# Butler Slug Test Solution for Confined Aquifers

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A mathematical solution by Butler (1998) is useful for determining the hydraulic conductivity of **confined** aquifers. The solution accounts for inertial effects in the well and oscillatory slug test response in high-hydraulic conductivity (high-K) aquifers. Analysis involves matching a type curve to water-level displacement data collected during an underdamped slug test. The Butler (1998) solution also incorporates frictional well loss in small-diameter wells (Butler 2002).

AQTESOLV provides visual and automatic methods for matching the Butler solution to slug test data. This easy-to-use and intuitive software promotes rapid and accurate determination of aquifer properties.

## Assumptions

The following assumptions apply to the use of the Butler slug test solution:

- aquifer has infinite areal extent
- aquifer is homogeneous and of uniform thickness
- aquifer potentiometric surface is initially horizontal
- control well is fully or partially penetrating
- a volume of water, V, is injected or discharged instantaneously from the control well
- aquifer is nonleaky confined
- flow is steady

## Solution

Options

AQTESOLV provides the following options for the Butler method for underdamped slug tests:

- partially penetrating wells
- correction for gravel pack porosity
- correction for frictional well loss
- hydraulic conductivity anisotropy

## Benchmark

## References

Butler, J.J., Jr., 1998. The Design, Performance, and Analysis of Slug Tests, Lewis Publishers, New York, 252p. [errata]