(Received 15 February 2007; accepted 25 November 2008)

**Published Online: **2009

**CODEN:** GTJOAD

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Pressure transducers are frequently used to monitor slug tests, and to collect a data set for height *Z* of water column versus time *t*. Direct application of the data to draw a velocity graph usually produces a wide scatter, thus limiting the usefulness of the velocity graph method. This paper proposes to interpret the data set in five steps. First, a *Z*(*t*) plot is drawn to assess the uncertainty in the *Z* data. Second, a limited number of data points are selected to reduce the uncertainty to about ±10 % in the velocity graph. Third, the velocity graph is drawn to obtain the hydraulic conductivity *k* and the piezometric error *H*_{0}, if any, giving the piezometric level for the test. Fourth, the graph of ln(*Z*−*H*_{0}) versus *t* is drawn to verify its linearity and check the *k* value of the velocity graph. Fifth, the graph of *Z* versus log_{10}(*t*) can be used in a curve fitting process to yield directly both *H*_{0} and *k*, thus providing a second method to interpret the data set, which may be the only one possible when the *Z*(*t*) data are inaccurate. Examples are provided to illustrate the five steps and common problems.

**Author Information:**

Chapuis, Robert P.*École Polytechnique de Montréal, *

**Stock #:** GTJ101058

**ISSN:** 0149-6115

**DOI:** 10.1520/GTJ101058

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AuthorTitle Interpreting Slug Tests with Large Data Sets

Symposium , 0000-00-00

Committee D18