An evaluation of alternative procedures using the Bou-Rouch method for sampling hyporheic invertebrates

2000 ◽  
Vol 57 (8) ◽  
pp. 1545-1550 ◽  
Author(s):  
Gary W Hunt ◽  
Emily H Stanley
Keyword(s):  
Sample Volume ◽  
Taxon Richness ◽  
Sediment Composition ◽  
Density Estimates ◽  
Pumping Rate ◽  
Well Design ◽  
Alternative Procedures ◽  
Pumping Rates ◽  
Larger Sample

This study assesses the influence of well design, pumping rate, and sample volume on hyporheic invertebrate density and richness estimates in three streams differing in sediment composition. A comparison of five well designs, i.e., temporary wells with no pores and with 4-, 6-, and 8-mm pores along the lower 15 cm and permanent wells with 6-mm pores, revealed no significant differences in either total invertebrate densities or taxon richness. Pumping rates, i.e., 1.5 versus 4 L·min-1, significantly affected density estimates at two streams and taxon richness at one of the three streams, shown by higher values at the faster pumping rate. A comparison of five sample volume sizes, i.e., 0.5, 1.0, 1.5, 2.0, and 2.5 L, indicated that smaller sample volumes produced significantly higher estimates of density, while larger sample volumes gave significantly higher estimates of taxon richness. These results underscore the importance of maintaining consistent pumping rates and sample volume sizes throughout the course of a study.

scholarly journals Thermal-Plume fibre Optic Tracking (T-POT) test for flow velocity measurement in groundwater boreholes

2015 ◽  
Vol 5 (1) ◽  
pp. 161-175 ◽  
Author(s):  
T. Read ◽  
V. F. Bense ◽  
O. Bour ◽  
T. Le Borgne ◽  
N. Lavenant ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Fractured Rock ◽  
Electrical Heating ◽  
Multiple Point ◽  
Thermal Plume ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Pumping Rate ◽  
Average Flow Velocity ◽  
Pumping Rates

Abstract. We develop an approach for measuring in-well fluid velocities using point electrical heating combined with spatially and temporally continuous temperature monitoring using Distributed Temperature Sensing (DTS). The method uses a point heater to warm a discrete volume of water. The rate of advection of this plume, once the heating is stopped, equates to the average flow velocity in the well. We conducted Thermal-Plume fibre Optic Tracking (T-POT) tests in a borehole in a fractured rock aquifer with the heater at the same depth and multiple pumping rates. Tracking of the thermal plume peak allowed the spatially varying velocity to be estimated up to 50 m downstream from the heating point, depending on the pumping rate. The T-POT technique can be used to estimate the velocity throughout long intervals provided that thermal dilution due to inflows, dispersion, or cooling by conduction do not render the thermal pulse unresolvable with DTS. A complete flow log may be obtained by deploying the heater at multiple depths, or with multiple point heaters.

scholarly journals Groundwater Evaluation and Management in Ain Sukhna, Egypt

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Alaa Nabil El-Hazek ◽  
Neveen B. Abdelmageed ◽  
Hatem M. Mekhemer ◽  
Dalia H. Amin
Keyword(s):  
Economic Development ◽  
Steady State ◽  
Conceptual Model ◽  
Groundwater Management ◽  
The Other ◽  
Solid Model ◽  
Pumping Rate ◽  
Pumping Rates ◽  
State Case ◽  
Good Agreement

Ain Sukhna has become one of the most important economic areas in Egypt recently. As a result of this economic development, the demand for water has increased, with special emphasis on groundwater. Therefore, in this paper, several scenarios are assessed in order to reach the best scenario for groundwater management giving the opportunity to achieve the development needs of that region.Groundwater Modeling System (GMS) software is used to construct the solid model forsimulating the geometry of the aquifer layers. Then, a conceptual model is developed and calibrated in steady state case. The calibration results are satisfactory showing a good agreement between the calculated and observed heads. Finally, four scenarios are simulated with different pumping possibilities ranging from -25% to + 50% of the current pumping rates. The results show that it will be better if the current pumping rate is reduced by 25% which can make the drawdown values less than the other possibilities. It is also shown that the best recommended places to drill more wells can be in the east and south directions where the least drawdown values are found.

scholarly journals Optimized Pumping Strategy for Reducing the Spatial Extent of Saltwater Intrusion along the Coast of Wadi Ham, UAE

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1503 ◽  
Author(s):  
Modou A. Sowe ◽  
Sadhasivam Sathish ◽  
Nicolas Greggio ◽  
Mohamed M. Mohamed
Keyword(s):  
Saltwater Intrusion ◽  
Transport Model ◽  
Saline Water ◽  
Anthropogenic Impacts ◽  
Optimum Number ◽  
Constant Number ◽  
Pumping Rate ◽  
Discharge Rates ◽  
Pumping Wells ◽  
Pumping Rates

Many coastal aquifers are facing severe anthropogenic impacts such as urbanization, industrialization and agricultural activities are resulting in a saltwater intrusion. This establishes the need for a sustainable groundwater management strategy aimed to overcome the situation. Pumping of brackish/saline water to mitigate saltwater intrusion is a major potential approach to effectively control saltwater intrusion. However, this method has many challenges including selection of appropriate discharge rates under an optimum number of pumping wells and at specified wells distance from the shoreline. Hence, this study developed a Finite Element Flow and solute transport model (FEFLOW) to simulate three scenarios to assess the most appropriate pumping rates, number of wells and optimum well locations from the shoreline. These parameters were assessed and evaluated with respect to the change in groundwater saline concentration at different distance from the coastline. The 15,000 mg L−1 isosalinity contour line was used as a linear threshold to assess the progression of saltwater intrusion along three major locations in the aquifer. Scenario One was simulated with a constant number of wells and rate of pumping. Shifting of pumping wells to several distances from the shoreline was conducted. Scenario Two assessed the most appropriate number of pumping wells under constant pumping rates and distances from the shoreline and in scenario 3, the optimum pumping rates under a constant number of wells and distance from the shoreline were simulated. The results showed that the pumping of brackish/saline water from a distance of 1500 m from the shoreline using 16 pumping wells at a total pumping rate of 8000 m3 d−1 is the most effective solution in contrasting the saltwater intrusion in the Wadi Ham coastal aquifer.

Changing the Status Quo: Cases of Production Restoration in Inactive Offshore Oil Wells

2021 ◽  
Author(s):  
Arlen Sarsekov ◽  
Salem Ali Al Kindi ◽  
Manal Albeshr ◽  
Yin Luo ◽  
Bulat Kamaletdinov ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Acid Content ◽  
Oil And Gas ◽  
Gas Reservoirs ◽  
Pumping Rate ◽  
The Status ◽  
Modeling Software ◽  
Pumping Rates ◽  
Line Pressure ◽  
Reduced Rate

Abstract The United Arab Emirates oil and gas reservoirs are continuously intersected with a growing number of horizontal wells and longer drains at varying bottomhole static temperatures. This results in a variety of naturally flowing and more challenging wells where stimulation is required for sustainable flow. Hence it became important to not only rely on plain acid systems for production gain, but to also include more sophisticated acid stimulation systems that can provide improved results in more challenging environments where plain acid may be found lacking. These results were recently achieved via the introduction of single-phase retarded acid (SPRA) as well as viscoelastic diverting acid (VEDA) in inactive wells offshore. The application of SPRA and VEDA was subsequent to extensive laboratory testing including core flow tests, solubility tests, and emulsion tendency testing to the performance of these blends against existing acid recipes such as plain HCl and polymer-based diverting acid. These tests proved that a combination of SPRA and VEDA would allow maximizing lateral coverage in heterogenous reservoirs due to the chemical diversion capabilities from thief zones without imposing further damage that polymer-based diverted acids may cause. The combined SPRA and VEDA would also enhance acid wormhole penetration due to the reduced rate of reaction caused by acid retardation. Such tests were supported with software simulations that provided acid dosage, pumping rate, and pumping method sensitives. Proposing SPRA and VEDA at higher pumping rates enabled the delivery of previously unattainable production influx at sustainable wellhead pressures. In addition, 28% acid content typically used for dolomitic reservoirs was considered unnecessary as 20% retarded acid proved sufficient in such environments. This allowed bullheading treatments, which was previously not possible due to the restriction on pumping 28% acid content across wellheads to avoid causing corrosive damage. Other treatment parameters such as volumes, rates, and acid/diverter sequence and ratio were also adjusted for optimal wormhole penetration across all zones using a fit-for-purpose carbonate matrix acidizing modeling software. The success of SPRA and VEDA was clear in post-treatment evaluation for the cases of previously shut-in wells. These wells were able to produce sustainably at the required tubinghead pressure (production line pressure) after unsuccessful attempts to flow prior to stimulation. The novelty of this paper is the assessment between legacy carbonate stimulation results in UAE using plain HCl acid and polymer-based diverting acid (PDA) and using SPRA and VEDA in shut-in or inactive wells. It also highlights the game-changing solutions that suit the increasing challenges observed in offshore inactive wells including well placement, lithology, bottomhole static temperature, and permeability contrast.

Optimization of Temporary Plugging Parameters Under Rough Fractures

2019 ◽  
Author(s):  
Lishan Yuan ◽  
Fujian Zhou ◽  
Ben Li ◽  
Junjie Gao ◽  
Caizhong Wang ◽  
...  
Keyword(s):  
Pumping Rate ◽  
Experimental Procedure ◽  
Fracture Width ◽  
Carrier Fluid ◽  
High Particle Concentration ◽  
Carrier Liquid ◽  
High Particle ◽  
Wide Range ◽  
Particle Ratio ◽  
Pumping Rates

Abstract Temporary-plugging-and-diverting (TPD) fracturing technology is widely used in the development of the unconventional reservoir. The operational procedure of temporary plugging and the size and combination of diverters are very much concerned by field engineers. This study compares different pumping procedure of diverters and optimizes the combination and pumping rate of diverters under the different width of the fracture. The experimental method is based on a simulated fracture apparatus, which is manufactured by the 3D printing technology. The surface morphology of the fracture is obtained through a 3D scanning of a fracture. The experimental procedure is pumping the carrier liquid and diverter mixtures into the fracture while recording pumping pressure and the outlet volume of carrier fluid. The fracture plugging efficiency was evaluated through the recorded parameters. The diverter concentration and composition were optimized at a wide range of fracture width (1 mm to 4 mm). Low the diverter concentration could help to reduce the operational risk of the diversion. Under the low concentration of the diverters, the plugging mechanism is that the large particle diverters bridge in the fracture due to the fracture tortuosity and roughness; the smaller particle and fiber diverters then fill the voids of the large particles and form a strong and low permeable diverter pack. The results indicate that pumping the mixture particle and fiber diverters are more beneficial to plug the fracture than pumping them separately and sequentially. High particle concentration has a two-sided effect, which leads to the existence of an optimal fiber-to-particle ratio. The concentration of diverters could decrease when the size of diverters is increased. At a constant fracture width, higher pumping rates can help to temporarily plug the fracture more efficiently.

scholarly journals The Quest for Fine-Scale Anisotropy in the Relict Radiation

1978 ◽  
Vol 79 ◽  
pp. 317-326 ◽  
Author(s):  
Paul E. Boynton
Keyword(s):  
Large Scale ◽  
Sample Volume ◽  
Density Fluctuations ◽  
Initial Spectrum ◽  
Density Perturbations ◽  
The Universe ◽  
Larger Sample ◽  
Careful Comparison ◽  
Characteristic Scales ◽  
Insight Into

Up to Symposium Session IV, the observed properties of the large scale structure of the Universe have been discussed in terms of studies based on the spatial distribution of galaxies with redshift less than one; studies which indicate clustering on characteristic scales up to ~20 Mpc or equivalently ~1015M⊙. Such a survey is rather local in scope compared to what in principle could be inferred from the measurement of temperature fluctuations in the relict radiation surviving from Z ≃ 1000 as the fossil imprint of “primordial” density fluctuations on scales up to the horizon at the epoch of decoupling, M ≃ 1019M⊙. However, the investigation of structure over a still-larger sample volume and scales greater than 1015M⊙ is not a possibility which I wish to stress in this paper. Rather, given our present state of ignorance about the formation of structure, perhaps a more fruitful first approach would be to examine small angular scales in the relict radiation for insight into the evolution of density perturbations by a careful comparison between the observationally inferred “initial” spectrum of mass inhomogeneities present back at the epoch of decoupling, and the mass spectrum of clustering which characterizes the present Universe.

scholarly journals Biased Estimation of Groundwater Velocity from a Push-Pull Tracer Test Due to Plume Density and Pumping Rate

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1558 ◽  
Author(s):  
Hong-Hyun Kim ◽  
Eun-Hee Koh ◽  
Seong-Sun Lee ◽  
Kang-Kun Lee
Keyword(s):  
Numerical Simulations ◽  
Drift Time ◽  
Tracer Tests ◽  
Tracer Test ◽  
Linear Velocity ◽  
Test Results ◽  
Groundwater Velocity ◽  
Pumping Rate ◽  
Laboratory Test Results ◽  
Pumping Rates

The single-well push-pull tracer test is a convenient and cost-effective tool to estimate hydrogeological properties of a subsurface aquifer system. However, it has a limitation that test results can be affected by various experimental designs. In this study, a series of laboratory-scale push-pull tracer tests were conducted under various conditions controlling input tracer density, pumping rate, drift time, and hydraulic gradient. Based on the laboratory test results, numerical simulations were performed to evaluate the effects of density-induced plume sinking and pumping rate on the proper estimation of groundwater background linear velocity. Laboratory tests and numerical simulations indicated that the actual linear velocity was underestimated for the higher concentration of the input tracer because solute travel distance and direction during drift time were dominantly affected by the plume density. During the pulling phase, reasonable pumping rates were needed to extract the majority of injected tracer mass to obtain a genuine center of mass time (tcom). This study presents a graph showing reasonable pumping rates for different combinations of plume density and background groundwater velocity. The results indicate that careful consideration must be given to the design and interpretation of push-pull tracer tests.

scholarly journals Thermal-plume fibre optic tracking (T-POT) test for flow velocity measurement in groundwater boreholes

2015 ◽  
Vol 4 (2) ◽  
pp. 197-202 ◽  
Author(s):  
T. Read ◽  
V. F. Bense ◽  
R. Hochreutener ◽  
O. Bour ◽  
T. Le Borgne ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Fractured Rock ◽  
Electrical Heating ◽  
Multiple Point ◽  
Thermal Plume ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Pumping Rate ◽  
Average Flow Velocity ◽  
Pumping Rates

Abstract. We develop an approach for measuring in-well fluid velocities using point electrical heating combined with spatially and temporally continuous temperature monitoring using distributed temperature sensing (DTS). The method uses a point heater to warm a discrete volume of water. The rate of advection of this plume, once the heating is stopped, equates to the average flow velocity in the well. We conducted thermal-plume fibre optic tracking (T-POT) tests in a borehole in a fractured rock aquifer with the heater at the same depth and multiple pumping rates. Tracking of the thermal plume peak allowed the spatially varying velocity to be estimated up to 50 m downstream from the heating point, depending on the pumping rate. The T-POT technique can be used to estimate the velocity throughout long intervals provided that thermal dilution due to inflows, dispersion, or cooling by conduction does not render the thermal pulse unresolvable with DTS. A complete flow log may be obtained by deploying the heater at multiple depths, or with multiple point heaters.

Optimising sample volume and replicates using the Bou-Rouch method for the rapid assessment of hyporheic fauna

2009 ◽  
Vol 60 (1) ◽  
pp. 83 ◽  
Author(s):  
Samuel Kibichii ◽  
Jan-Robert Baars ◽  
Mary Kelly-Quinn
Keyword(s):  
Small Volume ◽  
Rapid Assessment ◽  
Sample Volume ◽  
Taxon Richness ◽  
Ecological Studies ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Alluvial Groundwater ◽  
Optimum Sample ◽  
Flowing Stream

Despite the widespread use of the Bou-Rouch method in obtaining hyporheic samples in ecological studies, problems persist in comparing data because of differences in volume and number of samples taken in various studies. Towards standardising this method, we conducted a study in the Delour River, Ireland, between March and September 2006. The hyporheic habitat was divided into three lateral zones: the flowing stream (SS); the stream–terrestrial ecotone (EC); and the terrestrial margin (TM). Between 3 and 6 random insertions of the stand pipe were made into the hyporheic habitat at 0.2 m and 0.5 m in each zone. Ten consecutive 1-L samples were pumped at each point to determine an optimum sample volume and replicates needed to estimate taxon richness and abundance. The optimum sample combinations range between 6 and 15 3- to 10-L samples depending on depth and habitat zone. Our results show that both spatial and temporal scales are important factors in considering the optimum combinations of sample volume and number of independent spatial replicates needed to sample stream hyporheos, with the zone closer to the flowing stream requiring many small-volume samples whereas areas further away towards the alluvial groundwater need larger volumes with small numbers of replicates.

Effect of Pinnotheres hickmani on Neutral Red Clearance by Mytilus edulis

1979 ◽  
Vol 30 (4) ◽  
pp. 547 ◽  
Author(s):  
C Pregenzer Jr
Keyword(s):  
Mytilus Edulis ◽  
Neutral Red ◽  
Probability Level ◽  
Pumping Rate ◽  
Pumping Rates

The effect of P. hickmani on the pumping rate of M. edulis was investigated. The crab significantly reduces the pumping rate at the 90% probability level. Pumping rates obtained are consistent with those reported in the literature where neutral red was used as the medium to be cleared.

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