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A Program for Analyzing Transient and Steady‐State Soil Gas Pump Tests
Author(s) -
Falta Ronald W.
Publication year - 1996
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1996.tb02064.x
Subject(s) - transient (computer programming) , compressibility , mechanics , nonlinear system , fortran , permeability (electromagnetism) , steady state (chemistry) , flow (mathematics) , compressibility factor , geotechnical engineering , petroleum engineering , geology , chemistry , physics , computer science , biochemistry , quantum mechanics , membrane , operating system
Soil gas pump tests are commonly performed to identify important unsaturated zone parameters such as the effective gas permeability tensor and the influence of tight or leaky confining units. An interactive FORTRAN computer program called GASSOLVE has been developed for analyzing these tests under both transient and steady‐state conditions. The code uses one of two general analytical solutions for radially symmetric gas flow to a well: the solution for transient compressible gas flow to a partially penetrating well in which the ground surface is open to the atmosphere; and the solution for transient compressible gas flow to a partially penetrating well bounded above by a leaky confining layer. Pump tests involving steady‐state conditions, fully penetrating wells, or tight confining layers are considered as special cases of these solutions. The field gas pressure data from multiple observation wells are inverted using a multidimensional nonlinear optimization routine to provide a best fit of the data with the selected analytical solution.