The analysis of slug tests in the frequency domain

摘要

In this paper a generalized analytical frequency domain method for the evaluation of transmissivity tests is presented. For a confined homogeneous aquifer the Kelvin functions represent a satisfactory set of solutions for the equation of radial flow in the frequency domain. Depending on the type of transmissivity test, simple analytical frequency‐dependent transfer functions can be defined, which relate the reaction of the aquifer to any pressure disturbance. Hence a numerical Fourier transform of the field data can be performed to determine a transfer function of data, which can be fitted with the analytical one. In order to estimate the hydraulic parameters a special logarithmic Fourier transform was used to analyze synthetic data of a slug test to verify this approach. The consideration of transmissivity tests in the frequency domain leads to some promising prospects. With this method a radius of penetration for each excitation frequency can be defined. Furthermore, analytical solutions for radial symmetric permeability distributions are available (e.g., consideration of a gravel pack or a developed zone). The frequency domain approach is also extended to a new type of low‐cost transmissivity test, the hydraulic impedance t