Analysis of pulse interference tests

Abstract

Pulse interference tests, which are conducted by monitoring the response in an observation well to a slug test conducted in a source well, are an attractive alternative to the pumping test method for determining the transmissivity and storativity of low‐storativity geological formations. An analytical model for analyzing the results of pulse interference tests affected by well bore storage in the observation well is developed in this paper using the Laplace transform method. By numerically inverting the Laplace space solution the practical range of the pulse interference test method and the influence of radial distance and well bore storage on the response in the observation well are explored. Results show that the influence of observation well storage can be significant, particularly for larger well bore storage coefficients and for almost all practical radial distances. In addition, a graphical method, based on the analytical model, is developed for analyzing the results of pulse interference tests in which observation well bore storage is negligible and for the case where the source and observation well storage coefficients are equal. A field example is also presented to illustrate and compare the use of the analytical model and graphical method for the field case where observation well storage is present and the case where it is not.