An inverse method for soil permeability estimation from gas pump tests

Xun-Hong Chen

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

This paper applies an inverse method to analyzing the sensitivities of gas flow for the estimation of horizontal and vertical soil permeabilities. Because a Galerkin finite-element model is used to simulate gas flow, the inverse method provides flexibility in the treatment of complex system conditions (for example, a partially confined vadose zone). The analysis of sensitivities to vertical and horizontal soil permeabilities provides important information for optimal design of the gas pump test. Theoretical examples demonstrate that the magnitudes of sensitivity coefficients and their spatial correlation are largely dependent on the locations of data points, the radial extent of surface seal, and soil anisotropy. A surface seal can increase the magnitude of the sensitivities and reduce the correlation between the sensitivities. Therefore, the quality of the estimation of soil permeability is improved. Results of computational experiments show that when the correlation between the sensitivities is larger, computation of the parameter values may require more iterations to converge from a narrower range of initial estimates and the calculated soil parameter values are generally less reliable. Measurement error could result in high uncertainty in parameter estimation.

Original languageEnglish (US)
Pages (from-to)751-763
Number of pages13
JournalComputers and Geosciences
Volume25
Issue number7
DOIs
StatePublished - Aug 1 1999

Fingerprint

pump
Pumps
permeability
Soils
Gases
gas
gas flow
soil
Seals
Flow of gases
Measurement errors
vadose zone
Parameter estimation
Large scale systems
Anisotropy
anisotropy
method
test
experiment
Experiments

Keywords

  • Gas flow
  • Least squares analysis
  • Sensitivity coefficients
  • Soil permeability

ASJC Scopus subject areas

  • Information Systems
  • Computers in Earth Sciences

Cite this

An inverse method for soil permeability estimation from gas pump tests. / Chen, Xun-Hong.

In: Computers and Geosciences, Vol. 25, No. 7, 01.08.1999, p. 751-763.

Research output: Contribution to journalArticle

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