Harmonic analysis of flow in open boreholes due to barometric pressure cycles

Neeper, D.A.

doi:10.1016/s0169-7722(02)00086-4

Cited by 33 publications

(52 citation statements)

References 13 publications

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“…This process is named barometric pumping (BP), and the well is called a barometric pumping well (BPW) [ Jennings and Patil , 2002]. A BPW exhales the volatile or semivolatile organic contaminants out of the soil and inhales the fresh air into the soil without mechanical pumping; thus, it is a favored passive remediation technology in the unsaturated zone [ Ellerd et al , 1999; Rossabi and Falta , 2002; Neeper , 2003]. Passive soil vapor extraction (PSVE) harnesses this natural breathing process to remediate volatile organic compounds (VOCs).…”

Section: Introductionmentioning

confidence: 99%

Gas flow to a barometric pumping well in a multilayer unsaturated zone

You

Zhan

2011

Water Resources Research

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[1] When an open well is installed in an unsaturated zone, gas can flow between the subsurface and the well depending on the gas pressure gradient near the well. This well is called a barometric pumping well (BPW). Quantifying gas flow rate to and from a BPW is indispensable to optimize the passive soil vapor extraction in remediation of volatile organic compounds in the unsaturated zone. This study presents a two-dimensional (2-D) semianalytical solution for a multilayer unsaturated zone (ML solution) to determine gas flow rate to and from a BPW. The gas flow rate is approximated by a decomposing method frequently used in previous studies, that is, first solving the one-dimensional (1-D) vertical flow equation in response to the surface barometric pressure fluctuations and then superimposing this solution on that of the 1-D horizontally radial flow equation. The error induced by this approximation is quantified by a 2-D numerical simulation for the first time in this study. Results show that the maximum error induced is 20% at the peak flow rates. The ML solution is demonstrated to be sufficient for predicting subsurface gas pressure and gas flow rate in a multilayer unsaturated zone by the barometric pumping test at the Hanford site.Citation: You, K., H. Zhan, and J. Li (2011), Gas flow to a barometric pumping well in a multilayer unsaturated zone, Water Resour.

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Section: Introductionmentioning

confidence: 99%

Gas flow to a barometric pumping well in a multilayer unsaturated zone

You

Zhan

2011

Water Resources Research

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“…In this study, TIC was determined to be the primary air transport mechanism inside the borehole, yet the fact that barometric pumping did not play a significant role (Figures a5 and b5) needs further discussion, especially noting that barometric pumping has been previously reported as the main transport mechanism inside boreholes (e.g., Neeper, ; You et al, ). We argue that the borehole geometry is the main parameter that determines which transport mechanisms will be more significant.…”

Section: Resultsmentioning

confidence: 73%

“…Several mechanisms can drive advective gas exchange at the borehole‐atmosphere interface and inside a borehole or cavity. These include (1) barometric pumping, which is the inward and outward motion of subsurface air due to cycles in atmospheric pressure (Mourzenko et al, ; Neeper, ; Perina, ; Rossabi & Falta, ); (2) thermal‐induced convection (TIC), also referred to as free convection, which initiates when there are unstable density gradients resulting from temperature differences between the atmospheric air and that within underground voids, such as porous media or boreholes (Calonne et al, ; Ganot et al, ; Luetscher et al, ; Luetscher & Jeannin, ; Nachshon et al, ; Weisbrod et al, ; Weisbrod & Dragila, ); and (3) wind‐induced convection (WIC) within a cavity that is driven by pressure differences generated from surface winds (Amos et al, ; Ishihara et al, ; Nachshon et al, ; Reicosky et al, ).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms Controlling Air Stratification Within a Large Diameter Borehole and Atmospheric Exchange

et al. 2018

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Large boreholes dot the landscape across much of the arid low latitudes. Here we explore air dynamics within these features to understand their significance to gas transport at the Earth‐atmosphere interface. We instrumented a large‐diameter (3.4 m) borehole and the borehole‐atmosphere interface to explore under natural conditions the role of atmospheric variability on gas transport down to the water table at a depth of 59 m. Two independent tracers that naturally existed inside the borehole, water vapor and CO2, were used to map diffusive and advective transport regions and rates. We hypothesize that temporal variations in atmospheric and borehole air temperature determine the transport regime; thus, we conducted two separate 1‐month observations, during summer and winter. Of several potential air transport mechanisms known to act within cavities, thermal‐induced convection (TIC) was found to be the dominating advective mechanism inside the borehole. During winter, TIC circulated atmospheric air throughout the entire borehole down to the water table. During summer, however, atmospheric air reached only down to the middle of the borehole, indicating stable stratification below that depth; TIC was limited to the upper mixed layer overlying a diffusive transport layer. During times when TIC was suppressed, the stratified borehole air developed relatively low temperatures, and accumulated elevated CO2 concentrations and high vapor content, which were then vented to the atmosphere during convective active periods.

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“…However, few careful studies of its fundamentals, such as the gas flow rate and mass removal effectiveness, have been conducted [18], which has hampered the wide use of passive SVE in field applications. Present available references include the studies conducted by Ellerd et al [9], Rossabi and Falta [27], Neeper [19] and Rossabi [25]. Rossabi and Falta [27] and Rossabi [25] developed impulse-response solutions for gas flow rate to/from a BPW for a one-layer soil system.…”

Section: Passive Soil Vapor Extractionmentioning

confidence: 99%

“…Rossabi and Falta [27] and Rossabi [25] developed impulse-response solutions for gas flow rate to/from a BPW for a one-layer soil system. Neeper [19] presented a harmonic analysis of gas flow rate for an open borehole in infinite strata with different horizontal permeability. However, they all derived their 2-D gas flow solutions by superimposing the solutions of two 1-D gas flow problems: the 0309-1708/$ -see front matter Ó 2010 Elsevier Ltd. All rights reserved.…”

Section: Passive Soil Vapor Extractionmentioning

confidence: 99%