scholarly journals Estimation of aquitard hydraulic conductivity and skeletal specific storage considering non-Darcy flow

2021 ◽  
Author(s):  
Chao Zhuang ◽  
Long Yan ◽  
Zhi-fang Zhou ◽  
Jin-guo Wang ◽  
Zhi Dou
Keyword(s):  
Hydraulic Conductivity ◽  
Darcy Flow ◽  
Specific Storage

Utilizing time-lapse hydraulic tomography to characterize the subsurface changes during methane and heat injection experiments

2020 ◽  
Author(s):  
Linwei Hu ◽  
Márk Somogyvári ◽  
Sebastian Bauer
Keyword(s):  
Hydraulic Conductivity ◽  
Thermal Water ◽  
Water Injection ◽  
Time Lapse ◽  
Hot Water ◽  
Heterogeneous Structure ◽  
Specific Storage ◽  
Pumping Tests ◽  
Hydraulic Diffusivity ◽  
Hydraulic Tomography

<p>Storage options for the energy storage in the subsurface includes the injection and storage of the “energy gas” (e.g., methane, hydrogen, compressed air) or thermal water into the underground formations. The heterogeneous structure of the storage formations could play a crucial role on the potential storage capacity, as well as the formulation of post treatment strategy. Hence, innovative techniques are required for characterizing the high-resolution formation heterogeneity and monitoring the gas or heat plume distribution in the subsurface after their injections.  Previous studies have shown that flow properties can vary as the gas or thermal water being injected into the aquifer. In this study, we propose a time-lapse hydraulic tomography (HT) method for characterizing the baseline hydraulic information and depicting the hydraulic property changes through a series of cross-well pumping tests. These tests were implemented in two pilot sites for methane and hot water injection tests at Wittstock, Germany. In order to generate a three-dimensional tomographical configuration, each pumping test was conducted at certain depth in a testing well, accompanying with multiple observation points at other wells. Depth-variant pumping and observation segments were formed by the double-packer system. As a result, we achieved 198 and 135 baseline drawdown curves for the methane and heat sites, respectively. For these measured data, we initially evaluated the effective hydraulic conductivity and specific storage of the aquifer according to certain analytical fitting methods. Furthermore, the vertical anisotropy of the hydraulic conductivity was also estimated. Sequentially, the fitted hydraulic parameters and analytical drawdown curves were utilized for correcting the well skin effects on hydraulic traveltimes and attenuations, as they have an unneglectable impact on them.  The corrected hydraulic traveltimes and attenuations were used for the inversion of the baseline hydraulic diffusivity and specific storage, respectively. Hydraulic conductivity distribution was then estimated through these two parameters. After we achieved the baseline information, HT was executed again by repeating the tomographical pumping tests after methane and hot water injections. The same data processing and inversion techniques were applied to the drawdown curves derived from the post-injection period. Inverted hydraulic diffusivity, specific storage, and hydraulic conductivity were compared to the baseline inversion results. Changes on these hydraulic properties could provide the information of the spatial distribution of methane or heat plume.</p>

Hydrologic Characteristics and Response of Fractured Till and Clay Confining a Shallow Aquifer

1975 ◽  
Vol 12 (1) ◽  
pp. 23-43 ◽  
Author(s):  
G. E. Grisak ◽  
J. A. Cherry
Keyword(s):  
Hydraulic Conductivity ◽  
Fractured Rock ◽  
Nuclear Research ◽  
Pumping Test ◽  
Shallow Aquifer ◽  
Ratio Method ◽  
Clay Loam ◽  
Specific Storage ◽  
Groundwater Movement ◽  
Lacustrine Clay

Fractures in glacial till and glaciolacustrine clay were observed in excavations up to 20 ft (6.1 m) in depth and in drill cores at the Whiteshell Nuclear Research Establishment (WNRE) in southeastern Manitoba. The fractures are characteristically coated with carbonate and oxide precipitates, which indicate groundwater movement through the fractures. The fractures impart an effective bulk hydraulic conductivity to the clay–loam till and lacustrine clay, as evidenced by tritium tracer experiments and piezometer responses in the till and clay to pumping of an underlying sandy aquifer.The intergranular hydraulic conductivity of clay–loam till and glaciolacustrine clay in the Interior Plains, as determined from laboratory consolidation test data, is in the range of 2 × 10−10 to 9 × 10−11 ft s−1 (6 × 10−9 to 2.7 × 10−9 cm s−1). The bulk hydraulic conductivity of the fractured clay–loam till at WNRE, as determined from finite-element mathematical modeling, is about 6 × 10−9 ft s−1 (1.8 × 10−7 cm s−1). The model value represents the effective hydraulic conductivity imparted to the till by the fractures.Seven pumping tests, ranging in duration from 8.75 to 120 h were conducted on the sandy aquifer and drawdown data in the aquifer were analyzed to obtain the hydraulic conductivity and storativity of the aquifers.A 32 day pumping test on the aquifer showed that many of the piezometers in the till and clay respond quickly and strongly to the aquifer drawdown, while others show no noticeable response. The responding piezometers intersect open fractures whereas the others do not. Analysis of the piezometer drawdowns during the long-term pumping test using the Neuman and Witherspoon ‘ratio’ method indicates that the rapid piezometer drawdowns in the confining layers can be accounted for by assigning specific storativity values in the range of 1 × 10−5 to 5 × 10−6 ft−1 (3 × 10−5 to 1.5 × 10−5 m−1) to the clay–loam till and lacustrine clay. These values are typical of fractured rock. If intergranular specific storage values are used, the calculated piezometer drawdowns are very small or negligible.

scholarly journals Extensometer forensics: what can the data really tell us?

2019 ◽  
Vol 28 (2) ◽  
pp. 637-655
Author(s):  
Thomas J. Burbey
Keyword(s):  
Hydraulic Conductivity ◽  
Land Subsidence ◽  
Numerical Models ◽  
Water Levels ◽  
Depth Interval ◽  
Key Factors ◽  
Specific Storage ◽  
Las Vegas Valley ◽  
Multiple Frequencies ◽  
Parameter Values

AbstractExtensometer data have an advantage over satellite-based data for monitoring land subsidence in that extensometer data provide continuous measurements (hourly or better temporal resolution) at very high precision (several tens of microns) over a known depth interval; the latter is important for isolating groundwater pumping from other causes of land subsidence attributed to tectonics or eustatic adjustments in the Earth’s crust. This investigation aims to identify a semi-analytical procedure for quantifying aquifer and aquitard properties from a single extensometer record in lieu of the time-consuming development of more complex numerical models to quantify and constrain these parameter values. In spite of a limited 12-year record and the fact that water levels both decline and increase on an annual basis, this study successfully and reasonably estimated both aquifer and aquitard parameters at the Lorenzi extensometer site in Las Vegas Valley, Nevada (USA), when compared to the estimates developed numerically. The key factors that allow for estimates of elastic and inelastic skeletal-specific storage and hydraulic conductivity of the aquitards and elastic specific storage and hydraulic conductivity of the intervening aquifers is the presence of pumping cycles at multiple frequencies, and measured heads at all the aquifer units covered in the extensometer record. There is an inherent assumption that the aquitards possess the same hydrologic characteristics and are homogeneous and isotropic. This assumption is also a usual limitation in numerical modeling of these settings because of the complex temporal head relationships occurring within the aquitards that are rarely, if ever, measured.

scholarly journals Prediction of solute transport in a heterogeneous aquifer utilizing hydraulic conductivity and specific storage tomograms

2015 ◽  
Vol 51 (7) ◽  
pp. 5504-5520 ◽  
Author(s):  
S. Jiménez ◽  
R. Brauchler ◽  
R. Hu ◽  
L. Hu ◽  
S. Schmidt ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Solute Transport ◽  
Specific Storage ◽  
Heterogeneous Aquifer

Transient Hydraulic Tests in Granite: Fissured Porous Medium Analysis and Results

1981 ◽  
Vol 6 ◽  
Author(s):  
John H. Black ◽  
John A. Barker
Keyword(s):  
Hydraulic Conductivity ◽  
Water Movement ◽  
Granitic Rocks ◽  
Interval Length ◽  
Rock Matrix ◽  
Test Interval ◽  
Specific Storage ◽  
Test Analysis ◽  
Fissured Rock ◽  
Apparent Relationship

ABSTRACTSlug and pulse tests have been used extensively to measure the hydraulic conductivity and specific storage of granitic rocks. After several hundred tests using an I.G.S. design of straddle packer test equipment, it became clear that the conventional methods of test analysis were inadequate. The straddle packer equipment developed by IGS allows the time scale of a test to be altered without repositioning the packers so that a range of tests can be carried out on the same test interval. The new analysis procedure presented here uses a model of fissured rock which incorporates water movement in both the fissures and the rock matrix. A new variable is introduced which includes the parameters matrix hydraulic conductivity, matrix specific storage fissure specific storage and fissure hydraulic conductivity together with the controllable variables, effective casing radius and packer interval length. Examples of analysis using multiple tests in the same interval are presented together with the apparent relationship between measured hydraulic conductivity and specific storage. It would appear that a small number of fissures endow the rock mass with the bulk of its hydraulic conductivity and that many of the higher hydraulic conductivity tests are probably associated with localised “pipe flow”.

scholarly journals Parameter estimation of a multiple aquifer-aquitard system from a single extensometer record: Las Vegas, Nevada, USA

2020 ◽  
Vol 382 ◽  
pp. 51-56
Author(s):  
Thomas J. Burbey
Keyword(s):  
Hydraulic Conductivity ◽  
Analytical Procedure ◽  
Las Vegas ◽  
Numerical Models ◽  
Water Levels ◽  
Key Factors ◽  
Specific Storage ◽  
Las Vegas Valley ◽  
Multiple Frequencies ◽  
Parameter Values

Abstract. The purpose of this investigation is to develop a semi-analytical procedure for quantifying aquifer and aquitard properties from a single extensometer record in lieu of the time-consuming development of more complex numerical models to quantify and constrain these parameter values. Despite a limited 12-year record and the fact that water levels both decline and increase on an annual basis, estimates of both aquifer and aquitard parameters have been reasonably estimated at the Lorenzi extensometer site in Las Vegas Valley, Nevada when compared to the estimates developed numerically. The key factors that allow for accurate estimates of elastic and inelastic skeletal specific storage and hydraulic conductivity of the aquitards and elastic specific storage and hydraulic conductivity of the intervening aquifers is the presence of pumping cycles at multiple frequencies, and measured heads at all the aquifer units covered in the extensometer record and the inherent assumption that the aquitards have identical hydrologic characteristics and are homogeneous and isotropic. This latter assumption is also a usual limitation in numerical modelling of these settings because of the complex temporal head relationships occurring within the aquitards that are rarely, if ever, measured.

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