT theoretical uptake and the Diphonix(®) appeared to be capacity limited and also affected by matrix interferences. Isotopes of uranium (U(235)/U(238)) were measured in both environments with a precision and accuracy of 1.6-2.2% and 1.2-1.4%, respectively. This initial study shows the potential of using Diphonix(®)-DGT for monitoring of uranium in the aquatic environment. Copyright © 2014. Published by Elsevier B.V.

  12. [Ecosystem service valuation of Ertan Reservoir watershed in mitigating reservoir sand sedimentation]. (United States)

    Wu, Nan; Gao, Ji-xi; Sudebilige; Ennaanay, Driss; Mendoza, Guillermo F; Luo, Zun-lan; Li, Dai-qing; Tian, Mei-rong


    By using software ArcGIS 9.2, an evaluation model was established to simulate the ecosystem service of Ertan Reservoir watershed in mitigating the sand sedimentation in the reservoir. In the meantime, sediment delivery ratio and universal soil loss equation were used to simulate the spatial patterns of the annual sediment yield and sediment retention in the watershed as well as the value during the service life period. In 2000, the total quantity of soil retention in the watershed was 12. 1 x 10(8) t x a(-1). The region with higher soil retention was near the main and branch streams of Yalong River, and that with higher sediment delivery ratio was near the streams and the Ertan Reservoir. The region with higher sediment yield and sediment retention was around the reservoir. The actual sediment yield in the study area was 629.3 x 10(4) t x a(-1), occupying 12.7% of the actual soil erosion volume. Farmland was the most important source of sediment yield, with its sediment yield occupying 62.9% of the total. The contribution of forestland to the mitigation of reservoir sand sedimentation was higher than that of the other lands on a per unit area basis. For the reservoir's designed operating life (100 a), the total value of the watershed in the service of mitigating Ertan Reservoir sand sedimentation was 2.75 billion yuan.

  13. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister


    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  14. Session: Reservoir Technology

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel L.; Bodvarsson, Gudmundur S.; Wannamaker, Philip E.; Horne, Roland N.; Shook, G. Michael


    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five papers: ''Reservoir Technology'' by Joel L. Renner; ''LBL Research on the Geysers: Conceptual Models, Simulation and Monitoring Studies'' by Gudmundur S. Bodvarsson; ''Geothermal Geophysical Research in Electrical Methods at UURI'' by Philip E. Wannamaker; ''Optimizing Reinjection Strategy at Palinpinon, Philippines Based on Chloride Data'' by Roland N. Horne; ''TETRAD Reservoir Simulation'' by G. Michael Shook

  15. Reservoir assessment of the Nubian sandstone reservoir in South Central Gulf of Suez, Egypt (United States)

    El-Gendy, Nader; Barakat, Moataz; Abdallah, Hamed


    The Gulf of Suez is considered as one of the most important petroleum provinces in Egypt and contains the Saqqara and Edfu oil fields located in the South Central portion of the Gulf of Suez. The Nubian sandstone reservoir in the Gulf of Suez basin is well known for its great capability to store and produce large volumes of hydrocarbons. The Nubian sandstone overlies basement rocks throughout most of the Gulf of Suez region. It consists of a sequence of sandstones and shales of Paleozoic to Cretaceous age. The Nubian sandstone intersected in most wells has excellent reservoir characteristics. Its porosity is controlled by sedimentation style and diagenesis. The cementation materials are mainly kaolinite and quartz overgrowths. The permeability of the Nubian sandstone is mainly controlled by grain size, sorting, porosity and clay content especially kaolinite and decreases with increase of kaolinite. The permeability of the Nubian Sandstone is evaluated using the Nuclear Magnetic Resonance (NMR technology) and formation pressure data in addition to the conventional logs and the results were calibrated using core data. In this work, the Nubian sandstone was investigated and evaluated using complete suites of conventional and advanced logging techniques to understand its reservoir characteristics which have impact on economics of oil recovery. The Nubian reservoir has a complicated wettability nature which affects the petrophysical evaluation and reservoir productivity. So, understanding the reservoir wettability is very important for managing well performance, productivity and oil recovery.

  16. Ichthyofaunal Diversity and Water Quality in the Kangsabati Reservoir, West Bengal, India

    Directory of Open Access Journals (Sweden)

    Amalesh Bera


    Full Text Available The ichthyofauna in relation to water quality was studied on monthly basis from March, 2010 to February, 2011 in the Kangsabati Reservoir, West Bengal. The study revealed that physicochemical parameters of Kangsabati Reservoir were congenial for 39 fish species of commercial importance, belonging to 7 orders, 15 families, and 26 genera. The Cypriniformes were dominant with 17 species, followed by Siluriformes and Perciformes, with 7 species each, Channiformes with 3 species, Osteoglossiformes and Synbranchiformes with 2 species each, and Anguilliformes with 1 species. Regarding their conservation status, 27 species were of least concern, 1 species was vulnerable, 6 species were near threatened, 1 species was data deficient, and 4 species were not evaluated (IUCN-Version 2014.1. Economical values have also been evaluated. Water parameters such as temperature, pH, alkalinity, dissolved oxygen, hardness, free CO2, salinity, total inorganic nitrogen, and phosphate were recorded and found suitable for fish production. Conductivity, transparency, and high chloride level are minor limiting factor that may needs rectification for improved fisheries management.

  17. Assessing contribution of DOC from sediments to a drinking-water reservoir using optical profiling (United States)

    Downing, Bryan D.; Bergamaschi, Brian A.; Evans, David G.; Boss, Emmanuel


    Understanding the sources of dissolved organic carbon (DOC) in drinking-water reservoirs is an important management issue because DOC may form disinfection by-products, interfere with disinfection, or increase treatment costs. DOC may be derived from a host of sources-algal production of DOC in the reservoir, marginal production of DOC from mucks and vascular plants at the margins, and sediments in the reservoir. The purpose of this study was to assess if release of DOC from reservoir sediments containing ferric chloride coagulant was a significant source of DOC to the reservoir. We examined the source-specific contributions of DOC using a profiling system to measure the in situ distribution of optical properties of absorption and fluorescence at various locations in the reservoir. Vertical optical profiles were coupled with discrete water samples measured in the laboratory for DOC concentration and optical properties: absorption spectra and excitation emission matrix spectra (EEMs). Modeling the in situ optical data permitted estimation of the bulk DOC profile in the reservoir as well as separation into source-specific contributions. Analysis of the source-specific profiles and their associated optical characteristics indicated that the sedimentary source of DOC to the reservoir is significant and that this DOC is labile in the reservoir. We conclude that optical profiling is a useful technique for understanding complex biogeochemical processes in a reservoir.

  18. Determination of reservoir fluid and reservoir fluid behavior

    Directory of Open Access Journals (Sweden)

    Marianna Mihočová


    Full Text Available The report gives the comprehensive information about reservoir fluids. The five reservoir fluids (black oils, volatile oils,retrograde gas – condensates, wet gases and dry gases are defined because production of each fluid requires different engineeringtechniques. The fluid type must be determined very early in the life of a reservoir (often before sampling or initial production becausefluid type is the critical factor in many of the decisions that must be made about producing the fluid form the reservoir.

  19. Reservoirs of hope

    International Development Research Centre (IDRC) Digital Library (Canada)

    RESEARCH THAT MATTERS. Reservoirs of hope. An IDRC-funded shared learning effort helps farmers deliver fresh water — and the prospect of a brighter ... in the dark — to a place where they would queue, sometimes for hours, to gather enough water for that day's consumption. By the time they arrived back home with ...

  20. Assessment of Ilam Reservoir Eutrophication Response in Controlling Water Inflow

    Directory of Open Access Journals (Sweden)

    Fereshteh Nourmohammadi Dehbalaei


    Full Text Available In this research, a 2D laterally averaged model of hydrodynamics and water quality, CE-QUAL-W2, was applied to simulate water quality parameters in the Ilam reservoir. The water quality of Ilam reservoir was obtained between mesotrophic and eutrophic based on the measured data including chlorophyll a, total phosphorus and subsurface oxygen saturation. The CE-QUAL-W2 model was calibrated and verified by using the data of the year 2009 and 2010, respectively. Nutrients, chlorophyll a and dissolved oxygen were the water quality constituents simulated by the CE-QUAL-W2 model. The comparison of the simulated water surface elevation with the measurement records indicated that the flow was fully balanced in the numerical model. There was a good agreement between the simulated and measured results of the hydrodynamics and water quality constituents in the calibration and verification periods. Some scenarios have been made base on decreasing in water quantity and nutrient inputs of reservoir inflows. The results have shown that the water quality improvements of the Ilam reservoir will not be achieved by reducing a portion of the reservoir inflow. The retention time of water in reservoir would be changed by decreasing of inflows and it made of the negative effects on the chlorophyll-a concentration by reduction of nutrient inputs and keeping constant of discharge inflow to reservoir, the concentration of total phosphorus would be significantly changed and also the concentration of chlorophyll-a was constant approximately. Thus, the effects of control in nutrient inputs are much more than control in discharge inflows in the Ilam reservoir.

  1. Reservoir technology - geothermal reservoir engineering research at Stanford. Fifth annual report, October 1, 1984-September 30, 1985

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Miller, F.G.; Brigham, W.E.


    The objective is to carry out research on geothermal reservoir engineering techniques useful to the geothermal industry. A parallel objective is the training of geothermal engineers and scientists. The research is focused toward accelerated development of hydrothermal resources through the evaluation of fluid reserves, and the forecasting of field behavior with time. Injection technology is a research area receiving special attention. The program is divided into reservoir definition research, modeling of heat extraction from fractured reservoirs, application and testing of new and proven reservoir engineering technology, and technology transfer. (ACR)

  2. Trace Metal Levels in Rainbow Trout (Oncorhynchus mykiss) Cultured in Net Cages in a Reservoir and Evaluation of Human Health Risks from Consumption. (United States)

    Varol, Memet; Kaya, Gülderen Kurt; Alp, Sumru Anık; Sünbül, Muhammet Raşit


    Although fish consumption has positive health effects, metals accumulated in fish can cause human health risks. In this study, the levels of ten metals in rainbow trout (Oncorhynchus mykiss) farmed in the Keban Dam Reservoir, which has the biggest rainbow trout production capacity in Turkey, were determined and compared with the maximum permissible levels (MPLs). Also, human health risks associated with rainbow trout consumption were assessed. The metal concentrations in rainbow trout were found below the MPLs. The estimated daily intake of each metal was much lower than the respective tolerable daily intake. The target hazard quotient (THQ) for individual metal and total THQ for combined metals did not exceed 1, indicating no health risk for consumers. The cancer risk (CR) value for inorganic arsenic was within the acceptable lifetime risk range of 10-6 and 10-4. For carcinogenic and non-carcinogenic effects, the maximum allowable fish consumption rates were high enough to ensure the human health. According to these results, the consumption of rainbow trout farmed in the Keban Dam Reservoir does not pose a risk on human health.

  3. Reservoir-induced seismicity associated with the Itoiz Reservoir, Spain: a case study (United States)

    Durá-Gómez, Inmaculada; Talwani, Pradeep


    Reservoir-induced seismicity was observed in 2004 after the impoundment of the Itoiz Reservoir in the central-western Pyrenees, Spain. Subsequent annual filling cycles were accompanied by large epicentral growth in the northern part of the Jaca-Pamplona basin. Based on the evaluation of the available geohydrologic data, we suggest that the seismicity is associated with the diffusion of increased pore pressures along the carbonate megabreccia systems of the Early to Middle Eocene age Hecho Group. Assuming 1-D pore-pressure diffusion from the Itoiz Reservoir, we estimate that excess pore pressures of ~100-500 kPa are adequate to induce M >= 3.0 earthquakes in this geological terrane. The results of this study have potential applicability in regions where reservoirs are built over karst terranes.

  4. Aplication Of Life Cycle Assessment On Water Quality Caesed By Fish Culture Activity In Cirata Reservoir, Indonesia

    Directory of Open Access Journals (Sweden)

    Tri Heru Prihadi


    Full Text Available Life Cycle Assessment (LCA is an environmental analytical tool used for evaluating the environmental performance of products by compiling and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout the life cycle of product.Sources of the decomposition at Cirata Reservoir are from industrial activities, household waste, agricultural waste, and the leftover from the activities of floating net fish cages. The wastes are in the form of fat, protein and carbohydrat. In decomposition process and the rate of destruction process of organic matters in the sediment  is carried our by bacteria, resulting in the oxygen dissolved in the waters will decrease. This lessens the oxygen at Cirata reservoir so that decomposition process takes place anaerobically at the bottom of the waters. The methodology was conducted by  water and sediment sampling, measuring water quality on location and laboratory analysis for samples of water and sediment. Analysis result showed that the data of water quality collected in every station was relatively homogeneous. The quality of water at measuring time approached critical treshold required for fish raising. The result showed that the level of decomposition Sediment Organic Metter, water quality in Cirata reservoir based on IKA_STORET valued class I, II, and III catagorized as worse. Valued DO, sulfide, Fenol, BOD, COD, Total Fosfat byone  water quality standar. The destruction will occur by itself, depending on the availability of oxygen on the sediment and interface when there is bacteria serving as heterotraphic aerobic in line with the availability of dissolved oxygen for bacteria to do the decomposition activity in the sediment. The result would be confirmed on dendogram classification hierarchy, result revealed that stations of observation were divided into 2 groups according to affecting characteristics. Group 1 covering stasion 1 and 2, group 2 which covering station 3

  5. Daily reservoir sedimentation model: Case study from the Fena Valley Reservoir, Guam (United States)

    Marineau, Mathieu D.; Wright, Scott A.


    A model to compute reservoir sedimentation rates at daily timescales is presented. The model uses streamflow and sediment load data from nearby stream gauges to obtain an initial estimate of sediment yield for the reservoir’s watershed; it is then calibrated to the total deposition calculated from repeat bathymetric surveys. Long-term changes to reservoir trapping efficiency are also taken into account. The model was applied to the Fena Valley Reservoir, a water supply reservoir on the island of Guam. This reservoir became operational in 1951 and was recently surveyed in 2014. The model results show that the highest rate of deposition occurred during two typhoons (Typhoon Alice in 1953 and Typhoon Tingting in 2004); each storm decreased reservoir capacity by approximately 2–3% in only a few days. The presented model can be used to evaluate the impact of an extreme event, or it can be coupled with a watershed runoff model to evaluate potential impacts to storage capacity as a result of climate change or other hydrologic modifications.

  6. Geothermal reservoirs - A brief review


    Ganguly, Sayantan; Kumar, Mohan MS


    A brief discussion and review of the geothermal reservoir systems, geothermal energy and modeling and simulation of the geothermal reservoirs has been presented here. Different types of geothermal reservoirs and their governing equations have been discussed first. The conceptual and numerical modeling along with the representation of flow though fractured media, some issues related to non isothermal flow through fractured media, the efficiency of the geothermal reservoir, structure of the num...

  7. CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen (United States)

    Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.


    Energy Technology Data Exchange (ETDEWEB)

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant


    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones

  9. Dissolved-solids loads discharged from irrigated areas near Manila, Utah, May 2007-October 2012, and relation of loads to selected variables (United States)

    Thiros, Susan A.; Gerner, Steven J.


    The Manila/Washam Salinity Project (MWSP) is a cooperative effort by the Natural Resources Conservation Service (NRCS) and local farmers and ranchers to reduce the transport of dissolved solids to Flaming Gorge Reservoir from irrigated agricultural lands near Manila, Utah. To estimate dissolved-solids loads from the MWSP area, discharge and water quality from Birch Spring Draw and other selected outflows and inflows were monitored from May 2007 to October 2012. An average annual May–April streamflow of 5,960 acre-feet discharged from Birch Spring Draw at site BSD-2 to Flaming Gorge Reservoir during 2007–12, containing an average dissolved-solids load of 14,660 tons. An average May–April net dissolved-solids load of 24,300 tons per year discharged from the MWSP area, estimated from the relation between streamflow and dissolved-solids concentration at site BSD-2 and other measured inflows and outflows.

  10. Release of dissolved carbohydrates by

    NARCIS (Netherlands)

    Van Oostende, N.; Moerdijk-Poortvliet, T.C.W.; Boschker, H.T.S.; Vyverman, W.; Sabbe, K.


    The coccolithophore Emiliania huxleyi plays a pivotal role in the marine carbon cycle. However, we have only limited understanding of how its life cycle and bacterial interactions affect the production and composition of dissolved extracellular organic carbon and its transfer to the

  11. Tracing fluid flow in geothermal reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Rose, P.E.; Adams, M.C. [Univ. of Utah, Salt Lake City, UT (United States)


    A family of fluorescent compounds, the polycyclic aromatic sulfonates, were evaluated for application in intermediate- and high-temperature geothermal reservoirs. Whereas the naphthalene sulfonates were found to be very thermally stable and reasonably detectable, the amino-substituted naphthalene sulfonates were found to be somewhat less thermally stable, but much more detectable. A tracer test was conducted at the Dixie Valley, Nevada, geothermal reservoir using one of the substituted naphthalene sulfonates, amino G, and fluorescein. Four of 9 production wells showed tracer breakthrough during the first 200 days of the test. Reconstructed tracer return curves are presented that correct for the thermal decay of tracer assuming an average reservoir temperature of 227{degrees}C. In order to examine the feasibility of using numerical simulation to model tracer flow, we developed simple, two-dimensional models of the geothermal reservoir using the numerical simulation programs TETRAD and TOUGH2. By fitting model outputs to measured return curves, we show that numerical reservoir simulations can be calibrated with the tracer data. Both models predict the same order of elution, approximate tracer concentrations, and return curve shapes. Using these results, we propose a method for using numerical models to design a tracer test.

  12. Landfill liners from dam reservoir sediments

    Directory of Open Access Journals (Sweden)

    Koś Karolina


    Full Text Available Landfill liners from dam reservoir sediments. Every municipal solid waste landfill has to be properly secured to protect the natural environment from possible leachate. Most often an artificial sealing is used, which is based on a soil liner from cohesive soils (clays, silts. Usability evaluation of bottom sediments from Rzeszowski Reservoir for building these liners was presented in the paper. Sediments from dam reservoirs, gathered as a result of the siltation process, can be a valuable material for earthworks purposes. Determination of their possible ways of usage is important, especially before the planned dredging, because thanks to that this material will not be put on a heap. Based on the analysis of the geotechnical parameters of these sediments it was stated that this material can be preliminary allowed for using in liners.

  13. Distribution Dynamics of Vegetative Cells and Cyst of Ceratium hirundinella in Two Reservoirs, Turkey

    Directory of Open Access Journals (Sweden)



    Full Text Available The seasonal variation and vertical and horizontal distributions of Ceratium hirundinella (O.F.Müller Dujardin and occurrence of its cyst form in Erfelek and Dodurga Reservoirs (Sinop, Turkey were studied between August 2010 and July 2011. Our results showed that cyst form was observed with vegetative cells in phytoplankton. Ceratium hirundinella was recorded in high numbers in autumn/winter periods in these reservoirs. Winter conditions did not affect presence/absence of the species, but influenced the cell densities. Vegetative cells were observed mostly in lacustrine and transition zones, horizontally in two reservoirs and also cyst form was recorded in Erfelek Reservoir but not found in Dodurga Reservoir vertically. Dissolved oxygen had positive correlation with vegetative cells and also pH, conductivity and redox potential were important factors for vegetative cells and cyst occurrence.

  14. Ileoanal anastomosis with proximal ileal reservoir: an experimental study. (United States)

    Schraut, W H; Block, G E


    Endorectal ileoanal anastomosis with proximal interposition of an ileal reservoir was evaluated experimentally in dogs as an approach to retain sphincteric control of defecation after proctocolectomy. Two months after the operative procedure, eight animals with a reservoir had four to eight semisolid stools per day and were continent. In contrast, six animals with straight ileoanal anastomosis were incontinent with 10 to 14 evacuations per day. Motility studies demonstrated a reduction of propulsive peristalsis within the undistended reservoir, which is considered the responsible factor for increased intestinal transit time and reduced stool frequency. Filling of the reservoir to capacity elicited strong peristaltic contractions, which may assure a more complete evacuation of the reservoir during defecation. Reservoir capacity increased substantially (150% to 200%) within 2 months but only to a minor degree thereafter, indicating that the reservoir does not dilate progressively into an atonic viscus. Motility patterns remained unaltered as the reservoir became more complaint with time. Mucosal alterations (flattening of villi, submucosal inflammation) were detected in the reservoir but did not result in nutritional defects within an observation period of 1 year.

  15. Integration of seismic interpretation and well logging analysis of Abu Roash D Member, Gindi Basin, Egypt: Implication for detecting and evaluating fractured carbonate reservoirs (United States)

    Sarhan, Mohammad Abdelfattah; Basal, A. M. K.; Ibrahim, Ibrahim Mohamed


    Based on seismic interpretation, the time structure map on top of the Abu Roash D Member in the area of study within the Gindi Basin displays an NE-SW anticline plunging toward the NE intersected by two NE-SW reverse faults. This faulted anticline has been interpreted to have formed by the Late Cretaceous tectonic inversion resulting from the NW movement of the African Plate relative to Laurasia. This anticline creates a distinctive closure which may represent a possible structural hydrocarbon trap in the fractured limestone of the Abu Roash D Member in this area. Through well-logging analysis, the variable cementation exponent ;m; has been calculated using the Pickett Plot for the available wells in order to examine the presence of fractures within the entire carbonate Abu Roash D Member. The calculated ;m; for Abu Roash D in the two studied wells are 1.56 and 1.34 for SWQ-21 and SWQ-25; respectively which is indicative of the fractured limestone nature. The application of the correct ;m; (1.56) instead of 2 (traditional for the intergranular carbonate) for SWQ-21 well has revealed that, the water saturation for the uppermost part of Abu Roash D Member is lower than 50% (normal cut off for carbonate) possessing high porosity and reflecting good reservoir quality. The cross-plot between Archie water saturation (Sw) and neutron porosity (ΦN) for the uppermost part of this Member follows hyperbola with low BVW (Φ*Sw) value (0.06) which means that the reservoir is at irreducible state. The visual inspection for the log curve shapes in addition to the application of the presented technique in SWQ-25 well shows that the entire carbonate of Abu Roash D Member is water producing (Sw>50%). These results indicate that the upperpost part of the Abu Roash D Member in well SWQ-21 is fractured limestone and highly promising for hydrocarbon exploration within the Gindi Basin.

  16. Chickamauga Reservoir 1992 fisheries monitoring cove rotenone results

    Energy Technology Data Exchange (ETDEWEB)

    Kerley, B.L.


    The Tennessee Valley Authority (TVA) is required by the National Pollutant Discharge Elimination System (NPDES) Permit for Sequoyah Nuclear Plant (SQN) to conduct and report annually a nonradiological operational monitoring program to evaluate potential effects of SQN on Chickamauga Reservoir. This monitoring program was initially designed to identify potential changes in water quality and biological communities in Chickamauga Reservoir resulting from operation of SQU. Chickamauga Reservoir cove rotenone sampling has also been conducted as part of the preoperational monitoring program for Watts Bar Nuclear Plant (WBN) to evaluate the combined effects of operating two nuclear facilities on one reservoir once WBU becomes operational. The purpose of this report is to present results of cove rotenone sampling conducted on Chickamauga Reservoir in 1992.

  17. Hidden cycle of dissolved organic carbon in the deep ocean. (United States)

    Follett, Christopher L; Repeta, Daniel J; Rothman, Daniel H; Xu, Li; Santinelli, Chiara


    Marine dissolved organic carbon (DOC) is a large (660 Pg C) reactive carbon reservoir that mediates the oceanic microbial food web and interacts with climate on both short and long timescales. Carbon isotopic content provides information on the DOC source via δ(13)C and age via Δ(14)C. Bulk isotope measurements suggest a microbially sourced DOC reservoir with two distinct components of differing radiocarbon age. However, such measurements cannot determine internal dynamics and fluxes. Here we analyze serial oxidation experiments to quantify the isotopic diversity of DOC at an oligotrophic site in the central Pacific Ocean. Our results show diversity in both stable and radio isotopes at all depths, confirming DOC cycling hidden within bulk analyses. We confirm the presence of isotopically enriched, modern DOC cocycling with an isotopically depleted older fraction in the upper ocean. However, our results show that up to 30% of the deep DOC reservoir is modern and supported by a 1 Pg/y carbon flux, which is 10 times higher than inferred from bulk isotope measurements. Isotopically depleted material turns over at an apparent time scale of 30,000 y, which is far slower than indicated by bulk isotope measurements. These results are consistent with global DOC measurements and explain both the fluctuations in deep DOC concentration and the anomalous radiocarbon values of DOC in the Southern Ocean. Collectively these results provide an unprecedented view of the ways in which DOC moves through the marine carbon cycle.

  18. Direct hydrocarbon exploration and gas reservoir development technology

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Young Hoon; Oh, Jae Ho; Jeong, Tae Jin [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)] [and others


    In order to enhance the capability of petroleum exploration and development techniques, three year project (1994 - 1997) was initiated on the research of direct hydrocarbon exploration and gas reservoir development. This project consists of four sub-projects. (1) Oil(Gas) - source rock correlation technique: The overview of bio-marker parameters which are applicable to hydrocarbon exploration has been illustrated. Experimental analysis of saturated hydrocarbon and bio-markers of the Pohang E and F core samples has been carried out. (2) Study on surface geochemistry and microbiology for hydrocarbon exploration: the test results of the experimental device for extraction of dissolved gases from water show that the device can be utilized for the gas geochemistry of water. (3) Development of gas and gas condensate reservoirs: There are two types of reservoir characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. (4) Numerical modeling of seismic wave propagation and full waveform inversion: Three individual sections are presented. The first one is devoted to the inversion theory in general sense. The second and the third sections deal with the frequency domain pseudo waveform inversion of seismic reflection data and refraction data respectively. (author). 180 refs., 91 figs., 60 tabs.

  19. Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil

    Directory of Open Access Journals (Sweden)

    AS Mansano

    Full Text Available The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold. The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L−1, while the lowest was in the dry/cold (2016.0 ind L−1. Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea, predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI. The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species.

  20. Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

    Directory of Open Access Journals (Sweden)

    Zhang Wei


    Full Text Available To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%–30.91%, 83.29%–90.51%, and 61.54–68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff.

  1. Status of Blue Ridge Reservoir

    Energy Technology Data Exchange (ETDEWEB)


    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Blue Ridge Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports and data available, as well as interview with water resource professionals in various federal, state, and local agencies. Blue Ridge Reservoir is a single-purpose hydropower generating project. When consistent with this primary objective, the reservoir is also operated to benefit secondary objectives including water quality, recreation, fish and aquatic habitat, development of shoreline, aesthetic quality, and other public and private uses that support overall regional economic growth and development. 8 refs., 1 fig.

  2. Relative lake level fluctuations and their influence on productivity and resilience in tropical lakes and reservoirs

    NARCIS (Netherlands)

    Kolding, J.; Zwieten, van P.A.M.


    Lakes and reservoirs are traditionally characterised from static morphological or chemical parameters such as depth and dissolved solids, while the dynamic impact of shifting water supplies has received little attention. There is increasing evidence, however, that the hydrodynamic regime in tropical

  3. Recycling irrigation reservoir stratification and implications for crop health and production. (United States)

    Stratification is often assumed to only take place in deep water bodies. Recycling irrigation reservoirs often are shallow; however, they receive agricultural runoff containing elevated concentrations of nutrients and sediments. This study investigated the temperature, dissolved oxygen and pH charac...

  4. Biofouling on Reservoir in Sea Water (United States)

    Yoon, H.; Eom, C.; Kong, M.; Park, Y.; Chung, K.; Kim, B.


    The organisms which take part in marine biofouling are primarily the attached or sessile forms occurring naturally in the shallower water along the coast [1]. This is mainly because only those organisms with the ability to adapt to the new situations created by man can adhere firmly enough to avoid being washed off. Chemical and microbiological characteristics of the fouling biofilms developed on various surfaces in contact with the seawater were made. The microbial compositions of the biofilm communities formed on the reservoir polymer surfaces were tested for. The quantities of the diverse microorganisms in the biofilm samples developed on the prohibiting polymer reservoir surface were larger when there was no concern about materials for special selection for fouling. To confirm microbial and formation of biofilm on adsorbents was done CLSM (Multi-photon Confocal Laser Scanning Microscope system) analysis. Microbial identified using 16S rRNA. Experiment results, five species which are Vibrio sp., Pseudoalteromonas, Marinomonas, Sulfitobacter, and Alteromonas discovered to reservoir formed biofouling. There are some microorganism cause fouling and there are the others control fouling. The experimental results offered new specific information, concerning the problems in the application of new material as well as surface coating such as anti-fouling coatings. They showed the important role microbial activity in fouling and corrosion of the surfaces in contact with the any seawater. Acknowledgement : This research was supported by the national research project titled "The Development of Technology for Extraction of Resources Dissolved in Seawater" of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Land, Transport and Maritime Affairs. References [1] M. Y. Diego, K. Soren, and D. J. Kim. Prog. Org. Coat. 50, (2004) p.75-104.

  5. Chemical quality of surface water in the Flaming Gorge Reservoir area, Wyoming and Utah (United States)

    Madison, R.J.; Waddell, Kidd M.


    Construction of Flaming Gorge Dam on the Green River by the U.S. Bureau of Reclamation started in 1959, and storage began in November 1962. A reconnaissance study was made during the period 1966-68 to determine the effects of the reservoir on the chemical quality of the effluent water and to describe the quality of the impounded water and inflowing water.The major inflow to the reservoir is from the Green River, which contributes an average of 81 percent of the water and 59 percent of the inflow load of dissolved solids. Together, Blacks Fork and Henrys Fork contribute an average of about 16 percent of the water and about 23 percent of the dissolved-solids load, whereas minor tributaries contribute approximately 3 percent of the total inflow water to the reservoir, but about 18 percent of the total incoming load of dissolved solids.The concentration of dissolved solids in the reservoir in October 1966 was about 150 mg/l (milligrams per liter) greater than the concentration of the 1962-66 inflow and in September 1968 about 95 mg/l greater than the concentration of the 1962-68 inflow. The increased concentration is due. mostly to leaching of minerals from the reservoir bottom. For the 1963-68 water years, about 1.2 million tons of dissolved solids was leached from inundated areas. The major observable difference between the chemical composition of the inflow during 1963-66 and that of the reservoir in 1966 is an increase in the percentage of sulfate and a decrease in the percentage of bicarbonate. Impoundment of water in Flaming Gorge Reservoir during the 1963-68 water years caused the concentration of dissolved solids in the river system to increase by 130 mg/l, or about 32 percent over what would have occurred without the reservoir. Evaporation accounted for an increase of 15 mg/l, and leaching accounted for an increase of 115 mg/l.

  6. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays. (United States)

    Wang, Jingxian; Bovee, Toine F H; Bi, Yonghong; Bernhöft, Silke; Schramm, Karl-Werner


    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activities. The estrogenic activity was assessed using a rapid yeast estrogen bioassay, based on the expression of a green fluorescent reporter protein. Weak anti-estrogenic activity was detected in sediments from an area close to the dam of the reservoir, and weak estrogenic activities ranging from 0.3 to 1 ng 17β-estradiol (E2) equivalents (EQ) g(-1) dry weight sediment (dw) were detected in sediments from the Wanzhou to Guojiaba areas. In the upstream areas Wanzhou and Wushan, sediments demonstrated additive effects in co-administration of 1 nM E2 in the yeast test system, while sediments from the downstream Badong and Guojiaba areas showed estrogenic activities which seemed to be more than additive (synergistic activity). There was an increasing tendency in estrogenic activity from upstream of TGR to downstream, while this tendency terminated and converted into anti-estrogenic activity in the area close to the dam. The AhR activity was detected employing rat hepatoma cell line (H4IIE). EROD activities were found homogenously distributed in sediments in TGR ranging from 200 to 311 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) EQ g(-1) dw for total AhR agonists and from 45 to 76 pg TCDD EQ g(-1) dw for more persistent AhR agonists. The known AhR agonists polycyclic aromatic hydrocarbon, polychlorinated biphenyl, and PCDD/F only explained up to 8 % of the more persistent AhR agonist activity in the samples, which suggests that unidentified AhR-active compounds represented a great proportion of the TCDD EQ in sediments from TGR. These findings of estrogenic potential and dioxin-like activity in TGR sediments provide possible weight-of-evidence of potential

  7. Fractured reservoir discrete feature network technologies. Final report, March 7, 1996 to September 30, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Dershowitz, William S.; Einstein, Herbert H.; LaPoint, Paul R.; Eiben, Thorsten; Wadleigh, Eugene; Ivanova, Violeta


    This report summarizes research conducted for the Fractured Reservoir Discrete Feature Network Technologies Project. The five areas studied are development of hierarchical fracture models; fractured reservoir compartmentalization, block size, and tributary volume analysis; development and demonstration of fractured reservoir discrete feature data analysis tools; development of tools for data integration and reservoir simulation through application of discrete feature network technologies for tertiary oil production; quantitative evaluation of the economic value of this analysis approach.

  8. Presence of riparian vegetation increases biotic condition of fish assemblages in two Brazilian reservoirs


    Fabio Cop Ferreira; Ursulla Pereira Souza; Miguel Petrere Junior


    Abstract The riparian vegetation in lakes and reservoirs is source of course wood structures such as trunks and branches and is used as sheltering, spawning and foraging habitats for fishes. The reduction of these submerged structures can thus, affect the composition and structure of fish assemblages in reservoirs. Aim To evaluate the influence of riparian vegetation on the biotic condition of fish assemblage by adapting the Reservoir Fish Assemblage Index (RFAI) to two reservoirs in the Upp...

  9. Predicting reservoir wettability via well logs (United States)

    Feng, Cheng; Fu, Jinhua; Shi, Yujiang; Li, Gaoren; Mao, Zhiqiang


    Wettability is an important factor in controlling the distribution of oil and water. However, its evaluation has so far been a difficult problem because no log data can directly indicate it. In this paper, a new method is proposed for quantitatively predicting reservoir wettability via well log analysis. Specifically, based on the J function, diagenetic facies classification and the piecewise power functions, capillary pressure curves are constructed from conventional logs and a nuclear magnetic resonance (NMR) log respectively. Under the influence of wettability, the latter is distorted while the former remains unaffected. Therefore, the ratio of the median radius obtained from the two kinds of capillary pressure curve is calculated to reflect wettability, a quantitative relationship between the ratio and reservoir wettability is then established. According to the low-permeability core sample capillary pressure curve, NMR {{T}2} spectrum and contact angle experimental data from the bottom of the Upper Triassic reservoirs in western Ordos Basin, China, two kinds of constructing capillary pressure curve models and a predictive wettability model are calibrated. The wettability model is verified through the Amott wettability index and saturation exponent from resistivity measurement and their determined wettability levels are comparable, indicating that the proposed model is quite reliable. In addition, the model’s good application effect is exhibited in the field study. Thus, the quantitatively predicting reservoir wettability model proposed in this paper provides an effective tool for formation evaluation, field development and the improvement of oil recovery.

  10. The influence of a severe reservoir drawdown on springtime zooplankton and larval fish assemblages in Red Willow Reservoir, Nebraska (United States)

    DeBoer, Jason A.; Webber, Christa M.; Dixon, Taylor A.; Pope, Kevin L.


    Reservoirs can be dynamic systems, often prone to unpredictable and extreme water-level fluctuations, and can be environments where survival is difficult for zooplankton and larval fish. Although numerous studies have examined the effects of extreme reservoir drawdown on water quality, few have examined extreme drawdown on both abiotic and biotic characteristics. A fissure in the dam at Red Willow Reservoir in southwest Nebraska necessitated an extreme drawdown; the water level was lowered more than 6 m during a two-month period, reducing reservoir volume by 76%. During the subsequent low-water period (i.e., post-drawdown), spring sampling (April–June) showed dissolved oxygen concentration was lower, while turbidity and chlorophyll-a concentration were greater, relative to pre-drawdown conditions. Additionally, there was an overall increase in zooplankton density, although there were differences among taxa, and changes in mean size among taxa, relative to pre-drawdown conditions. Zooplankton assemblage composition had an average dissimilarity of 19.3% from pre-drawdown to post-drawdown. The ratio of zero to non-zero catches was greater post-drawdown for larval common carp and for all larval fishes combined, whereas we observed no difference for larval gizzard shad. Larval fish assemblage composition had an average dissimilarity of 39.7% from pre-drawdown to post-drawdown. Given the likelihood that other dams will need repair or replacement in the near future, it is imperative for effective reservoir management that we anticipate the likely abiotic and biotic responses of reservoir ecosystems as these management actions will continue to alter environmental conditions in reservoirs.

  11. Taxonomical and ecological characteristics of the desmids placoderms in reservoir: analyzing the spatial and temporal distribution

    Directory of Open Access Journals (Sweden)

    Sirlene Aparecida Felisberto


    Full Text Available AIM: This study aimed to evaluate the influence of river-dam axis and abiotic factors on the composition of Closteriaceae, Gonatozygaceae, Mesotaeniaceae and Peniaceae in a tropical reservoir METHODS: Water samples for physical, chemical and periphyton analysis were collected in April and August 2002 in different regions along the axis of the river-dam of Rosana Reservoir, River Basin Paranapanema. The substrates collected, always in the litoranea region, were petioles of Eichhornia azurea (Swartz Kunth. To examine the relationship of abiotic variables with reservoir zones and between the floristic composition of desmids, we used principal component analysis (PCA and canonical correspondence analysis (CCA RESULTS: The results of the PCA explained 81.3% of the total variability in the first two axes. In the first axis, the variables of conductivity, water temperature and the pH were related to the sampling regions of April with higher values, while for the month of August, nitrate, total phosphorus and dissolved oxygen showed higher values. We identified 20 taxa, distributed in the genera Closterium (14, Gonatozygon (4, Netrium (1 and Penium (1. Spatially, the higher taxa were recorded in the lacustrine region for both collection periods. The canonical correspondence analysis (CCA summarized 62.2% of total data variability of taxa in the first two axes, and in August, Closterium incurvum Brébisson, C. cornu Ehrenberg ex Ralfs and Gonatozygon monotaenium De Bary, were related to higher values of turbidity and nitrate to the lacustrine and intermediate regions CONCLUSION: Thus, the formation of groups was due to the regions along the longitudinal axis, then the seasonal period, which must be related to the low current velocity, the higher values of temperature and the water transparency, especially in late summer

  12. Inversion of multicomponent seismic data and rock-physics intepretation for evaluating lithology, fracture and fluid distribution in heterogeneous anisotropic reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ilya Tsvankin; Kenneth L. Larner


    Within the framework of this collaborative project with the Lawrence Livermore National Laboratory (LLNL) and Stanford University, the Colorado School of Mines (CSM) group developed and implemented a new efficient approach to the inversion and processing of multicomponent, multiazimuth seismic data in anisotropic media. To avoid serious difficulties in the processing of mode-converted (PS) waves, we devised a methodology for transforming recorded PP- and PS-wavefields into the corresponding SS-wave reflection data that can be processed by velocity-analysis algorithms designed for pure (unconverted) modes. It should be emphasized that this procedure does not require knowledge of the velocity model and can be applied to data from arbitrarily anisotropic, heterogeneous media. The azimuthally varying reflection moveouts of the PP-waves and constructed SS-waves are then combined in anisotropic stacking-velocity tomography to estimate the velocity field in the depth domain. As illustrated by the case studies discussed in the report, migration of the multicomponent data with the obtained anisotropic velocity model yields a crisp image of the reservoir that is vastly superior to that produced by conventional methods. The scope of this research essentially amounts to building the foundation of 3D multicomponent, anisotropic seismology. We have also worked with the LLNL and Stanford groups on relating the anisotropic parameters obtained from seismic data to stress, lithology, and fluid distribution using a generalized theoretical treatment of fractured, poroelastic rocks.

  13. Geoprocessing techniques to evaluate the spatial distribution of natural rain erosion potential in the Hydrographic Basin of Cachoeira Dourada Reservoir – Brazil

    Directory of Open Access Journals (Sweden)

    João Batista Pereira CABRAL


    Full Text Available Natural potential erosion were defined from their main natural conditioners in the region of hydrographic basin of Cachoeira Dourada (between Goiás and Minas Gerais states −Brazil, with geoprocessing techniques and the Universal Soil Loss Equation (USLE. Upon the decision for natural erosion potential, a matrix with values of erosivity (R, erodibility (K, declivity, and ramp length (LS was elaborated, where classes of low, medium, high, very high, and extremely high natural erosion potential (NEP were established. Spatial distribution for the factors R, K, LS, and PNE was defined. The highest average R index for the rainy series was 8173.50 MJ ha mm-1 h-1 year-1. The period with data from 30 years (1973 – 2002 showed that the reservoir basin displayed areas susceptible to rill and interill erosion (69.16% of the total. There is a predominance of low erosion potential among the classes, which can be explained due to the soil predominant classes as well as to the low declivity. Areas with medium to extremely high erosion potential require the adoption of measures to avoid start and development of more severe erosion processes (ravines and gullies.

  14. Geothermal reservoir management

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, C.R.; Golabi, K.


    The optimal management of a hot water geothermal reservoir was considered. The physical system investigated includes a three-dimensional aquifer from which hot water is pumped and circulated through a heat exchanger. Heat removed from the geothermal fluid is transferred to a building complex or other facility for space heating. After passing through the heat exchanger, the (now cooled) geothermal fluid is reinjected into the aquifer. This cools the reservoir at a rate predicted by an expression relating pumping rate, time, and production hole temperature. The economic model proposed in the study maximizes discounted value of energy transferred across the heat exchanger minus the discounted cost of wells, equipment, and pumping energy. The real value of energy is assumed to increase at r percent per year. A major decision variable is the production or pumping rate (which is constant over the project life). Other decision variables in this optimization are production timing, reinjection temperature, and the economic life of the reservoir at the selected pumping rate. Results show that waiting time to production and production life increases as r increases and decreases as the discount rate increases. Production rate decreases as r increases and increases as the discount rate increases. The optimal injection temperature is very close to the temperature of the steam produced on the other side of the heat exchanger, and is virtually independent of r and the discount rate. Sensitivity of the decision variables to geohydrological parameters was also investigated. Initial aquifer temperature and permeability have a major influence on these variables, although aquifer porosity is of less importance. A penalty was considered for production delay after the lease is granted.

  15. Characteristics of hydrothermal activity in the Tarim Basin and its reworking effect on carbonate reservoirs

    Directory of Open Access Journals (Sweden)

    Wei Liu


    Full Text Available Hydrothermal activity is common in the Tarim Basin. In this paper, petrologic and geochemical features of the hydrothermal products in the carbonate rocks in this basin were analyzed so as to figure out the effect of hydrothermal activity on the Lower Palaeozoic carbonate reservoirs in this area. It is shown that the hydrothermal fluids in the Tarim Basin are generally high in CO2 content, but very low in Mg2+ content. Then, the reworking effect of hydrothermal activity on reservoir was further discussed. It is indicated that the component of hydrothermal fluid is the deciding factor for the reworking of reservoirs. The study provided the following findings. Firstly, hydrothermal fluid is rich in CO2. Dissolution is intense in the vicinity of fracture zones and dissolved pores of different sizes are developed. Therefore, small-scale high-quality reservoirs with good porosity and permeability are formed. Secondly, hydrothermal fluid itself is low in magnesium content and some additional magnesium can be produced from Cambrian dolomites by means of dissolution, but the scale of hydrothermal dolomitization is small. Thirdly, the hydrothermal fluids rich in CO2 form high-quality dissolved vug typed reservoirs by means of dissolving surrounding rocks and their distribution are controlled by faulting. Fourthly, the saddle-like dolomite with hydrothermal origin fills dissolved vugs. Furthermore, the hydrothermal activity in the vicinity of faults results in the recrystallization or excessive growth of dolomite crystal, blocking existed pores, which is a type of destructive diagenesis as a whole. The study results can provide a reference for carbonate reservoir prediction of deep basin.

  16. The Potosi Reservoir Model 2013

    Energy Technology Data Exchange (ETDEWEB)

    Adushita, Yasmin; Smith, Valerie; Leetaru, Hannes


    As a part of a larger project co-funded by the United States Department of Energy (US DOE) to evaluate the potential of formations within the Cambro-Ordovician strata above the Mt. Simon as potential targets for carbon sequestration in the Illinois and Michigan Basins, the Illinois Clean Coal Institute (ICCI) requested Schlumberger to evaluate the potential injectivity and carbon dioxide (CO2) plume size of the Cambrian Potosi Formation. The evaluation of this formation was accomplished using wireline data, core data, pressure data, and seismic data from the US DOE-funded Illinois Basin–Decatur Project (IBDP) being conducted by the Midwest Geological Sequestration Consortium in Macon County, Illinois. In 2010, technical performance evaluations on the Cambrian Potosi Formation were performed through reservoir modeling. The data included formation tops from mud logs, well logs from the VW1 and the CCS1 wells, structural and stratigraphic formation from three dimensional (3D) seismic data, and field data from several waste water injection wells for Potosi Formation. Intention was for two million tons per annum (MTPA) of CO2 to be injected for 20 years. In the preceding, the 2010 Potosi heterogeneous model (referred to as the "Potosi Dynamic Model 2010" in this topical report) was re-run using a new injection scenario; 3.2 MTPA for 30 years. The extent of the Potosi Dynamic Model 2010, however, appeared too small for the new injection target. It was not sufficiently large enough to accommodate the evolution of the plume. The new model, Potosi Dynamic Model 2013a, was built by extending the Potosi Dynamic Model 2010 grid to 30 miles x 30 miles (48.3km x48.3km), while preserving all property modeling workflows and layering. This model was retained as the base case of Potosi Dynamic Model 2013a. The Potosi reservoir model was updated to take into account the new data from the verification well VW2 which was drilled in 2012. The new porosity and permeability modeling was

  17. Advances in photonic reservoir computing (United States)

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.


    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  18. Miscible displacement in the Weyburn reservoir: A laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S.S (Saskatchewan Research Council, Saskatoon, SK (Canada)); Dyer, S.B. (PanCanadian Petorleum Ltd., AB (Canada))


    A laboratory study was conducted to evaluate the applicability of various solvents (including the potential source of carbon dioxide extracted from flue gas) for the recovery of oil from a southeast Saskatchewan reservoir, the Weyburn. The physical, chemical, and phase behavior (PVT) properties of the dead oil, reservoir fluid, and reservoir fluid with carbon dioxide, were determined. Slim tube tests were conducted for the Weyburn reservoir fluid with pure carbon dioxide, with wellhead gas from the Steelman gas plant, and with two impure carbon dioxide gases (one containing 9.9 mol % CH[sub 4] and the other containing 5.1 mol % N[sub 2] and 5.1 mol % CH[sub 4]), at various pressures and the reservoir temperature of 59[degree]C. Tests were also carried out to determine the maximum amount of impurities that can be tolerated for the miscible process. The minimum miscibility pressures (MMP) determined for the systems demonstrated that miscible displacement using pure CO[sub 2] or impure gas containing up to 9.9 mol % CH[sub 4] as a solvent is a promising enhanced oil recovery (EOR) technique for southest Saskatchewan reservoirs. The MMPs are below the estimated reservoir fracture pressure. The wellhead gas from the Steelman gas plant is not a suitable EOR agent for the Weyburn reservoir. MMPs determined by the rising bubble method were in good agreement with slim tube test results, and this method is considered superior. 20 refs., 8 figs., 15 tabs.

  19. Reservoir management cost-cutting

    Energy Technology Data Exchange (ETDEWEB)

    Gulati, M.S.


    This article by Mohinder S. Gulati, Chief Engineer, Unocal Geothermal Operations, discusses cost cutting in geothermal reservoir management. The reservoir engineer or geoscientist can make a big difference in the economical outcome of a project by improving well performance and thus making geothermal energy more competitive in the energy marketplace. Bringing plants online in less time and proving resources to reduce the cycle time are some of the ways to reduce reservoir management costs discussed in this article.

  20. Water quality of the Lexington Reservoir, Santa Clara County, California, 1978-80 (United States)

    Iwatsubo, R.T.; Sylvester, M.A.; Gloege, I.S.


    Analysis of water samples from Lexington Reservoir and Los Gatos Creek upstream from the reservoir from June 1978 through September 1980 showed that water generally met water-quality objectives identified by California Regional Water Quality Control Board, San Francisco Bay Region. Water-temperature profiles show that Lexington Reservoir is a warm monomictic lake. During summer, dissolved-oxygen concentrations generally were not reduced below 5.0 mg/L in the hyplimnion; only once during the study did bottom waters become anoxic. Water transparency decreased with depth. The euphotic zone ranged from 1.0 to 5.4 m, depending on suspended solids and algae, and was greater in summer than in spring. Calcium and bicarbonate were dominant ions at all stations except during spring, following the rainy season, when waters were a mixed cation bicarbonate type. Nitrogen concentrations were greater in samples from reservoir stations than in those from Los Gatos Creek, with most of the nitrogen in ammonia and organic forms. The amount of dissolved nitrate appeared to be related to phytoplankton abundance. Phosphorus and trace-element concentrations were low at all stations. Estimates of net primary productivity and Carlson 's trophic-state index, based on chlorophyll-a concentrations, indicated that reservoir classification ranges from oligotrophic to mesotrophic. Blue-green algae generally were predominant in reservoir samples. (USGS)

  1. Development and application of a new biotechnology of the molasses in-situ method; detailed evaluation for selected wells in the Romashkino carbonate reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.; Lungerhausen, D. [Erdoel-Erdgas Gommern GmbH (Germany); Murtada, H.; Rosenthal, G. [VEBA OEL AG, Gelsenkirchen (Germany)


    On the basis of different laboratory studies, by which special strains of the type Clostridium tyrobutyricum were found, the application of molasses in-situ method for the enhanced recovery of oil in Romashkino oil field was executed. In an anaerobic, 6%-molasses medium the strains produce about 11,400 mg/l of organic acids (especially butyric acid), 3,200 mg/l ethanol, butanol, etc., and more than 350 ml/g of molasses biogas with a content of 80% C0{sub 2} and 20% H{sub 2}. The metabolics of Clostridium tyrobutyricum depress the growth of SRB, whereas methanogenic bacteria grow in an undiluted fermented molasses medium very well. In this way the dominant final fermentation process is methanogenesis. By laboratory studies with original cores under the conditions of the carbonate reservoir in Bashkir, the recovery of oil increased from 15% after waterflooding to 29% OOIP during the treatment with molasses and bacteria. We developed a new biotechnological method for a self-regulated, automatic continuous culture and constructed a special pilot plant with a high technical standard. The plant produced during the pilot on Romashkino field (September 1992 to August 1994) about 1,000 m{sup 3} of clean inoculum with a content of 3-4 billion cells per ml. This inoculum was injected in slugs together with 15,000 m{sup 3} of molasses medium, first in one, later in five wells. We will demonstrate for two example wells the complex microbiological and chemical changes in the oil, gas, and water phases, and their influences on the recover of oil.

  2. Novel approach of aceclofenac fast dissolving tablet. (United States)

    Dave, Vivek; Yadav, Sachdev; Sharma, Swapnil; Vishwakarma, Pushpendra; Ali, Nasir


    Fast disintegrating tablets (FDTs) have received ever increasing demand during the last decade, and the field has become a hastily growing area in the pharmaceutical industry. Upon introduction into the mouth, these tablets dissolve or disintegrate in the mouth in the absence of additional water for easy administration of active pharmaceutical ingredients. Aceclofenac, an NSAID, has been recommended orally for the treatment of bone and connective tissue disorder and thus the formulation of the same resulted in development of several FDT technologies. The present aim is to formulate a tablet which disintegrate and dissolve rapidly and give its rapid onset of action: analgesic, antipyretic and anti-inflammatory action. Besides, the conventional tablets also show poor patient compliance an attempt had been made to formulate for FDT of aceclofenac by using various super disintegrants like sodium starch glycolate, croscarmellose sodium and crosspovidone (polyplasdone XL) and PEG 6000 followed by novel technique. The tablets were evaluated for friability, hardness, weight variation, disintegration time, wetting time, in vitro dissolution studies and drug content studies. It was concluded that the batch which was prepared by using combination of crosspovidone and sodium starch glycolate as a super disintegrant shows excellent disintegration time, enhance dissolution rate, taste masking and hence lead to improve efficacy and bioavailability of drug.


    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  4. Morphofunctional changes of phytoplankton community during pluvial anomaly in a tropical reservoir. (United States)

    Câmara, F R A; Rocha, O; Pessoa, E K R; Chellappa, S; Chellappa, N T


    The present study focuses on the structure and function of phytoplankton community during periods of marked changes in hydrological traits, influenced by an atypical climatic event (La Niña) and its impact on Armando Ribeiro Gonçalves Reservoir of Rio Grande do Norte, situated in the Caatinga biome of northeastern Brazil. The main questions addressed were: What are the effects of environmental factors on the temporal variation of Morphologically Based Functional Group (MBFG) of phytoplankton community? How does the composition of cyanobacterial species shift in relation to high and low trends of phytoplankton diversity? The samples were collected monthly during 2008-2009 and analyzed for pH, temperature, electrical conductivity, dissolved oxygen content and the nutrients, such as, nitrate-nitrogen, ammoniacal nitrogen, total nitrogen and orthophosphate. Phytoplankton samples were collected for both qualitative and quantitative analyses to evaluate species richness index and species diversity index. The data was divided into two distinct hydrodynamic periods of instability and stability. The results demonstrate considerable changes in dissolved oxygen content, water transparency and nitrogen nutrients, which directly influenced the MBFG of phytoplankton community in space and time. The instability of reservoir water was caused by heavy rainfall, which exerts atypical external disturbances. The seasonal variation of MBFG demonstrates a change in cyanobacterial composition and their diversity during instability and stability periods. MBFG VII, composed by colonial cyanobacteria with mucilage, was associated with reduced values of electrical conductance and alterations in pH. The predominance of filamentous species with heterocyst (MBFG III) occurs only during the hydrodynamic stability period and did not show significant association with analyzed parameters. The co-dominance of MBGFs III, V and VII along with high species diversity of phytoplankton community

  5. Morphofunctional changes of phytoplankton community during pluvial anomaly in a tropical reservoir

    Directory of Open Access Journals (Sweden)

    FRA Câmara

    Full Text Available AbstractThe present study focuses on the structure and function of phytoplankton community during periods of marked changes in hydrological traits, influenced by an atypical climatic event (La Niña and its impact on Armando Ribeiro Gonçalves Reservoir of Rio Grande do Norte, situated in the Caatinga biome of northeastern Brazil. The main questions addressed were: What are the effects of environmental factors on the temporal variation of Morphologically Based Functional Group (MBFG of phytoplankton community? How does the composition of cyanobacterial species shift in relation to high and low trends of phytoplankton diversity? The samples were collected monthly during 2008-2009 and analyzed for pH, temperature, electrical conductivity, dissolved oxygen content and the nutrients, such as, nitrate-nitrogen, ammoniacal nitrogen, total nitrogen and orthophosphate. Phytoplankton samples were collected for both qualitative and quantitative analyses to evaluate species richness index and species diversity index. The data was divided into two distinct hydrodynamic periods of instability and stability. The results demonstrate considerable changes in dissolved oxygen content, water transparency and nitrogen nutrients, which directly influenced the MBFG of phytoplankton community in space and time. The instability of reservoir water was caused by heavy rainfall, which exerts atypical external disturbances. The seasonal variation of MBFG demonstrates a change in cyanobacterial composition and their diversity during instability and stability periods. MBFG VII, composed by colonial cyanobacteria with mucilage, was associated with reduced values of electrical conductance and alterations in pH. The predominance of filamentous species with heterocyst (MBFG III occurs only during the hydrodynamic stability period and did not show significant association with analyzed parameters. The co-dominance of MBGFs III, V and VII along with high species diversity of

  6. modeling of modeling of reservoir in reservoir in artificial neu

    African Journals Online (AJOL)


    the three hydropower reser parameters parameters and Artificial rtificial rtificial Neural Network (ANN) eural Network (ANN) and the modeled reservoir inflow .... MODELING OF RESERVOIR INFLOW FOR HYDROPOWER DAMS USING ARTIFICIAL NEURAL NETWORK ..... Based Model of an Industrial Oil-Fired Boiler”.

  7. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drillings. Annual technical progress report, June 13, 1996 to June 12, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Nevans, Jerry W.; Blasingame, Tom; Doublet, Louis; Kelkar, Mohan; Freeman, George; Callard, Jeff; Moore, David; Davies, David; Vessell, Richard; Pregger, Brian; Dixon, Bill


    Infill drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, does not optimize reservoir development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. New and emerging technologies, such as geostatistical modeling, rigorous decline curve analysis, reservoir rock typing, and special core analysis can be used to develop a 3-D simulation model for prediction of infill locations. Other technologies, such as inter-well injection tracers and magnetic flow conditioners, can also aid in the efficient evaluation and operation of both injection and producing wells. The purpose of this project was to demonstrate useful and cost effective methods of exploitation of the shallow shelf carbonate reservoirs of the Permian Basin located in West Texas.

  8. Simulation of Sediment and Cesium Transport in the Ukedo River and the Ogi Dam Reservoir during a Rainfall Event using the TODAM Code

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yasuo; Yokuda, Satoru T.; Kurikami, Hiroshi


    The accident at the Fukushima Daiichi Nuclear Power Plant in March 2011 caused widespread environmental contamination. Although decontamination activities have been performed in residential areas of the Fukushima area, decontamination of forests, rivers, and reservoirs is still controversial because of the economical, ecological, and technical difficulties. Thus, an evaluation of contaminant transport in such an environment is important for safety assessment and for implementation of possible countermeasures to reduce radiation exposure to the public. The investigation revealed that heavy rainfall events play a significant role in transporting radioactive cesium deposited on the land surface, via soil erosion and sediment transport in rivers. Therefore, we simulated the sediment and cesium transport in the Ukedo River and its tributaries in Fukushima Prefecture, including the Ogaki Dam Reservoir, and the Ogi Dam Reservoir of the Oginosawa River in Fukushima Prefecture during and after a heavy rainfall event by using the TODAM (Time-dependent, One-dimensional Degradation And Migration) code. The main outcomes are the following: • Suspended sand is mostly deposited on the river bottom. Suspended silt and clay, on the other hand, are hardly deposited in the Ukedo River and its tributaries except in the Ogaki Dam Reservoir in the Ukedo River even in low river discharge conditions. • Cesium migrates mainly during high river discharge periods during heavy rainfall events. Silt and clay play more important roles in cesium transport to the sea than sand does. • The simulation results explain variations in the field data on cesium distributions in the river. Additional field data currently being collected and further modeling with these data may shed more light on the cesium distribution variations. • Effects of 40-hour heavy rainfall events on clay and cesium transport continue for more than a month. This is because these reservoirs slow down the storm-induced high

  9. Thermodynamic properties of gases dissolved in electrolyte solutions. (United States)

    Tiepel, E. W.; Gubbins, K. E.


    A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

  10. A quantitative assessment of the contributions of climatic indicators to changes in nutrients and oxygen levels in a shallow reservoir in China (United States)

    Zhang, Chen; Zhang, Wenna; Liu, Hanan; Gao, Xueping; Huang, Yixuan


    Climate change has an indirect effect on water quality in freshwater ecosystems, but it is difficult to assess the contribution of climate change to the complex system. This study explored to what extent climatic indicators (air temperature, wind speed, and rainfall) influence nutrients and oxygen levels in a shallow reservoir, Yuqiao Reservoir, China. The study comprises three parts—describing the temporal trends of climatic indicators and water quality parameters during the period 1992-2011, analyzing the potential impacts of climate on water quality, and finally developing a quantitative assessment to evaluate how climatic factors govern nutrient levels in the reservoir. Our analyses showed that the reservoir experienced substantial cold periods (1992-2001) followed by a warm period (2002-2011). The results showed that increasing air temperature in spring, autumn, and winter and increasing annual wind speed decrease total phosphorus (TP) concentration in the reservoir in spring, summer, and winter. According to the quantitative assessment, the increase in air temperature in spring and winter had a larger contribution to the decrease in TP concentration (47.2 and 64.1%), compared with the influence from decreased wind speed and rainfall. The field data suggest that nutrients decline due to enhanced uptake by macrophytes in years when spring was warmer and the macrophytes started to grow earlier in the season. The increasing wind speed and air temperature in spring also significantly contribute to the increase in dissolved oxygen concentration. This study helps managers to foresee how potential future climate change might influence water quality in similar lake ecosystems.

  11. Evaluation of Abnormal Chromosomes in Rice Field Frogs (Fejervarya limnocharis from Reservoirs Affected by Leachate with Cadmium, Chromium and Lead Contamination

    Directory of Open Access Journals (Sweden)

    Uraiwan Phoonaploy


    Full Text Available The objectives of this study were to investigate abnormal chromosomes in rice field frogs (Fejervarya limnocharis in reservoirs affected by leachate compared with a non-affected area. Nine individual of F. limnocharis were collected, and abnormal chromosomes were studied using bone marrow. The level of heavy metal concentrations (cadmium (Cd, chromium (Cr and lead (Pb were measured in water, sediment and F. limnocharis samples. The average concentrations of Cd, Cr and Pb in the water and sediment samples from the municipal landfill and non-affected areas were 0.002±0.000, 0.545±0.876 and 0.021±0.009 and not detected, 0.046±0.032 and 0.009±0.002 mg/l in water as well as 0.472±0.060, 18.652±6.791 and 5.369±0.645 and 0.234±0.019, 4.769±0.142 and 2.176±0.783 mg/kg in sediment, respectively. The municipal landfill values were lower than the permissible limit of the water and soil quality standards, while Cr exceeded the water standard. The average Cd, Cr and Pb concentrations in the F. limnocharis samples from the municipal landfill and non-affected areas were 0.023±0.007, 1.857±0.498 and 0.393±0.128 and 0.007±0.000, 1.349±0.083 and 0.183±0.005 mg/kg, respectively, with the Cd and Cr levels both lower than the standards, but not the Pb levels. The diploid chromosome number of F. limnocharis in both areas was 2n=26, and the percentage of chromosome abnormalities of F. limnocharis in the municipal landfill area were higher than the non-affected area. There were eleven types of chromosome abnormalities, including a single chromatid gap, isochromatid gap, single chromatid break, isochromatid break, centric fragmentation, deletion, fragmentation, translocation, centromere gap, iso-arm fragmentation and single chromatid decompose. The most common chromosome abnormality in the samples from the municipal landfill area was fragmentation. The difference in the percentage of chromosome abnormality in F. limnocharis from both areas was

  12. A Bayesian approach for evaluation of the effect of water quality model parameter uncertainty on TMDLs: A case study of Miyun Reservoir. (United States)

    Liang, Shidong; Jia, Haifeng; Xu, Changqing; Xu, Te; Melching, Charles


    Facing increasingly serious water pollution, the Chinese government is changing the environmental management strategy from solely pollutant concentration control to a Total Maximum Daily Load (TMDL) program, and water quality models are increasingly being applied to determine the allowable pollutant load in the TMDL. Despite the frequent use of models, few studies have focused on how parameter uncertainty in water quality models affect the allowable pollutant loads in the TMDL program, particularly for complicated and high-dimension water quality models. Uncertainty analysis for such models is limited by time-consuming simulation and high-dimensionality and nonlinearity in parameter spaces. In this study, an allowable pollutant load calculation platform was established using the Environmental Fluid Dynamics Code (EFDC), which is a widely applied hydrodynamic-water quality model. A Bayesian approach, i.e. the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, which is a high-efficiency, multi-chain Markov Chain Monte Carlo (MCMC) method, was applied to assess the effects of parameter uncertainty on the water quality model simulations and its influence on the allowable pollutant load calculation in the TMDL program. Miyun Reservoir, which is the most important surface drinking water source for Beijing, suffers from eutrophication and was selected as a case study. The relations between pollutant loads and water quality indicators are obtained through a graphical method in the simulation platform. Ranges of allowable pollutant loads were obtained according to the results of parameter uncertainty analysis, i.e. Total Organic Carbon (TOC): 581.5-1030.6t·yr(-1); Total Phosphorus (TP): 23.3-31.0t·yr(-1); and Total Nitrogen (TN): 480-1918.0t·yr(-1). The wide ranges of allowable pollutant loads reveal the importance of parameter uncertainty analysis in a TMDL program for allowable pollutant load calculation and margin of safety (MOS) determination. The sources

  13. Dilution limits dissolved organic carbon utilization in the deep ocean

    KAUST Repository

    Arrieta, Jesus


    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

  14. Experimental study on total dissolved gas supersaturation in water

    Directory of Open Access Journals (Sweden)

    Lu QU


    Full Text Available More and more high dams have been constructed and operated in China. The total dissolved gas (TDG supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth, aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG. The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines. Furthermore, the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs. These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection.

  15. Evaluating the Implications of Climate Phenomenon Indices in Supporting Reservoir Operation Using the Artificial Neural Network and Decision-Tree Methods: A Case Study on Trinity Lake in Northern California (United States)

    Yang, T.; Akbari Asanjan, A.; Gao, X.; Sorooshian, S.


    Reservoirs are fundamental human-built infrastructures that collect, store, and deliver fresh surface water in a timely manner for all kinds of purposes, including residential and industrial water supply, flood control, hydropower, and irrigation, etc. Efficient reservoir operation requires that policy makers and operators understand how reservoir inflows, available storage, and discharges are changing under different climatic conditions. Over the last decade, the uses of Artificial Intelligence and Data Mining (AI & DM) techniques in assisting reservoir management and seasonal forecasts have been increasing. Therefore, in this study, two distinct AI & DM methods, Artificial Neural Network (ANN) and Random Forest (RF), are employed and compared with respect to their capabilities of predicting monthly reservoir inflow, managing storage, and scheduling reservoir releases. A case study on Trinity Lake in northern California is conducted using long-term (over 50 years) reservoir operation records and 17 known climate phenomenon indices, i.e. PDO and ENSO, etc., as predictors. Results show that (1) both ANN and RF are capable of providing reasonable monthly reservoir storage, inflow, and outflow prediction with satisfactory statistics, and (2) climate phenomenon indices are useful in assisting monthly or seasonal forecasts of reservoir inflow and outflow. It is also found that reservoir storage has a consistent high autocorrelation effect, while inflow and outflow are more likely to be influenced by climate conditions. Using a Gini diversity index, RF method identifies that the reservoir discharges are associated with Southern Oscillation Index (SOI) and reservoir inflows are influenced by multiple climate phenomenon indices during different seasons. Furthermore, results also show that, during the winter season, reservoir discharges are controlled by the storage level for flood-control purposes, while, during the summer season, the flood-control operation is not as

  16. Total mercury concentrations in fish from Urrá reservoir (Sinú river, Colombia. Six years of monitoring

    Directory of Open Access Journals (Sweden)

    José Marrugo-Negrete


    Full Text Available Objective. The aim of this study was to monitor the total mercury (T-Hg concentrations in fish from the Urrá reservoir, after impoundment. Materials and methods. Five fish species at different trophic levels were sampled from 2004 to 2009 and analyzed by cold-vapor atomic absorption spectroscopy for T-Hg concentrations in muscle tissue. Water quality parameters were evaluated. Results. The highest (1.39±0.69 μg/g ww and lowest (0.15±0.02 μg/g ww T-Hg concentrations were detected in Hoplias malabaricus (piscivorous and Cyphocharax magdalenae (iliophagous/detritivorous respectively, whereas Leporinus muyscorum (omnivorous had an intermediate level (0.40±0.11 μg/g ww. The organic matter content in the water increased with time and depth, whereas dissolved oxygen and pH decreased. A covariance analysis (with fish length as a covariate shows a steady increase of T-Hg levels in all the studied species after impoundment. Conclusions. The T-Hg concentrations in the evaluated fish species, increased after impoundment. The water quality variables showed conditions favoring Hg methylation and its biomagnification, this last was evident in the fish food chain of the reservoir.

  17. Characterization of dissolved organic matter in drinking water sources impacted by multiple tributaries. (United States)

    Rosario-Ortiz, Fernando L; Snyder, Shane A; Suffet, I H


    The characterization of dissolved organic matter (DOM) in drinking water sources is important as this material contributes to the formation of disinfection by-products (DBPs) and affects how water treatment unit operations are optimized. Drinking water utilities often draw water from sources impacted by multiple tributaries, with possible shifts in DOM concentrations and reactivity over time, depending on specific environmental conditions. In this study, results are presented on the characterization of DOM under varying ambient conditions from the four main tributaries of Lake Mead, a large reservoir in the southwest United States. The tributaries include the Las Vegas Wash (LVW), Muddy River (MR), Virgin River (VR) and the upper Colorado River (UCR). One additional sample was collected at the outflow of the reservoir (lower Colorado River (LCR)). The DOM was characterized by both bulk parameters (specific ultraviolet absorbance (SUVA)) and specific physicochemical properties, i.e. size, polarity and fluorescence. The analyses were performed emphasizing limited changes in its natural configuration by eliminating analytical preparation steps, excluding sample filtration (0.45 microm filter). Results indicate that each tributary had a different molecular weight distribution, as well as fluorescence properties, which helped in the identification of the relative source of DOM (allochthonous versus autochthonous). The largest apparent molecular weight distribution was observed for DOM samples collected at the MR site, which is fed mostly by groundwater seepage. The smallest apparent molecular weight was observed for DOM collected at the LCR site, suggesting that retention in the reservoir resulted in a decrease in molecular weight as a probable result of photo oxidation and microbial processes. Fluorescence analysis aided the differentiation of DOM by clearly identifying waters that were affected by microbial activity (LVW, UCR, and LCR), either by wastewater influence

  18. Investigation of organic carbon transformation in soils of dominant dissolved organic carbon source zones (United States)

    Pissarello, Anna; Miltner, Anja; Oosterwoud, Marieke; Fleckenstein, Jan; Kästner, Matthias


    Over the past 20 years both a decrease in soil organic matter (SOM) and an increase in the dissolved organic carbon (DOC) concentrations in surface water bodies, including drinking water reservoirs, have been recorded in the northern hemisphere. This development has severe consequences for soil fertility and for drinking water purification. As both processes occur simultaneously, we assume that microbial SOM degradation, which transforms SOM into CO2 and DOC, is a possible source of the additional DOC in the surface water. In addition we speculate that both processes are initially triggered by physical mechanisms, resulting in a modification of the organic matter solubility equilibria and thus in higher SOM availability and DOC mobilization. The general hypothesis of the study is therefore that SOM loss and DOC increase are combined consequences of enhanced microbial degradation of SOM and that this is a result of climate variations and global change, e.g. the increase of the temperature, the alteration of the water regime (i.e. increase of the frequency of drying and rewetting cycles and a higher number of heavy rain events), but also the decrease of the atmospheric acid deposition resulting in an increase of soil pH values. The general goal of the study is the identification of the dominant processes and controlling factors involved in soil microbial carbon turnover and mobilization of DOC in soils from catchment areas that contribute DOC to the receiving waters and the downstream Rappbode reservoir, which showed a pronounced increase in DOC concentration in recent years. This reservoir is the source of drinking water for about one million people in northern Germany. Preliminary screening experiments, consisting of 65-day soil batch incubation experiments, have been conducted in order to select the parameters (and the parameter ranges) of relevance for further in-depth experiments. During the experiments, different soil systems were exposed to different

  19. Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson


    Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, contains more than 70 billion barrels of remaining oil in place and is an ideal venue to validate this technology. We have demonstrated the potential of HPAI for oil-recovery improvement in preliminary laboratory tests and a reservoir pilot project. To more completely test the technology, this project emphasized detailed characterization of reservoir properties, which were integrated to access the effectiveness and economics of HPAI. The characterization phase of the project utilized geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum

  20. A review of reservoir desiltation

    DEFF Research Database (Denmark)

    Brandt, Anders


    physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation......physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation...

  1. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.


    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  2. Reservoir engineering report for the magma-SDG and E geothermal experimental site near the Salton Sea, California

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, R.C.


    A description of the Salton Sea geothermal reservoir is given and includes approximate fault locations, geology (lithology), temperatures, and estimates of the extent of the reservoir. The reservoir's temperatures and chemical composition are also reviewed. The flow characteristics are discussed after analyses of drillstem tests and extended well tests. The field production, reserves and depletion are estimated, and the effects of fractures on flow and depletion are discussed. The reservoir is believed to be separated into an ''upper'' and ''lower'' portion by a relatively thick and continuous shale layer. The upper reservoir is highly porous, with high permeability and productivity. The lower reservoir is at least twice as large as the upper but has much lower storativity and permeability in the rock matrix. The lower reservoir may be highly fractured, and its temperatures and dissolved solids are greater than those of the upper reservoir. The proven reserves of heat in the upper reservoir are about /sup 1///sub 4/ GW.yr (in the fluid) and /sup 1///sub 3/ GW.yr (in the rock). In the lower reservoir the proven reserves of heat are 5/sup 3///sub 4/ GW.yr (in the fluid) and 17 GW.yr (in the rock). Unproven reserves greatly exceed these numbers. Injection tests following well completion imply that hydraulic fracturing has taken place in two of the SDG and E wells and at least one other well nearby.

  3. Genital tract reservoirs. (United States)

    Galvin, Shannon R; Cohen, Myron S


    The purpose of this article is to review recent findings about HIV in the genital tract. HIV is primarily a sexually transmitted disease, and the efficiency of transmission must reflect the biology of the genital tract. In addition, it has become increasingly clear that the male and female genital tract represent a unique reservoir that requires independent and detailed study. This review will address new data on the source of HIV in the genital tract, factors that affect HIV genital viral burden, ways that genital HIV differs from circulating HIV, drug resistance in the genital tract, and new insights and models of genital HIV transmission and immune response. Understanding how HIV infects, resides, and survives in the genital milieu is critical to understanding the disease itself, and devising ways to halt its spread.


    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi


    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  5. Reservoir pressure evolution model during exploration drilling

    Directory of Open Access Journals (Sweden)

    Korotaev B. A.


    Full Text Available Based on the analysis of laboratory studies and literature data the method for estimating reservoir pressure in exploratory drilling has been proposed, it allows identify zones of abnormal reservoir pressure in the presence of seismic data on reservoir location depths. This method of assessment is based on developed at the end of the XX century methods using d- and σ-exponentials taking into account the mechanical drilling speed, rotor speed, bit load and its diameter, lithological constant and degree of rocks' compaction, mud density and "regional density". It is known that in exploratory drilling pulsation of pressure at the wellhead is observed. Such pulsation is a consequence of transferring reservoir pressure through clay. In the paper the mechanism for transferring pressure to the bottomhole as well as the behaviour of the clay layer during transmission of excess pressure has been described. A laboratory installation has been built, it has been used for modelling pressure propagation to the bottomhole of the well through a layer of clay. The bulge of the clay layer is established for 215.9 mm bottomhole diameter. Functional correlation of pressure propagation through the layer of clay has been determined and a reaction of the top clay layer has been shown to have bulge with a height of 25 mm. A pressure distribution scheme (balance has been developed, which takes into account the distance from layers with abnormal pressure to the bottomhole. A balance equation for reservoir pressure evaluation has been derived including well depth, distance from bottomhole to the top of the formation with abnormal pressure and density of clay.

  6. Advances in photonic reservoir computing

    Directory of Open Access Journals (Sweden)

    Van der Sande Guy


    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  7. Occurrence, seasonal variation and risk assessment of antibiotics in the reservoirs in North China. (United States)

    Li, Nan; Zhang, Xinbo; Wu, Wei; Zhao, Xinhua


    The occurrence and seasonal variability of five groups (tetracycline, quinolone, chloramphenicol, macrolide and sulfonamide) of antibiotics were investigated in the surface water of four reservoirs. The dissolved concentrations of 29 antibiotics were in the ngL(-1) level. Trace levels of all target antibiotics were analyzed using solid-phase extraction followed by liquid chromatography electrospray tandem mass spectrometry. All of the antibiotics were detected at all sampling sites, indicating widespread occurrence of antibiotics in the study area. The detection of florfenicol, josamycin, kitasamycin, spiramycin and sulfameter is the first report of these compounds in reservoir samples. The results showed an association between the presence of some antibiotics at Panjiakou reservoir and cage culture of fish. Twenty-three types of antibiotics showed significant seasonal variations (pantibiotics detected could cause very low risk to algae, daphnid and fish. Further health risk need to be investigated because these reservoirs are drinking water sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Dissolved Concentration Limits of Radioactive Elements

    Energy Technology Data Exchange (ETDEWEB)

    Y. Chen; E.R. Thomas; F.J. Pearson; P.L. Cloke; T.L. Steinborn; P.V. Brady


    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of radioactive elements under possible repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, and measurements made in laboratory experiments and field work. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 radioactive elements (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium), which are important to calculated dose. Model outputs are mainly in the form of look-up tables plus one or more uncertainty terms. The rest are either in the form of distributions or single values. The results of this analysis are fundamental inputs for total system performance assessment to constrain the release of these elements from waste packages and the engineered barrier system. Solubilities of plutonium, neptunium, uranium, americium, actinium, thorium, protactinium, lead, and radium have been re-evaluated using the newly updated thermodynamic database (Data0.ymp.R2). For all of the actinides, identical modeling approaches and consistent environmental conditions were used to develop solubility models in this revision. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, activity coefficients, and selection of solubility controlling phase have been quantified or otherwise addressed. Moreover, a new blended plutonium solubility model has been developed in this revision, which gives a mean solubility that is three orders of magnitude lower than the plutonium solubility model used for the Total System Performance Assessment for the Site Recommendation. Two alternative neptunium solubility models have also been

  9. Gravity observations for hydrocarbon reservoir monitoring

    NARCIS (Netherlands)

    Glegola, M.A.


    In this thesis the added value of gravity observations for hydrocarbon reservoir monitoring and characterization is investigated. Reservoir processes and reservoir types most suitable for gravimetric monitoring are identified. Major noise sources affecting time-lapse gravimetry are analyzed. The

  10. Riverine dissolved carbon concentration and yield in subtropical catchments, Taiwan (United States)

    Chen, Pei-Hao; Shih, Yu-ting; Huang, -Chuan, Jr.


    Dissolved carbon is not highly correlated to carbon cycle, but also a critical water quality indicator and affected by interaction of terrestrial and aquatic environment at catchment scale. However, the rates and extent of the dissolved carbon export are still poorly understood and scarcely quantified especially for typhoon events. In this study, regular and events' data of riverine dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) were monitored to estimate the export. Meanwhile, the hydrological model and mixing model were used for determination of DOC and DIC flow pathways at 3 sites of Tsengwen reservoir in southern Taiwan in 2014-2015. Results showed that the mean DOC concentration was 1.5 - 2.2 mg l-1 (flow weighted) without seasonal variation. The average DOC yield was 3.1 ton-C km-2 yr-1. On the other hand, DIC concentration ranged from 15 to 25.8 mg l-1, but DIC concentration in dry season was higher than wet season. Mean annual DIC yield was 51 ton-C km-2 yr-1. The export-ratio of DOC:DIC was 1:16.5, which was extremely lower than that of worldwide large rivers (DOC:DIC=1:4.5 in average) and other mountainous rivers (DOC:DIC=1:4.6 in average). Both DOC and DIC concentration showed the dramatically discrepant change in typhoon events. The DOC concentration increased to 4-8 folds rapidly before the flood peak. However, DIC concentration was diluted to one third with discharge simultaneously and returned slowly to base concentration in more than a week. According to the hydrological model, events contributed 14.6% of the annual discharge and 21.9% and 11.1% of DOC and DIC annual flux, respectively. Furthermore, 68.9% of events' discharge derived from surface runoff which carried out 91.3% of DOC flux and 51.1% of DIC flux. It implied that increases of surface runoff transported DOC form near soil surface, but diluted DIC concentration likely implied the contribution of groundwater. Our study characterized the specialty of dissolved carbon

  11. Reservoir Sedimentation Based on Uncertainty Analysis


    Farhad Imanshoar; Afshin Jahangirzadeh; Hossein Basser; Shatirah Akib; Babak Kamali; Tabatabaei, Mohammad Reza M.; Masoud Kakouei


    Reservoir sedimentation can result in loss of much needed reservoir storage capacity, reducing the useful life of dams. Thus, sufficient sediment storage capacity should be provided for the reservoir design stage to ensure that sediment accumulation will not impair the functioning of the reservoir during the useful operational-economic life of the project. However, an important issue to consider when estimating reservoir sedimentation and accumulation is the uncertainty involved in reservoir ...

  12. Water resources review: Ocoee reservoirs, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Cox, J.P.


    Tennessee Valley Authority (TVA) is preparing a series of reports to make technical information on individual TVA reservoirs readily accessible. These reports provide a summary of reservoir purpose and operation; physical characteristics of the reservoir and watershed; water quality conditions; aquatic biological conditions; and designated, actual and potential uses of the reservoir and impairments of those use. This reservoir status report addressed the three Ocoee Reservoirs in Polk County, Tennessee.

  13. How reservoirs alter drinking water quality: Organic matter sources, sinks, and transformations (United States)

    Kraus, Tamara E.C.; Bergamaschi, Brian A.; Hernes, Peter J.; Doctor, Daniel H.; Kendall, Carol; Downing, Bryan D.; Losee, Richard F.


    Within reservoirs, production, transformation, and loss of dissolved organic matter (DOM) occur simultaneously. While the balance between production and loss determines whether a reservoir is a net sink or source of DOM, changes in chemical composition are also important because they affect DOM reactivity with respect to disinfection by-product (DBP) formation. The composition of the DOM pool also provides insight into DOM sources and processing, which can inform reservoir management. We examined the concentration and composition of DOM in San Luis Reservoir, a large off-stream impoundment of the California State Water Project. We used a wide array of DOM chemical tracers including dissolved organic carbon (DOC) concentration, trihalomethane and haloacetic acid formation potentials (THMFP and HAAFP, respectively), absorbance properties, isotopic composition, lignin phenol content, and structural groupings determined by 13C nuclear magnetic resonance (NMR). There were periods when the reservoir was a net source of DOC due to the predominance of algal production (summer), a net sink due to the predominance of degradation (fall–winter), and balanced between production and consumption (spring). Despite only moderate variation in bulk DOC concentration (3.0–3.6 mg C/L), changes in DOM composition indicated that terrestrial-derived material entering the reservoir was being degraded and replaced by aquatic-derived DOM produced within the reservoir. Substantial changes in the propensity of the DOM pool to form THMs and HAAs illustrate that the DBP precursor pool was not directly coupled to bulk DOC concentration and indicate that algal production is an important source of DBP precursors. Results suggest reservoirs have the potential to attenuate DOM amount and reactivity with respect to DBP precursors via degradative processes; however, these benefits can be decreased or even negated by the production of algal-derived DOM.

  14. Evaluation of Five Treatment Plants for the Removal of Microcystins in Drinking Water

    Directory of Open Access Journals (Sweden)

    Manuel Álvarez Cortiñas


    Full Text Available In Galicia there are supplies that collect water from reservoirs showing growth of cyanobacteria that could produce toxins. The drinking water treatment plants (DWTPs of these supplies should provide adequate treatment and be subjected to maintenance. WHO guidelines make recommendations on the most suitable treatments for removing microcystins. The Department of Health developed a protocol of action against these events jointly with water basin authorities. 4 reservoirs and five treatment plants were identified for this study. The treatments of the plants, the maintenance carried out at the DWTPs and the results for sestonic and dissolved toxins analyzed by the Public Health Laboratory of Galicia in the reservoirs near the point of collection, before the treatment plants and after them, during the 2013-2014 biennium were evaluated.

  15. Development and field testing of a chemical system for enhanced oil recovery. Phase 1. Polymer evaluation and field trial in the reservoir Eddesse-Nord. Final report. Entwicklung und Einsatz eines chemischen Systems zur Tertiaerentoelung von Erdoellagerstaetten. Steigerung des Ausbeutegrades am Beispiel der Lagerstaette Eddesse-Nord. Phase 1. Polymerfluten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Westerkamp, A.; Littmann, W.


    As a result of thorough petrophysical and stratigraphic evaluation, the wealden sand M of the north german oilfield Eddesse Nord has been found to be a suitable model reservoir for performing a polymer pilot project. The evaluation of the most suitable polymer for this highly saline reservoir was made by chemical optimization of products within the classes of acrylamide copolymers, cellulosics and biopolysaccharides. The final choice was a xanthan gum, that could be optimally adjusted to the reservoir conditions with respect to flow behaviour in the model formation. A reservoir simulation study was performed using a computer model with polymer option. After successful history matching, prediction runs were carried out to evaluate the flood performance and to design the flood parameters like slug size, polymer concentration, injection rate and flow pattern. Injection facilities were designed and installed in the field. The injection of a water preslug was commenced in September 1984. During the water flood phase a secondary gas cap was displaced, which had developed during primary production, and additional data for adjustment of the computer simulation program could be collected. Polymer injection started in October 1985 and was completed by May 1988 after injection of 15 500 m{sup 3} of polymer solution. No injectivity problems occured during polymer injection. The pressure trace and water cut reduction in the three production wells matched very well the predictions of the simulation program. (orig.) With 20 tabs., 83 figs.

  16. Influence of limnological zones on the spatial distribution of fish assemblages in three Brazilian reservoirs

    Directory of Open Access Journals (Sweden)

    Bárbara Becker


    Full Text Available Reservoirs can have both positive and negative effects on differing fish species depending on the species concerned and reservoir morphology, flow regime, and basin location.  We assessed the influence of limnological zones on the ichthyofauna of three large Neotropical reservoirs in two different river basins. We sampled fish through use of gill nets set at 40 systematically selected sites on each reservoir. We used satellite images, algae, and suspended solids concentrations to classify those sites as lacustrine or riverine. We observed significant differences in assemblage composition between riverine and lacustrine zones of each reservoir. We either tested if the same region (lacustrine or riverine showed the same patterns in different reservoirs. In São Simão, the riverine zone produced greater abundances of native species, long-distance migratory species, diversity, and richness, whereas the lacustrine zone supported greater total and non-native species abundances. Conversely, in Três Marias, the riverine zone supported greater total and non-native species abundances, whereas the others traits evaluated did not differ significantly between zones. Only lacustrine sites occurred in Volta Grande Reservoir. The same zones in the three reservoirs usually had significantly different patterns in the traits evaluated. The differences in spatial patterns observed between reservoirs could be explained partly by the differing morphologies (complex versus linear, the differential influence of tributaries of each reservoir and basin positions (presence or absence of upstream dams of the reservoirs.

  17. Limnological characteristics of a reservoir in semiarid Northeastern Brazil subject to intensive tilapia farming (Orechromis niloticus Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Luis Artur Valões Bezerra


    Full Text Available AIM: There is currently no consensus regarding the physical and chemical variability of tropical reservoirs. In semiarid Northeastern Brazil, reservoirs are among other things used for human consumption, industrial water supply and intensive fish farming, all of which can impact water quality. The objective of this study was to evaluate the physical and chemical variability of the water in Sítios Novos, a reservoir in semiarid Northeastern Brazil, comparing samples collected in areas of intensive tilapia (Oreochromis niloticus farming to samples from areas not directly impacted by aquaculture, in both the dry and the rainy season. METHODS: Between October 2010 and July 2011, data were collected on temperature, conductivity, pH, turbidity, salinity, chlorophyll a, dissolved oxygen, oxygen demand, total phosphorus and total nitrogen levels in the water column using a multiparametric probe at four different sampling locations. Physical and chemical differences between the four locations were evaluated with the Kruskal-Wallis (KW test and Dunn's post test, while the t test, followed by Welchʼs correction, was used to compare samples collected in different seasons. RESULTS: No influence of intensive aquaculture was detected when comparing sampling locations near fish farms (180C and 300C to locations not directly impacted by aquaculture (LIMN1, near the dam, and LIMN2, near the debouch of the São Gonçalo river. However, the sampling locations differed significantly (p<0.05 with regard to conductivity, pH, turbidity and chlorophyll a levels. CONCLUSIONS: The physical and chemical variability was greater between seasons than between locations when the data were analyzed with the t test. That analysis showed significant differences for 22 of 40 comparisons between the 10 physical and chemical parameters in the two seasons at the four sampling locations. In conclusion, the physical and chemical variability registered for the Sítios Novos reservoir

  18. Reservoir age variations and stable isotope values of bulk sediment in a core from the Limfjord, Denmark

    DEFF Research Database (Denmark)

    Philippsen, Bente; Olsen, Jesper; Rasmussen, Peter

    on radiocarbon dating of shells and on stable isotope measurements of bulk sediment from 7400 to 1300 cal BP. Reservoir ages in coastal waters and estuaries can differ considerably from the global model ocean. The seas around Denmark have a reservoir age of c. 400 years, while a hardwater effect of a few...... of shells, compared to a terrestrial age model, resulted in reservoir ages with Delta-R values between -150 and +320 years. The d13C and C/N values of bulk organic matter follow a line which endpoints are the values of terrestrial and marine plants, respectively. The relative contribution of the two sources...... thousand years is possible for freshwater with a high content of dissolved carbonate. On the other hand, freshwater without a significant content of 14C-dead carbon does not have a reservoir age. In coastal waters, the different water sources mix and produce highly variable reservoir ages. Due to Holocene...


    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot


    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

  20. Small reservoir effects on headwater water quality in the rural-urban fringe, Georgia Piedmont, USA

    Directory of Open Access Journals (Sweden)

    Dr.. Amber R. Ignatius, Geographer


    Full Text Available Small reservoirs are prevalent landscape features that affect the physical, chemical, and biological characteristics of headwater streams. Tens of thousands of small reservoirs, often less than a hectare in size, were constructed over the past century within the United States. While remote-sensing and geographic-mapping technologies assist in identifying and quantifying these features, their localized influence on water quality is uncertain. We report a year-long physicochemical study of nine small reservoirs (0.15–2.17 ha within the Oconee and Broad River Watersheds in the Georgia Piedmont. Study sites were selected along an urban-rural gradient with differing amounts of agricultural, forested, and developed land covers. Sites were sampled monthly for discharge and inflow/outflow water quality parameters (temperature, specific conductance, pH, dissolved oxygen, turbidity, alkalinity, total phosphorus, total nitrogen, nitrate, ammonium. While the proportion of developed land cover within watersheds had positive correlations with reservoir specific conductivity values, agricultural and forested land covers showed correlations (positive and negative, respectively with reservoir alkalinity, total nitrogen, nitrate, and specific conductivity. The majority of outflow temperatures were warmer than inflows for all land uses throughout the year, especially in the summer. Outflows had lower nitrate concentrations, but higher ammonium. The type of outflow structure was also influential; top-release dams showed higher dissolved oxygen and pH than bottom-release dams. Water quality effects were still evident 250 m below the dam, albeit reduced.

  1. [Summer Greenhouse Gases Exchange Flux Across Water-air Interface in Three Water Reservoirs Located in Different Geologic Setting in Guangxi, China]. (United States)

    Li, Jian-hong; Pu, Jun-bing; Sun, Ping-an; Yuan, Dao-xian; Liu, Wen; Zhang, Tao; Mo, Xue


    Due to special hydrogeochemical characteristics of calcium-rich, alkaline and DIC-rich ( dissolved inorganic carbon) environment controlled by the weathering products from carbonate rock, the exchange characteristics, processes and controlling factors of greenhouse gas (CO2 and CH4) across water-air interface in karst water reservoir show obvious differences from those of non-karst water reservoir. Three water reservoirs (Dalongdong reservoir-karst reservoir, Wulixia reservoir--semi karst reservoir, Si'anjiang reservoir-non-karst reservoir) located in different geologic setting in Guangxi Zhuang Autonomous Region, China were chosen to reveal characteristics and controlling factors of greenhouse gas exchange flux across water-air interface. Two common approaches, floating chamber (FC) and thin boundary layer models (TBL), were employed to research and contrast greenhouse gas exchange flux across water-air interface from three reservoirs. The results showed that: (1) surface-layer water in reservoir area and discharging water under dam in Dalongdong water reservoir were the source of atmospheric CO2 and CH4. Surface-layer water in reservoir area in Wulixia water reservoir was the sink of atmospheric CO2 and the source of atmospheric CH4, while discharging water under dam was the source of atmospheric CO2 and CH4. Surface-layer water in Si'anjiang water reservoir was the sink of atmospheric CO2 and source of atmospheric CH4. (2) CO2 and CH4 effluxes in discharging water under dam were much more than those in surface-layer water in reservoir area regardless of karst reservoir or non karst reservoir. Accordingly, more attention should be paid to the CO2 and CH4 emission from discharging water under dam. (3) In the absence of submerged soil organic matters and plants, the difference of CH4 effluxes between karst groundwater-fed reservoir ( Dalongdong water reservoir) and non-karst area ( Wulixia water reservoir and Si'anjiang water reservoir) was less. However, CO2

  2. [Morphologic changes in ileoanal reservoirs 2 years after their construction]. (United States)

    Enríquez Navascues, J M; Capote, L; Devesa, J M; Morales, V; Carda, P; Vicente, E; Ferrero, E


    A study was made of the histologic changes in the mucosa of the ileoanal reservoirs of 10 patients who 2 years earlier had undergone ileoanal anastomosis with a J reservoir for ulcerative colitis (CU). In biopsies of the reservoirs were evaluated: 1) basic morphologic changes; 2) morphometric differences with respect to normal ileal mucosa; 3) the immunohistochemical pattern (IHQ) (IgA, IgG, IgM and CEA) of the reservoir mucosa as compared to normal ileum, active ulcerative colitis. Crohn's disease and celiaca; 4) the possible existence of atypias or dysplasias of the reservoir mucosa; and 5) the number of argentaffin cells per field. The basic morphologic alteration consisted of colonic metaplasia. Reservoir biopsies exhibited partial (8 cases) or subtotal atrophy (2 cases) of the mucosa. With respect to the normal ileum there was a decrease in villi height (p less than 0.05), an increase in crypt depth (p less than 0.05) and a higher index of mucosal regeneration, with a larger number of cells and mitoses per crypt (p less than 0.05). Fifty percent of the reservoirs presented a chronic inflammatory pattern with an acute component in 30% of them. The immunohistochemical pattern of the reservoirs not inflamed was similar to that of normal ileum (IgA much greater than IgM greater than IgG) and that of the inflamed reservoirs was similar to that of intestinal inflammatory disease (marked increase in the IgG. CEA (similar to what?) an alteration of local immune homeostasis could have of the genesis of pictures of "pouchitis". No alarming signs of atypia or dysplasia were found, nor changes in the population of argentaffin cells.

  3. Advanced reservoir characterization and evaluation of CO{sub 2} gravity drainage in the naturally fractured Spraberry Trend Area. First annual technical progress report, September 1, 1995--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Schechter, D.S.


    The overall goal of this project is to assess the economic feasibility of CO{sub 2} flooding the naturally fractured Spraberry Trend Area in West Texas. This objective is being accomplished by conducting research in four areas: (1) extensive characterization of the reservoirs, (2) experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, (3) analytical and numerical simulation of Spraberry reservoirs, and, (4) experimental investigations on CO{sub 2} gravity drainage in Spraberry whole cores. This report provides results of the first year of the five-year project for each of the four areas.

  4. Bioavailability and characterization of dissolved organic nitrogen and dissolved organic phosphorus in wastewater effluents. (United States)

    Qin, Chao; Liu, Haizhou; Liu, Lei; Smith, Scott; Sedlak, David L; Gu, April Z


    There is still a great knowledge gap in the understanding of characteristics and bioavailability of dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) in wastewater effluents, which surmise implications related to both discharge regulation and treatment practice. In this study, we simultaneously investigated the characteristics and bioavailability of both DON and DOP, with separated hydrophilic versus hydrophobic fractions, in highly-treated wastewater effluents for the first time. The tertiary effluents from two wastewater treatment plants were separated into two fractions by XAD-8 resin coupled with anion exchange resin based on the hydrophobicity. Results showed that the majority of DON was present in hydrophilic forms while more DOP existed in hydrophobic forms. Hydrophilic DON contributed to 64.0%-72.2% of whole DON, while hydrophobic DOP accounted for 61.4%-80.7% of total DOP for the two plants evaluated. The effluents and their fractions were then subject to bioavailability assay based on 14-day algae growth. The results indicated that majority (~73-75%) of the effluent DOP, particularly the hydrophobic fraction with lower C/P ratio was more likely to be bioavailable for algal growth. The bioavailable fraction of DON varied widely (28%-61%) for the two plants studied and the hydrophilic fraction with lower C/N ratio seemed to exhibit higher bioavailability than the hydrophobic portion. The differences in bioavailable DON and DOP distributions of effluents from those two plants could be attributed to different receiving effluent compositions and wastewater treatment processes. In addition, fluorescence excitation-emission matrices (EEMs) combined with parallel factor analysis (PARAFAC) were used to characterize the dissolved organic matter (DOM) in wastewater effluent, which provided insights into the nature of organic matter in wastewater samples with different characteristics and originating sources. Copyright © 2014. Published by

  5. Carbonized eggshell membrane as a natural polysulfide reservoir for highly reversible Li-S batteries. (United States)

    Chung, Sheng-Heng; Manthiram, Arumugam


    Carbonized sucrose-coated eggshell membranes (CSEMs) consisting of natural micropores function well as a polysulfide reservoir in Li/dissolved polysulfide cells. The bottom CSEM current collector encapsulates the active material, while the upper CSEM inhibitor intercepts the migrating polysulfides. This design with CSEM allows the dissolved polysulfides to be localized and the electrochemical reactions within the cathode region to be stabilized, resulting in high discharge capacity, long-term cycle stability, and high sulfur loading. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Temporal variability in water quality parameters--a case study of drinking water reservoir in Florida, USA. (United States)

    Toor, Gurpal S; Han, Lu; Stanley, Craig D


    Our objective was to evaluate changes in water quality parameters during 1983-2007 in a subtropical drinking water reservoir (area: 7 km(2)) located in Lake Manatee Watershed (area: 338 km(2)) in Florida, USA. Most water quality parameters (color, turbidity, Secchi depth, pH, EC, dissolved oxygen, total alkalinity, cations, anions, and lead) were below the Florida potable water standards. Concentrations of copper exceeded the potable water standard of water quality threshold of 20 μg l(-1). Concentrations of total N showed significant increase from 1983 to 1994 and a decrease from 1997 to 2007. Total P showed significant increase during 1983-2007. Mean concentrations of total N (n = 215; 1.24 mg l(-1)) were lower, and total P (n = 286; 0.26 mg l(-1)) was much higher than the EPA numeric criteria of 1.27 mg total N l(-1) and 0.05 mg total P l(-1) for Florida's colored lakes, respectively. Seasonal trends were observed for many water quality parameters where concentrations were typically elevated during wet months (June-September). Results suggest that reducing transport of organic N may be one potential option to protect water quality in this drinking water reservoir.

  7. 2011 Groundhog Reservoir Bathymetric Contours (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey performed a bathymetric survey of Groundhog Reservoir using a man-operated boat-mounted multibeam echo sounder integrated with a global...

  8. Cycling downwards - dissolved organic matter in soils

    NARCIS (Netherlands)

    Kaiser, K.; Kalbitz, K.


    Dissolved organic matter has been recognized as mobile, thus crucial to translocation of metals, pollutants but also of nutrients in soil. We present a conceptual model of the vertical movement of dissolved organic matter with soil water, which deviates from the view of a chromatographic stripping

  9. Hydrolysis kinetics of dissolved polymer substrates

    NARCIS (Netherlands)

    Sanders, W.T.M.; Zeeman, G.; Lettinga, G.


    In this paper, the relation between the hydrolysis rate of dissolved polymer substrates and sludge concentration was investigated in two ways, viz. by laboratory experiments and by computer simulations. In the simulations, the hydrolysis of dissolved polymer components was regarded as a general

  10. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    KAUST Repository

    Hussain, Maaruf


    Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to


    Energy Technology Data Exchange (ETDEWEB)

    T. Scott Hickman; James J. Justice


    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  12. Climate variability, soil conservation, and reservoir sedimentation (United States)

    Rivers carry sediments which, upon entering a reservoir, settle to the bottom. The process of deposition and gradual accumulation of sediments in the reservoir is referred to as reservoir sedimentation. As reservoir sedimentation progresses, the storage capacity allocated for sediment deposition wil...

  13. Improving reservoir conformance using gelled polymer systems

    Energy Technology Data Exchange (ETDEWEB)

    Green, D.W.; Willhite, G.P.


    The general objectives are to (1) to identify and develop gelled polymer systems which have potential to improve reservoir conformance of fluid displacement processes, (2) to determine the performance of these systems in bulk and in porous media, and (3) to develop methods to predict the capability of these systems to recover oil from petroleum reservoirs. This work focuses on three types of gel systems - an aqueous polysaccharide (KUSPI) system that gels as a function of pH, the chromium-based system where polyacrylamide and xanthan are crosslinked by CR(III) and an organic crosslinked system. Development of the KUSPI system and evaluation and identification of a suitable organic crosslinked system will be done. The laboratory research is directed at the fundamental understanding of the physics and chemistry of the gelation process in bulk form and in porous media. This knowledge will be used to develop conceptual and mathematical models of the gelation process. Mathematical models will then be extended to predict the performance of gelled polymer treatments in oil reservoirs. Accomplishments for this period are presented for the following tasks: development and selection of gelled polymer systems, physical and chemical characterization of gel systems; and mathematical modeling of gel systems.

  14. Geothermal reservoir simulation to enhance confidence in predictions for nuclear waste disposal


    Kneafsey, Timothy J.; Pruess, Karsten; O?Sullivan, Michael J.; Bodvarsson, Gudmundur S.


    Numerical simulation of geothermal reservoirs is useful and necessary in understanding and evaluating reservoir structure and behavior, designing field development, and predicting performance. Models vary in complexity depending on processes considered, heterogeneity, data availability, and study objectives. They are evaluated using computer codes written and tested to study single and multiphase flow and transport under nonisothermal conditions. Many flow and heat transfer processes mod...

  15. Modeling CO2 Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO2 Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W. Lynn [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Rush, Jason [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Raney, Jennifer [University Of Kansas Center For Research, Inc. Lawrence, KS (United States)


    surface lineaments. b. Provide real-time analysis of the project dataset, including automated integration and viewing of well logs, core, core analyses, brine chemistry, and stratigraphy using the Java Profile app. A cross-section app allows for the display of log data for up to four wells at a time. 6. Integrated interpretations from the project’s interactive web-based mapping system to gain insights to aid in assessing the efficacy of geologic CO2 storage in Kansas and insights toward understanding recent seismicity to aid in evaluating induced vs. naturally occurring earthquakes. 7. Developed a digital type-log system, including web-based software to modify and refine stratigraphic nomenclature to provide stakeholders a common means for communication about the subsurface. 8. Contracted use of a nuclear magnetic resonance (NMR) log and ran it slowly to capture response and characterize larger pores common for carbonate reservoirs. Used NMR to extend core analyses to apply permeability, relative permeability to CO2, and capillary pressure to the major rock types, each uniquely expressed as a reservoir quality index (RQI), present in the Mississippian and Arbuckle rocks. 9. Characterized and evaluated the possible role of microbes in dense brines. Used microbes to compliment H/O stable isotopes to fingerprint brine systems. Used perforation/swabbing to obtain samples from multiple hydrostratigraphic units and confirmed equivalent results using less expensive drill stem tests (DST). 10. Used an integrated approach from whole core, logs, tests, and seismic to verify and quantify properties of vuggy, brecciated, and fractured carbonate intervals. 11. Used complex geocellular static and dynamic models to evaluate regional storage capacity using large parallel processing. 12. Carbonates are complex reservoirs and CO2-EOR needs to move to the next generation to increase effectiveness of CO2 and efficiency and safety of the injection.

  16. Importance of dissolved organic carbon for phytoplankton nutrition in a eutrophic reservoir

    Czech Academy of Sciences Publication Activity Database

    Znachor, Petr; Nedoma, Jiří


    Roč. 32, č. 3 (2010), s. 367-376 ISSN 0142-7873 R&D Projects: GA ČR(CZ) GP206/07/P407; GA ČR(CZ) GA206/06/0462; GA ČR(CZ) GA206/05/0007; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517 Keywords : mixotrophy * phytoplankton * PDMPO * DOC * autoradiography * diatom s Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.749, year: 2010

  17. Carbon dioxide emissions from lakes and reservoirs of China: A regional estimate based on the calculated pCO2 (United States)

    Wen, Zhidan; Song, Kaishan; Shang, Yingxin; Fang, Chong; Li, Lin; Lv, Lili; Lv, Xianguo; Chen, Lijiang


    The role of inland water in CO2 exchange with the atmosphere was evaluated on the basis of calculated partial pressure of CO2 (pCO2) from sampling of 207 lakes and 84 reservoirs across China in late summer. The results suggested that almost 60% of these water bodies were supersaturated with CO2 with respect to atmosphere, and the collected reservoirs samples exhibited higher mean pCO2 than lakes. The mean pCO2 in fresh water lakes was about 3.5 times of the value in saline lakes. The lakes and reservoirs were divided into five groups (Inner Mongolia -Xinjiang plateau region, Tibetan Plateau region, Northeastern plain and mountainous region, Yunnan- Guizhou Plateau region, and Eastern plain region). The Yunnan- Guizhou Plateau region showed the highest pCO2 compared with other regions, most likely due to the typical karst landforms, karst processes may promote aqueous CO2 concentration, and karstification has a significant effect on the capture of atmospheric CO2. Inner Mongolia-Xinjiang plateau and Tibetan Plateau region reserviors showed negative CO2 flux to atmosphere, other waters in this study all supersaturated with CO2 with respect to the atmosphere. A which We analyzed the relationship between pCO2 and environmental variables, and results showed that some indicators had correlations with pCO2 in individual region such as total phosphorus, dissolved organic matter, and total suspended solids, but the relationship could not be observed with all surveyed waters. This indicated that it might be much more effective in a smaller regional scale than the broadened scale when the environmental factors were used as the predictor of pCO2 in lakes. Therefore, the common algorithm that extrapolates CO2 concentration or emission flux from the study region to a wider scale might not be accurate because of the changes in the environmental and water quality conditions.

  18. Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir. (United States)

    Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, David; Mrkvička, Tomáš


    Man-made reservoirs are common across the world and provide a wide range of ecological services. Environmental conditions in riverine reservoirs are affected by the changing climate, catchment-wide processes and manipulations with the water level, and water abstraction from the reservoir. Long-term trends of environmental conditions in reservoirs thus reflect a wider range of drivers in comparison to lakes, which makes the understanding of reservoir dynamics more challenging. We analysed a 32-year time series of 36 environmental variables characterising weather, land use in the catchment, reservoir hydrochemistry, hydrology and light availability in the small, canyon-shaped Římov Reservoir in the Czech Republic to detect underlying trends, trend reversals and regime shifts. To do so, we fitted linear and piecewise linear regression and a regime shift model to the time series of mean annual values of each variable and to principal components produced by Principal Component Analysis. Models were weighted and ranked using Akaike information criterion and the model selection approach. Most environmental variables exhibited temporal changes that included time-varying trends and trend reversals. For instance, dissolved organic carbon showed a linear increasing trend while nitrate concentration or conductivity exemplified trend reversal. All trend reversals and cessations of temporal trends in reservoir hydrochemistry (except total phosphorus concentrations) occurred in the late 1980s and during 1990s as a consequence of dramatic socioeconomic changes. After a series of heavy rains in the late 1990s, an administrative decision to increase the flood-retention volume of the reservoir resulted in a significant regime shift in reservoir hydraulic conditions in 1999. Our analyses also highlight the utility of the model selection framework, based on relatively simple extensions of linear regression, to describe temporal trends in reservoir characteristics. This approach can

  19. Structure and dynamics of phytoplankton community in the Botafogo reservoir-Pernambuco-Brazil


    Lira, Giulliari Alan da Silva Tavares; Bittencourt-Oliveira,Maria do Carmo; MOURA, Ariadne do Nascimento


    The aim of the present study was to investigate the structure and dynamics of the phytoplankton in the Botafogo reservoir-PE-Brazil. Phytoplankton assemblages were identified from current literature and density was estimated using an inverted microscope. Concurrently to the sampling of biotic variables, measurements of abiotic parameters, such as water temperature, dissolved oxygen and pH, were determined using field probes and transparency was determined with a Secchi disk. Total phosphorus ...

  20. Modelling CO2emissions from water surface of a boreal hydroelectric reservoir. (United States)

    Wang, Weifeng; Roulet, Nigel T; Kim, Youngil; Strachan, Ian B; Del Giorgio, Paul; Prairie, Yves T; Tremblay, Alain


    To quantify CO 2 emissions from water surface of a reservoir that was shaped by flooding the boreal landscape, we developed a daily time-step reservoir biogeochemistry model. We calibrated the model using the measured concentrations of dissolved organic and inorganic carbon (C) in a young boreal hydroelectric reservoir, Eastmain-1 (EM-1), in northern Quebec, Canada. We validated the model against observed CO 2 fluxes from an eddy covariance tower in the middle of EM-1. The model predicted the variability of CO 2 emissions reasonably well compared to the observations (root mean square error: 0.4-1.3gCm -2 day -1 , revised Willmott index: 0.16-0.55). In particular, we demonstrated that the annual reservoir surface effluxes were initially high, steeply declined in the first three years, and then steadily decreased to ~115gCm -2 yr -1 with increasing reservoir age over the estimated "engineering" reservoir lifetime (i.e., 100years). Sensitivity analyses revealed that increasing air temperature stimulated CO 2 emissions by enhancing CO 2 production in the water column and sediment, and extending the duration of open water period over which emissions occur. Increasing the amount of terrestrial organic C flooded can enhance benthic CO 2 fluxes and CO 2 emissions from the reservoir water surface, but the effects were not significant over the simulation period. The model is useful for the understanding of the mechanism of C dynamics in reservoirs and could be used to assist the hydro-power industry and others interested in the role of boreal hydroelectric reservoirs as sources of greenhouse gas emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Sampling from stochastic reservoir models constrained by production data

    Energy Technology Data Exchange (ETDEWEB)

    Hegstad, Bjoern Kaare


    When a petroleum reservoir is evaluated, it is important to forecast future production of oil and gas and to assess forecast uncertainty. This is done by defining a stochastic model for the reservoir characteristics, generating realizations from this model and applying a fluid flow simulator to the realizations. The reservoir characteristics define the geometry of the reservoir, initial saturation, petrophysical properties etc. This thesis discusses how to generate realizations constrained by production data, that is to say, the realizations should reproduce the observed production history of the petroleum reservoir within the uncertainty of these data. The topics discussed are: (1) Theoretical framework, (2) History matching, forecasting and forecasting uncertainty, (3) A three-dimensional test case, (4) Modelling transmissibility multipliers by Markov random fields, (5) Up scaling, (6) The link between model parameters, well observations and production history in a simple test case, (7) Sampling the posterior using optimization in a hierarchical model, (8) A comparison of Rejection Sampling and Metropolis-Hastings algorithm, (9) Stochastic simulation and conditioning by annealing in reservoir description, and (10) Uncertainty assessment in history matching and forecasting. 139 refs., 85 figs., 1 tab.

  2. Soybean yield in relation to distance from the Itaipu reservoir (United States)

    de Faria, Rogério Teixeira; Junior, Ruy Casão; Werner, Simone Silmara; Junior, Luiz Antônio Zanão; Hoogenboom, Gerrit


    Crops close to small water bodies may exhibit changes in yield if the water mass causes significant changes in the microclimate of areas near the reservoir shoreline. The scientific literature describes this effect as occurring gradually, with higher intensity in the sites near the shoreline and decreasing intensity with distance from the reservoir. Experiments with two soybean cultivars were conducted during four crop seasons to evaluate soybean yield in relation to distance from the Itaipu reservoir and determine the effect of air temperature and water availability on soybean crop yield. Fifteen experimental sites were distributed in three transects perpendicular to the Itaipu reservoir, covering an area at approximately 10 km from the shoreline. The yield gradient between the site closest to the reservoir and the sites farther away in each transect did not show a consistent trend, but varied as a function of distance, crop season, and cultivar. This finding indicates that the Itaipu reservoir does not affect the yield of soybean plants grown within approximately 10 km from the shoreline. In addition, the variation in yield among the experimental sites was not attributed to thermal conditions because the temperature was similar within transects. However, the crop water availability was responsible for higher differences in yield among the neighboring experimental sites related to water stress caused by spatial variability in rainfall, especially during the soybean reproductive period in January and February.

  3. Numerical modeling of fluid effects on seismic properties of fractured magmatic geothermal reservoirs


    M. Grab; B. Quintal; E. Caspari; H. Maurer; Greenhalgh, S


    Seismic investigations of geothermal reservoirs over the last 20 years have sought to interpret the resulting tomograms and reflection images in terms of the degree of reservoir fracturing and fluid content. Since the former provides the pathways and the latter acts as the medium for transporting geothermal energy, such information is needed to evaluate the quality of the reservoir. In conventional rock physics-based interpretations, this hydro-mechanical information is appr...

  4. basement reservoir geometry and properties (United States)

    Walter, bastien; Geraud, yves; Diraison, marc


    Basement reservoirs are nowadays frequently investigated for deep-seated fluid resources (e.g. geothermal energy, groundwater, hydrocarbons). The term 'basement' generally refers to crystalline and metamorphic formations, where matrix porosity is negligible in fresh basement rocks. Geothermal production of such unconventional reservoirs is controlled by brittle structures and altered rock matrix, resulting of a combination of different tectonic, hydrothermal or weathering phenomena. This work aims to characterize the petro-structural and petrophysical properties of two basement surface analogue case studies in geological extensive setting (the Albert Lake rift in Uganda; the Ifni proximal margin of the South West Morocco Atlantic coast). Different datasets, using field structural study, geophysical acquisition and laboratory petrophysical measurements, were integrated to describe the multi-scale geometry of the porous network of such fractured and weathered basement formations. This study points out the multi-scale distribution of all the features constituting the reservoir, over ten orders of magnitude from the pluri-kilometric scale of the major tectonics structures to the infra-millimetric scale of the secondary micro-porosity of fractured and weathered basements units. Major fault zones, with relatively thick and impermeable fault core structures, control the 'compartmentalization' of the reservoir by dividing it into several structural blocks. The analysis of these fault zones highlights the necessity for the basement reservoirs to be characterized by a highly connected fault and fracture system, where structure intersections represent the main fluid drainage areas between and within the reservoir's structural blocks. The suitable fluid storage areas in these reservoirs correspond to the damage zone of all the fault structures developed during the tectonic evolution of the basement and the weathered units of the basement roof developed during pre

  5. Vertical Distribution of Bacterial Community Diversity and Water Quality during the Reservoir Thermal Stratification

    Directory of Open Access Journals (Sweden)

    Hai-Han Zhang


    Full Text Available Reservoir thermal stratification drives the water temperature and dissolved oxygen gradient, however, the characteristic of vertical water microbial community during thermal stratification is so far poorly understood. In this work, water bacterial community diversity was determined using the Illumina Miseq sequencing technique. The results showed that epilimnion, metalimnion and hypolimnion were formed steadily in the JINPEN drinking water reservoir. Water temperature decreased steadily from the surface (23.11 °C to the bottom (9.17 °C. Total nitrogen ranged from 1.07 to 2.06 mg/L and nitrate nitrogen ranged from 0.8 to 1.84 mg/L. The dissolved oxygen concentration decreased sharply below 50 m, and reached zero at 65 m. The Miseq sequencing revealed a total of 4127 operational taxonomic units (OTUs with 97% similarity, which were affiliated with 15 phyla including Acidobacteria, Actinobacteria, Armatimonadetes, Bacteroidetes, Caldiserica, Chlamydiae, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria, and Verrucomicrobia. The highest Shannon diversity was 4.41 in 45 m, and the highest Chao 1 diversity was 506 in 5 m. Rhodobacter dominated in 55 m (23.24% and 65 m (12.58%. Prosthecobacter dominated from 0.5 to 50 m. The heat map profile and redundancy analysis (RDA indicated significant difference in vertical water bacterial community composition in the reservoir. Meanwhile, water quality properties including dissolved oxygen, conductivity, nitrate nitrogen and total nitrogen have a dramatic influence on vertical distribution of bacterial communities.

  6. Chemical quality and temperature of water in Flaming Gorge Reservoir, Wyoming and Utah, and the effect of the reservoir on the Green River (United States)

    Bolke, E.L.; Waddell, Kidd M.


    The major tributaries to Flaming Gorge Reservoir contribute an average of about 97 percent of the total streamflow and 82 percent of the total load of dissolved solids. The Green River is the largest tributary, and for the 1957-72 water years it contributed 81 percent of the total streamflow and 70 percent of the total load of dissolved solids. The principal constituents in the tributary streamflow are calcium and sulfate during periods of lowest flow and calcium and bicarbonate during periods of highest flow.Flaming Gorge Dam was closed in November 1962, and the most significant load changes of chemical constituents due to the net effect of inflow, outflow, leaching, and chemical precipitation in the reservoir have been load changes of sulfate and bicarbonate. The average increase of dissolved load of sulfate in the reservoir for the 1969-72 water years was 110,000 tons (99,790 t) per year, which was 40,000 tons (36,287 t) per year less than for the 1963-66 water years. The average decrease of dissolved load of bicarbonate in the reservoir for 1969-72 was 40,000 tons (36,287 t) per year, which was the same as the decrease for 1963-66.Anaerobic conditions were observed in the deep, uncirculated part of the reservoir near the dam during the 1971 and 1972 water years, and anaerobic or near-anaerobic conditions were observed near the confluence of the Blacks Fork and Green River during the summers of 1971 and 1972.The water in Flaming Gorge Reservoir is in three distinct layers, and the upper two layers (the epilimnion and the metalimnion) mixed twice during each of the 1971-72 water years. The two circulation periods were in the spring and fall. The water in the deepest layer (the hypolimnion) did not mix with the waters of the upper zones because the density difference was too great and because the deep, narrow shape of the basin probably inhibits mixing.The depletion of flow in the Green River downstream from Flaming Gorge Dam between closure of the dam and the end

  7. Hydrology and water quality of Elkhead Creek and Elkhead Reservoir near Craig, Colorado, July 1995-September 2001 (United States)

    Kuhn, Gerhard; Stevens, Michael R.; Elliott, John G.


    The U.S. Geological Survey, in cooperation with the Colorado River Water Conservation District, collected and analyzed baseline streamflow and water-quality information for Elkhead Creek and water-quality and trophic-state information for Elkhead Reservoir from July 1995 through September 2001. In the study area, Elkhead Creek is a meandering, alluvial stream dominated by snowmelt in mountainous headwaters that produces most of the annual discharge volume and discharge peaks during late spring and early summer. During most of water year 1996 (a typical year), daily mean discharge at station 09246400 (downstream from the reservoir) was similar to daily mean discharge at station 09246200 (upstream from the reservoir). Flow-duration curves for stations 09246200 and 09246400 were nearly identical, except for discharges less than about 10 cubic feet per second. Specific conductance generally had an inverse relation to discharge in Elkhead Creek. During late fall and winter when discharge was small and derived mostly from ground water, specific conductance was high, whereas during spring and early summer, when discharge was large and derived mostly from snowmelt, specific conductance was low. Water temperatures in Elkhead Creek were smallest during winter, about 0.0 degrees Celsius (oC), and largest during summer, about 20?25oC. Concentrations of major ions, nutrients, trace elements, organic carbon, and suspended sediment in Elkhead Creek indicated no substantial within-year variability and no substantial differences in variability from one year to the next. A seasonal pattern in the concentration data was evident for most constituents. The seasonal concentration pattern for most of the dissolved constituents followed the seasonal pattern of specific conductance, whereas some nutrients, some trace elements, and suspended sediment followed the seasonal pattern of discharge. Statistical differences between station 09246200 (upstream from the reservoir) and station


    Energy Technology Data Exchange (ETDEWEB)

    Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olsen; Deanna Combs; Dhiraj Dembla; Leonel Gomez


    The Bureau of Economic Geology and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plant that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data are being gathered during the demonstration phase to improve the accuracy of the reservoir model. The results of the demonstration are being closely monitored to provide a basis for improving the design of the HPAI field deployment plan. The results of the reservoir characterization field demonstration and monitoring program will be documented and widely disseminated to facilitate adoption of this technology by oil operators in the Permian Basin and elsewhere in the US.

  9. Identification of Environment Chase in Surround of Sermo Reservoir; and the Influence Possibility for Function and at the Age of Reservoi

    Directory of Open Access Journals (Sweden)

    Sudarmadji Sudarmadji


    Full Text Available Sermo reservoir is the only one belongs to Yogyakarta Special Province; it is relatively a new reservoir with the area of 1.9 kilometer square and its capacity of 25 million cubic meter: It started to operate since 1996 as flood control, irigation, water supply, tourism and fishery purposes. As a reservoir it could be considered to be a manmade lake, as its condition nearly similar to a lake. Since it operated (even during construction period there were some significant environmental changes within the reservoir and in the area around the reservoir due to the human activities. These changes could threat the sustainability of the reservoir itself This research aims to identiflr the human activities living around the reservoir and visitors coming to the area, and to evaluate the potensial of the activities to produce wastes which is discharging in into the reservoir; which may threat the sustainability of the reservoir: The observatorium in the field has been conducted in the area of the reservoir and its sorrounding. I t was firund fiom the observation that activities o f fishery using net (karamba, tourism altogether with its facilities, land use around the reservoir for agriculture purposes, mining of class C ore, have given a lot of contribution to wastes (liquid and solids and sediments into the reservoir: Those activities may cause water quality of the reservoir lo decrease as well as reducing the reservoir depth. Those situation was observed in the northern and north western parts of the reservoir Water quality degradation of the reservoir may threat reservoir as source of domestic water supply, while the sedimentation may reduce the life time of the reservoir The fishery and tourism activities was estimated as a main cause of water quality degradation, beside agricultural and domestic wastes originated from sattlement area around the reservoir: Sediments coming into the reservoir are derived fiom transported and movement of

  10. Application of Integrated Reservoir management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    B. Pregger; D. Davies; D. Moore; G. Freeman; J. Callard; J.W. Nevans; L. Doublet; R. Vessell; T. Blasingame


    Infill drilling if wells on a uniform spacing without regard to reservoir performance and characterization foes not optimize reservoir development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. New and emerging technologies, such as geostatistical modeling, rigorous decline curve analysis, reservoir rock typing, and special core analysis can be used to develop a 3-D simulation model for prediction of infill locations.

  11. The detailed analysis of natural radionuclides dissolved in spa waters of the Kłodzko Valley, Sudety Mountains, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Walencik-Łata, A., E-mail: [University of Silesia, Institute of Physics, Department of Nuclear Physics and Its Applications, Uniwersytecka 4 St., 40-007 Katowice (Poland); Kozłowska, B.; Dorda, J. [University of Silesia, Institute of Physics, Department of Nuclear Physics and Its Applications, Uniwersytecka 4 St., 40-007 Katowice (Poland); Przylibski, T.A. [Wrocław University of Technology, Faculty of Geoengineering, Mining and Geology, Division of Geology and Mineral Waters, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław (Poland)


    A survey was conducted to measure natural radioactivity in spa waters from the Kłodzko Valley. The main goal of this study was to determine the activity concentration of uranium, radium and radon isotopes in the investigated groundwaters. Samples were collected several times from 35 water intakes from 5 spas and 2 mineral water bottling plants. The authors examined whether the increased gamma radiation background, as well as the elevated values of radium and uranium content in reservoir rocks, have a significant impact on the natural radioactivity of these waters. The second objective of this research was to provide information about geochemistry of U, Ra, Rn radionuclides and the radiological and chemical risks incurred by ingestion of isotopes with drinking water. On the basis of results obtained, it is feasible to assess the health hazard posed by ingestion of natural radioactivity with drinking waters. Moreover, the data yielded by this research may be helpful in the process of verification of the application of these waters in balneotherapy. In addition, annual effective radiation doses resulting from the isotopes consumption were calculated on the basis of the evaluated activity concentrations. In dose assessment for uranium and radium isotopes, the authors provided values for different human age groups. The obtained uranium content in the investigated waters was compared with the currently valid regulations concerning the quality of drinking water. Based on the activity concentrations data, the activity isotopic ratios {sup 234}U/{sup 238}U, {sup 226}Ra/{sup 238}U, {sup 222}Rn/{sup 238}U, {sup 222}Rn/{sup 226}Ra and the correlations between radionuclides content were then examined. In brief, it may be concluded on the basis of the obtained results that radon solubility is inversely proportional to radium and uranium dissolution in environmental water circulation. The presented study allows conclusions to be drawn on the radionuclide circulation among

  12. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    in porous media. The main conclusion of most previous studies was that it is the rock wettability alteration towards more water wetting condition that helps improving the oil recovery. In the first step of this project, we focused on verifying this conclusion. Coreflooding experiments were carried out using...... imbibition rather than forced flooding. The objective of the third step of this project was to investigate the potential of high salinity waterflooding process by carrying out experiments with reservoir chalk samples. We carried out waterflooding instead of spontaneous imbibition using core plugs...... reservoirs by injecting brine of low salinity. However, this effect has not been thoroughly investigated for carbonates. At the final stage of this project, we have experimentally investigated the oil recovery potential of low salinity water flooding in the carbonate rocks. We used both reservoir carbonate...

  13. Dissolved Trace Metals in the Tay Estuary (United States)

    Owens, R. E.; Balls, P. W.


    Dissolved trace metals have been studied over an annual cycle in the relatively pristine Tay estuary (Scotland). The absence of a major anthropogenic signal has enabled some of the more subtle natural processes controlling trace metal distributions to be identified. Concentration ranges of dissolved metals in the Tay are similar to, or lower than, those observed in more industrialized estuaries. All metals behave non-conservatively in the Tay. Interactions with biogenic and detrital particulate phases are important in controlling dissolved trace metal concentrations. The degradation of organic matter appears to be particularly important for Cu. Removal of dissolved metals was observed in the turbidity maximum zone; a simple model was used to demonstrate that this could be accounted for by adsorption onto suspended particulate matter. At high salinity, coincident peaks of all six metals with ammonia and phosphate are attributed to sewage inputs from Dundee at the mouth of the estuary.

  14. Phytoplankton functional groups for ecological assessment in young sub-tropical reservoirs: case study of the Nam-Theun 2 Reservoir, Laos, South-East Asia

    Directory of Open Access Journals (Sweden)

    Joanna Martinet


    Full Text Available The early stages following the creation of reservoirs are typically physical and biological unstable periods due to the conversion from a lotic to a lentic ecosystem. The sub-tropical Nam Theun 2 Reservoir (Laos was impounded in 2008. Several limnological parameters were monitored from March 2009 to December 2011 in order to understand the evolution of the phytoplankton community. A strong inter annual variability of hydrodynamic pattern was observed. Rainfall and hydraulic balance were the main physical factors driving the community structure. Periods of highest hydraulic stability led to a phytoplankton biomasses increase. The first assemblages were dominated by the S-C-strategists reaching high biomasses but low diversity. Over the three years, phytoplankton became more diverse due to a diversification of ecological niches, mostly explained by a greater water transparency and a more stable thermal stratification. The applicability of functional groups for biomonitoring in this young sub-tropical reservoir was investigated and compared to a classical taxonomical approach. The dominant functional groups (Lo, A, E, F, N and P characterized the NT2 Reservoir as meso-oligotrophic with a tolerance to low nutrients supply. Our results support the hypothesis that a functional group approach is more informative than a species-based approach to assess trophic level and dissolved organic carbon concentrations in such reservoirs.

  15. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    DEFF Research Database (Denmark)

    Brandt, Anders; Swenning, Joar


    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  16. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    P. K. Pande


    Initial drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. These reservoirs are typically characterized by: o Large, discontinuous pay intervals o Vertical and lateral changes in reservoir properties o Low reservoir energy o High residual oil saturation o Low recovery efficiency

  17. Investigation of seasonal thermal flow in a real dam reservoir using 3-D numerical modeling

    Directory of Open Access Journals (Sweden)

    Üneş Fatih


    Full Text Available Investigations indicate that correct estimation of seasonal thermal stratification in a dam reservoir is very important for the dam reservoir water quality modeling and water management problems. The main aim of this study is to develop a hydrodynamics model of an actual dam reservoir in three dimensions for simulating a real dam reservoir flows for different seasons. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. In order to include the Coriolis force effect on the flow in a dam reservoir, Coriolis force parameter is also added the model equations. Those equations are constructed using actual dimensions, shape, boundary and initial conditions of the dam and reservoir. Temperature profiles and flow visualizations are used to evaluate flow conditions in the reservoir. Reservoir flow’s process and parameters are determined all over the reservoir. The mathematical model developed is capable of simulating the flow and thermal characteristics of the reservoir system for seasonal heat exchanges. Model simulations results obtained are compared with field measurements obtained from gauging stations for flows in different seasons. The results show a good agreement with the field measurements.

  18. Nonlinear Multigrid for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour; Eskildsen, Klaus Langgren; Engsig-Karup, Allan Peter


    A feasibility study is presented on the effectiveness of applying nonlinear multigrid methods for efficient reservoir simulation of subsurface flow in porous media. A conventional strategy modeled after global linearization by means of Newton’s method is compared with an alternative strategy...... efficiency for a black-oil model. Furthermore, the use of the FAS method enables a significant reduction in memory usage compared with conventional techniques, which suggests new possibilities for improved large-scale reservoir simulation and numerical efficiency. Last, nonlinear multilevel preconditioning...

  19. Dissolved gases in hydrothermal (phreatic) and geyser eruptions at Yellowstone National Park, USA (United States)

    Hurwitz, Shaul; Clor, Laura; McCleskey, R. Blaine; Nordstrom, D. Kirk; Hunt, Andrew G.; Evans, William C.


    Multiphase and multicomponent fluid flow in the shallow continental crust plays a significant role in a variety of processes over a broad range of temperatures and pressures. The presence of dissolved gases in aqueous fluids reduces the liquid stability field toward lower temperatures and enhances the explosivity potential with respect to pure water. Therefore, in areas where magma is actively degassing into a hydrothermal system, gas-rich aqueous fluids can exert a major control on geothermal energy production, can be propellants in hazardous hydrothermal (phreatic) eruptions, and can modulate the dynamics of geyser eruptions. We collected pressurized samples of thermal water that preserved dissolved gases in conjunction with precise temperature measurements with depth in research well Y-7 (maximum depth of 70.1 m; casing to 31 m) and five thermal pools (maximum depth of 11.3 m) in the Upper Geyser Basin of Yellowstone National Park, USA. Based on the dissolved gas concentrations, we demonstrate that CO2 mainly derived from magma and N2 from air-saturated meteoric water reduce the near-surface saturation temperature, consistent with some previous observations in geyser conduits. Thermodynamic calculations suggest that the dissolved CO2 and N2 modulate the dynamics of geyser eruptions and are likely triggers of hydrothermal eruptions when recharged into shallow reservoirs at high concentrations. Therefore, monitoring changes in gas emission rate and composition in areas with neutral and alkaline chlorine thermal features could provide important information on the natural resources (geysers) and hazards (eruptions) in these areas.

  20. Temperature and dissolved oxygen stratification in the lake Rudrasagar: Preliminary investigations

    Directory of Open Access Journals (Sweden)

    M. Pal


    Full Text Available Temperature drives the major physico-chemical and biological actions in inland water bodies. The higher the water temperature, the greater the biogeochemical activity influenced by the environmental intrinsic and extrinsic parameters. Temperature also controls the dynamics of sustainability of various aquatic organisms that live in lakes and reservoirs, though higher life forms, such as fish, insects, zooplankton, phytoplankton, and other aquatic species all have a recommended temperature variety. The increase in water temperature due to the increase in atmospheric air temperature results in lake water column stratification and the dissolved oxygen level variation in aquatic systems are greatly affected. The vertical distributions of dissolved oxygen in the water column are highly dependent due to change in vertical temperature gradient. In the present paper, an effort has been made to investigate the impact of temperature stratification on dissolved oxygen variability in the Rudrasagar, a natural lake in western Tripura. The changes in dissolved oxygen distribution in this natural lake will give us an idea of regional lake health condition and will also establish the need of further large scale research concerning the development of a biophysical-coupled model.

  1. Methods for geothermal reservoir detection emphasizing submerged environments

    Energy Technology Data Exchange (ETDEWEB)

    Case, C.W.; Wilde, P.


    This report has been prepared for the California State Lands Commission to aid them in evaluating exploration programs for geothermal reservoirs, particularly in submerged land environments. Three charts show: (1) a logical progression of specific geologic, geochemical, and geophysical exploration techniques for detecting geothermal reservoirs in various geologic environments with emphasis on submerged lands, (2) various exploration techniques which can be used to develop specific information in geothermal areas, and (3) if various techniques will apply to geothermal exploration according to a detailed geologic classification. A narrative in semi-outline form supplements these charts, providing for each technique; a brief description, advantages, disadvantages, special geologic considerations, and specific references. The specific geologic situation will control the exploration criterion to be used for reservoir detection. General guidelines are established which may be of use in evaluating such a program, but the optimum approach will vary with each situation.

  2. Integrated methodology for constructing a quantified hydrodynamic model for application to clastic petroleum reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Honarpour, M. M.; Schatzinger, R. A.; Szpakiewicz, M. J.; Jackson, S. R.; Sharma, B.; Tomutsa, L.; Chang, M. M.


    A comprehensive, multidisciplinary, stepwise methodology is developed for constructing and integration geological and engineering information for predicting petroleum reservoir performance. This methodology is based on our experience in characterizing shallow marine reservoirs, but it should also apply to other deposystems. The methodology is presented as Part 1 of this report. Three major tasks that must be studied to facilitate a systematic approach for constructing a predictive hydrodynamic model for petroleum reservoirs are addressed: (1) data collection, organization, evaluation, and integration; (2) hydrodynamic model construction and verification; and (3) prediction and ranking of reservoir parameters by numerical simulation using data derived from the model. 39 refs., 62 figs., 13 tabs.

  3. 1D Thermal-Hydraulic-Chemical (THC) Reactive transport modeling for deep geothermal systems: A case study of Groß Schönebeck reservoir, Germany (United States)

    Driba, D. L.; De Lucia, M.; Peiffer, S.


    Fluid-rock interactions in geothermal reservoirs are driven by the state of disequilibrium that persists among solid and solutes due to changing temperature and pressure. During operation of enhanced geothermal systems, injection of cooled water back into the reservoir disturbs the initial thermodynamic equilibrium between the reservoir and its geothermal fluid, which may induce modifications in permeability through changes in porosity and pore space geometry, consequently bringing about several impairments to the overall system.Modeling of fluid-rock interactions induced by injection of cold brine into Groß Schönebeck geothermal reservoir system situated in the Rotliegend sandstone at 4200m depth have been done by coupling geochemical modeling Code Phreeqc with OpenGeoSys. Through batch modeling the re-evaluation of the measured hydrochemical composition of the brine has been done using Quintessa databases, the results from the calculation indicate that a mineral phases comprising of K-feldspar, hematite, Barite, Calcite and Dolomite was found to match the hypothesis of equilibrium with the formation fluid, Reducing conditions are presumed in the model (pe = -3.5) in order to match the amount of observed dissolved Fe and thus considered as initial state for the reactive transport modeling. based on a measured composition of formation fluids and the predominant mineralogical assemblage of the host rock, a preliminary 1D Reactive transport modeling (RTM) was run with total time set to 30 years; results obtained for the initial simulation revealed that during this period, no significant change is evident for K-feldspar. Furthermore, the precipitation of calcite along the flow path in the brine results in a drop of pH from 6.2 to a value of 5.2 noticed over the simulated period. The circulation of cooled fluid in the reservoir is predicted to affect the temperature of the reservoir within the first 100 -150m from the injection well. Examination of porosity change in

  4. Spatial and temporal variation of Dona Francisca reservoir (Jacuí river, Rio Grande do Sul State, a subtropical reservoir - doi: 10.4025/actascibiolsci.v34i3.10078

    Directory of Open Access Journals (Sweden)

    Maria Angélica Oliveira


    Full Text Available The present study examined the behavior of a reservoir located on subtropical latitude (Dona Francisca reservoir. The limnological variables measured were dissolved oxygen, temperature, pH and electric conductivity. Measurements were taken quarterly at different sampling sites along the reservoir. The results indicated the formation of longitudinal zones regarding circulation patterns and stratification, beyond the influence from the water masses of the main tributary. The vertical profiles were obtained. The behavior of the reservoir is similar to others previously studied in the country, but with shorter time-lag stratification and a narrower range, possibly due to the shorter residence time of the water, and to the latitude, where summer is shorter.

  5. Hydrogeochemical processes controlling water and dissolved gas chemistry at the Accesa sinkhole (southern Tuscany, central Italy

    Directory of Open Access Journals (Sweden)

    Franco Tassi


    Full Text Available The 38.5 m deep Lake Accesa is a sinkhole located in southern Tuscany (Italy that shows a peculiar water composition, being characterized by relatively high total dissolved solids (TDS values (2 g L-1 and a Ca(Mg-SO4 geochemical facies. The presence of significant amounts of extra-atmospheric gases (CO2 and CH4, which increase their concentrations with depth, is also recognized. These chemical features, mimicking those commonly shown by volcanic lakes fed by hydrothermal-magmatic reservoirs, are consistent with those of mineral springs emerging in the study area whose chemistry is produced by the interaction of meteoric-derived waters with Mesozoic carbonates and Triassic evaporites. Although the lake has a pronounced thermocline, water chemistry does not show significant changes along the vertical profile. Lake water balance calculations demonstrate that Lake Accesa has >90% of its water supply from sublacustrine springs whose subterranean pathways are controlled by the local structural assessment that likely determined the sinking event, the resulting funnel-shape being then filled by the Accesa waters. Such a huge water inflow from the lake bottom (~9·106 m3 yr-1 feeds the lake effluent (Bruna River and promotes the formation of water currents, which are able to prevent the establishment of a vertical density gradient. Consequently, a continuous mixing along the whole vertical water column is established. Changes of the drainage system by the deep-originated waters in the nearby former mining district have strongly affected the outflow rates of the local mineral springs; thus, future intervention associated with the ongoing remediation activities should carefully be evaluated to preserve the peculiar chemical features of Lake Accesa.

  6. Reservoir Sedimentation Based on Uncertainty Analysis

    Directory of Open Access Journals (Sweden)

    Farhad Imanshoar


    Full Text Available Reservoir sedimentation can result in loss of much needed reservoir storage capacity, reducing the useful life of dams. Thus, sufficient sediment storage capacity should be provided for the reservoir design stage to ensure that sediment accumulation will not impair the functioning of the reservoir during the useful operational-economic life of the project. However, an important issue to consider when estimating reservoir sedimentation and accumulation is the uncertainty involved in reservoir sedimentation. In this paper, the basic factors influencing the density of sediments deposited in reservoirs are discussed, and uncertainties in reservoir sedimentation have been determined using the Delta method. Further, Kenny Reservoir in the White River Basin in northwestern Colorado was selected to determine the density of deposits in the reservoir and the coefficient of variation. The results of this investigation have indicated that by using the Delta method in the case of Kenny Reservoir, the uncertainty regarding accumulated sediment density, expressed by the coefficient of variation for a period of 50 years of reservoir operation, could be reduced to about 10%. Results of the Delta method suggest an applicable approach for dead storage planning via interfacing with uncertainties associated with reservoir sedimentation.


    Directory of Open Access Journals (Sweden)



    Full Text Available Extraction of oil from some Iranian reservoirs due to high viscosity of their oil or reducing the formation permeability due to asphaltene precipitation or other problems is not satisfactory. Hydraulic fracturing method increases production in the viscous oil reservoirs that the production rate is low. So this is very important for some Iranian reservoirs that contain these characteristics. In this study, hydraulic fracturing method has been compositionally simulated in a heavy oil reservoir in southern Iran. In this study, the parameters of the fracture half length, the propagation direction of the cracks and the depth of fracturing have been considered in this oil reservoir. The aim of this study is to find the best scenario which has the highest recovery factor in this oil reservoir. For this purpose the parameters of the length, propagation direction and depth of fracturing have been optimized in this reservoir. Through this study the cumulative oil production has been evaluated with the compositional simulation for the next 10 years in this reservoir. Also at the end of this paper, increasing the final production of this oil reservoir caused by optimized hydraulic fracturing has been evaluated.

  8. Unconventional Reservoirs: Ideas to Commercialization (United States)

    Tinker, S. W.


    There is no shortage of coal, oil, and natural gas in the world. What are sometimes in short supply are fresh ideas. Scientific innovation combined with continued advances in drilling and completion technology revitalized the natural gas industry in North America by making production from shale economic. Similar advances are now happening in shale oil. The convergence of ideas and technology has created a commercial environment in which unconventional reservoirs could supply natural gas to the North American consumer for 50 years or more. And, although not as far along in terms of resource development, oil from the Eagle Ford and Bakken Shales and the oil sands in Alberta could have a similar impact. Without advanced horizontal drilling, geosteering, staged hydraulic-fracture stimulation, synthetic and natural proppants, evolution of hydraulic fluid chemistry, and high-end monitoring and simulation, many of these plays would not exist. Yet drilling and completion technology cannot stand alone. Also required for success are creative thinking, favorable economics, and a tolerance for risk by operators. Current understanding and completion practices will leave upwards of 80% of oil and natural gas in the shale reservoirs. The opportunity to enhance recovery through advanced reservoir understanding and imaging, as well as through recompletions and infill drilling, is considerable. The path from ideas to commercialization will continue to provide economic results in unconventional reservoirs.

  9. Prevention of Reservoir Interior Discoloration

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, K.F.


    Contamination is anathema in reservoir production. Some of the contamination is a result of welding and some appears after welding but existed before. Oxygen was documented to be a major contributor to discoloration in welding. This study demonstrates that it can be controlled and that some of the informal cleaning processes contribute to contamination.


    African Journals Online (AJOL)

    groupe Ill (8 cas) une poche de Kock a ete realisee avec des ureteres directement implantes dans la boucle afférente au-dessus de la valve ileale construite de mamelon d'intussusception. Dans tous les types de reservoirs nous avons employe 45 centimetres de l'ileon. En preoperatoire tous sauf quatre ureteres etaient ...

  11. Potential methane reservoirs beneath Antarctica

    NARCIS (Netherlands)

    Wadham, J.L.; Arndt, S.|info:eu-repo/dai/nl/304835706; Tulaczyk, S.; Stibal, M.; Tranter, M.; Telling, J.; Lis, G.P.; Lawson, E.; Ridgwell, A.; Dubnick, A.; Sharp, M.J.; Anesio, A.M.; Butler, C.E.H.


    Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been

  12. Data assimilation in reservoir management

    NARCIS (Netherlands)

    Rommelse, J.R.


    The research presented in this thesis aims at improving computer models that allow simulations of water, oil and gas flows in subsurface petroleum reservoirs. This is done by integrating, or assimilating, measurements into physics-bases models. In recent years petroleum technology has developed

  13. Reservoirs in the United States (United States)

    Harbeck, G. Earl


    Man has engaged in the control of flowing water since history began. Among his early recorded efforts were reservoirs for muncipal water-supplies constructed near ancient Jerusalem to store water which was brought there in masonry conduits. 1/  Irrigation was practiced in Egypt as early as 2000 B. C. There the "basin system" was used from ancient times until the 19th century. The land was divided , into basins of approximately 40,000 acres, separated by earthen dikes. 2/  Flood waters of the Nile generally inundated the basins through canals, many of which were built by the Pharaohs. Even then the economic consequences of a deficient annual flood were recognized. Lake Maeris, which according to Herodotus was an ancient storage reservoir, is said to have had an area of 30,000 acres. In India, the British found at the time of their occupancy of the Presidency of Madras about 50,000 reservoirs for irrigation, many believed to be of ancient construction. 3/ During the period 115-130 A. D. reservoirs were built to improve the water-supply of Athens. Much has been written concerning the elaborate collection and distribution system built to supply Rome, and parts of it remain to this day as monuments to the engineering skill employed by the Romans in solving the problem of large-scale municipal water-supplies.

  14. Indiana continent catheterizable urinary reservoir. (United States)

    Castillo, O A; Aranguren, G; Campos-Juanatey, F


    Radical pelvic surgery requires continent or incontinent urinary diversion. There are many techniques, but the orthotopic neobladder is the most used. A continent catheterizable urinary reservoir is sometimes a good alternative when this derivation is not possible or not indicated. This paper has aimed to present our experience with the Indiana pouch continent urinary reservoir. The series is made up of 85 patients, 66 women and 19 men, with a mean age of 56 years (31-77 years). Variables analyzed were operating time, estimated blood loss, transfusion rate, hospital stay and peri-operatory complications. The main indication in 49 cases was resolution of complications related to the treatment of cervical cancer. Average operation time was 110.5 minutes (range 80-130 minutes). Mean blood loss was 450 cc (100-1000 cc). Immediate postoperative complications, all of which were treated medically, occurred in 16 patients (18.85%). One patient suffered anastomotic leakage. Hospital stay was 19 days (range 5-60 days) and there was no mortality in the series. Late complications occurred in 26 patients (32%), these being ureteral anastomotic stenosis in 11 cases, cutaneous stoma stenosis in 9 cases and reservoir stones in 6 cases. The Indiana continent catheterizable urinary reservoir is a valid option for the treatment of both urological and gynecological malignancies as well as for the management of pelvic morbidity related to the treatment of pelvic cancers. Copyright © 2013 AEU. Published by Elsevier Espana. All rights reserved.

  15. Reservoir characterization with limited information

    Energy Technology Data Exchange (ETDEWEB)

    Sutterlin, P.G. (Wichita State Univ., KS (United States)); Visher, G.S. (Geological Service and Ventures, Inc., Tulsa, OK (United States))


    It is now possible to estimate the external geometry and the internal reservoir heterogeneity of potential producing zones from a single well. Information from logs and samples often is sufficient to make a unique interpretation of the depositional origin of the potential producing zone. Most wells drilled in the Mid-Continent test specific structural or stratigraphic prospects based upon limited subsurface information. Even without core, seismic, and dipmeter information, multivariant analysis of logs and samples is sufficient for comparison to Holocene depositional patterns, Recognition of the origin of the reservoir interval allow a comparison to similar producing reservoirs. Production experience can be used to design both completion and field development programs. Patterns of direction permeability, geometry of flow units, sweep potential, and primary and secondary recovery potential can be estimated. This allows decisions to be made on well spacing, perforation interval, and frac design. The analysis of all available information can make the difference in completing a successful well and in confirming the play concept. A common failure is that an early effort is not made in synthesizing information to make the correct decisions. The expert system illustrated provides the framework for data analysis and the nature of information that can be used for determining probabilities for specific reservoir characteristics.

  16. Geological model of supercritical geothermal reservoir related to subduction system (United States)

    Tsuchiya, Noriyoshi


    Following the Great East Japan Earthquake and the accident at the Fukushima Daiichi Nuclear power station on 3.11 (11th March) 2011, geothermal energy came to be considered one of the most promising sources of renewable energy for the future in Japan. The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. Supercritical geothermal resources could be evaluated in terms of present volcanic activities, thermal structure, dimension of hydrothermal circulation, properties of fracture system, depth of heat source, depth of brittle factures zone, dimension of geothermal reservoir. On the basis of the GIS, potential of supercritical geothermal resources could be characterized into the following four categories. 1. Promising: surface manifestation d shallow high temperature, 2 Probability: high geothermal gradient, 3 Possibility: Aseismic zone which indicates an existence of melt, 4 Potential : low velocity zone which indicates magma input. Base on geophysical data for geothermal reservoirs, we have propose adequate tectonic model of development of the supercritical geothermal reservoirs. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550

  17. Determination of total and organic mercury and evaluation of methylation and demethylation processes in sediments of the Rio Grande Reservoir, State of Sao Paulo, Brazil; Determinacao de mercurio total e organico e avaliacao dos processos de metilacao e desmetilacao em sedimentos do Reservatorio Rio Grande, Estado de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Franklin, Robson Leocadio


    The Rio Grande reservoir is located in the metropolitan area of Sao Paulo and it is a very important water supply for this region. In the present study bottom waters and sediment samples collected in this reservoir, in four sampling points, in four campaigns, from September 2008 to January 2010, were analyzed. Firstly total Hg was determined in sediment and bottom waters by cold vapor atomic absorption technique (CV AAS). Following, the analytical methodology for organic Hg was adapted from literature, where the organomercurial compounds were extracted with dichloromethane in acid medium and subsequent destruction of organic compounds by bromine chloride. The validation of this methodology, in terms of precision and accuracy, was performed by means of IAEA 405 and BCR-CRM 580 reference materials analyses. For methylation and demethylation processes evaluation in this environment, the following physical and chemical parameters were assessed, in situ: pH, water temperature, redox potential (EH), transparency and depth. For the sediment samples, granulometry, total organic carbon, sulphate-reducing bacteria, total N and P, besides the metals Co, Cu, Fe and Mn were evaluated. The selection of these parameters was related to the factors that influence the behavior of MeHg in the sediments and its transition zone. Total Hg ranging from 1.0 to 71.0 mg kg'-{sup 1} and organic mercury from <10.0 to 47.2 {mu}g kg{sup -1} in sediments and methylation rates from 0.06 to 1.4% were found, along the reservoir. Different methylation conditions along the reservoir and its influences were also discussed. As supplementary study the concentration of some metals and trace elements in the sediments by neutron activation analysis technique was determined. As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc and Zn and rare earth elements Ce, Eu, La, Lu, Nd, Sm and Yb were determined. The enrichment factor in relation to earth crust values using Sc as normalizer element reached values

  18. Relationships between secchi disk visibility, water temperature and dissolved oxygen in freshwater fishpond


    Ali, M.H.; Cagauan, A.G.


    A study was conducted to determine the relationships between secchi disk variability, water temperature and dissolved oxygen in fish ponds. Multiple regression correlation analysis was done to evaluate the relationships between the variables. Results indicated that the ranges of secchi disk visibility, water temperature and dissolved oxygen in the study ponds were just within the ranges of the variables for tilapia culture. Multiple regression correlation showed no (or insignificant) relation...



    Vikas Sharma et al


    In the present investigation, fast dissolving tablets of Carvedilol were formulated by using various natural superdisintegrant like Plantago ovata, Lepidium sativum, Fenugreek and Guar gum. A Direct compression method was used to prepare fast dissolving tablets containing Carvedilol as a model drug using natural superdisintegrants. Prepared formulations were evaluated for Precompression parameters such as micromeritic properties like angle of repose, %compressibility and Hausner’s ratio. Tabl...

  20. Reservoir Cathode for Electric Space Propulsion Project (United States)

    National Aeronautics and Space Administration — We propose a reservoir cathode to improve performance in both ion and Hall-effect thrusters. We propose to adapt our existing reservoir cathode technology to this...

  1. Reservoir Cathode for Electric Space Propulsion Project (United States)

    National Aeronautics and Space Administration — We propose a hollow reservoir cathode to improve performance in ion and Hall thrusters. We will adapt our existing reservoir cathode technology to this purpose....


    African Journals Online (AJOL)



    Oct 24, 2012 ... Key words: Reservoir sand, Well log, Water saturation, Linear and Steiber. Introduction. Reservoir .... they are known to be more chemically immature and may .... Wireline and Testing, Houston Texas, pp. 21 –. 89. Wan Qin ...

  3. Limnology of a lateral lagoon system connected to a Neotropical reservoir (Rosana reservoir, São Paulo/Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Mateus Ferrareze


    Full Text Available The aim of this work was to perform a comparative analysis of four lateral lagoons and of the main channel of the Rosana Reservoir (Paranapanema river, southeast Brazil. The fieldwork was conducted during dry and rainy periods of 2004 and 2005. The analyzed variables were chlorophyll a, turbidity, total phosphorus, total nitrogen, dissolved nutrients (ammonium, nitrate, nitrite, phosphate and silicate, Secchi disk transparency, suspended solids, temperature, pH, dissolved oxygen and electrical conductivity. Intense summer rainfall provided a high input of allochthonous material into the system, resulting in conspicuous changes - high turbidity and nutrient concentrations and low transparency, especially in the reservoir channel. The cluster analysis showed a clear segregation between the reservoir sampling site and the lagoons. The results evidenced the strong influence of regional factors on the limnological structure and functioning of these environments. The alternation between dry and rainy periods changes significantly the characteristics of the main channel and lagoons, mainly due to the contribution of tributaries. Spatially, the system exhibited a remarkable limnological variability. This shows the need to consider these distinct habitats in regional conservation strategy, presently focused on terrestrial habitats.

  4. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago


    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie\\'s parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  5. Characterizing spatiotemporal variations of chromophoric dissolved organic matter in headwater catchment of a key drinking water source in China. (United States)

    Chen, Yihan; Yu, Kaifeng; Zhou, Yongqiang; Ren, Longfei; Kirumba, George; Zhang, Bo; He, Yiliang


    Natural surface drinking water sources with the increasing chromophoric dissolved organic matter (CDOM) have profound influences on the aquatic environment and drinking water safety. Here, this study investigated the spatiotemporal variations of CDOM in Fengshuba Reservoir and its catchments in China. Twenty-four surface water samples, 45 water samples (including surface water, middle water, and bottom water), and 15 pore water samples were collected from rivers, reservoir, and sediment of the reservoir, respectively. Then, three fluorescent components, namely two humic-like components (C1 and C2) and a tryptophan-like component (C3), were identified from the excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) for all samples. For spatial distributions, the levels of CDOM and two humic-like components in the reservoir were significantly lower than those in the upstream rivers (p catchment. For temporal variations, the mean levels of CDOM and three fluorescent components did not significantly change in rivers, suggesting that perennial anthropic activity maybe an important factor impacting the concentration and composition of river CDOM but not the precipitation and runoff. However, these mean values of CDOM for the bulk waters of the reservoir changed markedly along with seasonal variations, indicating that the hydrological processes in the reservoir could control the quality and quantity of CDOM. The different correlations between the fluorescent components and primary water parameters in the river, reservoir, and pore water samples further suggest that the reservoir is an important factor regulating the migration and transformation of FDOM along with the variations of different environmental gradients.

  6. Integration of dynamical data in a geostatistical model of reservoir; Integration des donnees dynamiques dans un modele geostatistique de reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Costa Reis, L.


    We have developed in this thesis a methodology of integrated characterization of heterogeneous reservoirs, from geologic modeling to history matching. This methodology is applied to the reservoir PBR, situated in Campos Basin, offshore Brazil, which has been producing since June 1979. This work is an extension of two other thesis concerning geologic and geostatistical modeling of the reservoir PBR from well data and seismic information. We extended the geostatistical litho-type model to the whole reservoir by using a particular approach of the non-stationary truncated Gaussian simulation method. This approach facilitated the application of the gradual deformation method to history matching. The main stages of the methodology for dynamic data integration in a geostatistical reservoir model are presented. We constructed a reservoir model and the initial difficulties in the history matching led us to modify some choices in the geological, geostatistical and flow models. These difficulties show the importance of dynamic data integration in reservoir modeling. The petrophysical property assignment within the litho-types was done by using well test data. We used an inversion procedure to evaluate the petrophysical parameters of the litho-types. The up-scaling is a necessary stage to reduce the flow simulation time. We compared several up-scaling methods and we show that the passage from the fine geostatistical model to the coarse flow model should be done very carefully. The choice of the fitting parameter depends on the objective of the study. In the case of the reservoir PBR, where water is injected in order to improve the oil recovery, the water rate of the producing wells is directly related to the reservoir heterogeneity. Thus, the water rate was chosen as the fitting parameter. We obtained significant improvements in the history matching of the reservoir PBR. First, by using a method we have proposed, called patchwork. This method allows us to built a coherent

  7. Raft River well stimulation experiments: geothermal reservoir well stimulation program

    Energy Technology Data Exchange (ETDEWEB)


    The Geothermal Reservoir Well Stimulation Program (GRWSP) performed two field experiments at the Raft River KGRA in 1979. Wells RRGP-4 and RRGP-5 were selected for the hydraulic fracture stimulation treatments. The well selection process, fracture treatment design, field execution, stimulation results, and pre- and post-job evaluations are presented.

  8. 33 CFR 211.81 - Reservoir areas. (United States)


    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Reservoir areas. 211.81 Section... Lands in Reservoir Areas Under Jurisdiction of Department of the Army for Cottage Site Development and Use § 211.81 Reservoir areas. Delegations, rules and regulations in §§ 211.71 to 211.80 are applicable...

  9. 32 CFR 644.4 - Reservoir Projects. (United States)


    ... 32 National Defense 4 2010-07-01 2010-07-01 true Reservoir Projects. 644.4 Section 644.4 National... HANDBOOK Project Planning Civil Works § 644.4 Reservoir Projects. (a) Joint land acquisition policy for reservoir projects. The joint policies of the Department of the Interior and the Department of the Army...

  10. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nurhandoko, Bagus Endar B., E-mail:, E-mail: [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4" t" hfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia); Susilowati, E-mail:, E-mail: [Rock Fluid Imaging Lab., Bandung (Indonesia)


    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.

  11. Latitudinal gradients in degradation of marine dissolved organic carbon.

    Directory of Open Access Journals (Sweden)

    Carol Arnosti

    Full Text Available Heterotrophic microbial communities cycle nearly half of net primary productivity in the ocean, and play a particularly important role in transformations of dissolved organic carbon (DOC. The specific means by which these communities mediate the transformations of organic carbon are largely unknown, since the vast majority of marine bacteria have not been isolated in culture, and most measurements of DOC degradation rates have focused on uptake and metabolism of either bulk DOC or of simple model compounds (e.g. specific amino acids or sugars. Genomic investigations provide information about the potential capabilities of organisms and communities but not the extent to which such potential is expressed. We tested directly the capabilities of heterotrophic microbial communities in surface ocean waters at 32 stations spanning latitudes from 76°S to 79°N to hydrolyze a range of high molecular weight organic substrates and thereby initiate organic matter degradation. These data demonstrate the existence of a latitudinal gradient in the range of complex substrates available to heterotrophic microbial communities, paralleling the global gradient in bacterial species richness. As changing climate increasingly affects the marine environment, changes in the spectrum of substrates accessible by microbial communities may lead to shifts in the location and rate at which marine DOC is respired. Since the inventory of DOC in the ocean is comparable in magnitude to the atmospheric CO(2 reservoir, such a change could profoundly affect the global carbon cycle.

  12. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management, Class III

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott; Phillips, Chris; Nguyen, John; Moos, Dan; Tagbor, Kwasi


    This project was intended to increase recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs, transferring technology so that it can be applied in other sections of the Wilmington field and by operators in other slope and basin reservoirs is a primary component of the project.

  13. Gas content of Gladys McCall reservoir brine

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, C.G.; Randolph, P.L.


    On October 8, 1983, after the first full day of production from Sand No.8 in the Gladys McCall well, samples of separator gas and separator brine were collected for laboratory P-V-T (pressure, volume, temperature) studies. Recombination of amounts of these samples based upon measured rates at the time of sample collection, and at reservoir temperature (290 F), revealed a bubble point pressure of 9200 psia. This is substantially below the reported reservoir pressure of 12,783 psia. The gas content of the recombined fluids was 30.19 SCF of dry gas/STB of brine. In contrast, laboratory studies indicate that 35.84 SCF of pure methane would dissolve in each STB of 95,000 mg/L sodium chloride brine. These results indicate that the reservoir brine was not saturated with natural gas. By early April, 1987, production of roughly 25 million barrels of brine had reduced calculated flowing bottomhole pressure to about 6600 psia at a brine rate of 22,000 STB/D. If the skin factor(s) were as high as 20, flowing pressure drop across the skin would still be only about 500 psi. Thus, some portion of the reservoir volume was believed to have been drawn down to below the bubble point deduced from the laboratory recombination of separator samples. When the pressure in a geopressured geothermal reservoir is reduced to below the bubble point pressure for solution gas, gas is exsolved from the brine flowing through the pores in the reservoir rock. This exsolved gas is trapped in the reservoir until the fractional gas saturation of pore volume becomes large enough for gas flow to commence through a continuous gas-filled channel. At the same time, the gas/brine ratio becomes smaller and the chemistry of the remaining solution gas changes for the brine from which gas is exsolved. A careful search was made for the changes in gas/brine ratio or solution gas chemistry that would accompany pressure dropping below the bubble point pressure. Changes of about the same magnitude as the scatter in

  14. Reservoir characterization of the Smackover Formation in southwest Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Kopaska-Merkel, D.C.; Hall, D.R.; Mann, S.D.; Tew, B.H.


    The Upper Jurassic Smackover Formation is found in an arcuate belt in the subsurface from south Texas to panhandle Florida. The Smackover is the most prolific hydrocarbon-producing formation in Alabama and is an important hydrocarbon reservoir from Florida to Texas. In this report Smackover hydrocarbon reservoirs in southwest Alabama are described. Also, the nine enhanced- and improved-recovery projects that have been undertaken in the Smackover of Alabama are evaluated. The report concludes with recommendations about potential future enhanced- and improved-recovery projects in Smackover reservoirs in Alabama and an estimate of the potential volume of liquid hydrocarbons recoverable by enhanced- and improved-recovery methods from the Smackover of Alabama.

  15. Ensemble-Based Data Assimilation in Reservoir Characterization: A Review

    Directory of Open Access Journals (Sweden)

    Seungpil Jung


    Full Text Available This paper presents a review of ensemble-based data assimilation for strongly nonlinear problems on the characterization of heterogeneous reservoirs with different production histories. It concentrates on ensemble Kalman filter (EnKF and ensemble smoother (ES as representative frameworks, discusses their pros and cons, and investigates recent progress to overcome their drawbacks. The typical weaknesses of ensemble-based methods are non-Gaussian parameters, improper prior ensembles and finite population size. Three categorized approaches, to mitigate these limitations, are reviewed with recent accomplishments; improvement of Kalman gains, add-on of transformation functions, and independent evaluation of observed data. The data assimilation in heterogeneous reservoirs, applying the improved ensemble methods, is discussed on predicting unknown dynamic data in reservoir characterization.

  16. Assessment of geotechnical issues associated with the PGS reservoir dyke

    Energy Technology Data Exchange (ETDEWEB)

    Besaw, David; Donnely, C.; Ghiabi, Hani; Doyle, Warren [Hatch, (Canada); Diallo, Alain [Ontario Power Generation, (Canada)


    The PGS reservoir has had several issues with seepage and seepage-related phenomena since its construction in 1953. In 1958, a major sinkhole on the upstream side of the near chaining 6+00 was found. Ontario Hydro decided to draw down the reservoir, repair the sinkhole area immediately and undertake a major grouting program. This paper presented a study of geotechnical issues associated with the PGS reservoir dyke. This study was launched to investigate the potential remedial solutions to maintain the long term safety of the dyke and to determine the ways to expand the energy generating capability of the facility. In this paper, the recent Hatch findings on the geology, construction history, hydrogeological setting and seepage evaluation were presented. Next, the assessment of future measures for seepage control and energy enhancement opportunities were discussed.

  17. A review on mouth dissolving films. (United States)

    Dahiya, Meenu; Saha, Sumit; Shahiwala, Aliasgar F


    The ultimate goal of any drug delivery system is the successful delivery of the drug to the body; however, patient compliance must not be overlooked. Fast dissolving drug delivery systems, such as, Mouth Dissolving Films (MDF), offer a convenient way of dosing medications, not only to special population groups with swallowing difficulties such as children and the elderly, but also to the general population. MDF are the novel dosage forms that disintegrate and dissolve within the oral cavity. Intra-oral absorption permits rapid onset of action and helps by-pass first-pass effects, thereby reducing the unit dose required to produce desired therapeutic effect. The present review provides an overview of various polymers that can be employed in the manufacture of MDF and highlights the effect of polymers and plasticizers on various physico-mechanical properties of MDF. It further gives a brief account of formulation of MDF and problems faced during its manufacture.

  18. Dissolving Microneedle Patches for Dermal Vaccination. (United States)

    Leone, M; Mönkäre, J; Bouwstra, J A; Kersten, G


    The dermal route is an attractive route for vaccine delivery due to the easy skin accessibility and a dense network of immune cells in the skin. The development of microneedles is crucial to take advantage of the skin immunization and simultaneously to overcome problems related to vaccination by conventional needles (e.g. pain, needle-stick injuries or needle re-use). This review focuses on dissolving microneedles that after penetration into the skin dissolve releasing the encapsulated antigen. The microneedle patch fabrication techniques and their challenges are discussed as well as the microneedle characterization methods and antigen stability aspects. The immunogenicity of antigens formulated in dissolving microneedles are addressed. Finally, the early clinical development is discussed.

  19. Impact of physicochemical parameters on phytoplankton compositions and abundances in Selameko Manmade Reservoir, Debre Tabor, South Gondar, Ethiopia (United States)

    Wassie, Tilahun Adugna; Melese, Ayalew Wondie


    Impact of physicochemical parameters on 2 compositions and abundances in Selameko Reservoir, Debre Tabor, South Gondar from August 2009 to May 2010 was assessed. Water quality parameters, such as temperature, water transparency, water depth, dissolved oxygen, pH, total dissolved solids, phosphate, nitrate, and silicate were measured in situ from two sites (littoral and open water zone) of the reservoir. Phytoplankton compositions and abundances were analyzed in Tana fisheries and other aquatic organisms' research center. ANOVA result of the physicochemical parameters included chlorophyll-a showed the presence of significance difference among seasons and between sites ( P Diatom, Blue green algae and Green algae) of phytoplankton were identified during the study period. From all groups, diatoms were the most abundant at both sites and Blue green algae were the least abundant. ANOVA of all phytoplankton showed highly significant difference among seasons and between sites ( P < 0.05). ANOVA of all phytoplankton showed highly significant difference among seasons and between sites ( P < 0.05). Based on the stepwise regression, a total number of phytoplanktons had positive correlation with some of the physicochemical parameters (R2 = 0.99, P < 0.001, N = 16). The study concluded that some of physicochemical parameters (NO3-N and PO4-P) indicated the presence of reservoir water pollution. This is supported by the presence of pollution-resistant phytoplankton species such as Melosira and Microcystis. The reservoir water was eutrophic (productive) throughout the year. To avoid such pollution, basin and reservoir management are recommended.

  20. Trophic State Evolution and Nutrient Trapping Capacity in a Transboundary Subtropical Reservoir: A 25-Year Study (United States)

    Cunha, Davi Gasparini Fernandes; Benassi, Simone Frederigi; de Falco, Patrícia Bortoletto; do Carmo Calijuri, Maria


    Artificial reservoirs have been used for drinking water supply, other human activities, flood control and pollution abatement worldwide, providing overall benefits to downstream water quality. Most reservoirs in Brazil were built during the 1970s, but their long-term patterns of trophic status, water chemistry, and nutrient removal are still not very well characterized. We aimed to evaluate water quality time series (1985-2010) data from the riverine and lacustrine zones of the transboundary Itaipu Reservoir (Brazil/Paraguay). We examined total phosphorus and nitrogen, chlorophyll a concentrations, water transparency, and phytoplankton density to look for spatial and temporal trends and correlations with trophic state evolution and nutrient retention. There was significant temporal and spatial water quality variation ( P water quality and structure of the reservoir were mainly affected by one internal force (hydrodynamics) and one external force (upstream cascading reservoirs). Nutrient and chlorophyll a concentrations tended to be lower in the lacustrine zone and decreased over the 25-year timeframe. Reservoir operational features seemed to be limiting primary production and phytoplankton development, which exhibited a maximum density of 6050 org/mL. The relatively small nutrient concentrations in the riverine zone were probably related to the effect of the cascade reservoirs upstream of Itaipu and led to relatively low removal percentages. Our study suggested that water quality problems may be more pronounced immediately after the filling phase of the artificial reservoirs, associated with the initial decomposition of drowned vegetation at the very beginning of reservoir operation.

  1. How well will the Surface Water and Ocean Topography (SWOT) mission observe global reservoirs? (United States)

    Solander, Kurt C.; Reager, John T.; Famiglietti, James S.


    Accurate observations of global reservoir storage are critical to understand the availability of managed water resources. By enabling estimates of surface water area and height for reservoir sizes exceeding 250 m2 at a maximum repeat orbit of up to 21 days, the NASA Surface Water and Ocean Topography (SWOT) satellite mission (anticipated launch date 2020) is expected to greatly improve upon existing reservoir monitoring capabilities. It is thus essential that spatial and temporal measurement uncertainty for water bodies is known a priori to maximize the utility of SWOT observations as the data are acquired. In this study, we evaluate SWOT reservoir observations using a three-pronged approach that assesses temporal aliasing, errors due to specific reservoir spatial properties, and SWOT performance over actual reservoirs using a combination of in situ and simulated reservoir observations from the SWOTsim instrument simulator. Results indicate temporal errors to be less than 5% for the smallest reservoir sizes (100 km2). Surface area and height errors were found to be minimal (area SWOT, this study will be have important implications for future applications of SWOT reservoir measurements in global monitoring systems and models.

  2. Identification and assessment of potential water quality impact factors for drinking-water reservoirs. (United States)

    Gu, Qing; Deng, Jinsong; Wang, Ke; Lin, Yi; Li, Jun; Gan, Muye; Ma, Ligang; Hong, Yang


    Various reservoirs have been serving as the most important drinking water sources in Zhejiang Province, China, due to the uneven distribution of precipitation and severe river pollution. Unfortunately, rapid urbanization and industrialization have been continuously challenging the water quality of the drinking-water reservoirs. The identification and assessment of potential impacts is indispensable in water resource management and protection. This study investigates the drinking water reservoirs in Zhejiang Province to better understand the potential impact on water quality. Altogether seventy-three typical drinking reservoirs in Zhejiang Province encompassing various water storage levels were selected and evaluated. Using fifty-two reservoirs as training samples, the classification and regression tree (CART) method and sixteen comprehensive variables, including six sub-sets (land use, population, socio-economy, geographical features, inherent characteristics, and climate), were adopted to establish a decision-making model for identifying and assessing their potential impacts on drinking-water quality. The water quality class of the remaining twenty-one reservoirs was then predicted and tested based on the decision-making model, resulting in a water quality class attribution accuracy of 81.0%. Based on the decision rules and quantitative importance of the independent variables, industrial emissions was identified as the most important factor influencing the water quality of reservoirs; land use and human habitation also had a substantial impact on water quality. The results of this study provide insights into the factors impacting the water quality of reservoirs as well as basic information for protecting reservoir water resources.

  3. Production performance laws of vertical wells by volume fracturing in CBM reservoirs

    Directory of Open Access Journals (Sweden)

    Liehui Zhang


    Full Text Available Volume fracturing technology has been widely applied in the development of coalbed methane (CBM reservoirs. As for the stimulated reservoir volume (SRV created by volume fracturing, the seepage laws of fluids are described more accurately and rationally in the rectangular composite model than in the traditional radial composite model. However, the rectangular composite model considering SRV cannot be solved using the analytical or semi-analytical function method, and its solution from the linear flow model has larger errors. In view of this, SRV areas of CBM reservoirs were described by means of dual-medium model in this paper. The complex CBM migration mechanisms were investigated comprehensively, including adsorption, desorption, diffusion and seepage. A well testing model for rectangular composite fracturing wells in CBM reservoirs based on unsteady-state diffusion was built and solved using the boundary element method combined with Laplace transformation, Stehfest numerical inversion and computer programming technology. Thus, production performance laws of CBM reservoirs were clarified. The flow regimes of typical well testing curves were divided and the effects on change laws of production performance from the boundary size of gas reservoirs, permeability of volume fractured areas, adsorption gas content, reservoir permeability and SRV size were analyzed. Eventually, CBM reservoirs after the volume fracturing stimulation were described more accurately and rationally. This study provides a theoretical basis for a better understanding of the CBM migration laws and an approach to evaluating and developing CBM reservoirs efficiently and rationally.

  4. 4. International reservoir characterization technical conference

    Energy Technology Data Exchange (ETDEWEB)



    This volume contains the Proceedings of the Fourth International Reservoir Characterization Technical Conference held March 2-4, 1997 in Houston, Texas. The theme for the conference was Advances in Reservoir Characterization for Effective Reservoir Management. On March 2, 1997, the DOE Class Workshop kicked off with tutorials by Dr. Steve Begg (BP Exploration) and Dr. Ganesh Thakur (Chevron). Tutorial presentations are not included in these Proceedings but may be available from the authors. The conference consisted of the following topics: data acquisition; reservoir modeling; scaling reservoir properties; and managing uncertainty. Selected papers have been processed separately for inclusion in the Energy Science and Technology database.

  5. Monitoring Reservoirs Using MERIS And LANDSAT Fused Images : A Case Study Of Polyfitos Reservoir - West Macedonia - Greece (United States)

    Stefouli, M.; Charou, E.; Vasileiou, E.; Stathopoulos, N.; Perrakis, A.


    the irrigation network in the area We evaluate the possibility to merge two different resolution satellite data i.e. MERIS/ENVISAT and LANDSAT to facilitate the study of the Polyfitos reservoir. State of the art data fusion techniques, that preserve the best characteristics (spatial, temporal, spectral) of the two types of images are implemented and used to mining information concerning selected parameters. Summer 2011 Landsat and ENVISAT MERIS satellite images are used in order to extract lake water quality parameters such as water clarity -and sediment content. Assessment of the whole watershed of Polyfitos reservoir is carried out for the last 25 years. The methodology presented here can be used to support existing reservoir monitoring programs as it gives regular measurements for the whole of the watershed area of the reservoir. The results can be made available to end-users / reservoir managers, using web/GIS techniques. They can also support environmental awareness of the conditions of watershed of Polyfitos reservoir.

  6. Calibration of Seismic Attributes for Reservoir Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Pennington, Wayne D.; Acevedo, Horacio; Green, Aaron; Len, Shawn; Minavea, Anastasia; Wood, James; Xie, Deyi


    This project has completed the initially scheduled third year of the contract, and is beginning a fourth year, designed to expand upon the tech transfer aspects of the project. From the Stratton data set, demonstrated that an apparent correlation between attributes derived along `phantom' horizons are artifacts of isopach changes; only if the interpreter understands that the interpretation is based on this correlation with bed thickening or thinning, can reliable interpretations of channel horizons and facies be made. From the Boonsville data set , developed techniques to use conventional seismic attributes, including seismic facies generated under various neural network procedures, to subdivide regional facies determined from logs into productive and non-productive subfacies, and developed a method involving cross-correlation of seismic waveforms to provide a reliable map of the various facies present in the area. The Teal South data set provided a surprising set of data, leading us to develop a pressure-dependent velocity relationship and to conclude that nearby reservoirs are undergoing a pressure drop in response to the production of the main reservoir, implying that oil is being lost through their spill points, never to be produced. The Wamsutter data set led to the use of unconventional attributes including lateral incoherence and horizon-dependent impedance variations to indicate regions of former sand bars and current high pressure, respectively, and to evaluation of various upscaling routines.

  7. Mixing it up in the ocean carbon cycle and the removal of refractory dissolved organic carbon. (United States)

    Shen, Yuan; Benner, Ronald


    A large quantity of reduced carbon is sequestered in the ocean as refractory dissolved molecules that persist through several circuits of global overturning circulation. Key aspects of the cycling of refractory dissolved organic carbon (DOC) remain unknown, making it challenging to predict how this large carbon reservoir will respond to climate change. Herein we investigate mechanisms that remove refractory DOC using bioassay experiments with DOC isolated from surface, mesopelagic and deep waters of the Atlantic Ocean. The isolated DOC was refractory to degradation by native microbial communities, even at elevated concentrations. However, when the refractory DOC was introduced to a series of novel environmental conditions, including addition of a labile substrate, a microbial community from coastal waters and exposure to solar radiation, a substantial fraction (7-13%) was removed within 1.5 years. Our results suggest that while refractory molecules can persist in the ocean for millennia, removal is rapid when they encounter their fate. The observed and projected climate-induced slowdown of global overturning circulation could reduce the exposure of refractory molecules to disparate removal processes. Assuming a constant rate of production, the reservoir size of refractory DOC could increase as overturning circulation slows, providing a negative feedback to rising atmospheric CO 2 .

  8. Multilevel techniques for Reservoir Simulation

    DEFF Research Database (Denmark)

    Christensen, Max la Cour

    The subject of this thesis is the development, application and study of novel multilevel methods for the acceleration and improvement of reservoir simulation techniques. The motivation for addressing this topic is a need for more accurate predictions of porous media flow and the ability to carry...... based on element-based Algebraic Multigrid (AMGe). In particular, an advanced AMGe technique with guaranteed approximation properties is used to construct a coarse multilevel hierarchy of Raviart-Thomas and L2 spaces for the Galerkin coarsening of a mixed formulation of the reservoir simulation...... equations. By experimentation it is found that the AMGe based upscaling technique provided very accurate results while reducing the computational time proportionally to the reduction in degrees of freedom. Furthermore, it is demonstrated that the AMGe coarse spaces (interpolation operators) can be used...

  9. Reasons for reservoir effect variability

    DEFF Research Database (Denmark)

    Philippsen, Bente


    , aquatic plants and fish from the rivers Alster and Trave range between zero and about 3,000 radiocarbon years. The reservoir age of water DIC depends to a large extent on the origin of the water and is for example correlated with precipitation amounts. These short-term variations are smoothed out in water...... plants. Their carbon should represent an average value of the entire growth season. However, there are large reservoir age variations in aquatic plants and animals as well. These can best be explained by the multitude of carbon sources which can be utilized by aquatic organisms, and which have...... potentially very different radiocarbon ages. Finally, I will discuss the influence of bomb carbon on radiocarbon dating of modern freshwater samples....

  10. Use of a novel acoustic dissolved oxygen transmitter for fish telemetry

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Aarestrup, Kim; Steffensen, J.F.


    The multiple responses of fishes to changes in dissolved oxygen saturations have been studied widely in the laboratory. In contrast only few studies have included field observations. The objective of the present study was to evaluate the performance of a novel acoustic dissolved oxygen transmitter...... for field biotelemetry. The results demonstrated that the output of the transmitter was unaffected by three different temperatures (10 to 30 degrees C) and described the dissolved oxygen saturation with high accuracy (r(2) > 0.99) over the entire range of 0 to 191% saturation. The response time (>= 90......% of end value) of the transmitter was 12 s both in terms of decreasing (100 to 0%) and increasing (0 to 100%) oxygen saturations. When externally attached to fishes the present findings support the use of the transmitter for reliable dissolved oxygen measurements on individuals living in environments...

  11. Orally dissolving strips: A new approach to oral drug delivery system. (United States)

    Bala, Rajni; Pawar, Pravin; Khanna, Sushil; Arora, Sandeep


    Recently, fast dissolving films are gaining interest as an alternative of fast dissolving tablets. The films are designed to dissolve upon contact with a wet surface, such as the tongue, within a few seconds, meaning the consumer can take the product without need for additional liquid. This convenience provides both a marketing advantage and increased patient compliance. As the drug is directly absorbed into systemic circulation, degradation in gastrointestinal tract and first pass effect can be avoided. These points make this formulation most popular and acceptable among pediatric and geriatric patients and patients with fear of choking. Over-the-counter films for pain management and motion sickness are commercialized in the US markets. Many companies are utilizing transdermal drug delivery technology to develop thin film formats. In the present review, recent advancements regarding fast dissolving buccal film formulation and their evaluation parameters are compiled.

  12. Diurnal variability of CO2 and CH4 emissions from tropical reservoirs (United States)

    Linkhorst, Annika; Reinaldo Paran