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1.
Traditional analysis methods used to determine hydraulic properties from pumping tests work well in many porous media aquifers, but they often do not work in heterogeneous and fractured‐rock aquifers, producing non‐plausible and erroneous results. The generalized radial flow model developed by Barker (1988) can reveal information about heterogeneity characteristics and aquifer geometry from pumping test data by way of a flow dimension parameter. The physical meaning of non‐integer flow dimensions has long been a subject of debate and research. We focus on understanding and interpreting non‐radial flow through high permeability conduits within fractured aquifers. We develop and simulate flow within idealized non‐radial flow conduits and expand on this concept by simulating pumping in non‐fractal random fields with specific properties that mimic persistent sub‐radial flow responses. Our results demonstrate that non‐integer flow dimensions can arise from non‐fractal geometries within aquifers. We expand on these geometric concepts and successfully simulate pumping in random fields that mimic well‐test responses seen in the Culebra Dolomite above the Waste Isolation Pilot Plant. 相似文献
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Numerical Modeling of Axisymmetric Flow 总被引：1，自引：0，他引：1
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Sanford Ballard 《Ground water》1996,34(2):231-240
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L. Rothenburg A. Bogobowicz 《Stochastic Environmental Research and Risk Assessment (SERRA)》1990,4(3):175-191
This paper presents an analysis of Hagen-Poiseulle flow through plane random anisotropic networks of interconnected channels. Macroscopic permeability tensor of the network is expressed in terms of statistico-geometrical characteristics like the degree of anisotropy in channel orientations, average co-ordination number of the network and first two moments of channel length distribution. Analytical results are illustrated and verified using numerical analysis of flow in a simulated random network. The emphasis of the paper is on the effects of anisotropy on distributions of flow rates in channels. It is shown that, due to anisotropy the maximum flow rate generally occurs in channels that are not aligned along the direction of the macroscopic pressure gradient. 相似文献
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This paper presents an analysis of Hagen-Poiseulle flow through plane random anisotropic networks of interconnected channels. Macroscopic permeability tensor of the network is expressed in terms of statistico-geometrical characteristics like the degree of anisotropy in channel orientations, average co-ordination number of the network and first two moments of channel length distribution. Analytical results are illustrated and verified using numerical analysis of flow in a simulated random network. The emphasis of the paper is on the effects of anisotropy on distributions of flow rates in channels. It is shown that, due to anisotropy the maximum flow rate generally occurs in channels that are not aligned along the direction of the macroscopic pressure gradient. 相似文献
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William B. Kerfoot 《Ground Water Monitoring & Remediation》1984,4(4):188-192
In glacial outwash deposits, the movement of ground water Is determined by small scale irregularities in the pattern of hydraulic conductivity. Permeability determinations on split spoon samples obtained from coring the site are not sufficient to predict the patchiness of flow since it cannot define continuity of the strata. The lattice work pattern can be determined by vertical profiling with direct ground water flow measurement. The rate and direction of flow is combined with head gradient changes to compute hydraulic conductivity changes across the site.
The results of the tests can be plotted on triangular graphs depicting the fundamental Darcy equation. The local conditions reflect a mathematical "patchiness" of hydraulic conductivity unique to outwash deposits.
The procedure was employed to determine flow characteristics and define the zone of contribution to porous bottom kettle lakes. The zone of contribution was defined by projecting backward from the vertical profiling and shallow measurements and taking into account the daily rain water recharge rate across the site.
For the unconfined aquifer north of the pond, shallow ground water flow measurements were necessary to define the recharge portion of the shoreline. Vertical profiling was required to define the recharge volume since the rate of flow was not even with depth. A simple differential equation for determining the recharge area is presented along with the calculations. 相似文献
The results of the tests can be plotted on triangular graphs depicting the fundamental Darcy equation. The local conditions reflect a mathematical "patchiness" of hydraulic conductivity unique to outwash deposits.
The procedure was employed to determine flow characteristics and define the zone of contribution to porous bottom kettle lakes. The zone of contribution was defined by projecting backward from the vertical profiling and shallow measurements and taking into account the daily rain water recharge rate across the site.
For the unconfined aquifer north of the pond, shallow ground water flow measurements were necessary to define the recharge portion of the shoreline. Vertical profiling was required to define the recharge volume since the rate of flow was not even with depth. A simple differential equation for determining the recharge area is presented along with the calculations. 相似文献
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Existing resistance formulas produce a wide range of friction-factor estimates for gravel bed streams. The purpose of this paper is to develop a reliable resistance formula in terms of the Darcy-Weisbach friction factor f Published data were screened and used to establish the formula. The existing formulas have considered thatfis a function of relative roughness D84/R only, where R is the hydraulic radius and 1984 is the particle size referred to the intermediate diameter that equals or exceeds that of 84 percent of bed sediments. In this paper, f is considered as a ftmction of Froude number in addition to the relative roughness, ffor D84/R〉l displays a different trend than that for Dsn/R〈l perhaps due to the invalid assumption of a logarithmic velocity distribution for D84/R〉l. Anfformula for Dsa/R〈l has been established. 相似文献
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Flow and Containment of Injected Wastes 总被引：2，自引：0，他引：2
《Ground Water Monitoring & Remediation》1986,6(3):37-48
Proper design, construction, testing and maintenance of Class 1 (hazardous waste) injection wells can guarantee that all waste is delivered to the injection zone. To assess the effects of waste injection, analytical models were developed which predict waste movement and pressure increases within the injection zone, and describe upward permeation through confining layers.
A basic plume model was used to track waste from several injection wells with varied injection history at DuPont's Victoria Texas site. To determine the maxi-mum distance that any portion of the waste might travel, special purpose models were employed to account for (1) density differences between the waste and the native formation brine, and (2) layered permeability variation within the injection zone. The results were generalized to a "multiplying factor concept," which facilitates development of a worst-case scenario.
A pressure distribution model based on the Theis (1935) equation for radial flow was applied to the Victoria site, with modifications to account for multiple wells, injection history and geological complexities.
Permeation into an intact confining layer was investigated by a new technique based on the Hantush and Jacob (1955) "leaky aquifer" theory. The model defines the maximum permeation distance, taking into account post-injection pressure decay.
Defects within confining layers, such as faults, fractures and abandoned wells, have been considered. Studies to evaluate their detailed characteristics are continuing. Initial results indicate that faults and fractures are not likely to provide conductive pathways in Gulf Coast settings, and site-specific evaluations are required to assess the impact of abandoned wells. 相似文献
A basic plume model was used to track waste from several injection wells with varied injection history at DuPont's Victoria Texas site. To determine the maxi-mum distance that any portion of the waste might travel, special purpose models were employed to account for (1) density differences between the waste and the native formation brine, and (2) layered permeability variation within the injection zone. The results were generalized to a "multiplying factor concept," which facilitates development of a worst-case scenario.
A pressure distribution model based on the Theis (1935) equation for radial flow was applied to the Victoria site, with modifications to account for multiple wells, injection history and geological complexities.
Permeation into an intact confining layer was investigated by a new technique based on the Hantush and Jacob (1955) "leaky aquifer" theory. The model defines the maximum permeation distance, taking into account post-injection pressure decay.
Defects within confining layers, such as faults, fractures and abandoned wells, have been considered. Studies to evaluate their detailed characteristics are continuing. Initial results indicate that faults and fractures are not likely to provide conductive pathways in Gulf Coast settings, and site-specific evaluations are required to assess the impact of abandoned wells. 相似文献
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流动成像测井研究进展 总被引：2，自引：3，他引：2
流动成像测井属于对非均匀介质动态的非线性测量，通过对油气井内多相流体信息的投影扫描和反演处理，实时成像显示流体分布及流动状况，国外研制的电导法，电容法仪器采用电导探针或电容元件构成阵列测量探头，分别利用油气与水的导电特性和介电特性差异辨识井内流体，对流动截面的测量局限于个别点上，已在水平井中见到应用效果，但对物场信息投影测量的数据量和分辨率未能满足成像要求。我国提出的电磁法采用环状阵列电极构成测量探头，综合利用油气与水的导电和介电特性差异辨识井内流体，可以测量获得多相流体流动截面的清晰图像，为研究开发全新的流动成像测井系统奠定了良好基础。 相似文献
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A new MODFLOW package (Nonlinear Flow Process; NLFP) simulating nonlinear flow following the Forchheimer equation was developed and implemented in MODLFOW‐2005. The method is based on an iterative modification of the conductance calculated and used by MODFLOW to obtain an effective Forchheimer conductance. The package is compatible with the different layer types, boundary conditions, and solvers as well as the wetting capability of MODFLOW. The correct implementation is demonstrated using four different benchmark scenarios for which analytical solutions are available. A scenario considering transient flow in a more realistic setting and a larger model domain with a higher number of cells demonstrates that NLFP performs well under more complex conditions, although it converges moderately slower than the standard MODFLOW depending on the nonlinearity of flow. Thus, this new tool opens a field of opportunities to groundwater flow simulation with MODFLOW, especially for core sample simulation or vuggy karstified aquifers as well as for nonlinear flow in the vicinity of pumping wells. 相似文献
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The method of conformal mapping is applied to the analysis of transient flow toward parallel periodic drains in a semi-infinite aquifer taking into consideration the non-linear boundary conditions on the free surface. The mapping function is expressed as a power series in time and the seepage domain is mapped onto a domain of an auxiliary complex variable. Mapping is performed in such a manner that the free surface will always remain the real axis. Calculations are carried out for different ratios of drain depth to drain spacing using various drain diameter to depth ratios. 相似文献
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基于长期从事水工建筑物渗漏、管涌等安全隐患检测工作的需要,结合水工建筑物渗漏管涌隐患分布的特点,对水底及水体中的电场分布进行了分析研究.本文从水流场与电流场的相似性、渗流场与电流场的相似性以及动态导体充电法的相关理论三个方面阐述了流场法理论的客观性、合理性以及与动态导体充电法理论的兼容性.首先利用水流场与电流场的相似性解释异常水流场,其次从渗流场与电流场的相似性解释异常水流场,最后利用水工建筑物堤坝渗漏管涌通道地电模型,进一步论述了利用地下动态导体充电法中的不等位导体理论来认识流场法理论更为方便,并可以进行渗漏出口处的电流强度计算及进行正反演计算,同时证明了异常水流场与电流场有着近似的对应关系,以工程实例介绍了流场法在水工建筑物渗漏管涌检测中的应用. 相似文献
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The variation of effective hydraulic conductivity as a function of specific discharge in several 0.2-m and 0.3-m cubes of Key Largo Limestone was investigated. The experimental results closely match the Forchheimer equation. Defining the pore-size length scale in terms of Forchheimer parameters, it is demonstrated that significant deviations from Darcian flow will occur when the Reynolds number exceeds 0.11. A particular threshold model previously proposed for use in karstic formations does not show strong agreement with the data near the onset of nonlinear flow. 相似文献
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S. Puri 《Ground water》1984,22(5):538-543
Flow simulations supplemented resource evaluation studies of the Lower Greensand aquifer. The annual recharge has hitherto been considered to be the resource available for development although a large confined storage exists. Pumping is principally in urban areas but recent monitoring suggests that the aquifer may have suffered excessive drawdowns. Therefore, simulation studies were carried out to refine the annual recharge estimate, to define the past effects of pumping and to obtain an indication of future trends. Catchment water balance indicates average annual recharge of 28 × 106 m3. One-dimensional (ID) ground-water flow simulation suggests that regional abstractions affect outcrop-water levels. The study showed that the aquifer reached a new equilibrium with the current pumping regime. An improved insight to the aquifer has permitted the formulation of strategies for future resource development. 相似文献
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Jonathan J. Wylie Karl R. Helfrich Brian Dade John R. Lister John F. Salzig 《Bulletin of Volcanology》1999,60(6):432-440
During a basaltic fissure eruption heat transfer from the hot magma to the surrounding rock causes a dramatic increase in
the magmatic viscosity and solidification at the margins. Both viscosity contrast and solidification can amplify initial variations
in the flow rate and lead to localization of the flow along the strike of the fissure. However, for typical parameters, amplification
driven by solidification is slower and significantly weaker than amplification driven by viscosity variations. In fact, for
the parameters examined, the amplification due to solidification is so weak that its effect is almost insignificant, whereas
viscosity variation provides a strong active mechanism for flow localization. Laboratory experiments illustrate viscous localization
and suggest that this mechanism is robust. The dependence of viscosity on temperature can cause a small change in the pressure
of the magma chamber to lead to a large jump in the flow rate of magma through the fissure.
Received: 13 March 1998 / Accepted: 27 September 1998 相似文献
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In this paper, a new flow resistance equation for rill flow was deduced applying dimensional analysis and self‐similarity theory. At first, the incomplete self‐similarity hypothesis was used for establishing the flow velocity distribution whose integration gives the theoretical expression of the Darcy–Weisbach friction factor. Then the deduced theoretical resistance equation was tested by some measurements of flow velocity, water depth, cross section area, wetted perimeter, and bed slope carried out in 106 reaches of some rills shaped on an experimental plot. A relationship between the velocity profile, the channel slope, and the flow Froude number was also established. The analysis showed that the Darcy–Weisbach friction factor can be accurately estimated by the proposed theoretical approach based on a power–velocity profile. 相似文献