摘要:

AbstractThe objective of this research was to determine a well test model which could be used for determining the hydraulic parameters of T and S in the complex fractured carbonates of the Ozarks of southern Missouri. Municipal water well testing in the Ozarks is performed on deep wells completed in confined fractured carbonate aquifers where all of the flow to the wellbore is through the fractures but most of the storage is in the matrix blocks. Observation wells are not used because of cost. The methodology uses double porosity well test analysis including the inner boundary conditions of skin and wellbore storage. Using this method, S and T are obtained as well as the storativity ratio, ω, and the block to fracture flow parameter λ. Because wellbore storage, skin, and storativity are interrelated, a computer simulation to find the final S was necessary. Derivative curve analysis provided a constraint in determining the correctness of the simulation results. Failure to use this well test method proved to result in storativities which are much too large. An example is presente

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00830.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractOnshore reflection seismics have been used to characterize the geometry and lithology of ground‐water reservoirs. The study was carried out as a seismic sequence and facies analysis along Rabis Creek in western Denmark. A1350 m long seismic section was produced on a presumed homogeneous outwash sand plain. High resolution data to a depth of 160 m (200 msec two‐way time) were obtained along most of this section, and reflections from more than 400 m in depth were obtained locally. The seismic data have been correlated with electrical resistivity logs. The reservoir is, in contrast to the expectations, highly heterogeneous, composed of three distinguishable seismic sequences of unconsolidated sediments. Layers down to 1.5 m thick were recognized in the seismic data. The study shows that onshore reflection seismics provide a unique possibility of 2‐D reservoir scale characterization of geological structures. Combined with seismic facies and sequence analysis, seismic profiling forms a strong hydrogeological tool that may supplement traditional boring and logging me

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00831.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe combination of the analytic element method and a nonlinear parameter estimation technique forges a computationally efficient, information‐rich, and cost‐effective solution to the inverse ground‐water flow problem. The recommended model calibration method uses a nonlinear least‐squares objective, as quantified by misfitting the measured and modeled heads, and a modified Levenberg‐Marquardt algorithm. As detailed and demonstrated by a steady‐state regional aquifer model of Bemidji, Minnesota, automated calibration techniques make ground‐water modeling feasible for a wider variety of projects where tight budgets and a lack of tools may have previously made such modeling

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00832.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractEstablished pump‐and‐treat ground‐water remediation is criticized for being too expensive and time‐consuming, especially when cleanup standards are set at very low levels, e.g.,50 ft below ground surface) widespread ground‐water contamination. The perceived shortcomings of pump and treat result from (1) the tendency of most contaminants to sorb to formation materials, thus retarding contaminant removal; (2) geologic complexity, which requires detailed characterization for the design of optimal extraction systems within available resources; and (3) the failure to apply dynamic well field management techniques.The alternative, “smart pump and treat” consists of (1) detailed characterization of the geology, hydrology, and chemistry; (2) use of computer‐aided data interpretation, data display, and decision support systems; (3) removal of source terms, if possible; (4) initial design for plume containment and source remediation; (5) phased installation of the well field; (6) detailed monitoring of the remediation; (7) active ongoing reevaluation of the operating well field, including redesign as appropriate (dynamic management); (8) reinjection of treated ground water to speed the flushing of contaminants; and (9) setting of appropriate cleanup levels. Use of some or all of these techniques can dramatically reduce the time required to achieve cleanup goals and thus the cost of ground

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00833.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA ground‐water quality management model is applied to the Gloucester Landfill site, located near Ottawa, Canada, to examine the effectiveness of various single‐well pumping schemes for the capture of dissolved contaminants. Deterministic and stochastic design analyses are conducted through ground‐water solute transport modeling of the site. The purpose of the modeling analysis is to develop contaminant capture designs that both require minimum pumping rates and possess high probabilities of success.Optimization based upon deterministic simulation indicates that a well located at the front of the plume would effect plume capture and require the lowest pumping rate. However, a smaller total volume of water could be pumped and still effect plume capture if the well were located at the center of the plume and pumped at a higher rate for a shorter time. Stochastic optimization analyses are used to overdesign the pumping rates so that possible design error is overcome. The analyses indicate that design reliability may be increased from 50 to 90 percent by pumping an additional 18 percent at the front or 27 percent at the center of the plume. These pumping overdesign factors are the first such values calculated using the stochastic optimization approach applied to a field

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00834.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe knowledge of the value of longitudinal dispersivity is very important in the simulation of solute transport. Therefore, a method for the identification of longitudinal dispersivity in a solute transport laboratory experiment was developed. The solute was assumed to be ideal and the medium isotropic and homogeneous, with a one‐dimensional geometry. The sensitivity of the inversion method to a uniform random noise in porosity, which accounts for possible heterogeneities of the medium, and to concentration measurement errors, which are always present in a laboratory experiment, was analyzed. This analysis is necessary to estimate the reliability of the method. Then, supposing the concentration error distributed according to a Gaussian with zero mean, the probability distribution of the relative identification error was computed as a function of the standard deviation of the Gaussian. The mean value of the relative identification error was found to be positive, due to the nonlinearity of the identification algorith

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00835.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractTo study the effect of spatial variability of sediment hydraulic properties on multiphase flow, oil infiltration into a hypothetical glacial outwash aquifer, followed by oil extraction, was simulated using a cross‐sectional multiphase flow model. The analysis was simplified by neglecting capillary hysteresis. The first simulation used a uniform mean permeability and mean retention curve. This was followed by 50 Monte Carlo simulations conducted using 50 spatially variable permeability realizations and corresponding spatially variable retention curves. For the type of correlation structure considered in this study, which is similar to that of glacial outwash deposits, use of mean hydraulic properties reproduces the ensemble average oil saturation distribution obtained from the Monte Carlo simulations. However, spatial variability causes the oil saturation distribution in an individual oil lens to differ significantly from that of the mean lens. Oil saturations at a given location may be considerably higher than would be predicted using uniform mean properties. During cleanup by oil extraction from a well, considerably more oil may remain behind in the heterogeneous case than in the spatially uniform cas

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00836.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractStatistical analyses were used to determine the relation of hydrogeologic, well construction, and field measurement factors to the extremely variable yield of wells located in consolidated rocks in the Piedmont, Blue Ridge, and Valley and Ridge provinces of Pennsylvania. Specific capacity values (a total of 4,391) from the U.S. Geological Survey well record file were chosen as a measure of yield. Results underscore the importance in regional analysis of accounting for differences due to variables related to well construction and field measurement of specific capacity before attempting to account for differences due to hydrogeology. The approach taken was to organize a hierarchy of variables that relate to differences in specific capacity. Linear regression using log‐transformed specific capacity as the response variable provided estimates of the extent to which variables account for variation in the specific capacity values. Among the variables available for consideration, casing diameter, primary water use, and duration of discharge during the well production test are most important and can explain 24 percent of the variation observed in the specific capacity data. Lithology alone can account for only about 12 percent of the variation observed in the specific capacity data. However, a classification of rocks based on lithology and also accounting for differences in casing diameter, water use, duration of discharge, topographic setting, well depth, and casing depth can explain about half the variation in specific capacity value

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00837.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00838.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1993.tb00839.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY