Analytical solution for subsurface gas flow to a well induced by surface pressure fluctuations

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Hydrogeology

Background:

• Subsurface gas flow in vadose-zone wells is influenced by atmospheric pressure fluctuations.
• Barometric pumping is a phenomenon where changes in atmospheric pressure induce gas movement.
• Accurate prediction of this flow is crucial for environmental remediation systems.

Purpose of the Study:

• To develop a simple analytical model for predicting subsurface gas flow to vadose-zone wells.
• To determine the effective radial permeability (kr) near the well through model calibration.
• To enable quantitative prediction of induced well flow using only atmospheric pressure data.

Main Methods:

• An analytical model was developed to simulate gas flow in response to barometric pumping.
• Model calibration involved determining effective radial permeability (kr) using short-term data (< 2 weeks).
• The model combines a subsurface flow solution with a vertical gas pressure solution.

Main Results:

• The model successfully predicts subsurface gas flow induced by atmospheric pressure fluctuations.
• Effective radial permeability (kr) can be determined efficiently during model calibration.
• Only atmospheric pressure data are needed to predict the induced flow.

Conclusions:

• The developed analytical model provides a simple and effective method for predicting barometric pumping effects in vadose-zone wells.
• The ability to quantitatively predict induced flow using inexpensive measurements is valuable for remediation technologies.
• This approach offers a practical tool for managing and optimizing systems that utilize barometric pumping for environmental remediation.