Implications of Using Approximate Expressions for Well Function

Abstract

The computation of the well function is required in the analysis of pump test data for leaky or confined aquifers. Approximate expressions have recently been proposed to compute the well function over the whole range of the argument values. These proposed expressions are more computationally intensive and less accurate than some standard exponential integral approximations. Analysis of a synthetic data set using slope-matching technique shows that use of these recent expressions results in severe overprediction of the storage coefficient, especially for aquifers with low storage coefficient or high transmissivity.