General Solution for Tidal Behavior in Confined and Semiconfined Aquifers Considering Skin and Wellbore Storage Effects

Gao, Xuhua; Satô, Kôzô; Horne, Roland N.

doi:10.1002/essoar.10502090.1

Cited by 5 publications

(10 citation statements)

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“…Negative skin effects were included in the horizontal flow model for confined conditions (Gao et al., 2020; Hsieh et al., 1987). Pumping test skin values and AT slug test transmissivities were used in the model.…”

Section: Resultsmentioning

confidence: 99%

“…Numerous attempts were carried out to model the strong decrease in well sensitivities from O 1 to M 2 frequency for the volumetric and horizontal strains (Table 4), associated with positive or negative phase shifts that are relatively close to zero, using the models already published (Gao et al., 2020; Hsieh et al., 1987; Kitagawa et al., 2011; Wang, 2000; Wang et al., 2018). Unfortunately, none of the models were able to provide satisfactory results.…”

Section: Resultsmentioning

confidence: 99%

“…(d) Gao et al. (2020) added borehole skin effects to both the confined model (Hsieh et al., 1987) and the semi‐confined model (Wang et al., 2018). We note that Kitagawa et al.…”

Section: Methodsmentioning

confidence: 99%

“…(2018), while Gao et al. (2020) added borehole skin effects. Skin effects include changes in hydraulic heads and radial flow patterns caused by the modification of aquifer hydraulic conductivity near a well due to installation and subsequent fouling.…”

Section: Introductionmentioning

confidence: 99%

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Estimating Hydraulic Properties of the Shallow Subsurface Using the Groundwater Response to Earth and Atmospheric Tides: A Comparison With Pumping Tests

Valois

Rau

Vouillamoz

et al. 2022

Water Resources Research

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Knowledge of hydraulic and poroelastic subsurface properties is essential for groundwater (GW) resource management, especially in the context of increasing anthropogenic GW use and climate change. Classical single and cross-hole GW characterization uses an induced stimulus to generate a response that is further analyzed to derive subsurface properties. Single hole response tests (slug tests) should always be carried out because they can be easily done and involve very little effort and resources as compared to the monitoring and analysis of the atmospheric and Earth tide fluctuations. Responses from natural stimuli such as Earth tides (ET) or atmospheric tides (AT) can be however a useful approach that provides the ability to utilize existing wells and piezometers as an alternative or complementary technique to estimate these properties. When assessing hydraulic properties, the GW response to ET, barometric pressure (BP) or AT presents a passive approach and low-cost alternative compared to hydraulic testing if the time series are available (McMillan et al., 2019). While the response of GW to ET or AT has long been observed and recognized (e.g.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…(d) Gao et al. (2020) added borehole skin effects to both the confined model (Hsieh et al., 1987) and the semi‐confined model (Wang et al., 2018). We note that Kitagawa et al.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimating Hydraulic Properties of the Shallow Subsurface Using the Groundwater Response to Earth and Atmospheric Tides: A Comparison With Pumping Tests

Valois

Rau

Vouillamoz

et al. 2022

Water Resources Research

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“…Gao et al. (2020) discussed the effect of skin‐damage of well walls, even though this only has a weak effect on the phase shift of a leaky aquifer. Hanson and Owen (1982) and Bower (1983) give the analytical solutions for the tidal response of a saturated, laterally extensive, planar fracture, which predict opposite signs in the phase shifts to the O 1 and the M 2 tides.…”

Section: Discussionmentioning

confidence: 99%

Are Deep Aquifers Really Confined? Insights From Deep Groundwater Tidal Responses in the North China Platform

Zhang

Wang

et al. 2021

Water Resources Research

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Great amount of wastewaters coproduced from hydrofracking shales for the extraction of natural gas in the mid-continental US has been disposed into deep aquifers (e.g., McGarr et al., 2015;Walsh & Zoback, 2015;Weingarten et al., 2015). The US Environmental Protection Agency that regulates such practices to protect potable water sources from the injected wastewater focuses on well integrity and deep aquifers isolated from shallow groundwater by geologic barrier formations above the injection zone (e.g., Murray, 2014; U.S. Environmental Protection Agency, 2016). Concerns have been raised if the injected fluids may migrate upward and contaminate shallow groundwater (Vidic et al., 2013). Recent studies (Barbour et al., 2019;Wang et al., 2018) also showed that a targeted deep aquifer in Oklahoma (the Arbuckle aquifer) may be leaking near a USGS well, but no systematic evaluation of the confinement of aquifers buried by mudstones or shales has so far been made. The problem is timely and of global significance because the practice of Abstract Many deep aquifers overlain by barrier formations in the continental US are used as geological repositories for wastewaters coproduced from hydrocarbon exploration. This practice is to protect shallow groundwater following the US Environmental Protection Agency's regulation. Implicit in such practice is the assumption that deep aquifers overlain by mudstones or shales are confined so that the injected fluids will not migrate upward to contaminate shallow groundwater. However, no systematic test of this hypothesis has been made. Here we invert the groundwater response to both the M 2 and the O 1 tides and to the barometric pressure across a large (2.046 × 10 6 km 2 ) geologic regime, the North China Platform, to systematically evaluate the hydraulic parameters as functions of depth and time without a priori assumption. Our result, the first of such inversion, shows no depth dependence of aquifer confinement to a depth of 3,400 m and that deep confined aquifers overlain by barrier formations may become leaky after distant earthquakes. It suggests that monitoring of aquifer confinement may be needed to ensure if the targeted deep aquifer for wastewater injection is really confined. The results may be timely and of global significance because the practice of hydrofracking for natural gas and the deep injection for the disposal of the coproduced wastewaters in the US may soon be adopted by other countries, such as China.Plain Language Summary A great amount of wastewaters coproduced from hydrocarbon exploration in the mid-continental US has been injected into deep aquifers. Such practice has been based upon an implicit assumption that deep aquifers confined by aquitards are fully confined so that the injected toxic water will not leak back to contaminate shallow groundwater or the environment. This assumption, however, has never been carefully tested. Here we test this hypothesis using groundwater data from wells over a large geological regime, the North China Platform, as a function of...

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Groundwater Responses to Earth Tides: Evaluation of Analytical Solutions Using Numerical Simulation

2022

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Harmonic Earth tide components in well water levels have been used to estimate hydraulic and geomechanical subsurface properties. However, the robustness of various methods based on analytical solutions has not been established. First, we review the theory and examine the latest analytical solution used to relate well water levels to Earth tides. Second, we develop and verify a novel numerical model coupling hydraulics and geomechanics to Earth tide strains. Third, we assess subsurface conditions over depth for a range of realistic properties. Fourth, we simulate the well water level response to Earth tide strains within a 2D poroelastic layered aquifer system confined by a 100 m thick aquitard. We find that the non‐linear inversion of analytical solutions to match two observations (amplitudes and phases) to multiple unknown parameters is sensible to the initial guess. We reveal that undrained, confined conditions are necessary for the analytical solution to be valid. This occurs for the dominant M2 frequency at depths >50 m and requires specific storage at constant strain of Sϵ ≥ 10−6 m−1, hydraulic conductivity of the aquitard of kl ≤ 5 ⋅ 10−5 ms−1 and aquifer of ka ≥ 10−4 ms−1. We further illustrate that the analytical solution is valid in unconsolidated systems, whereas consolidated systems require additional consideration of the Biot modulus. Overall, a priori knowledge of the subsurface system supports interpretation of the groundwater response. Our results improve understanding of the effect of Earth tides on groundwater systems and its interpretation for subsurface properties.

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General Solution for Tidal Behavior in Confined and Semiconfined Aquifers Considering Skin and Wellbore Storage Effects

Cited by 5 publications

References 0 publications

Estimating Hydraulic Properties of the Shallow Subsurface Using the Groundwater Response to Earth and Atmospheric Tides: A Comparison With Pumping Tests

Estimating Hydraulic Properties of the Shallow Subsurface Using the Groundwater Response to Earth and Atmospheric Tides: A Comparison With Pumping Tests

Are Deep Aquifers Really Confined? Insights From Deep Groundwater Tidal Responses in the North China Platform

Groundwater Responses to Earth Tides: Evaluation of Analytical Solutions Using Numerical Simulation

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