A nonlinear model for analysis of slug-test data

Water Resources Research
By:  and 



While doing slug tests in high-permeability aquifers, we have consistently seen deviations from the expected response of linear theoretical models. Normalized curves do not coincide for various initial heads, as would be predicted by linear theories, and are shifted to larger times for higher initial heads. We have developed a general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the well bore, and a Hvorslev model for the aquifer, which explains these data features. The model produces a very good fit for both oscillatory and nonoscillatory field data, using a single set of physical parameters to predict the field data for various initial displacements at a given well. This is in contrast to linear models which have a systematic lack of fit and indicate that hydraulic conductivity varies with the initial displacement. We recommend multiple slug tests with a considerable variation in initial head displacement to evaluate the possible presence of nonlinear effects. Our conclusion is that the nonlinear model presented here is an excellent tool to analyze slug tests, covering the range from the underdamped region to the overdamped region.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A nonlinear model for analysis of slug-test data
Series title Water Resources Research
DOI 10.1029/97WR02710
Volume 34
Issue 1
Year Published 1998
Language English
Publisher American Geophysical Union
Description 12 p.
First page 55
Last page 66
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